User’s Guide Agilent Technologies 8719ET/20ET/22ET 8719ES/20ES/22ES Network Analyzers Part Number 08720-90392 Printed in USA July 2000 Supersedes May 2000 © Copyright 1999, 2000 Agilent Technologies
Notice The information contained in this document is subject to change without notice. Agilent Technologies makes no warranty of any kind with regard to this material, including but not limited to, the implied warranties of merchantability and fitness for a particular purpose. Agilent Technologies shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing, performance, or use of this material.
Safety Notes The following safety notes are used throughout this manual. Familiarize yourself with each of the notes and its meaning before operating this instrument. All pertinent safety notes for using this product are located in Chapter 8 , “Safety and Regulatory Information.” WARNING Warning denotes a hazard. It calls attention to a procedure which, if not correctly performed or adhered to, could result in injury or loss of life.
Documentation Map The Installation and Quick Start Guide provides procedures for installing, configuring, and verifying the operation of the analyzer. It also will help you familiarize yourself with the basic operation of the analyzer. The User’s Guide shows how to make measurements, explains commonly-used features, and tells you how to get the most performance from your analyzer. The Reference Guide provides reference information, such as specifications, menu maps, and key definitions.
Contents 1. Making Measurements Using This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2 More Instrument Functions Not Described in This Guide . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3 Making a Basic Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4 Step 1. Connect the device under test and any required test equipment. . . . . . . . . . . . . .
Contents Using Limit Lines to Test a Device. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-73 Setting Up the Measurement Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-73 Creating Flat Limit Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-74 Creating a Sloping Limit Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents Performing a Power Meter (Source) Calibration Over the IF Range . . . . . . . . . . . . . . . . .2-14 Setting the Analyzer to the RF Frequency Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-15 Performing a Power Meter Calibration Over the RF Range. . . . . . . . . . . . . . . . . . . . . . . .2-17 Performing the R-Channel Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-18 High Dynamic Range Swept RF/IF Conversion Loss . . . . . . . .
Contents Selecting Gate Shape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-36 4. Printing, Plotting, and Saving Measurement Results Using This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 Printing or Plotting Your Measurement Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3 Configuring a Print Function . . . . . . . . . . . . . . .
Contents Saving and Recalling Instrument States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-36 Places Where You Can Save . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-36 What You Can Save to the Analyzer's Internal Memory . . . . . . . . . . . . . . . . . . . . . . . . . .4-36 What You Can Save to a Floppy Disk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents To Use External Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13 To Use Fast 2-Port Calibration (ES Analyzers Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13 Increasing Dynamic Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15 Increase the Test Port Input Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents Modify the Cal Kit Thru Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-46 Minimizing Error When Using Adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-48 Making Non-Coaxial Measurements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-49 Fixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents SWR Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-29 Real Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-29 Imaginary Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-30 Group Delay Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents Frequency Offset Operation (Option 089) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-84 Differences between 8753 Network Analyzers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-85 8. Safety and Regulatory Information General Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-2 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Making Measurements 1-1
Making Measurements Using This Chapter Using This Chapter This chapter contains the following example procedures for making measurements. Mixer and time domain measurements are covered in Chapter 2 , "Making Mixer Measurements (Option 089 Only)" and Chapter 3 , “Making Time Domain Measurements.” This chapter also describes how to use most display, marker, and sequencing functions.
Making Measurements More Instrument Functions Not Described in This Guide More Instrument Functions Not Described in This Guide To learn about instrument functions not covered in this user’s guide, refer to the following chapters in the reference guide. “Menu Maps” contains maps of the instrument menu structure. “Hardkey/Softkey Reference” contains descriptions of all instrument functions.
Making Measurements Making a Basic Measurement Making a Basic Measurement There are five basic steps when you are making a measurement. 1. Connect the device under test and any required test equipment. CAUTION Damage may result to the device under test (DUT) if it is sensitive to the analyzer's default output power level. To avoid damaging a sensitive DUT, be sure to lower the output power before connecting the DUT to the analyzer. 2. Choose the measurement parameters. 3.
Making Measurements Making a Basic Measurement Setting the Frequency Range To set the center frequency to 134 MHz, press: Center 134 M/µ To set the span to 30 MHz, press: Span 30 M/µ You could also press the Start and Stop keys and enter the frequency range limits as start frequency and stop frequency values.
Making Measurements Making a Basic Measurement Step 5. Output the measurement results. To create a printed copy of the measurement results, press: Copy PRINT MONOCHROME (or PLOT ) Refer to Chapter 4 , “Printing, Plotting, and Saving Measurement Results,” for procedures on how to set up a printer and define a print, plot, or save results.
Making Measurements Measuring Magnitude and Insertion Phase Response Measuring Magnitude and Insertion Phase Response This measurement example shows you how to measure the maximum amplitude of a surface acoustic wave (SAW) filter and then how to view the measurement data in the phase format, which provides information about the phase response. Measuring the Magnitude Response 1. Connect your test device as shown in Figure 1-2. Figure 1-2 Device Connections for Measuring a Magnitude Response 2.
Making Measurements Measuring Magnitude and Insertion Phase Response If the channels are coupled (the default condition), this calibration is valid for both channels. 4. Reconnect your test device. 5. To better view the measurement trace, press: Scale Ref AUTO SCALE 6. To locate the maximum amplitude of the device response, as shown in Figure 1-3, press: Marker Search SEARCH: MAX Figure 1-3 Example Magnitude Response Measurement Results Measuring Insertion Phase Response 7.
Making Measurements Measuring Magnitude and Insertion Phase Response Figure 1-4 Example Insertion Phase Response Measurement The phase response shown in Figure 1-5 is undersampled; that is, there is more than 180° phase delay between frequency points. If the ∆Φ ≥ 180°, incorrect phase and delay information may result. Figure 1-5 shows an example of phase samples being with ∆Φ less than 180° and greater than 180°.
Making Measurements Using Display Functions Using Display Functions This section provides the necessary information for using the display functions. These functions are very helpful for displaying measurement data so that it will be easy to read.
Making Measurements Using Display Functions Titling the Active Channel Display 1. Press Display MORE TITLE to access the title menu. 2. Press ERASE TITLE and enter the title you want for your measurement display. • If you have a DIN keyboard attached to the analyzer, type the title you want from the keyboard. Then press ENTER to enter the title into the analyzer. You can enter a title that has a maximum of 50 characters.
Making Measurements Using Display Functions Viewing Both Primary Measurement Channels In some cases, you may want to view more than one measured parameter at a time. Simultaneous gain and phase measurements, for example, are useful in evaluating stability in negative feedback amplifiers. You can easily make such measurements using the dual channel display. 1. To see channels 1 and 2 in the same grid, press: Display DUAL | QUAD SETUP , set DUAL CHAN on OFF to ON, and SPLIT DISP to 1X.
Making Measurements Using Display Functions Figure 1-8 Example Dual Channel with Split Display On 3. To return to a single-graticule display, press: SPLIT DISPLAY 1X . NOTE You can control the stimulus functions of the two channels independent of each other by pressing Sweep Setup COUPLED CH OFF . Dual Channel Mode with Decoupled Stimulus The stimulus functions of the two channels can be controlled independently using COUPLED CH ON off in the stimulus menu.
Making Measurements Using Display Functions Dual Channel Mode with Decoupled Channel Power By decoupling the channel power or port power and using the dual channel mode, you can simultaneously view two measurements (or two sets of measurements, if both auxiliary channels are enabled) having different power levels. However, there are two configurations that will not sweep continuously. 1.
Making Measurements Using Display Functions 3. Press Display DUAL | QUAD SETUP , set DUAL CHAN to ON, set AUX CHAN to ON, and set SPLIT DISP to 4X . The display will appear as shown in Figure 1-9. Channel 1 is in the upper-left quadrant of the display, channel 2 is in the upper-right quadrant, and channel 3 is in the lower half of the display. Figure 1-9 Three-Channel Display 4. Press Chan 4 (or press Chan 2 , set AUX CHAN to ON).
Making Measurements Using Display Functions Figure 1-10 Four-Channel Display 5. Press Chan 4 . Observe that the amber LED adjacent to the Chan 4 key is lit and the CH4 indicator on the display has a box around it. This indicates that channel 4 is now active and can be configured. 6. Press Marker MARKER 1 MARKER 2 . Markers 1 and 2 appear on all four channel traces. Rotating the front panel control knob moves marker 2 on all four channel traces.
Making Measurements Using Display Functions 9. To independently control the channel markers: Press Marker Fctn MARKER MODE MENU , set MARKERS: to UNCOUPLED. Rotate the front panel control knob. Marker 2 moves only on the channel 3 trace. Once made active, a channel can be configured independently of the other channels in most variables except stimulus. For example, once channel 3 is active, you can change its format to a Smith chart by pressing Format SMITH CHART .
Making Measurements Using Display Functions 4 Param Displays Softkey The 4 PARAM DISPLAYS menu does two things: • provides a quick way to set up a four-parameter display • gives information for using softkeys in the Display menu Figure 1-11 shows the first 4 PARAM DISPLAYS screen. Six setup options are described with softkeys SETUP A through SETUP F . SETUP A is a four-parameter display where each channel is displayed on its own grid.
Making Measurements Using Display Functions Using Memory Traces and Memory Math Functions The analyzer has four available memory traces, one per channel. Memory traces are totally channel dependent: channel 1 cannot access the channel 2 memory trace or vice versa. Memory traces can be saved with instrument states: one memory trace can be saved per channel for each saved instrument state.
Making Measurements Using Display Functions To View the Measurement Data and Memory Trace The analyzer default setting shows you the current measurement data for the active channel. 1. To view a data trace that you have already stored to the active channel memory, press: Display MEMORY This is the only memory display mode where you can change the smoothing and gating of the memory trace. 2.
Making Measurements Using Display Functions Blanking the Display Pressing Display ADJUST DISPLAY BLANK DISPLAY switches off the analyzer display while leaving the instrument in its current measurement state. This feature may be helpful in prolonging the life of the LCD in applications where the analyzer is left unattended (such as in an automated test system). Turning the front panel knob or pressing any front panel key will restore normal display operation.
Making Measurements Using Display Functions You may choose to change the default colors to suit environmental needs, individual preferences, or to accommodate color deficient vision. You can use any of the available colors for any of the display elements listed: CH1 DATA/LIMIT LN CH3 DATA/LIMIT LN CH1 MEM CH3 MEM CH2 DATA/LIMIT LN CH4 DATA/LIMIT LN CH2 MEM CH4 MEM GRATICULE REF LINE TEXT WARNING To change the color of a display elements, press the softkey for that element (such as CH1 DATA ).
Making Measurements Using Display Functions BRIGHTNESS softkey and turn the analyzer front panel knob. If additional adjustment is needed, vary the degree of whiteness of the color. To accomplish this, press the COLOR softkey and turn the analyzer front panel knob. NOTE Color changes and adjustments remain in effect until changed again in these menus or the analyzer is powered off and then on again. Cycling the power changes all color adjustments to default values.
Making Measurements Using Markers Using Markers The Marker key displays a movable active marker on the screen and provides access to a series of menus to control up to five display markers for each channel. Markers are used to obtain numerical readings of measured values. They also provide capabilities for reducing measurement time by changing stimulus parameters, searching the trace for specific values, or statistically analyzing part or all of the trace.
Making Measurements Using Markers NOTE Using MARKERS: DISCRETE will also affect marker search and positioning functions when the value entered in a search or positioning function does not exist as a measurement point. The marker will be positioned to the closest adjacent point that satisfies the search or positioning value.
Making Measurements Using Markers Figure 1-13 Active and Inactive Markers Example • To switch off all of the markers, press: ALL OFF To Move Marker Information Off the Grids If marker information obscures the display traces, you can turn off the softkey menu and move the marker information off the display traces and into the softkey menu area. Pressing the backspace key performs this function. This is a toggle function. Pressing alternately hides and restores the current softkey menu.
Making Measurements Using Markers Figure 1-14 Marker Information Moved into the Softkey Menu Area pg654e 4. Restore the softkey menu and move the marker information back onto the graticules: Press . The display will be similar to Figure 1-15.
Making Measurements Using Markers Figure 1-15 Marker Information on the Graticules pg655e You can also restore the softkey menu by pressing a hardkey which opens a menu (such as Meas ) or pressing a softkey. To Use Delta (∆) Markers This is a relative mode, where the marker values show the position of the active marker relative to the delta reference marker. You can switch on the delta mode by defining one of the five markers as the delta reference. 1.
Making Measurements Using Markers Figure 1-16 Marker 1 as the Reference Marker Example 4. To change the reference marker to marker 2, press: ∆ MODE MENU ∆ REF=2 To Activate a Fixed Marker When a reference marker is fixed, it does not rely on a current trace to maintain its fixed position. This is convenient when comparing two different measurement conditions. To activate a fixed marker on the analyzer, press Marker MKR ZERO .
Making Measurements Using Markers Figure 1-17 Example of a Fixed Reference Marker Using MKR ZERO Using the ∆REF=∆FIXED MKR Key to Activate a Fixed Reference Marker 1. To set the frequency value of a fixed marker that appears on the analyzer display, press: Marker ∆MODE MENU ∆REF=∆FIXED MKR ∆MODE MENU FIXED MKR POSITION FIXED MKR STIMULUS and turn the front panel knob, or enter a value from the front panel keypad.
Making Measurements Using Markers Figure 1-18 Example of a Fixed Reference Marker Using (∆)REF=(∆)FIXED MKR To Couple and Uncouple Display Markers At a preset state, the markers have the same stimulus values on each channel, but they can be uncoupled so that each channel has independent markers. Press Marker Fctn MARKER MODE MENU and select from the following keys: • Choose MARKERS: COUPLED if you want the analyzer to couple the marker stimulus values for the display channels.
Making Measurements Using Markers To Use Polar Format Markers The analyzer can display the marker value as magnitude and phase, or as a real/imaginary pair: LIN MKR gives linear magnitude and phase, LOG MKR gives log magnitude and phase, Re/Im gives the real value first, then the imaginary value. You can use these markers only when you are viewing a polar display format. (The format is available from the Format key.
Making Measurements Using Markers To Use Smith Chart Markers For greater accuracy when using markers in the Smith chart format, activate the discrete marker mode. Press Marker Fctn MKR MODE MENU MARKERS:DISCRETE . To use Smith chart format: 1. Press Format SMITH CHART . 2. Press Marker Fctn MARKER MODE MENU SMITH MKR MENU and turn the front panel knob, or enter a value from the front panel keypad to read the resistive and reactive components of the complex impedance at any point along the trace.
Making Measurements Using Markers Figure 1-21 Example of Impedance Smith Chart Markers To Set Measurement Parameters Using Markers The analyzer allows you to set measurement parameters with the markers, without going through the usual key sequence. You can change certain stimulus and response parameters to make them equal to the current active marker value. Setting the Start Frequency 1.
Making Measurements Using Markers Setting the Stop Frequency 1. Press Marker Fctn and turn the front panel knob, or enter a value from the front panel keypad to position the marker at the value that you want for the stop frequency. 2. Press MARKER→STOP to change the stop frequency value to the value of the active marker. Figure 1-23 Example of Setting the Stop Frequency Using a Marker Setting the Center Frequency 1.
Making Measurements Using Markers Figure 1-24 Example of Setting the Center Frequency Using a Marker Setting the Frequency Span You can set the span equal to the spacing between two markers. If you set the center frequency before you set the frequency span, you will have a better view of the area of interest. 1. Press Marker ∆MODE MENU ∆REF=1 MARKER 2 . 2. Turn the front panel knob, or enter a value from the front panel keypad to position the markers where you want the frequency span.
Making Measurements Using Markers Figure 1-25 Example of Setting the Frequency Span Using Marker Setting the Display Reference Value 1. Press Marker Fctn and turn the front panel knob, or enter a value from the front panel keypad to position the marker at the value that you want for the analyzer display reference value. 2. Press MARKER→REFERENCE to change the reference value to the value of the active marker.
Making Measurements Using Markers Setting the Electrical Delay This feature adds phase delay to a variation in phase versus frequency, therefore it is only applicable for ratioed inputs. 1. Press Format PHASE . 2. Press Marker Fctn and turn the front panel knob, or enter a value from the front panel keypad to position the marker at a point of interest. 3.
Making Measurements Using Markers To Search for a Specific Amplitude These functions place the marker at an amplitude-related point on the trace. If you switch on tracking, the analyzer searches every new trace for the target point. Searching for the Maximum Amplitude 1. Press Marker Search to access the marker search menu. 2. Press SEARCH: MAX to move the active marker to the maximum point on the measurement trace.
Making Measurements Using Markers Figure 1-29 Example of Searching for the Minimum Amplitude Using a Marker Searching for a Target Amplitude 1. Press Marker Search to access the marker search menu. 2. Press SEARCH: TARGET to move the active marker to the target point on the measurement trace. 3. If you want to change the target amplitude value (default is −3 dB), press TARGET and enter the new value from the front panel keypad. You may also press Marker Search TARGET VALUE to enter the new value. 4.
Making Measurements Using Markers Searching for a Bandwidth The analyzer can automatically calculate and display the bandwidth (BW:), center frequency (CENT:), Q, and loss of the device under test at the center frequency. (Q stands for “quality factor,” defined as the ratio of a circuit's resonant frequency to its bandwidth.) These values are shown in the marker data readout. 1. Press Marker Search and SEARCH: MAX to place the marker near the center of the filter passband. 2.
Making Measurements Using Markers To Calculate the Statistics of the Measurement Data This function calculates the mean, standard deviation, and peak-to-peak values of the section of the displayed trace between the active marker and the delta reference. If there is no delta reference, the analyzer calculates the statistics for the entire trace. 1. Move marker 1 to any point that you want to reference: • Turn the front panel knob. OR • Enter the frequency value on the numeric keypad. 2.
Making Measurements Measuring Electrical Length and Phase Distortion Measuring Electrical Length and Phase Distortion Electrical Length The analyzer mathematically implements a function similar to the mechanical “line stretchers” of earlier analyzers. This feature simulates a variable length lossless transmission line, which you can add to or remove from the analyzer's receiver input to compensate for interconnecting cables, etc.
Making Measurements Measuring Electrical Length and Phase Distortion You may also want to select settings for the number of data points, averaging, and IF bandwidth. 3. Substitute a thru for the device and perform a response calibration by pressing: Cal CALIBRATE MENU RESPONSE THRU 4. Reconnect your test device. 5. To better view the measurement trace, press: Scale Ref AUTO SCALE Notice that in Figure 1-34 the SAW filter under test has considerable phase shift within only a 2 MHz span.
Making Measurements Measuring Electrical Length and Phase Distortion Alternatively, press Scale Ref ELECTRICAL DELAY and turn the front panel knob to increase the electrical length until you achieve the best flat line, as shown in Figure 1-35. The measurement value that the analyzer displays represents the electrical length of your device relative to the speed of light in free space. The physical length of your device is related to this value by the propagation velocity of its medium.
Making Measurements Measuring Electrical Length and Phase Distortion Measuring Phase Distortion This portion of the example shows you how to measure the linearity of the phase shift over a range of frequencies. The analyzer allows you to measure this linearity and read it in two different ways: deviation from linear phase, or group delay. Deviation From Linear Phase By adding electrical length to “flatten out” the phase response, you have removed the linear phase shift through your device.
Making Measurements Measuring Electrical Length and Phase Distortion Group Delay The phase linearity of many devices is specified in terms of group or envelope delay. The analyzer can translate this information into a related parameter, group delay. Group delay is the transmission time through your device under test as a function of frequency.
Making Measurements Measuring Electrical Length and Phase Distortion When you increase the aperture, the analyzer removes fine grain variations from the response. It is critical that you specify the group delay aperture when you compare group delay measurements. Figure 1-38 Group Delay Example Measurement with Smoothing 5.
Making Measurements Measuring Electrical Length and Phase Distortion Group delay is calculated by dividing the phase difference between points by the frequency spacing. Thus, if n equals the number of points, the number of phase difference values (or frequency segments) will be n−1. The first data point is repeated so that the total number of points remains n.
Making Measurements Characterizing a Duplexer (ES Analyzers Only) Characterizing a Duplexer (ES Analyzers Only) This measurement example demonstrates how to characterize a 3-port device, in this case a duplexer, using four-parameter display mode. You must use a test adapter or a special 3-port test adapter to route the signals from the analyzer (a two-port instrument) to the duplexer (a three-port device).
Making Measurements Characterizing a Duplexer (ES Analyzers Only) 3. Set up channel 1 for the Tx-Ant stimulus parameters (start/stop frequency, power level, IF bandwidth). In this example, a wide frequency range that covers both the Tx-Ant and Ant-Rx parameters has been chosen. 4. Uncouple the primary channels from each other and then press Sweep Setup and toggle COUPLED CH on OFF to OFF . 5. Press System CONFIGURE MENU USER SETTINGS . 6. Set up the desired mode.
Making Measurements Characterizing a Duplexer (ES Analyzers Only) 15.Set up a 2-graticule, 4-parameter display with transmission measurements on the top graticule and reflection measurements on the bottom graticule: Press Display DUAL|QUAD SETUP 4-PARAM DISPLAYS SETUP B Meas Trans: REV S12 (A/R) Chan 4 Refl: REV S22 (B/R) Chan 1 Trans:FWD S21 (B/R) Refl: FWD S11 (A/R) , then set DUAL CHAN on OFF to ON . Chan 3 The display will be similar to Figure 1-41.
Making Measurements Measuring Amplifiers Measuring Amplifiers The analyzer allows you to measure the transmission and reflection characteristics of many amplifiers and active devices. You can measure scalar parameters such as gain, gain flatness, gain compression, reverse isolation, return loss (SWR), and gain drift versus time. Additionally, you can measure vector parameters such as deviation from linear phase, group delay, complex impedance and AM-to-PM conversion.
Making Measurements Measuring Amplifiers Measuring Gain Compression Gain compression occurs when the input power of an amplifier is increased to a level that reduces the gain of the amplifier and causes a nonlinear increase in output power. The point at which the gain is reduced by 1 dB is called the 1 dB compression point. The gain compression will vary with frequency, so it is necessary to find the worst-case point of gain compression in the frequency band.
Making Measurements Measuring Amplifiers 4. To produce a normalized trace that represents gain compression, perform either step 5 or step 6. (Step 5 uses trace math and step 6 uses uncoupled channels and the display function D1/D2 to D2 ON .) 5. Press Display DATA →MEMORY DATA/MEM to produce a normalized trace. 6. To produce a normalized trace, perform the following steps: • Press Display DUAL | QUAD SETUP and select DUAL CHANNEL ON to view both channels simultaneously.
Making Measurements Measuring Amplifiers Figure 1-44 Gain Compression Using Linear Sweep and D2/D1 to D2 ON 12.If COUPLED CH OFF was selected, recouple the channel stimulus by pressing: Sweep Setup COUPLED CH ON 13.To place the marker exactly on a measurement point, press: Marker Fctn MARKER MODE MENU MARKERS:DISCRETE 14.To set the CW frequency before going into the power sweep mode, press: Seq SPECIAL FUNCTIONS 15.Press Sweep Setup MARKER→ CW SWEEP TYPE MENU POWER SWEEP .
Making Measurements Measuring Amplifiers NOTE A receiver calibration will improve the accuracy of this measurement. Refer to Chapter 6 , “Calibrating for Increased Measurement Accuracy.” 22.Press Marker Fctn MARKER MODE MENU MARKERS:COUPLED . 23.To find the 1 dB compression point on channel 1, press: Marker Search SEARCH:MAX SEARCH:TARGET −1 x1 Marker MKR ZERO Marker Search Notice that the marker on channel 2 tracked the marker on channel 1. 24.
Making Measurements Measuring Amplifiers Measuring Gain and Reverse Isolation Simultaneously (ES Analyzers Only) Since an amplifier will have high gain in the forward direction and high isolation in the reverse direction, the gain (S21) will be much greater than the reverse isolation (S12). Therefore, the power you apply to the input of the amplifier for the forward measurement (S21) should be considerably lower than the power you apply to the output for the reverse measurement (S12).
Making Measurements Measuring Amplifiers Figure 1-46 Gain and Reverse Isolation 1-59
Making Measurements Measuring Amplifiers Making High Power Measurements with Option 085 (ES Analyzers Only) Analyzers equipped with Option 085 can be configured to measure high power devices. This ability is useful if the required input power for a device under test is greater than the analyzer can provide, or if the maximum output power from an amplifier under test exceeds safe input limits for a standard analyzer. This section describes how to set up the analyzer to perform high power measurements.
Making Measurements Measuring Amplifiers 5. Switch on the booster amplifier. 6. Using a power meter, measure the output power from the coupled arm and the open port of the coupler. NOTE Depending on the power meter being used, additional attenuation may have to be added between the coupler port and the power meter. 7. Verify the gain of the booster amplifier.
Making Measurements Measuring Amplifiers Figure 1-48 High Power Test Setup (Step 2a) Figure 1-49 High Power Test Setup (Step 2b) Selecting Power Ranges and Attenuator Settings 14.Select a power range that will not exceed the maximum estimated power level that will force the DUT into compression.
Making Measurements Measuring Amplifiers 16.Estimate the maximum amount of gain that could be provided by the DUT and, as a result, the maximum amount of power that could be received by TEST PORT 2 when the DUT is in compression. For example, if a DUT with a maximum gain of +10 dB receives an input of +20 dBm, then the maximum amount of power that could be received by TEST PORT 2 is +30 dBm. Figure 1-50 Internal Signal Paths of the Option 085 Analyzer 17.
Making Measurements Measuring Amplifiers With the previous points in mind, the amount of attenuation can be calculated from the following equations: • Attenuator A = +20 dBm − 13 dB − (−10 dBm). Attenuator A = +17 dB • Attenuator B = +30 dBm − 13 dB − (−10 dBm). Attenuator B = +27 dB 18.Set the internal step attenuators to the values calculated in the previous step (rounding off to the highest 5 dB step). Press Power ATTENUATOR A 15 x1 ATTENUATOR B 25 x1 . 19.Switch on the booster amplifier.
Making Measurements Measuring Amplifiers Figure 1-51 High Power Test Setup (Step 3) 26.Make any other desired high power measurements. Ratio measurements such as gain will be correctly displayed. However, the displayed absolute power levels on the analyzer will not be correct. To correctly interpret power levels, the gain of the booster amplifier and the attenuator settings must be taken into consideration.
Making Measurements Measuring Amplifiers Making High Power Measurements with Option 012 (ES Analyzers Only) Analyzers equipped with Option 012 can be configured to measure devices that have high power outputs. With direct sampler access, you can insert attenuators between the couplers and samplers, protecting the samplers from excessive power. Figure 1-52 Internal Signal Paths of the Option 012 Analyzer 1.
Making Measurements Measuring Amplifiers With the previous points in mind, the amount of attenuation can be calculated from the following equations: • Attenuator value = +20 dBm − 13 dB − (−10 dBm). Attenuator Value = +17 dB 3. Choose the S21 measurement parameter by pressing Meas Trans: FWD S21 (B/R) . 4. Connect the attenuator between the B OUT and IN ports. 5. Perform a calibration. 6. Connect the DUT as shown in Figure 1-53 and view the measurement.
Making Measurements Using the Swept List Mode to Test a Device Using the Swept List Mode to Test a Device When using a list frequency sweep, the analyzer has the ability to sweep arbitrary frequency segments, each containing a list of frequency points. One major advantage of using list frequency sweep is that it allows you to measure the minimum number of data points, and only at the frequencies of interest. This serves to minimize the overall test time.
Making Measurements Using the Swept List Mode to Test a Device 2. Set the following measurement parameters: Meas Trans: FWD S21 (B/R) or on ET models: TRANSMISSN Center Span 900 500 M/µ M/µ Observe the Characteristics of the Filter Figure 1-55 Characteristics of a Filter • Generally, the passband of a filter exhibits low loss. A relatively low incident power may be needed to avoid overdriving the next stage of the DUT (if that stage contains an amplifier) or the network analyzer receiver.
Making Measurements Using the Swept List Mode to Test a Device Set Up the Lower Stopband Parameters 3. To set up the segment for the lower stopband, press ADD START STOP 650 M/µ 880 M/µ NUMBER of POINTS 51 x1 4. To maximize the dynamic range in the stopband (increasing the incident power and narrowing the IF bandwidth), press MORE LIST POWER ON off until ON is selected SEGMENT POWER LIST IF BW ON off until ON is selected SEGMENT IF BW RETURN 10 1000 x1 x1 DONE Set Up the Passband Parameters 5.
Making Measurements Using the Swept List Mode to Test a Device MORE SEGMENT POWER SEGMENT IF BW RETURN 10 300 x1 x1 DONE 9. Press DONE LIST FREQ [SWEPT] . Calibrate and Measure 1. Remove the DUT and perform a full two-port calibration. Refer to Chapter 6 , “Calibrating for Increased Measurement Accuracy.” 2. With the thru connected, set the scale to autoscale to observe the benefits of using swept list mode.
Making Measurements Using the Swept List Mode to Test a Device Figure 1-57 Filter Measurements Using Linear Sweep and Swept List Mode Using Linear Sweep (Power: 0 dBm/IF BW: 3700 Hz) Using Swept List Mode 1-72
Making Measurements Using Limit Lines to Test a Device Using Limit Lines to Test a Device Limit testing is a measurement technique that compares measurement data to constraints that you define. Depending on the results of this comparison, the analyzer will indicate if your device either passes or fails the test. Limit testing is implemented by creating individual flat, sloping, and single-point limit lines on the analyzer display.
Making Measurements Using Limit Lines to Test a Device You may also want to select settings for the number of data points, power, averaging, and IF bandwidth. 3. Substitute a thru for the device and perform a response calibration by pressing: Cal CALIBRATE MENU RESPONSE THRU 4. Reconnect your test device. 5.
Making Measurements Using Limit Lines to Test a Device 4. To define the limit as a flat line, press: LIMIT TYPE FLAT LINE RETURN 5.
Making Measurements Using Limit Lines to Test a Device • To create a limit line that tests the high side of the bandpass filter, press: ADD STIMULUS VALUE UPPER LIMIT −65 146 M/µ x1 LOWER LIMIT −200 x1 DONE LIMIT TYPE FLAT LINE RETURN ADD STIMULUS VALUE 160 M/µ DONE LIMIT TYPE SINGLE POINT RETURN Figure 1-60 Example Flat Limit Lines Creating a Sloping Limit Line This example procedure shows you how to make limits that test the shape factor of a SAW filter.
Making Measurements Using Limit Lines to Test a Device 2. To establish the start frequency and limits for a sloping limit line that tests the low side of the filter, press: ADD STIMULUS VALUE UPPER LIMIT DONE −65 LIMIT TYPE x1 123 M/µ LOWER LIMIT SLOPING LINE −200 x1 RETURN 3. To terminate the lines and create a sloping limit line, press: ADD STIMULUS VALUE UPPER LIMIT DONE −26 LIMIT TYPE x1 125 M/µ LOWER LIMIT SINGLE POINT −200 x1 RETURN 4.
Making Measurements Using Limit Lines to Test a Device Creating Single Point Limits In this example procedure, the following limits are set: • from −23 dB to −28.5 dB at 141 MHz • from −23 dB to −28.5 dB at 126.5 MHz 1. To access the limits menu and activate the limit lines, press: System LIMIT MENU CLEAR LIST YES LIMIT LINE LIMIT LINE ON EDIT LIMIT LINE 2.
Making Measurements Using Limit Lines to Test a Device Editing Limit Segments This example shows you how to edit the upper limit of a limit line. 1. To access the limits menu and activate the limit lines, press: LIMIT MENU System LIMIT LINE LIMIT LINE ON EDIT LIMIT LINE 2. To move the pointer symbol (>) on the analyzer display to the segment you wish to modify, press: SEGMENT or repeatedly OR SEGMENT and enter the segment number followed by x1 . 3.
Making Measurements Using Limit Lines to Test a Device NOTE Selecting the beep fail indicator BEEP FAIL ON is optional and will add approximately 50 ms of sweep cycle time. Because the limit test will still work if the limits lines are off, selecting LIMIT LINE ON is also optional. The limit test results appear on the right side on the analyzer display.
Making Measurements Using Limit Lines to Test a Device Figure 1-63 Example Stimulus Offset of Limit Lines • To return to 0 Hz offset, press: STIMULUS OFFSET 0 x1 • To offset all of the segments in the limit table by a fixed amplitude, press: AMPLITUDE OFFSET 5 x1 The analyzer beeps and a FAIL notation appears on the analyzer display. • To return to 0 dB offset, press: AMPLITUDE OFFSET 0 x1 • To offset the amplitude offset value by the active marker reading, press MARKER → AMP. OFS. .
Making Measurements Using Ripple Limits to Test a Device Using Ripple Limits to Test a Device Setting Up the List of Ripple Limits to Test Two tasks are involved in preparing for ripple testing: • First, set up the analyzer settings to view the frequency of interest. • Second, set up the analyzer to test over the appropriate frequencies against your specific limits. This example will show you how to set up the analyzer to test ripple limits.
Making Measurements Using Ripple Limits to Test a Device Figure 1-65 Connections for an Example Ripple Test Measurement 2. Press Preset and choose the measurement settings. For this example, the measurement settings are as follows: • Meas Trans: FWD S21 (B/R) or on ET models: TRANSMISSN • Center • Span • Scale Ref 1.8 3.4 G/n G/n AUTO SCALE You may also want to select settings for the number of data points, power, averaging, and IF bandwidth. 3.
Making Measurements Using Ripple Limits to Test a Device Figure 1-66 Filter Pass Band Before Ripple Test Setting Up Limits for Ripple Testing This section instructs you on setting up the ripple tests parameters. You must set up the analyzer to check the DUT at the correct frequencies and compare the measured values against the maximum allowable ripple value for each frequency band. To do this, you set up individual frequency bands.
Making Measurements Using Ripple Limits to Test a Device bandpass or to customize the ripple test to meet your specific requirements. 1. To access the ripple test menu, press: System LIMIT MENU RIPPLE LIMIT 2. To access the ripple test edit menu, press EDIT RIPL LIMIT . 3. Add the first frequency band (Frequency Band 1) to be tested by pressing ADD . 4. Set the lower frequency value of Frequency Band 1 by pressing: MINIMUM FREQUENCY 500 M/µ 5.
Making Measurements Using Ripple Limits to Test a Device The frequency band number is located in the left column of the list of frequency bands. 3. Make the changes to the selected band by pressing: a. MINIMUM FREQUENCY and the new value to change the lower frequency of the frequency band. b. MAXIMUM FREQUENCY and the new value to change the upper frequency of the frequency band. c. MAXIMUM RIPPLE and the new decibel value to change the maximum allowable ripple of the frequency band.
Making Measurements Using Ripple Limits to Test a Device 7. After you have added all of the new frequency bands, return to the ripple test menu by pressing DONE . Deleting Existing Frequency Bands Frequency band limits may be deleted for testing the ripple. This procedure guides you through deleting existing frequency band limits. You may delete individual frequency bands or delete all of the frequency bands from the list. 1. To access the ripple test edit menu, press: EDIT RIPL LIMIT 2.
Making Measurements Using Ripple Limits to Test a Device Figure 1-67 Filter Passband with Ripple Test Activated As the analyzer measures the ripple, a message is displayed indicating whether the measurement passes or fails: • If the ripple test passes, a RIPLn PASS message (where n = the channel number) is displayed in the color assigned to Channel 1 Memory. The ripple test must pass in all frequency bands before the pass message is displayed.
Making Measurements Using Ripple Limits to Test a Device ripple value above the lower ripple limit. The ripple that exceeds the maximum ripple value extends above the upper limit. This measured trace that extends above the upper limit is displayed in red. Figure 1-68 shows the filter pass band tested with the ripple limits activated. Notice that there are three sets of ripple limits shown. Also notice that the measured trace exceeds the upper ripple limit only in Frequency Band 3.
Making Measurements Using Ripple Limits to Test a Device and ripple test off status. When the Absolute and Margin choices are selected, the frequency band and measurement value are displayed to the right side of the pass/fail message described previously. This display is displayed in the same color as the pass/fail message. The frequency band of the displayed value is displayed as Bn (where n = the frequency band number). The frequency band may be changed to display the value of each band.
Making Measurements Using Ripple Limits to Test a Device Viewing the Ripple Value in Margin Format When RIPL VALUE [MARGIN ] is selected, the margin by which the ripple value passed or failed is displayed. The ripple value margin is the user-defined maximum ripple minus the absolute ripple value within the frequency band. This value is displayed in dB. A positive value is the margin that the ripple passes the ripple test in the frequency band.
Making Measurements Using Bandwidth Limits to Test a Bandpass Filter Using Bandwidth Limits to Test a Bandpass Filter The bandwidth testing mode can be used to test the bandwidth of a bandpass filter. The bandwidth test finds the peak of a signal in the passband and locates a point on each side of the passband at an amplitude below the peak (that you specify during the test setup). The frequency between these two points is the bandwidth of the filter.
Making Measurements Using Bandwidth Limits to Test a Bandpass Filter Figure 1-72 Connections for a Bandpass Filter Example Measurement 2. Press Preset and choose the measurement settings. For this example, the measurement settings are as follows: a. Meas Trans: FWD S21 (B/R) or on ET models: TRANSMISSN b. Center c. Span d. Scale Ref 321 200 M/µ M/µ AUTO SCALE You may also want to select settings for the number of data points, power, averaging, and IF bandwidth.
Making Measurements Using Bandwidth Limits to Test a Bandpass Filter 3. Substitute a thru for the device and perform a response calibration by pressing: Cal CALIBRATE MENU RESPONSE THRU 4. Reconnect your test device. Refer to Figure 1-73. Setting Up the Bandwidth Limits When you set up the bandwidth limits to test the bandpass filter, you will set • the amplitude below the peak that is used to measure the filter’s bandwidth. This setting is called N dB Points. • the Maximum Bandwidth value.
Making Measurements Using Bandwidth Limits to Test a Bandpass Filter performed. For example, BW1: indicates that the bandwidth test is being run on channel 1. See Figure 1-74. The test also displays a message indicating whether the filter passes or fails the bandwidth test. When the filter is passing the test, the message indicates Pass.
Making Measurements Using Bandwidth Limits to Test a Bandpass Filter Figure 1-75 Bandwidth Markers Placed 40 dB Below the Bandpass Peak Displaying the Bandwidth Value 1. Display the bandwidth value by pressing the BW DISPLAY on OFF softkey until ON is displayed on the softkey. When this softkey is set to the ON position, the measured bandwidth value is displayed in the upper left corner of the display, to the right of the bandwidth Pass/Wide/Narrow message.
Making Measurements Using Bandwidth Limits to Test a Bandpass Filter Figure 1-76 Filter Pass Band with Bandwidth Value Displayed 1-97
Making Measurements Using Test Sequencing Using Test Sequencing Test sequencing allows you to automate repetitive tasks. As you make a measurement, the analyzer memorizes the keystrokes. Later you can repeat the entire sequence by pressing a single key. Because the sequence is defined with normal measurement keystrokes, you do not need additional programming expertise. Subroutines and limited decision-making increases the flexibility of test sequences.
Making Measurements Using Test Sequencing Figure 1-77 Test Sequencing Help Instructions 2. To select a sequence position in which to store your sequence, press: SEQUENCE 1 SEQ1 This choice selects sequence position #1. The default title is SEQ1 for this sequence. Refer to "Changing the Sequence Title" on page 1-103 for information on how to modify a sequence title. 3. To create a test sequence, enter the parameters for the measurement that you wish to make.
Making Measurements Using Test Sequencing The previous keystrokes will create a displayed list as shown: Start of Sequence RECALL PRST STATE Trans: FWD S21 (B/R) LOG MAG CENTER 134 M/u SPAN 50 M/u SCALE/DIV AUTO SCALE 4. To complete the sequence creation, press: Seq CAUTION DONE SEQ MODIFY When you create a sequence, the analyzer stores it in volatile memory where it will be lost if you switch off the instrument power (except for sequence #6 which is stored in the analyzer non-volatile memory).
Making Measurements Using Test Sequencing 3. To move the cursor to the command that you wish to delete, press: or • If you wish to scroll through the sequence without executing each line as you do so, you can press the key and scroll through the command list backwards. • If you use the key to move the cursor through the list of commands, the commands are actually performed when the cursor points to them. This feature allows the sequence to be tested one command at a time. 4.
Making Measurements Using Test Sequencing The following list is the commands entered in "Creating a Sequence" on page 1-98. Notice that for longer sequences, only a portion of the list can appear on the screen at one time. Start of Sequence RECALL PRST STATE Trans: FWD S21 (B/R) LOG MAG CENTER 134 M/u SPAN 50 M/u SCALE/DIV AUTO SCALE 3.
Making Measurements Using Test Sequencing Changing the Sequence Title If you are storing sequences on a disk, you should replace the default titles (SEQ1, SEQ2, …). 1. To select a sequence that you want to retitle, press: Seq MORE TITLE SEQUENCE and select the particular sequence softkey. The analyzer shows the available title characters. The current title is displayed in the upper-left corner of the screen. 2.
Making Measurements Using Test Sequencing Storing a Sequence on a Disk 1. To format a disk, refer to Chapter 4 , “Printing, Plotting, and Saving Measurement Results.” 2. To save a sequence to the internal disk, press: Seq MORE STORE SEQ TO DISK and select the particular sequence softkey. The disk drive access light should turn on briefly. When it goes out, the sequence has been saved. CAUTION The analyzer will overwrite a file on the disk that has the same title.
Making Measurements Using Test Sequencing Printing a Sequence 1. Configure a compatible printer to the analyzer. (Refer to the “Options and Accessories” chapter of the reference guide.) 2. To print a sequence, press: Seq PRINT SEQUENCE and the softkey for the desired sequence. MORE If the sequence is on a disk, load the sequence (as described in a previous procedure) and then follow the printing sequence.
Making Measurements Using Test Sequencing Commands That Require a Clean Sweep Many front panel commands disrupt the sweep in progress, for example, changing the channel or measurement type. When the analyzer does execute a disruptive command in a sequence, some instrument functions are inhibited until a complete sweep is taken.
Making Measurements Using Test Sequencing NOTE Presetting the instrument does not run the Auto Sequence automatically. Gosub Sequence Command The GOSUB SEQUENCE softkey, located in the Sequencing menu, activates a feature that allows the sequence to branch off to another sequence, then return to the original sequence. For example, you could perform an amplifier measurement in the following manner: 1. Create sequence 1 for the specific purpose of performing the gain measurement and printing the results.
Making Measurements Using Test Sequencing The TESTSET I/O bits are set using the TESTSET I/O FWD and TESTSET I/O REV keys under the Seq TTL I/O TTL OUT keys. The values of the outputs (pins 11, 22, and 23) are described in Table 1-5. The value changes with the test port, so if the external control is required for both test port directions, the settings must be made under both TESTSET I/O FWD and TESTSET I/O REV .
Making Measurements Using Test Sequencing Electrical specifications for TTL low: • volts(L) ≤ 0.4 volts (V) • current = 0.2 milliamps (mA) Figure 1-78 Parallel Port Input and Output Bus Pin Locations in GPIO Mode Test Set Interconnect Control Figure 1-79 Test Set Interconnect Pin Designations Control of the external switch (8762B Option T24) can be done through the test set interface on the rear panel of the analyzer.
Making Measurements Using Test Sequencing Changing the switch state back to the standard mode requires a 7 to be entered in the “TESTSET I/O FWD.” Pin 1 on the external switch must be grounded. It can be grounded to: • the analyzer's chassis • the front panel binder post • the outer shell of the TEST SET-I/O INTERCONNECT connector • a ground pin on the TEST SET-I/O INTERCONNECT connector (pin 7, 12 or 18). Refer to Figure 1-79.
Making Measurements Using Test Sequencing Table 1-5 Test Set Interconnect Pin Designation Pin Number Pin Description Pin 16 NC Pin 17 Same as Limit Test output BNC connector Pin 18 Ground Pin 19 NC Pin 20 NC Pin 21 Ground Pin 22 TESTSET I/O Bit 0 (least significant bit). +5 V when TESTSET I/O has values of 1, 3, 5, or 7. Otherwise, bit is TTL low. Pin 23 TESTSET I/O Bit 1 (middle bit). +5 V when TESTSET I/O has values of 2, 3, 6, or 7. Otherwise, bit is TTL low.
Making Measurements Using Test Sequencing Decision Making Functions Decision making functions jump to a softkey location, not to a specific sequence title Limit test, loop counter, and do sequence commands jump to any sequence residing in the specified sequence position (1 through 6). These commands do not jump to a specific sequence title. Whatever sequence is in the selected softkey position, will run when these commands are executed.
Making Measurements Using Test Sequencing to Test a Device Using Test Sequencing to Test a Device Test sequencing allows you to automate repetitive tasks. As you make a measurement, the analyzer memorizes the keystrokes. Later you can repeat the entire sequence by pressing a single key.
Making Measurements Using Test Sequencing to Test a Device The following sequences will be created: SEQUENCE SEQ1 Start of Sequence CENTER 134 M/u SPAN 50 M/u DO SEQUENCE SEQUENCE 2 SEQUENCE SEQ2 Start of Sequence Trans:FWD S21 (B/R) LOG MAG SCALE/DIV AUTO SCALE You can extend this process of calling the next sequence from the last line of the present sequence to 6 internal sequences, or an unlimited number of externally stored sequences. 2.
Making Measurements Using Test Sequencing to Test a Device To create a second sequence that will perform a desired measurement function, decrement the loop counter, and call itself until the loop counter value is equal to zero, press: Seq Meas NEW SEQ/MODIFY SEQ Trans: FWD S21 (B/R) or on ET models: TRANSMISSN Scale Ref AUTO SCALE Marker Search Seq SEQUENCE 2 SEQ2 SEARCH: MAX SPECIAL FUNCTIONS DECR LOOP COUNTER DECISION MAKING IF LOOP COUNTER 0 SEQUENCE 2 SEQ2 Seq DONE SEQ MODIFY This will cr
Making Measurements Using Test Sequencing to Test a Device Save/Recall FILE UTILITIES FILE NAME FILE0 D T SEQUENCE FILE NAMING ERASE TITLE LOOP COUNTER DONE PLOT NAME PLOTFILE ERASE TITLE P DONE L LOOP COUNTER TRIGGER MENU Sweep Setup Save/Recall Copy Seq RETURN SINGLE SAVE STATE PLOT SPECIAL FUNCTIONS DECR LOOP COUNTER DECISION MAKING IF LOOP COUNTER 0 SEQUENCE 2 SEQ 2 Seq DONE SEQ MODIFY This will create the following displayed lists: Start of Sequence LOOP COUNTER 7 x1 INTERNAL D
Making Measurements Using Test Sequencing to Test a Device • The data file names generated by this sequence will be: DT00007.D1 through DT000001.D1 • The plot file names generated by this sequence will be: PL00007.FP through PL00001.FP To run the sequence, press: Preset SEQUENCE 1 SEQ 1 Limit Test Example Sequence This measurement example shows you how to create a sequence that will branch the sequence according to the outcome of a limit test.
Making Measurements Using Test Sequencing to Test a Device 2. To create a sequence that stores the measurement data for a device that has passed the limit test, press: Seq NEW SEQ MODIFY SELECT DISK Save/Recall DEFINE DISK-SAVE Seq SEQUENCE 2 SEQ2 INTERNAL DISK DATA ARRAY ON RETURN RETURN SAVE STATE DONE SEQ MODIFY This will create a displayed list for sequence 2, as shown: Start of Sequence INTERNAL DISK DATA ARRAY ON FILENAME FILE 0 SAVE FILE 3.
2 Making Mixer Measurements (Option 089 Only) 2-1
Making Mixer Measurements (Option 089 Only) Using This Chapter Using This Chapter This chapter contains the following: • Information on mixer measurement capabilities. • Information on mixer measurement considerations.
Making Mixer Measurements (Option 089 Only) Mixer Measurement Capabilities Mixer Measurement Capabilities The analyzer is capable of measuring the following mixer (frequency converter) parameters: Figure 2-1 Mixer Parameters • Transmission characteristics include conversion loss, conversion compression, group delay, and RF feedthrough. • Reflection characteristics include return loss, SWR and complex impedance. • Characteristics of the signal at the output port include the output power.
Making Mixer Measurements (Option 089 Only) Measurement Considerations Measurement Considerations In mixer transmission measurements, you have RF and LO inputs and an IF output. Also emanating from the IF port are several other mixing products of the RF and LO signals. In mixer measurements, leakage signals from one mixer port propagate and appear at the other two mixer ports.
Making Mixer Measurements (Option 089 Only) Measurement Considerations Figure 2-2 Conversion Loss versus Output Frequency Without Attenuators at Mixer Ports Figure 2-3 Example of Conversion Loss versus Output Frequency with Attenuation at All Mixer Ports Reducing the Effect of Spurious Responses By choosing test frequencies (frequency list mode), you can reduce the effect of spurious responses on measurements by avoiding frequencies that produce IF signal path distortion.
Making Mixer Measurements (Option 089 Only) Measurement Considerations Eliminating Unwanted Mixing and Leakage Signals By placing filters between the mixer's IF port and the receiver's input port, you can eliminate unwanted mixing and leakage signals from entering the analyzer's receiver. Filtering is required in both fixed and broadband measurements.
Making Mixer Measurements (Option 089 Only) Measurement Considerations Figure 2-5 Example of Conversion Loss versus Output Frequency With Correct IF Signal Path Filtering and Attenuation at all Mixer Ports How RF and IF Are Defined When you choose between RF < LO and RF > LO in the frequency offset menus, the analyzer determines which direction the internal source must sweep in order to achieve the requested IF frequency.
Making Mixer Measurements (Option 089 Only) Measurement Considerations Figure 2-6 Examples of Up Converters and Down Converters In standard mixer measurements, the input of the mixer is always connected to the analyzer's RF source, and the output of the mixer always produces the IF frequencies that are received by the analyzer's receiver. However, the ports labeled RF and IF on most mixers are not consistently connected to the analyzer's source and receiver ports, respectively.
Making Mixer Measurements (Option 089 Only) Measurement Considerations Figure 2-7 Down Converter Port Connections • In an up converter measurement where the UP CONVERTER softkey is selected, the notation on the setup diagram indicates that the analyzer's source frequency is labeled IF, connecting to the mixer IF port, and the analyzer's receiver frequency is labeled RF, connecting to the mixer RF port.
Making Mixer Measurements (Option 089 Only) Measurement Considerations Frequency Offset Mode Operation This mode of operation allows you to offset the analyzer's source by a fixed value, above or below the analyzer's receiver. That is, this allows you to use a device input frequency range that is different from the receiver input frequency range. Mixers or frequency converters, by definition, exhibit the characteristic of having different input and output frequencies.
Making Mixer Measurements (Option 089 Only) Measurement Considerations The following steps can be performed to observe this offset in power: 1. To set the power range to manual, press: Power PWR RANGE MAN 0 x1 Since the default source output power of the 8722ES is below 0 dBm, no reduction in source output power is required for this procedure. NOTE Setting the power range to manual prevents the internal source attenuator from switching when changing power levels.
Making Mixer Measurements (Option 089 Only) Measurement Considerations 5. Measure the output power in the R channel by pressing: Meas INPUT PORTS R Observe the 13 to 16 dB offset in measured power. The actual input power level to the R channel input must be 0 dBm or less, −10 dBm typical, to avoid receiver saturation effects. The minimum signal level must be greater than −35 dBm to provide sufficient signal for operation of the phaselock loop. 6.
Making Mixer Measurements (Option 089 Only) Conversion Loss Using the Frequency Offset Mode Conversion Loss Using the Frequency Offset Mode Conversion loss is the measure of efficiency of a mixer. It is the ratio of side-band IF power to RF signal power, and is usually expressed in dB. The mixer translates the incoming signal, (RF), to a replica, (IF), displaced in frequency by the local oscillator, (LO).
Making Mixer Measurements (Option 089 Only) Conversion Loss Using the Frequency Offset Mode Figure 2-11 Connections for R Channel and Source Calibration (IF Range) Setting Measurement Parameters for the IF Range 1. From the front panel of the analyzer, set the desired receiver (IF) frequency and source output power by pressing: System Start INSTRUMENT MODE 100 M/µ Stop 350 FREQ OFFS MENU M/µ If the LO frequency is not set to 0 Hz, press: LO FREQUENCY 0 x1 2.
Making Mixer Measurements (Option 089 Only) Conversion Loss Using the Frequency Offset Mode The Agilent E4418B and Agilent E4419B power meters have a “437 emulation” mode. This allows these power meters, with an Agilent 848X-series power sensor, to be used with the network analyzer. In this step, when selecting a power meter, choose the 438A/437 selection. NOTE 4. Press Cal PWRMTR CAL LOSS/SENSR LISTS CAL FACTOR SENSOR A and enter the correction factors as listed on the power sensor.
Making Mixer Measurements (Option 089 Only) Conversion Loss Using the Frequency Offset Mode The LO menu is used to set only the LO CW frequency. All other settings apply when using the HP/Agilent 8625A external source. 2. To select the converter type and a high-side LO measurement configuration, press: RETURN DOWN CONVERTER RF < LO 3.
Making Mixer Measurements (Option 089 Only) Conversion Loss Using the Frequency Offset Mode Performing a Power Meter Calibration Over the RF Range 1. Make the connections as shown in Figure 2-14 for the one-sweep power meter calibration over the RF range. Figure 2-14 Power Meter Calibration Equipment Setup for the RF Range 2. Use the power meter settings that were set up in steps 1 through 4 of the “Performing a Power Meter (Source) Calibration Over the IF Range” section. 3.
Making Mixer Measurements (Option 089 Only) Conversion Loss Using the Frequency Offset Mode Performing the R-Channel Measurement 1. Connect the equipment as shown in Figure 2-15. Figure 2-15 R-Channel Mixer Measurement Equipment Setup The analyzer is now displaying the conversion loss of the mixer calibrated with power meter accuracy. 2. To view the conversion loss in the best vertical resolution, press Scale Ref AUTOSCALE .
Making Mixer Measurements (Option 089 Only) Conversion Loss Using the Frequency Offset Mode Figure 2-16 Conversion Loss Example Measurement In this measurement, you set the input power and measured the output power. Figure 2-16 shows the absolute loss through the mixer versus mixer output frequency. If the mixer under test contained built-in amplification, then the measurement results would have shown conversion gain.
Making Mixer Measurements (Option 089 Only) High Dynamic Range Swept RF/IF Conversion Loss High Dynamic Range Swept RF/IF Conversion Loss The frequency offset mode enables the testing of high dynamic range frequency converters (mixers), by tuning the analyzer's high dynamic range receiver above or below its source, by a fixed offset. This capability allows the complete measurement of both pass and reject band mixer characteristics.
Making Mixer Measurements (Option 089 Only) High Dynamic Range Swept RF/IF Conversion Loss Figure 2-17 Connections for Power Meter Calibration 3. Select the analyzer as the system controller: Local SYSTEM CONTROLLER 4. Set the power meter's address: SET ADDRESSES ADDRESS: P MTR/HPIB aa (where aa is the power meter GPIB address) x1 5. Select the appropriate power meter by pressing POWER MTR [ ] until the correct model number is displayed (436A or 438A/437).
Making Mixer Measurements (Option 089 Only) High Dynamic Range Swept RF/IF Conversion Loss Because power meter calibration requires a longer sweep time, you may want to reduce the number of points before pressing TAKE CAL SWEEP . After the power meter calibration is finished, return the number of points to its original value and the analyzer will automatically interpolate this calibration. NOTE Perform a Receiver Calibration Over the IF Range 1. Connect the measurement equipment as shown in Figure 2-18.
Making Mixer Measurements (Option 089 Only) High Dynamic Range Swept RF/IF Conversion Loss Using the Mixer Measurement Diagram While the analyzer is still set to the IF frequency range, press: System INSTRUMENT MODE FREQ OFFS MENU LO MENU FREQUENCY:CW 1500 M/µ RETURN RETURN DOWN CONVERTER RF > LO . Note the RF frequency values on the diagram. Press Start 1.6 G/n Stop 2.5 G/n . Perform a Power Meter Calibration Over the RF Range 1. Connect the equipment as shown in Figure 2-19.
Making Mixer Measurements (Option 089 Only) High Dynamic Range Swept RF/IF Conversion Loss 2. Make the connections shown in Figure 2-20. 3. Set the LO source to the desired CW frequency of 1500 MHz and power level to 13 dBm.
Making Mixer Measurements (Option 089 Only) High Dynamic Range Swept RF/IF Conversion Loss 4. Set the analyzers LO frequency to match the frequency of the LO source by pressing: System INSTRUMENT MODE FREQ OFFS MENU LO FREQUENCY 1500 M/µ 5.
Making Mixer Measurements (Option 089 Only) Fixed IF Mixer Measurements Fixed IF Mixer Measurements A fixed IF can be produced by using both a swept RF and LO that are offset by a certain frequency. With proper filtering, only this offset frequency will be present at the IF port of the mixer. This measurement requires two external RF sources as stimuli. Figure 2-23 shows the hardware configuration for the fixed IF conversion loss measurement.
Making Mixer Measurements (Option 089 Only) Fixed IF Mixer Measurements NOTE You may have to consult the user's guide of the external source being used to determine how to set the source to receive SCPI commands. 3. Be sure to connect the 10 MHz reference signals of the external sources to the EXT REF connector on the rear panel of the analyzer (a BNC tee must be used).
Making Mixer Measurements (Option 089 Only) Fixed IF Mixer Measurements Putting the Analyzer into Tuned Receiver Mode SYSTEM CONTROLLER Local System INSTRUMENT MODE TUNED RECEIVER Setting Up a Frequency List Sweep of 26 Points Sweep Setup START STOP SWEEP TYPE MENU 100 100 EDIT LIST ADD M/µ M/µ NUMBER OF POINTS 26 x1 DONE DONE LIST FREQ Performing a Response Calibration INPUT PORTS B Meas Display MORE TITLE ERASE TITLE Input as title: POW:LEV 6DBM DONE SPECIAL FUNCTIONS Seq PERIPHERA
Making Mixer Measurements (Option 089 Only) Fixed IF Mixer Measurements Initializing a Loop Counter Value to 26 Seq SPECIAL FUNCTIONS LOOP COUNTER Scale Ref 2 26 x1 x1 REFERENCE POSITION REFERENCE VALUE Sweep Setup DECISION MAKING MKING 0 −20 x1 x1 TRIGGER MENU MANUAL TRG ON POINT TG ON POINT Addressing and Configuring the Two Sources Display MORE TITLE ERASE TITLE Input as title: FREQ:MODE CW;CW 500MHZ;:FREQ:CW:STEP 100MHZ DONE Seq SPECIAL FUNCTIONS PERIPHERAL HPIB ADDR 19 x1 21 x
Making Mixer Measurements (Option 089 Only) Fixed IF Mixer Measurements TUNED RECEIVER EDIT LIST ADD CW FREQ 100M/u NUMBER OF POINTS 26x1 DONE DONE LIST FREQ B TITLE POW:LEV 6DBM PERIPHERAL HPIB ADDR 19x1 TITLE TO PERIPHERAL TITLE FREQ:MODE CW;CW 100MHZ TITLE TO PERIPHERAL CALIBRATE: RESPONSE CAL STANDARD DONE CAL CLASS TITLE CONNECT MIXER PAUSE LOOP COUNTER 26x1 SCALE/DIV 2 x1 REFERENCE POSITION 0 x1 REFERENCE VALUE −20x1 MANUAL TRG ON POINT TITLE FREQ:MODE CW;CW 500MHZ;:FREQ:CW:STEP 100MHZ TITLE TO PERIP
Making Mixer Measurements (Option 089 Only) Fixed IF Mixer Measurements Sequence 2 Setup The following sequence makes a series of measurements until all 26 CW measurements are made and the loop counter value is equal to zero. This sequence includes: • taking data • incrementing the source frequencies • decrementing the loop counter • labeling the screen 1.
Making Mixer Measurements (Option 089 Only) Fixed IF Mixer Measurements Press Seq NEW SEQ/MODIFY SEQ SEQUENCE 2 SEQ2 and the analyzer will display the following sequence commands: SEQUENCE SEQ2 Start of Sequence WAIT x 1 x1 MANUAL TRG ON POINT TITLE FREQ:CW UP PERIPHERAL HPIB ADDR 19x1 TITLE TO PERIPHERAL PERIPHERAL HPIB ADDR 21x1 TITLE TO PERIPHERAL DECR LOOP COUNTER IF LOOP COUNTER <>0 THEN DO SEQUENCE 2 TITLE MEASUREMENT COMPLETED 2.
Making Mixer Measurements (Option 089 Only) Fixed IF Mixer Measurements When the sequences are finished you should have a result as shown in Figure 2-24. Figure 2-24 Example Fixed IF Mixer Measurement The displayed trace represents the conversion loss of the mixer at 26 points. Each point corresponds to one of the 26 different sets of RF and LO frequencies that were used to create the same fixed IF frequency.
Making Mixer Measurements (Option 089 Only) Phase or Group Delay Measurements Phase or Group Delay Measurements For information on group delay principles, refer to "Setting the Electrical Delay" on page 1-38. Phase Measurements When you are making linear measurements, you must provide a reference for determining phase by splitting the RF source power and send part of the signal into the reference channel.
Making Mixer Measurements (Option 089 Only) Phase or Group Delay Measurements Model Number Useful Frequency Range Group Delay ANZAC MCD-123 0.03 to 3 GHz 0.5 ns Mini-Circuits ZFM-4 dc to 1250 MHz 0.6 ns 1. Set the LO source to the desired CW frequency of 1000 MHz and power level to 13 dBm. 2. Initialize the analyzer by pressing Preset . 3. Set the analyzer’s LO frequency to match the frequency of the LO source by pressing: System INSTRUMENT MODE FREQ OFFS MENU LO FREQUENCY 1000 M/µ 4.
Making Mixer Measurements (Option 089 Only) Phase or Group Delay Measurements Figure 2-25 Connections for a Group Delay Measurement 6. To select the converter type and a high-side LO measurement configuration, press: System INSTRUMENT MODE FREQ OFFS MENU DOWN CONVERTER RF
Making Mixer Measurements (Option 089 Only) Phase or Group Delay Measurements 10.Replace the "calibration" mixer with the device under test. If measuring group delay, set the delay equal to the "calibration" mixer delay (for example −0.6 ns) by pressing: Scale Ref ELECTRICAL DELAY −06 G/n 11.Scale the data for best vertical resolution. Scale Ref AUTOSCALE Figure 2-26 Group Delay Measurement Example The displayed measurement trace shows the device under test delay, relative to the "calibration" mixer.
Making Mixer Measurements (Option 089 Only) Amplitude and Phase Tracking Amplitude and Phase Tracking The match between mixers is defined as the absolute difference in amplitude or phase response over a specified frequency range. The tracking between mixers is essentially how well the devices are matched over a specified interval. This interval may be a frequency interval or a temperature interval, or a combination of both.
Making Mixer Measurements (Option 089 Only) Conversion Compression Using the Frequency Offset Mode Conversion Compression Using the Frequency Offset Mode Conversion compression is a measure of the maximum RF input signal level where the mixer provides linear operation. The conversion loss is the ratio of the IF output level to the RF input level. This value remains constant over a specified input power range.
Making Mixer Measurements (Option 089 Only) Conversion Compression Using the Frequency Offset Mode System INSTRUMENT MODE FREQ OFFS MENU LO FREQUENCY 800 M/µ 4. To set the analyzer to the desired power sweep range, press: Power PWR RANGE MAN Start −10 Stop 10 POWER RANGES RANGE 0 x1 x1 5. Make the connections, as shown in Figure 2-29. CAUTION To prevent connector damage, use an adapter (part number 1250-1462) as a connector saver for R CHANNEL IN.
Making Mixer Measurements (Option 089 Only) Conversion Compression Using the Frequency Offset Mode 8. Make the connections as shown in Figure 2-30. CAUTION To prevent connector damage, use an adapter (part number 1250-1462) as a connector saver for R CHANNEL IN. Figure 2-30 Connections for the Second Portion of Conversion Compression Measurement 9. To set the frequency offset mode LO frequency, press: System INSTRUMENT MODE LO MENU FREQ OFFS MENU FREQUENCY:CW 600 M/µ 10.
Making Mixer Measurements (Option 089 Only) Conversion Compression Using the Frequency Offset Mode The measurements setup diagram is shown in Figure 2-31. Figure 2-31 Measurement Setup Diagram Shown on Analyzer Display 12.To view the mixer's output power as a function of its input power, press: VIEW MEASURE 13.To set up an active marker to search for the 1 dB compression point of the mixer, press: Scale Ref AUTO SCALE Marker Search SEARCH:MAX 14.
Making Mixer Measurements (Option 089 Only) Conversion Compression Using the Frequency Offset Mode Figure 2-32 Example Swept Power Conversion Compression Measurement 2-43
Making Mixer Measurements (Option 089 Only) Isolation Example Measurements Isolation Example Measurements Isolation is the measure of signal leakage in a mixer. Feedthrough is specifically the forward signal leakage to the IF port. High isolation means that the amount of leakage or feedthrough between the mixer's ports is very small. Isolation measurements do not use the frequency offset mode. Figure 2-33 illustrates the signal flow in a mixer.
Making Mixer Measurements (Option 089 Only) Isolation Example Measurements Figure 2-34 Connections for a Response Calibration 5. Perform a response calibration by pressing Cal THRU . NOTE CALIBRATE MENU RESPONSE A full 2-port calibration will increase the accuracy of isolation measurements. Refer to Chapter 5 , “Optimizing Measurement Results.” 6. Make the connections as shown in Figure 2-35.
Making Mixer Measurements (Option 089 Only) Isolation Example Measurements 7. To adjust the display scale, press: Scale Ref AUTO SCALE The measurement results show the mixer's LO to RF isolation.
Making Mixer Measurements (Option 089 Only) Isolation Example Measurements 4. To select a ratio B/R measurement, press: Meas NOTE INPUT PORTS B/R Isolation is dependent on LO power level and frequency. To ensure good test results, you should choose these parameters as close to actual operating conditions as possible. 5. Make the connections as shown in Figure 2-37. Figure 2-37 Connections for a Response Calibration 6. Perform a response calibration by pressing Cal THRU . CALIBRATE MENU RESPONSE 7.
Making Mixer Measurements (Option 089 Only) Isolation Example Measurements 8. Connect the external LO source to the mixer's LO port. 9. The measurement results show the mixer's RF feedthrough. NOTE You may see spurious responses on the analyzer trace due to interference caused by LO to IF leakage in the mixer. This can be reduced with averaging or by reducing the IF bandwidth.
Making Mixer Measurements (Option 089 Only) Isolation Example Measurements SWR / Return Loss Reflection coefficient (Γ) is defined as the ratio between the reflected voltage (Vr) and incident voltage (Vi). Standing wave ratio (SWR) is defined as the ratio of maximum standing wave voltage to the minimum standing wave voltage and can be derived from the reflection coefficient (Γ) using the following equation. Return loss can be derived from the reflection coefficient as well.
3 Making Time Domain Measurements 3-1
Making Time Domain Measurements Using This Chapter Using This Chapter This chapter contains the following: • An introduction to time domain measurements • Example procedures for making time domain transmission and reflection response measurements • Information on the following time domain concepts: — Time Domain Bandpass Mode on page 3-12 — Time Domain Low Pass Mode on page 3-15 — Transforming CW Time Measurements into the Frequency Domain on page 3-22 — Masking on page 3-26 — Windowing on page 3-27 — Rang
Making Time Domain Measurements Introduction to Time Domain Measurements Introduction to Time Domain Measurements The analyzers with Option 010 allow you to measure the time domain response of a device. Time domain analysis is useful for isolating a device problem in time or in distance. Time and distance are related by the velocity factor of your device under test (DUT) which is described in "Time Domain Bandpass Mode" on page 3-12.
Making Time Domain Measurements Introduction to Time Domain Measurements Figure 3-1 Device Frequency Domain and Time Domain Reflection Responses The time domain measurement shows the effect of each discontinuity as a function of time (or distance), and shows that the test device response consists of three separate impedance changes. The second discontinuity has a reflection coefficient magnitude of 0.035 (i.e. 3.5% of the incident signal is reflected).
Making Time Domain Measurements Making Transmission Response Measurements Making Transmission Response Measurements In this example measurement there are three components of the transmission response: • RF leakage at near zero time • the main travel path through the device (1.6 µs travel time) • the "triple travel" path (4.
Making Time Domain Measurements Making Transmission Response Measurements 5. To transform the data from the frequency domain to the time domain and set the sweep from 0 s to 6 µs, press: TRANSFORM MENU System Start 0 G/n Stop 6 BANDPASS TRANSFORM ON M/µ The other time domain modes, low pass step and low pass impulse, are described in "Time Domain Low Pass Mode" on page 3-15. 6.
Making Time Domain Measurements Making Transmission Response Measurements 11.To activate the gating function to remove any unwanted responses, press: GATE ON As shown in Figure 3-4, only response from the main path is displayed. NOTE You may remove the displayed response from inside the gate markers by pressing SPAN and turning the front panel knob to exchange the "flag" marker positions. Figure 3-4 Gating in a Time Domain Transmission Example Measurement 12.
Making Time Domain Measurements Making Transmission Response Measurements Figure 3-5 Gate Shape • To see the effect of the gating in the frequency domain, press: System TRANSFORM MENU TRANSFORM OFF OF Scale Ref AUTO SCALE Display DATA→MEM DISPLAY: DATA AND MEMORY System TRANSFORM MENU SPECIFY GATE GATE OFF This places the gated response in memory. Figure 3-6 shows the effect of removing the RF leakage and the triple travel signal path using gating.
Making Time Domain Measurements Making Reflection Response Measurements Making Reflection Response Measurements The time domain response of a reflection measurement is often compared with the time domain reflectometry (TDR) measurements. Like the TDR, the analyzer measures the size of the reflections versus time (or distance). Unlike the TDR, the time domain capability of the analyzer allows you to choose the frequency range over which you would like to make the measurement. 1.
Making Time Domain Measurements Making Reflection Response Measurements Figure 3-8 Device Response in the Frequency Domain 5. To transform the data from the frequency domain to the time domain, press: System TRANSFORM MENU BANDPASS TRANSFORM ON 6. To view the time domain over the length (<4 meters) of the cable under test, press: LIN MAG Format Start 0 Stop 35 x1 G/n The stop time corresponds to the length of the cable under test. The energy travels about 1 foot per nanosecond, or 0.
Making Time Domain Measurements Making Reflection Response Measurements 8. To position the marker on the reflection of interest, press: Marker and turn the front panel knob, or enter a value from the front panel keypad. In this example, the velocity factor was set to one-half the actual value, so the marker reads the time and distance to the reflection. 9.
Making Time Domain Measurements Time Domain Bandpass Mode Time Domain Bandpass Mode This mode is called bandpass because it works with band-limited devices. Traditional TDR requires that the test device be able to operate down to dc. Using bandpass mode, there are no restrictions on the measurement frequency range. Bandpass mode characterizes the test device impulse response.
Making Time Domain Measurements Time Domain Bandpass Mode Figure 3-10 A Reflection Measurement of Two Cables The ripples in reflection coefficient versus frequency in the frequency domain measurement are caused by the reflections at each connector "beating" against each other. One at a time, loosen the connectors at each end of the cable and observe the response in both the frequency domain and the time domain.
Making Time Domain Measurements Time Domain Bandpass Mode Table 3-1 Time Domain Reflection Formats Format Parameter LIN MAG Reflection Coefficient (unitless) (0 < ρ < 1) REAL Reflection Coefficient (unitless) (−1 < ρ < 1) LOG MAG Return Loss (dB) SWR Standing Wave Ratio (unitless) Transmission Measurements Using Bandpass Mode The bandpass mode can also transform transmission measurements to the time domain.
Making Time Domain Measurements Time Domain Low Pass Mode Time Domain Low Pass Mode This mode is used to simulate a traditional time domain reflectometry (TDR) measurement. It provides information to determine the type of discontinuity (resistive, capacitive, or inductive) that is present. Low pass provides the best resolution for a given bandwidth in the frequency domain. It may be used to give either the step or impulse response of the test device.
Making Time Domain Measurements Time Domain Low Pass Mode Table 3-2 Minimum Frequency Ranges for Time Domain Low Pass Number of Points Minimum Frequency Range Number of Points Minimum Frequency Range 3 50 MHz to 150 MHz 101 50 MHz to 5.05 GHz 11 50 MHz to 550 MHz 201 50 MHz to 10.05 GHz 21 50 MHz to 1.05 GHz 401 50 MHz to 20.05 GHz 51 50 MHz to 2.55 GHz 801 50 MHz to 40.
Making Time Domain Measurements Time Domain Low Pass Mode Interpreting the Low Pass Response Vertical Axis The vertical axis depends on the chosen format. In the low pass mode, the frequency domain data is taken at harmonically related frequencies and extrapolated to dc. Because this results in the inverse Fourier transform having only a real part (the imaginary part is zero), the most useful low pass step mode format in this application is the real format.
Making Time Domain Measurements Time Domain Low Pass Mode Figure 3-13 Simulated Low Pass Step and Impulse Response Waveforms (Real Format) Figure 3-14 shows example cables with discontinuities (faults) using the low pass step mode with the real format.
Making Time Domain Measurements Time Domain Low Pass Mode Figure 3-14 Low Pass Step Measurements of Common Cable Faults (Real Format) Transmission Measurements in Time Domain Low Pass Measuring Small Signal Transient Response Using Low Pass Step Use the low pass mode to analyze the test device's small signal transient response.
Making Time Domain Measurements Time Domain Low Pass Mode Figure 3-15 Time Domain Low Pass Measurement of an Amplifier Small Signal Transient Response Interpreting the Low Pass Step Transmission Response Horizontal Axis The low pass transmission measurement horizontal axis displays the average transit time through the test device over the frequency range used in the measurement. The response of the thru connection used in the calibration is a step that reaches 50% unit height at approximately time = 0.
Making Time Domain Measurements Time Domain Low Pass Mode Figure 3-16 Transmission Measurements Using Low Pass Impulse Mode 3-21
Making Time Domain Measurements Transforming CW Time Measurements into the Frequency Domain Transforming CW Time Measurements into the Frequency Domain The analyzer can display the amplitude and phase of CW signals versus time. For example, use this mode for measurements such as amplifier gain as a function of warmup time (i.e. drift). The analyzer can display the measured parameter (e.g. amplifier gain) for periods of up to 24 hours and then output the data to a digital plotter for hardcopy results.
Making Time Domain Measurements Transforming CW Time Measurements into the Frequency Domain Interpreting the Forward Transform Horizontal Axis In a frequency domain transform of a CW time measurement, the horizontal axis is measured in units of frequency. The center frequency is the offset of the CW frequency. For example, with a center frequency of 0 Hz, the CW frequency (250 MHz in the example) is in the center of the display.
Making Time Domain Measurements Transforming CW Time Measurements into the Frequency Domain Figure 3-19. Separating the Amplitude and Phase Components of Test-Device-Induced Modulation Forward Transform Range In the forward transform (from CW time to the frequency domain), range is defined as the frequency span that can be displayed before aliasing occurs, and is similar to range as defined for time domain measurements. In the range formula, substitute time span for frequency span.
Making Time Domain Measurements Transforming CW Time Measurements into the Frequency Domain Figure 3-20 Range of a Forward Transform Measurement To increase the frequency domain measurement range, increase the span. The maximum range is inversely proportional to the sweep time, therefore it may be necessary to increase the number of points or decrease the sweep time.
Making Time Domain Measurements Masking Masking Masking occurs when a discontinuity (fault) closest to the reference plane affects the response of each subsequent discontinuity. This happens because the energy reflected from the first discontinuity never reaches subsequent discontinuities. For example, if a transmission line has two discontinuities that each reflect 50% of the incident voltage, the time domain response (real format) shows the correct reflection coefficient for the first discontinuity ρ=0.
Making Time Domain Measurements Windowing Windowing The analyzer provides a windowing feature that makes time domain measurements more useful for isolating and identifying individual responses. Windowing is needed because of the abrupt transitions in a frequency domain measurement at the start and stop frequencies.
Making Time Domain Measurements Windowing Table 3-3 Impulse Width, Sidelobe Level, and Windowing Values Window Type Impulse Sidelobe Level Low Pass Impulse Width (50%) Step Sidelobe Level Step Rise Time (10 − 90%) Minimum −13 dB 0.60/Freq Span −21 dB 0.45/Freq Span Normal −44 dB 0.98/Freq Span −60 dB 0.99/Freq Span Maximum −75 dB 1.39/Freq Span −70 dB 1.48/Freq Span NOTE: The bandpass mode simulates an impulse stimulus. Bandpass impulse width is twice that of low pass impulse width.
Making Time Domain Measurements Windowing Figure 3-23 The Effects of Windowing on the Time Domain Responses of a Short Circuit (Real Format) 3-29
Making Time Domain Measurements Range Range In the time domain, range is defined as the length in time that a measurement can be made without encountering a repetition of the response, called aliasing. A time domain response repeats at regular intervals because the frequency domain data is taken at discrete frequency points, rather than continuously over the frequency band.
Making Time Domain Measurements Range In this example, the range is 100 ns, or 30 meters electrical length. To prevent the time domain responses from overlapping, the test device must be 30 meters or less in electrical length for a transmission measurement (15 meters for a reflection measurement). The analyzer limits the stop time to prevent the display of aliased responses.
Making Time Domain Measurements Resolution Resolution Two different resolution terms are used in the time domain: • response resolution • range resolution Response Resolution Time domain response resolution is defined as the ability to resolve two closely-spaced responses, or a measure of how close two responses can be to each other and still be distinguished from each other. For responses of equal amplitude, the response resolution is equal to the 50% (−6 dB) impulse width.
Making Time Domain Measurements Resolution discontinuity shadowing the response of a smaller discontinuity, all act to degrade the effective response resolution. Figure 3-24 illustrates the effects of response resolution. The solid line shows the actual reflection measurement of two approximately equal discontinuities (the input and output of an SMA barrel). The dashed line shows the approximate effect of each discontinuity, if they could be measured separately.
Making Time Domain Measurements Resolution Range Resolution Time domain range resolution is defined as the ability to locate a single response in time. If only one response is present, range resolution is a measure of how closely you can pinpoint the peak of that response. The range resolution is equal to the digital resolution of the display, which is the time domain span divided by the number of points on the display.
Making Time Domain Measurements Gating Gating Gating provides the flexibility of selectively removing time domain responses. The remaining time domain responses can then be transformed back to the frequency domain. For reflection (or fault location) measurements, use this feature to remove the effects of unwanted discontinuities in the time domain. You can then view the frequency response of the remaining discontinuities.
Making Time Domain Measurements Gating Setting the Gate Think of a gate as a bandpass filter in the time domain (see Figure 3-27). When the gate is on, responses outside the gate are mathematically removed from the time domain trace. Enter the gate position as a start and stop time (not frequency) or as a center and span time. The start and stop times are the bandpass filter −6 dB cutoff times. Gates can have a negative span, in which case the responses inside the gate are mathematically removed.
4 Printing, Plotting, and Saving Measurement Results 4-1
Printing, Plotting, and Saving Measurement Results Using This Chapter Using This Chapter This chapter contains instructions for the following tasks: • Printing or plotting your measurement results ❏ Configuring a print function ❏ Defining a print function ❏ Printing one measurement per page ❏ Printing multiple measurements per page ❏ Configuring a plot function ❏ Defining a plot function ❏ Plotting one measurement per page using a pen plotter ❏ Plotting multiple measurements per page using a pen plotter ❏
Printing, Plotting, and Saving Measurement Results Printing or Plotting Your Measurement Results Printing or Plotting Your Measurement Results You can print your measurement results to the following peripherals: • printers with GPIB interfaces • printers with parallel interfaces • printers with serial interfaces You can plot your measurement results to the following peripherals: • HPGL compatible printers with GPIB interfaces • HPGL compatible printers with parallel interfaces • plotters with GPIB interfac
Printing, Plotting, and Saving Measurement Results Configuring a Print Function Configuring a Print Function All copy configuration settings are stored in non-volatile memory. Therefore, they are not affected if you press Preset or switch off the analyzer power. 1. Connect the printer to the interface port. Figure 4-1 Printer Connections to the Analyzer 2.
Printing, Plotting, and Saving Measurement Results Configuring a Print Function 3. Select one of the following printer interfaces: • Choose PRNTR PORT GPIB if your printer has an GPIB interface, and then configure the print function as follows: a. Enter the GPIB address of the printer, followed by x1 . b. Press Local and SYSTEM CONTROLLER if there is no external controller connected to the GPIB bus. c. Press Local and USE PASS CONTROL if there is an external controller connected to the GPIB bus.
Printing, Plotting, and Saving Measurement Results Defining a Print Function Defining a Print Function NOTE The print definition is set to default values whenever the power is cycled. However, you can save the print definition by saving the instrument state. 1. Press Copy DEFINE PRINT . 2. Press PRINT: MONOCHROME or PRINT: COLOR . ❏ Choose PRINT: MONOCHROME if you are using a black and white printer, or you want just black and white from a color printer.
Printing, Plotting, and Saving Measurement Results Defining a Print Function To Reset the Printing Parameters to Default Values 1. Press Copy DEFINE PRINT DEFAULT PRNT SETUP .
Printing, Plotting, and Saving Measurement Results Printing One Measurement Per Page Printing One Measurement Per Page 1. Configure and define the print function, as explained in "Configuring a Print Function" on page 4-4 and "Defining a Print Function" on page 4-6. 2. Press Copy PRINT MONOCHROME . If you defined the AUTO-FEED OFF , press PRINTER FORM FEED after the message COPY OUTPUT COMPLETED appears.
Printing, Plotting, and Saving Measurement Results Printing Multiple Measurements Per Page Printing Multiple Measurements Per Page 1. Configure and define the print function, as explained in "Configuring a Print Function" on page 4-4 and "Defining a Print Function" on page 4-6. 2. Press Copy DEFINE PRINT and then press AUTO-FEED until the softkey label appears as AUTO-FEED OFF . 3. Press RETURN PRINT MONOCHROME to print a measurement on the first half page. 4.
Printing, Plotting, and Saving Measurement Results Configuring a Plot Function Configuring a Plot Function All copy configuration settings are stored in non-volatile memory. Therefore, they are not affected if you press Preset or switch off the analyzer power. Peripheral Interface Recommended Cables Parallel 92284A GPIB 10833A/33B/33D Serial 24542G 1. Connect the peripheral to the interface port using the recommended cable from the following list.
Printing, Plotting, and Saving Measurement Results Configuring a Plot Function Information regarding a printer compatibility guide (an up-to-date list of printers that are compatible with the network analyzer) is available in "Printing or Plotting Your Measurement Results" on page 4-3. 3. Configure the analyzer for one of the following printer interfaces: • Choose PRNTR PORT GPIB if your printer has an GPIB interface, and then configure the print function as follows: a.
Printing, Plotting, and Saving Measurement Results Configuring a Plot Function If You Are Plotting to a Pen Plotter 1. Press Local SET ADDRESSES PLOTTER PORT and then PLTR TYPE until PLTR TYPE [PLOTTER] appears. 2. Configure the analyzer for one of the following plotter interfaces: • Choose PLTR PORT GPIB if your plotter has an GPIB interface, and then configure the plot function as follows: a. Enter the GPIB address of the plotter (default is 05), followed by x1 . b.
Printing, Plotting, and Saving Measurement Results Configuring a Plot Function If You Are Plotting Measurement Results to a Disk Drive The plot files that you generate from the analyzer, contain the HPGL representation of the measurement display. The files will not contain any setup or formfeed commands. CAUTION Do not mistake the line switch for the disk eject button when you are removing the disk from the analyzer.
Printing, Plotting, and Saving Measurement Results Configuring a Plot Function Figure 4-4 Automatic File Naming Convention for LIF Format To Output the Plot Files • You can plot the files to a plotter from a personal computer. • You can output your plot files to an HPGL compatible printer, by following the sequence in "Outputting Plot Files from a PC to an HPGL Compatible Printer" on page 4-25.
Printing, Plotting, and Saving Measurement Results Defining a Plot Function Defining a Plot Function 1. Press Copy DEFINE PLOT . Choosing Display Elements • Choose which of the following measurement display elements that you want to appear on your plot: ❏ Choose PLOT DATA ON if you want the measurement data trace to appear on your plot. ❏ Choose PLOT MEM ON if you want the displayed memory trace to appear on your plot.
Printing, Plotting, and Saving Measurement Results Defining a Plot Function The peripheral ignores AUTO-FEED ON when you are plotting to a quadrant. NOTE Selecting Pen Numbers and Colors • Press MORE and select the plot element where you want to change the pen number. For example, press PEN NUM DATA and then modify the pen number. The pen number selects the color if you are plotting to an HPGL/2 compatible color printer. Press x1 after each modification.
Printing, Plotting, and Saving Measurement Results Defining a Plot Function Selecting Line Types • Press MORE and select each plot element line type that you want to modify. — Select LINE TYPE DATA to modify the line type for the data trace. Then enter the new line type (see Figure 4-6), followed by x1 . — Select LINE TYPE MEMORY to modify the line type for the memory trace. Then enter the new line type (see Figure 4-6), followed by x1 .
Printing, Plotting, and Saving Measurement Results Defining a Plot Function Figure 4-7 Locations of P1 and P2 in SCALE PLOT [GRAT] Mode Choosing Plot Speed • Press PLOT SPEED until the plot speed appears that you want. ❏ Choose PLOT SPEED [FAST] for normal plotting. ❏ Choose PLOT SPEED [SLOW] for plotting directly on transparencies. (The slower speed provides a more consistent line width.) To Reset the Plotting Parameters to Default Values Press Copy DEFINE PLOT MORE MORE YES .
Printing, Plotting, and Saving Measurement Results Plotting One Measurement Per Page Using a Pen Plotter Plotting One Measurement Per Page Using a Pen Plotter 1. Configure and define the plot, as explained in "Configuring a Plot Function" on page 4-10 and "Defining a Plot Function" on page 4-15. 2. Press Copy PLOT . ❏ If you defined the AUTO-FEED OFF , press PLOTTER FORM FEED after the message COPY OUTPUT COMPLETED appears.
Printing, Plotting, and Saving Measurement Results Plotting Multiple Measurements Per Page Using a Pen Plotter Plotting Multiple Measurements Per Page Using a Pen Plotter 1. Configure and define the plot, as explained in "Configuring a Plot Function" on page 4-10 and "Defining a Plot Function" on page 4-15. 2. Press Copy SEL QUAD . 3. Choose the quadrant where you want your displayed measurement to appear on the hardcopy.
Printing, Plotting, and Saving Measurement Results Plotting Multiple Measurements Per Page Using a Pen Plotter If You Are Plotting to an HPGL Compatible Printer 1. Configure and define the plot, as explained in "Configuring a Plot Function" on page 4-10 and "Defining a Plot Function" on page 4-15. 2. Press Copy received. NOTE PLOT PLOTTER FORM FEED to print the data the printer has Use test sequencing to automatically plot all four S-parameters. 1. Set all measurement parameters. 2.
Printing, Plotting, and Saving Measurement Results To View Plot Files on a PC To View Plot Files on a PC Plot files can be viewed and manipulated on a PC using a word processor or graphics presentation program. Plot files contain a text stream of HPGL (Hewlett-Packard Graphics Language) commands. In order to import a plot file into an application, that application must have an import filter for HPGL (often called HGL).
Printing, Plotting, and Saving Measurement Results To View Plot Files on a PC Using Ami Pro To view plot files in Ami Pro, perform the following steps: 1. From the FILE pull-down menu, select IMPORT PICTURE. 2. In the dialog box, change the File Type selection to HPGL. This automatically changes the file suffix in the filename box to *.PLT. NOTE The network analyzer does not use the suffix *.PLT, so you may want to change the filename filter to *.
Printing, Plotting, and Saving Measurement Results Outputting Plot Files from a PC to a Plotter Converting HPGL Files for Use with Other PC Applications A utility can convert hpgl (or .fp) files to other PC applications. This utility, named hp2xx, is available to be downloaded without charge (on donation basis only) from Free Software Foundation. You may download this file using the information available on the following Web site: ftp://ots.external.hp.
Printing, Plotting, and Saving Measurement Results Outputting Plot Files from a PC to an HPGL Compatible Printer Outputting Plot Files from a PC to an HPGL Compatible Printer To output the plot files to an HPGL compatible printer, you can use the HPGL initialization sequence linked in a series as follows: Step 1. Store the HPGL initialization sequence in a file named hpglinit. Step 2. Store the exit HPGL mode and form feed sequence in a file named exithpgl. Step 3.
Printing, Plotting, and Saving Measurement Results Outputting Single Page Plots Using a Printer Step 2. Store the exit HPGL mode and form feed sequence. 1. Create a test file by typing in each character as shown in the left column of Table 4-8. Do not insert spaces or linefeeds. 2. Name the file exithpgl. Table 4-8 HPGL Test File Commands Command Remark %0A exit HPGL mode E form feed Step 3. Send the HPGL initialization sequence to the printer.
Printing, Plotting, and Saving Measurement Results Outputting Multiple Plots to a Single Page Using a Printer Outputting Multiple Plots to a Single Page Using a Printer Refer to "Plotting Multiple Measurements Per Page Using a Pen Plotter" on page 4-20 for the naming conventions for plot files that you want printed on the same page. You can use the following batch file to automate the plot file printing. In this example, the batch file is be saved as “do_plot.bat.
Printing, Plotting, and Saving Measurement Results Plotting Multiple Measurements Per Page from Disk Plotting Multiple Measurements Per Page from Disk The following procedures show you how to store plot files on a LIF formatted disk.
Printing, Plotting, and Saving Measurement Results Plotting Multiple Measurements Per Page from Disk To Plot Multiple Measurements on a Full Page You may want to plot various files to the same page, for example, to show measurement data traces for different input settings, or parameters, on the same graticule. 1. Define the plot, as explained in "Defining a Plot Function" on page 4-15. 2. Press Copy PLOT DEFINE PRINT . The analyzer assigns the first available default filename for the displayed directory.
Printing, Plotting, and Saving Measurement Results Plotting Multiple Measurements Per Page from Disk Figure 4-10 Plotting Two Files on the Same Page To Plot Measurements in Page Quadrants 1. Define the plot, as explained in "Defining a Plot Function" on page 4-15. 2. Press Copy SEL QUAD . 3. Choose the quadrant where you want your displayed measurement to appear on the hardcopy. The selected quadrant appears in the brackets under SEL QUAD . Figure 4-11 Plot Quadrants 4. Press PLOT .
Printing, Plotting, and Saving Measurement Results Plotting Multiple Measurements Per Page from Disk 5. Make the next measurement that you want to see on your hardcopy. 6. Repeat this procedure for the remaining plot files that you want to see as quadrants on a page. If you want to see what quadrants you have already saved, press Save/Recall to view the directory.
Printing, Plotting, and Saving Measurement Results Titling the Displayed Measurement Titling the Displayed Measurement 1. Press Display MORE TITLE to access the title menu. 2. Press ERASE TITLE and enter the title you want for your measurement display. • If you have a DIN keyboard attached to the analyzer, type the title you want from the keyboard. Then press ENTER to enter the title into the analyzer. You can enter a title that has a maximum of 50 characters.
Printing, Plotting, and Saving Measurement Results Configuring the Analyzer to Produce a Time Stamp Configuring the Analyzer to Produce a Time Stamp You can set a clock, and then activate it, if you want the time and date to appear on your hardcopies. 1. Press System SET CLOCK . 2. Press SET YEAR and enter the current year, followed by x1 . 3. Press SET MONTH and enter the current month of the year, followed x1 . 4. Press SET DAY and enter the current day of the month, followed by x1 . 5.
Printing, Plotting, and Saving Measurement Results Printing or Plotting the List Values or Operating Parameters Printing or Plotting the List Values or Operating Parameters Press Copy LIST and select the information that you want to appear on your hardcopy. • Choose LIST VALUES if you want a tabular listing of the measured data points, and their current values, to appear on your hardcopy. This list will also include the limit test information, if you have the limits function activated.
Printing, Plotting, and Saving Measurement Results Solving Problems with Printing or Plotting Solving Problems with Printing or Plotting If you encounter a problem when you are printing or plotting, check the following list for possible causes: • Look in the analyzer display message area. The analyzer may show a message that will identify the problem. Refer to the "Error Messages" chapter of the reference guide if a message appears.
Printing, Plotting, and Saving Measurement Results Saving and Recalling Instrument States Saving and Recalling Instrument States Places Where You Can Save • analyzer internal memory • floppy disk using the analyzer's internal disk drive • floppy disk using an external disk drive • IBM compatible personal computer using GPIB mnemonics What You Can Save to the Analyzer's Internal Memory The number of registers that the analyzer allows you to save depends on the size of associated error-correction sets, and
Printing, Plotting, and Saving Measurement Results Saving and Recalling Instrument States What You Can Save to a Floppy Disk You can save an instrument state and measurement results to a disk. The default file names are FILEn, where n gets incremented by one each time a file with a default name is added to the directory. The default file names for data-only files are DATAyDz (DATAy.Dz for DOS), where y is incremented by one each time a file with a default name is added to the directory.
Printing, Plotting, and Saving Measurement Results Saving an Instrument State Saving an Instrument State 1. Press Save/Recall DEFINE PLOT and select one of the storage devices: ❏ SEL QUAD ❏ INTERNAL DISK ❏ EXTERNAL DISK connect an external disk drive to the analyzer’s GPIB connector, and configure as follows: a. Connect an external disk drive to the analyzer's GPIB connector, and configure as follows: b. Press Local DISK UNIT NUMBER and enter the drive where your disk is located, followed by x1 . c.
Printing, Plotting, and Saving Measurement Results Saving Measurement Results Saving Measurement Results Instrument states combined with measurements results can only be saved to disk. Files that contain data-only, and the various save options available under the DEFINE DISK-SAVE key, are also only valid for disk saves. The analyzer stores data in arrays along the processing flow of numerical data, from IF detection to display.
Printing, Plotting, and Saving Measurement Results Saving Measurement Results Figure 4-13 Data Processing Flow Diagram NOTE If the analyzer has an active two-port measurement calibration, all four S-parameters will be saved with the measurement results. All four S-parameters may be viewed if the raw data array has been saved. 1. If you want to title the displayed measurement, refer to "Titling the Displayed Measurement" on page 4-32. 2. Press Save/Recall SELECT DISK . 3.
Printing, Plotting, and Saving Measurement Results Saving Measurement Results is stored to disk in IEEE-64 bit real format (for LIF disks), and 32 bit PC format for DOS disks. This makes the DOS data files half the size of the LIF files. Selecting DATA ARRAY ON may store data to disk in the S2P ASCII data format. See "ASCII Data Formats" on page 4-41. NOTE ❏ GRAPHICS ON If you select GRAPHICS ON , the user graphics area is saved.
Printing, Plotting, and Saving Measurement Results Saving Measurement Results If DATA ARRAY ON , or DATA ONLY ON , or FORMAT ARY ON is selected, a CITIfile is saved for each displayed channel with the suffix letter “D”, or “F”, followed by a number. The number following “D” and “F” files is the channel number. When RAW ARRAY ON is selected, an “r1” file is saved for channel 1/channel 3, and an “r5” file is saved for channel 2/channel 4.
Printing, Plotting, and Saving Measurement Results Saving Measurement Results The "format" choice is selected by the current selection under the FORMAT menu. To select the DB format, the FORMAT must be LOG MAG. For MA, the FORMAT must be LIN MAG (unlike CITIfile), and all other FORMAT selections will output RI data. The S2P data will always represent the format array data, including effects of electrical delay and port extensions. A CITIfile will be saved at the same time.
Printing, Plotting, and Saving Measurement Results Saving Measurement Results Saving in Textual (CSV) Form Textual measurement results can be saved in a comma-separated value (CSV) format and imported into a spreadsheet application. Additional information is also saved as a preamble to the measurement results.
Printing, Plotting, and Saving Measurement Results Saving Measurement Results How the Analyzer Names These Files Sequentially When text files are saved, the analyzer generates the file names automatically in the following format: txtcss.csv where: txt is a constant that indicates that this is a text file, c is the indicator of the channel (1−4) on which the measurement data was taken. ss is a 2-digit, sequential indicator of the measurement (file index number).
Printing, Plotting, and Saving Measurement Results Saving Measurement Results Instrument State Files When an instrument state is saved to a floppy disk, some or all of the following files may be produced. This depends upon which arrays are selected under the DEFINE SAVE STATE softkey menu, and whether the selected save format is BINARY or ASCII. The “XX” part of the file name (FileXX) refers to the number of the instrument state.
Printing, Plotting, and Saving Measurement Results Saving Measurement Results (CITIfile format), without any direct frequency information. S11 appears first, S21 second, S12 third, and S22 last. If Channel 2 is active, the same type of file is produced but the file extension is .d2. If dual display is on, both d1 and .d2 files are produced. DataXX.d1, created only when DATA ONLY on OFF is turned ON, is either a binary file or an ASCII file in CITIfile format.
Printing, Plotting, and Saving Measurement Results Saving Measurement Results Files with .g0 File Extension FileXX.g0, produced only when GRAPHICS on OFF is turned ON, is a binary file containing the active measurement trace and display graticule. The contents of this file are not meant to be read in an external computer, so this file is only of use in the instrument. Binary Files The size of the data files is very small, about one tenth the size compared to the ASCII format.
Printing, Plotting, and Saving Measurement Results Saving Measurement Results Raw Arrays On the analyzer, press the Save/Recall DEFINE DISK-SAVE RAW ARRAY ON Data created the first time in this manner will be saved as filename “FILE00.r1”. The file extension .r1 indicates the data was created while channel 1 was active and stored in the analyzer's raw data array. If you save the data again, but while channel 2 is active, you will get a new file called “FILE01.r2”.
Printing, Plotting, and Saving Measurement Results Re-Saving an Instrument State Re-Saving an Instrument State If you re-save a file, the analyzer overwrites the existing file contents. NOTE You cannot re-save a file that contains data only. You must create a new file. 1. Press Save/Recall SELECT DISK and select the storage device. ❏ INTERNAL MEMORY ❏ INTERNAL DISK ❏ EXTERNAL DISK (If necessary, refer to the external disk setup procedure in "Saving an Instrument State" on page 4-38.) 2.
Printing, Plotting, and Saving Measurement Results Deleting a File Deleting a File 1. Press Save/Recall SELECT DISK . 2. Choose from the following storage devices: ❏ INTERNAL MEMORY ❏ INTERNAL DISK ❏ EXTERNAL DISK (If necessary, refer to the external disk setup procedure in "Saving an Instrument State" on page 4-38.) 3. Press RETURN . To Delete an Instrument State File ❏ Press the or keys or the front panel knob to highlight the name of the file that you want to delete.
Printing, Plotting, and Saving Measurement Results Renaming a File Renaming a File 1. Press Save/Recall AUTO-FEED OFF . 2. Choose from the following storage devices: ❏ INTERNAL MEMORY ❏ INTERNAL DISK ❏ EXTERNAL DISK (If necessary, refer to the external disk setup procedure in "Saving an Instrument State" on page 4-38.) 3. Press RETURN and then use the or keys or the front panel knob to highlight the name of the file that you want to rename. 4. Press RETURN FILE UTILITIES RENAME FILE ERASE TITLE . FLE 5.
Printing, Plotting, and Saving Measurement Results Recalling a File Recalling a File 1. Press Save/Recall SELECT DISK . 2. Choose from the following storage devices: ❏ INTERNAL MEMORY ❏ INTERNAL DISK ❏ EXTERNAL DISK (If necessary, refer to the external disk setup procedure in "Saving an Instrument State" on page 4-38.) 3. Press the or keys or the front panel knob to highlight the name of the file that you want to recall. 4. Press RETURN RECALL STATE . Formatting a Disk 1.
Printing, Plotting, and Saving Measurement Results Solving Problems with Saving or Recalling Files Solving Problems with Saving or Recalling Files If you encounter a problem when you are storing files to disk, or the analyzer internal memory, check the following list for possible causes: • Look in the analyzer display message area. The analyzer may show a message that will identify the problem. Refer to the "Error Messages" chapter of the reference guide if you view a message.
5 Optimizing Measurement Results 5-1
Optimizing Measurement Results Using This Chapter Using This Chapter This chapter describes techniques and analyzer functions that help you achieve the best measurement results.
Optimizing Measurement Results Taking Care of Microwave Connectors Taking Care of Microwave Connectors Proper connector care and connection techniques are critical for accurate, repeatable measurements. Refer to the calibration kit documentation for connector care information. Prior to making connections to the network analyzer, carefully review the information about inspecting, cleaning and gaging connectors. Having good connector care and connection techniques extends the life of these devices.
Optimizing Measurement Results Increasing Measurement Accuracy Increasing Measurement Accuracy The following all contribute to loss of accuracy in a measurement. Interconnecting Cables Cables that connect the device under test (DUT) to the analyzer are often the most significant contribution to random errors of your measurement. You should frequently perform the following steps as a precaution against errors caused by cable interconnections: • Inspect for lossy cables.
Optimizing Measurement Results Increasing Measurement Accuracy Temperature Drift Electrical characteristics will change with temperature due to the thermal expansion characteristics of devices within the analyzer, calibration devices, test devices, cables, and adapters. Therefore, the operating temperature is a critical factor in their performance. During a measurement calibration, the temperature of the calibration devices must be stable and within 25 ±5 °C. • Use a temperature-controlled environment.
Optimizing Measurement Results Increasing Measurement Accuracy Table 5-2 Differences between PORT EXTENSIONS and ELECTRICAL DELAY PORT EXTENSIONS ELECTRICAL DELAY Main Effect The end of a cable becomes the test port plane for all S-parameter measurements. Compensates for the electrical length of a cable. Set the cable's electrical length × 1 for transmission. Set the cable's electrical length × 2 for reflection. Measurements Affected All S-parameters. Only the currently selected S-parameter.
Optimizing Measurement Results Maintaining Test Port Output Power During Sweep Retrace Maintaining Test Port Output Power During Sweep Retrace During standard operation, the analyzer provides output power during its forward frequency sweep, but may not provide output power during its sweep retrace. If the device under test (such as an amplifier with AGC circuitry) requires constant power, then you can set the analyzer to maintain test port output power during its sweep retrace.
Optimizing Measurement Results Making Accurate Measurements of Electrically Long Devices Making Accurate Measurements of Electrically Long Devices A device with a long electrical delay, such as a long length of cable, a SAW filter, or normal devices measured over wide sweeps with very fast rates presents some unusual measurement problems to a network analyzer operating in swept frequency mode. Often the measured response is dependent on the analyzer's sweep time, and incorrect data may be obtained.
Optimizing Measurement Results Making Accurate Measurements of Electrically Long Devices Decreasing the Sweep Rate The sweep rate can be decreased by increasing the analyzer's sweep time. To increase the analyzer's sweep time, press Sweep Setup SWEEP TIME [MANUAL] and use the front panel knob, the and keys, or the front panel keypad enter in the appropriate sweep time. Alternatively, the number of points may be increased for the same frequency range, thereby reducing the sweep rate (in GHz/second).
Optimizing Measurement Results Increasing Sweep Speed Increasing Sweep Speed You can increase the analyzer sweep speed by avoiding the use of some features that require computational time for implementation and updating, such as bandwidth marker tracking. You can also increase the sweep speed by making adjustments to the measurement settings.
Optimizing Measurement Results Increasing Sweep Speed Sweep Speed-Related Errors IF delay occurs during swept measurements when the signal from the analyzer source is delayed in reaching the analyzer receiver because of an electrically long device. The receiver has a narrow IF band pass filter that tracks the receiver frequency because the receiver is sweeping. The delayed signal will be attenuated because the center of the internal IF filter has moved.
Optimizing Measurement Results Increasing Sweep Speed To Set the Auto Sweep Time Mode Auto sweep time mode is the default mode (the preset mode). This mode maintains the fastest sweep speed possible for the current measurement settings. • Press Sweep Setup SWEEP TIME 0 , to re-enter the auto mode. To Widen the System Bandwidth 1. Press Avg IF BW . 2. Increase the IF bandwidth to increase the sweep speed.
Optimizing Measurement Results Increasing Sweep Speed To View a Single Measurement Channel Viewing a single channel will increase the measurement speed if the analyzer's channels are in alternate, or uncoupled mode. 1. Press Display DUAL | QUAD SETUP AUX CHAN on OFF . DUAL CHAN on OFF 2. Press Chan 1 and Chan 2 to alternately view the two measurement channels. If you must view both measurement channels simultaneously (with dual channel), use the chop sweep mode, explained next. 3.
Optimizing Measurement Results Increasing Sweep Speed • Continuous: In this mode the analyzer will switch between the test ports on every sweep. Although this type of test set switching provides the greatest measurement accuracy, it requires a reverse sweep for every forward sweep. Analyzers configured with Option 007 or Option 085 use a mechanical switch and are not allowed to switch between test ports on every sweep in Continuous mode. A tsh indicator appears on the display instead.
Optimizing Measurement Results Increasing Dynamic Range Increasing Dynamic Range Dynamic range is the difference between the analyzer's maximum allowable input level and minimum measurable power. For a measurement to be valid, input signals must be within these boundaries.
Optimizing Measurement Results Reducing Noise Reducing Noise You can use two analyzer functions to help reduce the effect of noise on the data trace: • activate measurement averaging • reduce system bandwidth • use direct sampler access configurations (Option 012 Only) To Activate Averaging The noise is reduced with each new sweep as the effective averaging factor increments. 1. Press Avg AVERAGING FACTOR . 2. Enter a value followed by x1 . 3. Press AVERAGING ON .
Optimizing Measurement Results Reducing Noise To Use Direct Sampler Access Configurations (Option 012 Only) Direct sampler access to both the A and B samplers can decrease the noise floor of the analyzer. In the standard configuration (Option 012 with all jumpers in place), the signal entering one of the test ports passes through a coupler with 14 dB coupling before it reaches the sampler. Thus, the input signal is reduced by approximately 14 dB before it reaches the sampler.
Optimizing Measurement Results Reducing Receiver Crosstalk Reducing Receiver Crosstalk To reduce receiver crosstalk you can do the following: • Perform a response and isolation measurement calibration. • Set the sweep to the alternate mode. Alternate sweep is intended for measuring wide dynamic range devices, such as high pass and bandpass filters. This sweep mode removes a type of leakage term through the device under test, from one channel to another.
6 Calibrating for Increased Measurement Accuracy 6-1
Calibrating for Increased Measurement Accuracy How to Use This Chapter How to Use This Chapter This chapter is divided into the following subjects: • Calibration Considerations on page 6-4 • Procedures for Error Correcting Your Measurements on page 6-10 — frequency response error correction — frequency response and isolation error correction — enhanced frequency response error correction — one-port reflection error correction — full two-port error correction (ES Analyzers Only) • Power Meter Measurement Ca
Calibrating for Increased Measurement Accuracy Introduction Introduction The accuracy of network analysis is greatly influenced by factors external to the network analyzer. Components of the measurement setup, such as interconnecting cables and adapters, introduce variations in magnitude and phase that can mask the actual response of the device under test. Error correction is an accuracy enhancement procedure that removes systematic errors (repeatable measurement variations) in the test setup.
Calibrating for Increased Measurement Accuracy Calibration Considerations Calibration Considerations Measurement Parameters Calibration procedures are parameter-specific, rather than channel-specific. When a parameter is selected, the instrument checks the available calibration data, and uses the data found for that parameter.
Calibrating for Increased Measurement Accuracy Calibration Considerations • Greater than 100 dB: Same as 90 to 100 dB, but alternate mode should be used. See "To View a Single Measurement Channel" on page 5-13. Saving Calibration Data You should save the calibration data, either in the internal non-volatile memory or on a disk. If you do not save it, it will be lost if you select another calibration procedure for the same channel, or if you change stimulus values.
Calibrating for Increased Measurement Accuracy Calibration Considerations • The standard is an open termination, which by definition exhibits a certain amount of fringe capacitance (and therefore phase shift). Open terminations which are offset from the mating plane will exhibit a phase shift due to the offset in addition to the phase shift caused by the fringe capacitance. The most important point to remember is that these properties will not affect your measurements.
Calibrating for Increased Measurement Accuracy Calibration Considerations Table 6-1 Calibration Standard Types and Expected Phase Shift Test Port Connector Type 3.5-mm male 3.5-mm female Standard Type Offset Open Expected Phase Shift ( 360° × f × l ) 0° + Φ° capitance + ---------------------------------c 2.4-mm male 2.
Calibrating for Increased Measurement Accuracy Calibration Considerations Figure 6-1 Typical Responses of Calibration Standards after Calibration CH1 S11 1 U FS 1: 998.84 mU -179.92° 3 000 . 000 000 MHz CH1 S11 1 U FS 1: 999.62 mU 142.07° 3 000 . 000 000 MHz 1 Cor Cor 1 START .300 000 MHZ STOP 3 000 . 000 000 MHZ 7mm or Type-N Male Short (No Offset) CH1 S11 1 U FS .300 START 000 MHZ STOP 3 000 . 000 000 MHZ Type-N Female, 3.5mm Male or Female Offset Short 1: 998.25 mU -11.
Calibrating for Increased Measurement Accuracy Calibration Considerations in use, the notation C∆ will appear on the analyzer display. NOTE The preset state of the instrument can be configured so that interpolated error correction is on or off. Press System CONFIGURE MENU USER SETTINGS PRESET SETTINGS CAL INTERP ON off to configure the preset state of interpolated error correction. System performance is unspecified when using interpolated error correction.
Calibrating for Increased Measurement Accuracy Procedures for Error Correcting Your Measurements Procedures for Error Correcting Your Measurements This section has example procedures or information on the following topics: • frequency response correction • frequency response and isolation correction • enhanced frequency response correction • one-port reflection correction • full two-port correction (ES Analyzers Only) • TRL*/LRM* correction (ES Analyzers Only) • power meter measurement calibration procedur
Calibrating for Increased Measurement Accuracy Procedures for Error Correcting Your Measurements Table 6-2 Purpose and Use of Different Error Correction Procedures Correction Procedure Corresponding Measurement Errors Corrected Standard Devices S11 1-port Reflection of any one-port device or well terminated two-port device. Directivity, source match, frequency response. Short, open and load. S22 1-port (ES Analyzers Only) Reflection of any one-port device or well terminated two-port device.
Calibrating for Increased Measurement Accuracy Frequency Response Error Corrections Frequency Response Error Corrections You can remove the frequency response of the test setup for the following measurements: • reflection measurements • transmission measurements • combined reflection and transmission measurements Response Error Correction for Reflection Measurements 1. Press Preset . 2. Select the type of measurement you want to make.
Calibrating for Increased Measurement Accuracy Frequency Response Error Corrections Figure 6-2 Standard Connections for a Response Error Correction for Reflection Measurement 7. To measure the standard when the displayed trace has settled, press SHORT or OPEN . If the calibration kit you selected has a choice between male and female calibration standards, remember to select the sex that applies to the test port and not the standard.
Calibrating for Increased Measurement Accuracy Frequency Response Error Corrections Response Error Correction for Transmission Measurements 1. Press Preset . 2. Select the type of measurement you want to make. ❏ If you want to make a transmission measurement in the forward direction (S21), press: Meas Trans: FWD S21 (B/R) or on ET models: TRANSMISSN ❏ For ES analyzers, if you want to make a transmission measurement in the reverse direction (S12), press: Meas Trans: REV S12 (A/R) 3.
Calibrating for Increased Measurement Accuracy Frequency Response Error Corrections NOTE Do not use an open or short standard for a transmission response correction. NOTE You can save or store the measurement correction to use for later measurements. Refer to the Chapter 4 , “Printing, Plotting, and Saving Measurement Results” for procedures. 7. This completes the response correction for transmission measurements. You can connect and measure your device under test.
Calibrating for Increased Measurement Accuracy Frequency Response Error Corrections Figure 6-4 Standard Connections for a Receiver Calibration 3. To choose a non-ratioed measurement, press: Meas INPUT PORTS B For ES analyzers, press TEST PORTS 1 . This sets the source at PORT 1. 4. Set any other measurement parameters that you want for the device measurement: power, number of points, IF bandwidth. 5.
Calibrating for Increased Measurement Accuracy Frequency Response and Isolation Error Corrections Frequency Response and Isolation Error Corrections You can make a response and isolation correction for the following measurements: • reflection measurements • transmission measurements • combined reflection and transmission measurements Although you can perform a response and isolation correction for reflection measurements, we recommend that you perform an S11 one-port error correction; it is more accurate a
Calibrating for Increased Measurement Accuracy Frequency Response and Isolation Error Corrections 7. Make a "thru" connection between the points where you will connect your device under test. NOTE Include any adapters that you will have in the device measurement. That is, connect the standard device to the particular connector where you will connect your device under test. 8.
Calibrating for Increased Measurement Accuracy Frequency Response and Isolation Error Corrections 11.To measure the calibration standard, press: RESUME CAL SEQUENCE Cal ISOL'N STD 12.Return the averaging to the original state of the measurement. For example, reduce the averaging factor by at least four times or turn averaging off. 13.To compute the isolation error coefficients, press: RESUME CAL SEQUENCE Cal DONE RESP ISOL'N CAL The analyzer displays the corrected data trace.
Calibrating for Increased Measurement Accuracy Frequency Response and Isolation Error Corrections 5. If your calibration kit is different than the kit specified under the CAL KIT [ ] softkey, press: CAL KIT SELECT CAL KIT (select your type of kit) RETURN If your type of calibration kit is not listed in the displayed menu, refer to "Modifying Calibration Kits" on page 7-56. 6.
Calibrating for Increased Measurement Accuracy Frequency Response and Isolation Error Corrections The analyzer displays WAIT - MEASURING CAL STANDARD during the standard measurement. The analyzer underlines the softkey that you selected after it finishes the measurement, and computes the error coefficients. 9. Connect the load calibration standard to the test port. 10.To measure the standard for the isolation portion of the correction, press ISOL'N STD . a.
Calibrating for Increased Measurement Accuracy Enhanced Frequency Response Error Correction Enhanced Frequency Response Error Correction The enhanced frequency response error correction removes the following errors in the forward direction in ET models or in both the forward and reverse directions in ES models: • • • • removes directivity errors of the test setup removes source match errors of the test setup removes isolation errors of the test setup (optional) removes frequency response of the test setup
Calibrating for Increased Measurement Accuracy Enhanced Frequency Response Error Correction Figure 6-7 Standard Connections for Enhanced Response Calibration 8. To measure the standard, when the displayed trace has settled, press: OPEN The analyzer displays WAIT - MEASURING CAL STANDARD during the standard measurement. The analyzer underlines the OPEN softkey after it measures the standard. 9. Disconnect the open, and connect a short circuit to the test port. 10.
Calibrating for Increased Measurement Accuracy Enhanced Frequency Response Error Correction NOTE Include any adapters or cables that you will have in the device measurement. That is, connect the standard device where you will connect your device under test. NOTE The thru in most calibration kits is defined with zero length. The correction will not work properly if a non-zero length thru is used, unless the calibration kit is modified to change the defined thru to the length used.
Calibrating for Increased Measurement Accuracy Enhanced Frequency Response Error Correction 18.To compute the error coefficients, press: DONE ENH RESP CAL The analyzer displays the corrected measurement trace. The analyzer also shows the notation Cor at the left of the screen, indicating that error correction is on. NOTE You can save or store the measurement correction to use for later measurements. Refer to Chapter 4 , “Printing, Plotting, and Saving Measurement Results” for procedures. 19.
Calibrating for Increased Measurement Accuracy One-Port Reflection Error Correction One-Port Reflection Error Correction • removes directivity errors of the test setup • removes source match errors of the test setup • removes frequency response of the test setup You can perform a 1-port correction for an S11 or an S22 measurement for ES analyzers. The only difference between the two procedures is the measurement parameter that you select.
Calibrating for Increased Measurement Accuracy One-Port Reflection Error Correction NOTE Include any adapters that you will have in the device measurement. That is, connect the calibration standard to the particular connector where you will connect your device under test. Figure 6-8 Standard Connections for a One Port Reflection Error Correction 8.
Calibrating for Increased Measurement Accuracy One-Port Reflection Error Correction 13.To compute the error coefficients, press: DONE: 1-PORT CAL The analyzer displays the corrected data trace. The analyzer also shows the notation Cor to the left of the screen, indicating that the correction is switched on for this channel. NOTE The open, short, and load could be measured in any order, and need not follow the order in this example.
Calibrating for Increased Measurement Accuracy Full Two-Port Error Correction (ES Analyzers Only) Full Two-Port Error Correction (ES Analyzers Only) • removes directivity errors of the test setup in forward and reverse directions • removes source match errors of the test setup in forward and reverse directions • removes load match errors of the test setup in forward and reverse directions • removes isolation errors of the test setup in forward and reverse directions (optional) • removes frequency response
Calibrating for Increased Measurement Accuracy Full Two-Port Error Correction (ES Analyzers Only) Figure 6-9 Standard Connections for Full Two-Port Error Correction 6. To measure the standard, when the displayed trace has settled, press: FORWARD: OPEN The analyzer displays WAIT - MEASURING CAL STANDARD during the standard measurement. The analyzer underlines the OPEN softkey after it measures the standard. 7. Disconnect the open, and connect a short circuit to PORT 1. 8.
Calibrating for Increased Measurement Accuracy Full Two-Port Error Correction (ES Analyzers Only) 14.Make a "thru" connection between the points where you will connect your device under test as shown in Figure 6-9. NOTE Include any adapters or cables that you will have in the device measurement. That is, connect the standard device where you will connect your DUT. NOTE The thru in most calibration kits is defined with zero length.
Calibrating for Increased Measurement Accuracy Full Two-Port Error Correction (ES Analyzers Only) 17.To compute the error coefficients, press: DONE 2-PORT CAL The analyzer displays the corrected measurement trace. The analyzer also shows the notation Cor at the left of the screen, indicating that error correction is on. NOTE You can save or store the measurement correction to use for later measurements. Refer to Chapter 4 , “Printing, Plotting, and Saving Measurement Results” for procedures. 18.
Calibrating for Increased Measurement Accuracy Power Meter Measurement Calibration Power Meter Measurement Calibration A GPIB-compatible power meter can monitor and correct RF source power to achieve leveled power at the test port. During a power meter calibration, the power meter samples the power at each measurement point across the frequency band of interest. The analyzer then constructs a correction data table to correct the power output of the internal source.
Calibrating for Increased Measurement Accuracy Power Meter Measurement Calibration Interpolation in Power Meter Calibration If the frequency is changed in linear sweep, or the start/stop power is changed in power sweep, then the calibration data is interpolated for the new range. If calibration power is changed in any of the sweep types, the values in the power setting array are increased or decreased to reflect the new power level. Some accuracy is lost when this occurs.
Calibrating for Increased Measurement Accuracy Power Meter Measurement Calibration 3. Press EDIT and then press either the FREQUENCY or CAL FACTOR key, depending on which part of the segment you want to edit. ❏ If you are modifying the frequency, enter the new value, followed by a G/n , M/µ , or k/m key. ❏ If you are modifying the correction factor, enter the new value, followed by the x1 key. 4. Press DONE after you have finished modifying the segment. 5.
Calibrating for Increased Measurement Accuracy Power Meter Measurement Calibration NOTE Remember to subtract the through arm loss from the coupler arm loss before entering it into the power loss table, to ensure the correct power at the output of the coupler. 4. Repeat the previous two steps to enter up to 55 frequency segments, depending on the required accuracy.
Calibrating for Increased Measurement Accuracy Power Meter Measurement Calibration 3. Select the analyzer as the system controller: Local SYSTEM CONTROLLER 4. Set the power meter's address (“XX” represents the address in the following keystrokes: SET ADDRESSES ADDRESS: P MTR/HPIB XX x1 5. Select the appropriate power meter by pressing POWER MTR [ ] until the correct model number is displayed (436A or 438A/437). NOTE The E4418B and E4419B power meters have a “437 emulation” mode.
Calibrating for Increased Measurement Accuracy Power Meter Measurement Calibration Using Continuous Correction Mode You can set the analyzer to update the correction table at each sweep (as in a leveling application), using the continuous sample mode. When the analyzer is in this mode, it continuously checks power at every point in each sweep. You must keep the power meter connected as shown in Figure 6-11. This mode is also known as power meter leveling, and the speed is limited by the power meter.
Calibrating for Increased Measurement Accuracy Power Meter Measurement Calibration To Calibrate the Analyzer Receiver to Measure Absolute Power You can use the power meter calibration as a reference to calibrate the analyzer receiver to accurately measure absolute power. The following procedure shows you how to calibrate the receiver to any power level. 1. Set the analyzer test port power to the desired level: Power (enter power level) x1 2. Connect the power sensor to the analyzer test port 1. 3.
Calibrating for Increased Measurement Accuracy Calibrating for Noninsertable Devices Calibrating for Noninsertable Devices A test device having the same sex connector on both the input and output cannot be connected directly into a transmission test configuration.
Calibrating for Increased Measurement Accuracy Calibrating for Noninsertable Devices Figure 6-13 Adapters Needed The following requirements must also be met: • Calibration standards for performing a 2-port error correction for each connector type must be available. • Specified electrical length of adapter A3 within ± 1/4 wavelength for the measurement frequency range. For each port, a separate 2-port error correction needs to be performed to create two calibration sets.
Calibrating for Increased Measurement Accuracy Calibrating for Noninsertable Devices Perform the 2-port Error Corrections 1. Connect adapter A3 to adapter A2 on port 2 as shown in Figure 6-14. Figure 6-14 Two-Port Cal Set 1 2. Perform the 2-port error correction using calibration standards appropriate for the connector type at port 1 (the connector type for adapter A1). NOTE When using adapter removal calibration, you must save calibration sets to the internal disk, not to internal memory. 3.
Calibrating for Increased Measurement Accuracy Calibrating for Noninsertable Devices 6. Save the results to disk. Name the file "PORT2." 7. Determine the electrical delay of adapter A3 by performing steps 1 through 7 of "Modify the Cal Kit Thru Definition" on page 6-46. Remove the Adapter When the two sets of error correction files have been created (now referred to as "cal sets"), the adapter may be removed. 8. Press Cal • MORE ADAPTER REMOVAL .
Calibrating for Increased Measurement Accuracy Calibrating for Noninsertable Devices 16.To save the results of the new cal set, press Save/Recall INTERNAL MEMORY RETURN SAVE STATE . NOTE SELECT DISK Adapter removal can leave a residual state in internal memory. This is not a valid instrument state and should be deleted.
Calibrating for Increased Measurement Accuracy Calibrating for Noninsertable Devices Matched Adapters With this method, you use two precision matched adapters which are "equal." To be equal, the adapters must have the same match, Z0, insertion loss, and electrical delay. The adapters in most Agilent calibration kits have matched electrical length, even if the physical lengths appear different.
Calibrating for Increased Measurement Accuracy Calibrating for Noninsertable Devices Modify the Cal Kit Thru Definition With this method, it is only necessary to use a thru adapter. The calibration kit thru definition is modified to compensate for the adapter and then saved as a user kit. However, the electrical delay of the adapter must first be found. The adapter match will degrade the effective load match terms on both ports as well as degrade the transmission frequency response (tracking). 1.
Calibrating for Increased Measurement Accuracy Calibrating for Noninsertable Devices 10.Perform the desired calibration with this new user kit. 11.Connect the test device as shown in Step B of Figure 6-18 and measure the device.
Calibrating for Increased Measurement Accuracy Minimizing Error When Using Adapters Minimizing Error When Using Adapters To minimize the error introduced when you add an adapter to a measurement system, the adapter needs to have low SWR or mismatch, low loss, and high repeatability. Figure 6-19 Adapter Considerations In a reflection measurement, the directivity of a system is a measure of the error introduced by an imperfect signal separation device.
Calibrating for Increased Measurement Accuracy Making Non-Coaxial Measurements Making Non-Coaxial Measurements Non-coaxial, on-wafer measurements present a unique set of challenges for error correction in the analyzer: • The close spacing between the microwave probes makes it difficult to maintain a high degree of isolation between the input and the output. • The type of device measured on-wafer is often not always a simple two-port.
Calibrating for Increased Measurement Accuracy Making Non-Coaxial Measurements If You Want to Design Your Own Fixture Ideally, a fixture should provide a transparent connection between the test instrument and the test device. This means it should have no loss or electrical length and a flat frequency response, to prevent distortion of the actual signal. A perfect match to both the instrument and the test device eliminates reflected test signals.
Calibrating for Increased Measurement Accuracy Calibrating for Non-Coaxial Devices (ES Analyzers Only) Calibrating for Non-Coaxial Devices (ES Analyzers Only) The analyzer has the capability of making calibrations using the TRL*/LRM* method. TRL* and LRM* are implementations of the thru-reflect-line and line-reflect-match calibrations, modified for the three-sampler receiver architecture in the analyzer.
Calibrating for Increased Measurement Accuracy Calibrating for Non-Coaxial Devices (ES Analyzers Only) 6. For the purposes of this example, change the name of the standard by pressing LABEL STD and modifying the name to "LINE." 7. When the title area shows the new label, press: DONE STD DONE (DEFINED) Assign the Standards to the Various TRL Classes 8. To assign the calibration standards to the various TRL calibration classes, press: Cal CAL KIT MODIFY SPECIFY CLASS MORE MORE TRL REFLECT 9.
Calibrating for Increased Measurement Accuracy Calibrating for Non-Coaxial Devices (ES Analyzers Only) Perform the TRL Calibration 1. Press Cal CAL KIT SELECT CAL KIT USER KIT CALIBRATE MENU TRL*/LRM* 2-PORT . RETURN RETURN 2. To measure the "TRL THRU," connect the "zero length" transmission line between the two test ports. 3. To make the necessary four measurements, press: THRU THRU 4. To measure the "TRL SHORT," connect the short to PORT 1, and press: S11 REFL: TRLSHORT 5.
Calibrating for Increased Measurement Accuracy LRM Error Correction 11.Connect the load to PORT 1, and press: FWD ISOL’N ISOL’N STD ISOLATION DONE 12.You may repeat any of the previous steps. There is no requirement to go in the order of steps. When the analyzer detects that you have made all the necessary measurements, the message line will show PRESS 'DONE' IF FINISHED WITH CAL. Press DONE TRL/LRM .
Calibrating for Increased Measurement Accuracy LRM Error Correction 3. Press the following keys: SHORT MODIFY STD DEFINITION SPECIFY OFFSET OFFSET DELAY x1 STD OFFSET DONE STD DONE (DEFINED) 0 4. To define the THRU/LINE standard, press: 4 DEFINE STANDARD x1 DELAY/THRU MODIFY STD DEFINITION 0 x1 STD OFFSET DONE SPECIFY OFFSET OFFSET DELAY STD DONE (DEFINED) 5. To define the LINE/MATCH standard, press: 3 DEFINE STANDARD x1 LOAD 6.
Calibrating for Increased Measurement Accuracy LRM Error Correction Label the Calibration Kit 18.Press LABEL KIT and create a label up to 8 characters long. For this example, enter "LRM KIT1" and press DONE . 19.To save the newly defined kit into nonvolatile memory, press: KIT DONE (MODIFIED) NOTE SAVE USER KIT Refer to "Saving Modified Calibration Kits to a Disk" on page 7-65 for information about saving modified calibration kits, along with calibration data and instrument states, to a disk.
Calibrating for Increased Measurement Accuracy LRM Error Correction 10.Connect the load to PORT 2 and press LN/MATCH2 LOAD . 11.Repeat the previous LRM load measurement steps for PORT 2. 12.After the measurement is complete, press: DONE LINE/MATCH 13.To measure the "ISOLATION" class, press: ISOLATION ❏ You could choose not to perform the isolation measurement by pressing OMIT ISOLATION DONE TRL/LRM . NOTE You should perform the isolation measurement when the highest dynamic range is desired.
7 Operating Concepts 7-1
Operating Concepts Using This Chapter Using This Chapter This chapter provides conceptual information on how specific functions of the network analyzer operate.
Operating Concepts System Operation System Operation Network analyzers measure the reflection and transmission characteristics of devices and networks. A network analyzer test system consists of the following: • source • signal-separation devices • receiver • display The analyzer applies a signal that is transmitted through the test device, or reflected from its input, and then compares it with the incident signal generated by the swept RF source.
Operating Concepts System Operation to a highly stable crystal oscillator. For this purpose, a portion of the transmitted signal is routed to the R channel input of the receiver, where it is sampled by the phase detection loop and fed back to the source. The Source Step Attenuator The step attenuator contained in the source is used to adjust the power level to the test device without changing the level of the incident power in the reference path.
Operating Concepts Processing Processing The analyzer's receiver converts the R, A, and B input signals into useful measurement information. This conversion occurs in two main steps: • The swept high frequency input signals are translated to fixed low frequency IF signals, using analog sampling or mixing techniques. (Refer to the service guide for more details on the theory of operation.) • The IF signals are converted into digital data by an analog to digital converter (ADC).
Operating Concepts Processing While only a single flow path is shown, two identical paths are available, corresponding to channel 1 and channel 2. Each channel also has an auxiliary channel for which the data is processed along with the primary channel’s data. Channel 3 is the auxiliary channel for channel 1, while channel 4 is the auxiliary channel for channel 2. When the channels are uncoupled, each channel is processed and controlled independently.
Operating Concepts Processing Pre-Raw Data Arrays These data arrays store the results of all the preceding data processing operations. (Up to this point, all processing is performed real-time with the sweep by the IF processor. The remaining operations are not necessarily synchronized with the sweep, and are performed by the main processor.) When full 2-port error correction is on, the raw arrays contain all four S-parameter measurements required for accuracy enhancement.
Operating Concepts Processing Transform (Option 010 Only) This transform converts frequency domain information into the time domain when it is activated. The results resemble time domain reflectometry (TDR) or impulse-response measurements. The transform uses the chirp-Z inverse fast Fourier transform (FFT) algorithm to accomplish the conversion. The windowing operation, if enabled, is performed on the frequency domain data just before the transform.
Operating Concepts Output Power Output Power Understanding the Power Ranges The built-in synthesized source contains a programmable step attenuator that allows you to directly and accurately set power levels in twelve different power ranges. Each range has a total span of 20 dB (15 dB, 8722ET/ES). The twelve ranges cover the instrument's full operating range. In addition, some amount of overrange and underrange is permitted beyond the stated limits.
Operating Concepts Output Power NOTE After measurement calibration, you can change the power within a range and still maintain nearly full accuracy. In some cases better accuracy can be achieved by changing the power within a range. It can be useful to set different power levels for calibration and measurement to minimize the effects of sampler compression or noise floor. If you decide to switch power ranges, the calibration accuracy is degraded and accuracy is no longer specified.
Operating Concepts Sweep Time Sweep Time The SWEEP TIME [ ] softkey selects sweep time as the active entry and shows whether the automatic or manual mode is active. The following explains the difference between automatic and manual sweep time: • Manual sweep time. As long as the selected sweep speed is within the capability of the instrument, it will remain fixed, regardless of changes to other measurement parameters.
Operating Concepts Sweep Time In addition to the these parameters, the actual cycle time of the analyzer is also dependent on the following measurement parameters: • smoothing • limit test • trace math • marker statistics • time domain (Option 010 only) Refer to the specifications and characteristics chapters of the reference guide to see the minimum cycle time values for specific measurement parameters.
Operating Concepts Source Attenuator Switch Protection Source Attenuator Switch Protection The programmable step attenuator of the source can be switched between port 1 and port 2 when the test port power is uncoupled, or between channel 1 and channel 2 when the channel power is uncoupled. To avoid premature wear of the attenuator, measurement configurations requiring continuous switching between different power ranges are not allowed.
Operating Concepts Channel Stimulus Coupling Channel Stimulus Coupling COUPLED CH on OFF toggles the channel coupling of stimulus values. With COUPLED CH ON (the preset condition), both channels have the same stimulus values. (The inactive channel takes on the stimulus values of the active channel.
Operating Concepts Sweep Types Sweep Types The following sweep types will function with the interpolated error-correction feature (described in “Interpolated Error Correction” on page 6-8): • linear frequency • power sweep • CW time The following sweep types will not function with the interpolated error correction feature: • logarithmic frequency sweep • list frequency sweep Linear Frequency Sweep (Hz) The LIN FREQ softkey activates a linear frequency sweep that is displayed on a standard graticule with t
Operating Concepts Sweep Types NOTE Earlier 8719, 8720, and 8722 models allowed a maximum of 1632 points, but this value was reduced to 1601 to add the 4 channels in the 4-parameter display feature. One list is common to both channels. Once a frequency list has been defined and a measurement calibration performed on the full frequency list, one or all of the frequency segments can be measured and displayed without loss of calibration.
Operating Concepts Sweep Types The frequency subsweeps, or segments, can be defined in any of the following terms: • start/stop/number of points • start/stop/step • center/span/number of points • center/span/step • CW frequency The subsweeps can overlap, and do not have to be entered in any particular order. The analyzer sorts the segments automatically and lists them on the display in order of increasing start frequency, even if they are entered in center/span format.
Operating Concepts Sweep Types The frequency subsweeps, or segments, can be defined in any of the following terms: • start/stop/number of points/power/IFBW • start/stop/step/power/IFBW • center/span/number of points/power/IFBW • center/span/step/power/IFBW See “Setting Segment Power” and “Setting Segment IF Bandwidth” on page 7-19 for information on how to set the segment power and IF bandwidth. The subsweeps may be entered in any particular order but they cannot overlap.
Operating Concepts Sweep Types Setting Segment IF Bandwidth To enable the SEGMENT IF BW function, you must first select LIST IF BW ON off in the edit subsweep menu. List IF bandwidth is off by default and the asterisks that appear in the "IFBW" column of the list table indicate that the IF bandwidth for the sweep is being set by the normal analyzer controls. Narrow IF bandwidths require more data samples per point and thus slow down the measurement time.
Operating Concepts S-Parameters S-Parameters The Meas key accesses the S-parameter menu which contains softkeys that can be used to select the parameters or inputs that define the type of measurement being performed. Understanding S-Parameters S-parameters (scattering parameters) are a convention used to characterize the way a device modifies signal flow. A brief explanation of the S-parameters of a two-port device is provided, however, for additional details, refer to Application Notes 95-1 and 154.
Operating Concepts S-Parameters Figure 7-3 S-Parameters of a Two-Port Device S-parameters are exactly equivalent to these more common description terms, requiring only that the measurements be taken with all test device ports properly terminated.
Operating Concepts S-Parameters The S-Parameter Menu The S-parameter menu allows you to define the input ports and test set direction for S-parameter measurements. The analyzer automatically switches the direction of the measurement according to the selections you made in this menu. Therefore, the analyzer can measure all four S-parameters with a single connection. The S-parameter being measured is labeled at the top left corner of the display.
Operating Concepts S-Parameters Figure 7-4 Reflection Impedance and Admittance Conversions In a transmission measurement, the data can be converted to its equivalent series impedance or admittance using the model and equations shown in Figure 7-5. Figure 7-5 Transmission Impedance and Admittance Conversions NOTE Avoid the use of Smith chart, SWR, and delay formats for display of Z and Y conversions, as these formats are not easily interpreted.
Operating Concepts Analyzer Display Formats Analyzer Display Formats The Format key accesses the format menu. This menu allows you to select the appropriate display format for the measured data. The analyzer automatically changes the units of measurement to correspond with the displayed format. Special marker menus are available for the polar and Smith formats, each providing several different marker types for readout of values.
Operating Concepts Analyzer Display Formats Figure 7-7 Phase Format Group Delay Format The DELAY softkey selects the group delay format, with marker values given in seconds. The bandpass filter response formatted as group delay is shown in Figure 7-8. Group delay principles are described in the next few pages.
Operating Concepts Analyzer Display Formats Smith Chart Format The SMITH CHART softkey displays a Smith chart format. Refer to Figure 7-9. This is used in reflection measurements to provide a readout of the data in terms of impedance. The intersecting dotted lines on the Smith chart represent constant resistance and constant reactance values, normalized to the characteristic impedance, Z0, of the system.
Operating Concepts Analyzer Display Formats Polar Format The POLAR softkey displays a polar format as shown in Figure 7-10. Each point on the polar format corresponds to a particular value of both magnitude and phase. Quantities are read vectorally: the magnitude at any point is determined by its displacement from the center (which has zero value), and the phase by the angle counterclockwise from the positive x-axis.
Operating Concepts Analyzer Display Formats Linear Magnitude Format The LIN MAG softkey displays the linear magnitude format as shown in Figure 7-11. This is a Cartesian format used for unitless measurements such as reflection coefficient magnitude ρ or transmission coefficient magnitude τ, and for linear measurement units. It is used for display of conversion parameters and time domain transform data.
Operating Concepts Analyzer Display Formats SWR Format The SWR softkey reformats a reflection measurement into its equivalent SWR (standing wave ratio) value. See Figure 7-12. SWR is equivalent to (1 + ρ)/(1 − ρ), where ρ is the reflection coefficient. Note that the results are valid only for reflection measurements. If the SWR format is used for measurements of S21 or S12 the results are not valid.
Operating Concepts Analyzer Display Formats Imaginary Format The IMAGINARY softkey displays only the imaginary (reactive) portion of the measured data on a Cartesian format. This format is similar to the real format except that reactance data is displayed on the trace instead of resistive data. Group Delay Principles For many networks, the amount of insertion phase is not as important as the linearity of the phase shift over a range of frequencies.
Operating Concepts Analyzer Display Formats Figure 7-15 Higher Order Phase Shift The analyzer computes group delay from the phase slope. Phase data is used to find the phase change, ∆ Φ over a specified frequency aperture, ∆ f, to obtain an approximation for the rate of change of phase with frequency. Refer to Figure 7-16. This value, (τ)g, represents the group delay in seconds assuming linear phase change over ∆f. It is important that ∆ Φ be ≤ 180°, or errors will result in the group delay data.
Operating Concepts Analyzer Display Formats Figure 7-17 Variations in Frequency Aperture In determining the group delay aperture, there is a trade-off between resolution of fine detail and the effects of noise. Noise can be reduced by increasing the aperture, but this will tend to smooth out the fine detail. More detail will become visible as the aperture is decreased, but the noise will also increase, possibly to the point of obscuring the detail.
Operating Concepts Electrical Delay Electrical Delay The ELECTRICAL DELAY softkey adjusts the electrical delay to balance the phase of the test device. This softkey must be used in conjunction with COAXIAL DELAY or WAVEGUIDE DELAY (with cut-off frequency) in order to identify which type of transmission line the delay is being added to. These softkeys can be accessed by pressing the Scale Ref key.
Operating Concepts Noise Reduction Techniques Noise Reduction Techniques The Avg key is used to access three different noise reduction techniques: sweep-to-sweep averaging, display smoothing, and variable IF bandwidth. All of these can be used simultaneously. Averaging and smoothing can be set independently for each channel, and the IF bandwidth can be set independently if the stimulus is uncoupled.
Operating Concepts Noise Reduction Techniques sufficiently high number of display points to avoid misleading results. Do not use smoothing for measurements of high resonance devices or other devices with wide trace variations, as it will introduce errors into the measurement. Smoothing is used with Cartesian and polar display formats. It is also the primary way to control the group delay aperture, given a fixed frequency span. Refer to “Group Delay Principles” on page 7-30.
Operating Concepts Noise Reduction Techniques IF Bandwidth Reduction IF bandwidth reduction lowers the noise floor by digitally reducing the receiver input bandwidth. It works in all ratio and non-ratio modes. It has an advantage over averaging as it reliably filters out unwanted responses such as spurs, odd harmonics, higher frequency spectral noise, and line-related noise. Sweep-to-sweep averaging, however, is better at filtering out very low frequency noise.
Operating Concepts Measurement Calibration Measurement Calibration Measurement calibration is an accuracy enhancement procedure that effectively removes the system errors that cause uncertainty in measuring a test device. It measures known standard devices, and uses the results of these measurements to characterize the system.
Operating Concepts Measurement Calibration What Causes Measurement Errors? Network analysis measurement errors can be separated into systematic, random, and drift errors. Correctable systematic errors are the repeatable errors that the system can measure. These are errors due to mismatch and leakage in the test setup, isolation between the reference and test signal paths, and system frequency response. The system cannot measure and correct for the non-repeatable random and drift errors.
Operating Concepts Measurement Calibration directivity is the vector sum of all leakage signals appearing at the analyzer receiver input. The error contributed by directivity is independent of the characteristics of the test device and it usually produces the major ambiguity in measurements of low reflection devices.
Operating Concepts Measurement Calibration Figure 7-23 Load Match The error contributed by load match is dependent on the relationship between the actual output impedance of the test device and the effective match of the return port (port 2). It is a factor in all transmission measurements and in reflection measurements of two-port devices. The interaction between load match and source match is less significant when the test device insertion loss is greater than about 6 dB.
Operating Concepts Measurement Calibration Characterizing Microwave Systematic Errors One-Port Error Model In a measurement of the reflection coefficient (magnitude and phase) of a test device, the measured data differs from the actual, no matter how carefully the measurement is made. Directivity, source match, and reflection signal path frequency response (tracking) are the major sources of error. See Figure 7-24.
Operating Concepts Measurement Calibration However, all of the incident signal does not always reach the unknown. Refer to Figure 7-26. Some of (I) may appear at the measurement system input due to leakage through the test set or through a signal separation device. Also, some of (I) may be reflected by imperfect adapters between a signal separation device and the measurement plane. The vector sum of the leakage and the miscellaneous reflections is the effective directivity, EDF.
Operating Concepts Measurement Calibration Frequency response (tracking) error is caused by variations in magnitude and phase flatness versus frequency between the test and reference signal paths. These are due mainly to coupler roll off, imperfectly matched samplers, and differences in length and loss between the incident and test signal paths. The vector sum of these variations is the reflection signal path tracking error, ERF as shown in Figure 7-28.
Operating Concepts Measurement Calibration Figure 7-29 "Perfect Load" Termination Since the measured value for directivity is the vector sum of the actual directivity plus the actual reflection coefficient of the "perfect load," any reflection from the termination represents an error. System effective directivity becomes the actual reflection coefficient of the near "perfect load" as shown in Figure 7-30.
Operating Concepts Measurement Calibration Next, a short circuit termination whose response is known to a very high degree is used to establish another condition as shown in Figure 7-31. Figure 7-31 Short Circuit Termination The open circuit gives the third independent condition. In order to accurately model the phase variation with frequency due to fringing capacitance from the open connector, a specially designed shielded open circuit is used for this step.
Operating Concepts Measurement Calibration Device Measurement Now the unknown is measured to obtain a value for the measured response, S11M, at each frequency. Refer to Figure 7-33. Figure 7-33 Measured S11 This is the one-port error model equation solved for S11A.
Operating Concepts Measurement Calibration Figure 7-34 Major Sources of Error The transmission coefficient is measured by taking the ratio of the incident signal (I) and the transmitted signal (T). Refer to Figure 7-35. Ideally, (I) consists only of power delivered by the source, and (T) consists only of power emerging at the test device output. Figure 7-35 Transmission Coefficient As in the reflection model, source match can cause the incident signal to vary as a function of test device S11A.
Operating Concepts Measurement Calibration Figure 7-36 Load Match ELF The measured value, S21M, consists of signal components that vary as a function of the relationship between ESF and S11A as well as ELF and S22A, so the input and output reflection coefficients of the test device must be measured and stored for use in the S21A error-correction computation.
Operating Concepts Measurement Calibration In this case, omitting isolation is better than measuring the isolation standards without increasing the averaging factor.
Operating Concepts Measurement Calibration Figure 7-38 Full Two-Port Error Model A full two-port error model equations for all four S-parameters of a two-port device is shown in Figure 7-39. Note that the mathematics for this comprehensive model use all forward and reverse error terms and measured values. Thus, to perform full error-correction for any one parameter, all four S-parameters must be measured.
Operating Concepts Measurement Calibration Figure 7-39 Full Two-Port Error Model Equations 7-51
Operating Concepts Measurement Calibration How Effective Is Accuracy Enhancement? In addition to the errors removed by accuracy enhancement, other systematic errors exist due to limitations of dynamic accuracy, test set switch repeatability, and test cable stability. These, combined with random errors, also contribute to total system measurement uncertainty. Therefore, after accuracy enhancement procedures are performed, residual measurement uncertainties remain.
Operating Concepts Measurement Calibration Figure 7-41 Response versus S11 1-Port Calibration on Smith Chart The response of a device in a log magnitude format is shown in Figure 7-42. Figure 7-42a shows the response using a response calibration and Figure 7-42b the response using a full two-port calibration.
Operating Concepts Calibration Routines Calibration Routines There are twelve different error terms for a two-port measurement that can be corrected by accuracy enhancement in the analyzer. These are directivity, source match, load match, isolation, reflection tracking, and transmission tracking, each in both the forward and reverse direction.
Operating Concepts Calibration Routines Full Two-Port Calibration (ES Models Only) The full two-port calibration, activated by pressing the FULL 2-PORT softkey within the calibrate menu, provides directivity, source match, load match, isolation, and frequency response vector error-correction, in both forward and reverse directions, for transmission and reflection measurements of two-port devices.
Operating Concepts Modifying Calibration Kits Modifying Calibration Kits Modifying calibration kits is necessary only if unusual standards (such as in TRL*) are used or the very highest accuracy is required. Unless a calibration kit model is provided with the calibration devices used, a solid understanding of error-correction and the system error model are absolutely essential to making modifications.
Operating Concepts Modifying Calibration Kits Procedure The following steps are used to modify or define a user kit: 1. Select the predefined kit to be modified. (This is not necessary for defining a new calibration kit.) 2. Define the standards: • Define which "type" of standard it is. • Define the electrical characteristics (coefficients) of the standard. 3. Specify the class where the standard is to be assigned. 4. Store the modified calibration kit.
Operating Concepts Modifying Calibration Kits • LABEL KIT leads to a menu for constructing a label for the user-modified cal kit. If a label is supplied, it will appear as one of the five softkey choices in the select cal kit menu. The approach is similar to defining a display title, except that the kit label is limited to ten characters. • TRL/LRM OPTION brings up the TRL Option menu.
Operating Concepts Modifying Calibration Kits After a standard number is entered, selection of the standard type will present one of five menus for entering the electrical characteristics (model coefficients) corresponding to that standard type, such as OPEN . These menus are tailored to the current type, so that only characteristics applicable to the standard type can be modified.
Operating Concepts Modifying Calibration Kits — OFFSET defines the load as being offset. • DELAY/THRU defines the standard type as a transmission line of specified length, for calibrating transmission measurements. • ARBITRARY IMPEDANCE defines the standard type to be a load, but with an arbitrary impedance (different from system Z0). — TERMINAL IMPEDANCE allows you to specify the (arbitrary) impedance of the standard, in ohms. — FIXED defines the load as a fixed (not sliding) load.
Operating Concepts Modifying Calibration Kits Lastly, the standard must be defined as either coaxial or waveguide. If it is waveguide, dispersion effects are calculated automatically and included in the standard model. The following is a description of the softkeys located within the specify offset menu: • OFFSET DELAY allows you to specify the one-way electrical delay from the measurement (reference) plane to the standard, in seconds (s).
Operating Concepts Modifying Calibration Kits Specify Class Menu Once a standard has been defined, it must be assigned to a standard "class." This is a group of from one to seven standards that is required to calibrate for a single error term. The standards within a single class can be assigned to the locations listed in Table 7-2 according to their standard reference numbers. A class often consists of a single standard, but may be composed of more than one standard if band-limited standards are used.
Operating Concepts Modifying Calibration Kits The number of standard classes required depends on the type of calibration being performed, and is identical to the number of error terms corrected. A response calibration requires only one class, and the standards for that class may include an open, or short, or thru. A 1-port calibration requires three classes. A full 2-port calibration requires 10 classes, not including two for isolation.
Operating Concepts Modifying Calibration Kits • RESPONSE allows you to enter the standard numbers for a response calibration. This calibration corrects for frequency response in either reflection or transmission measurements, depending on the parameter being measured when a calibration is performed. (For default kits, the standard is either the open or short for reflection measurements, or the thru for transmission measurements.
Operating Concepts Modifying Calibration Kits NOTE The published specifications for this network analyzer system include accuracy enhancement with compatible calibration kits. Measurement calibrations made with user-defined or modified calibration kits are not subject to the analyzer specifications, although a procedure similar to the system verification procedure may be used.
Operating Concepts TRL*/LRM* Calibration (ES Models Only) TRL*/LRM* Calibration (ES Models Only) The network analyzer has the capability of making calibrations using the "TRL" (thru-reflect-line) method.
Operating Concepts TRL*/LRM* Calibration (ES Models Only) TRL Terminology Notice that the letters TRL, LRL, LRM, etc. are often interchanged, depending on the standards used. For example, "LRL" indicates that two lines and a reflect standard are used; "TRM" indicates that a thru, reflection and match standards are used. All of these refer to the same basic method. TRL* calibration is a modified form of TRL calibration. It is adapted for a receiver with three samplers instead of four samplers.
Operating Concepts TRL*/LRM* Calibration (ES Models Only) while the reverse source match (ESR) and forward load match (ELF) are both represented by ε22. In order to solve for these eight unknown TRL error terms, eight linearly independent equations are required. The first step in the TRL* 2-port calibration process is the same as the transmission step for a Full 2-port calibration.
Operating Concepts TRL*/LRM* Calibration (ES Models Only) Figure 7-44 8-term TRL (or TRL*) Error Model and Generalized Coefficients Source match and load match A TRL calibration assumes a perfectly balanced test set architecture as shown by the term which represents both the forward source match (ESF) and reverse load match (ELR), and by the ε22 term which represents both the reverse source match (ESR) and forward load match (ELF).
Operating Concepts TRL*/LRM* Calibration (ES Models Only) Improving Raw Source Match and Load Match for TRL*/LRM* Calibration A technique that can be used to improve the raw test port mismatch is to add high quality fixed attenuators. The effective match of the system is improved because the fixed attenuators usually have a return loss that is better than that of the network analyzer. Additionally, the attenuators provide some isolation of reflected signals.
Operating Concepts TRL*/LRM* Calibration (ES Models Only) Transmission magnitude uncertainty = EX + ETS21 + ESS11S21 + ELS22S21 where: ED = effective directivity ER = effective reflection tracking ES = effective source match EL = effective load match EX = effective crosstalk ET = effective transmission tracking Sxx= S-parameters of the device under test How True TRL/LRM Works (Option 400 Only) The TRL implementation with Option 400 requires a total of fourteen measurements to quantify ten unknowns as oppo
Operating Concepts TRL*/LRM* Calibration (ES Models Only) • Attenuation of the thru need not be known. • If the thru is used to set the reference plane, the insertion phase or electrical length must be well-known and specified. If a non-zero length thru is specified to have zero delay, the reference plane is established in the middle of the thru, resulting in phase errors during measurement of devices. REFLECT • Reflection coefficient Γ magnitude is optimally 1.0, but need not be known.
Operating Concepts TRL*/LRM* Calibration (ES Models Only) Fabricating and defining calibration standards for TRL/LRM When calibrating a network analyzer, the actual calibration standards must have known physical characteristics. For the reflect standard, these characteristics include the offset in electrical delay (seconds) and the loss (ohms/second of delay). The characteristic impedance, OFFSET Z0 , is not used in the calculations in that it is determined by the line standard.
Operating Concepts TRL*/LRM* Calibration (ES Models Only) where: f = frequency l = length of line v = velocity = speed of light × velocity factor which can be reduced to the following using frequencies in MHz and length in centimeters: 0.012 × f ( MHz ) × l ( cm ) Phase ( degrees ) approx = -----------------------------------------------------------VF So for an air line (velocity factor approximately 1) at 1000 MHz, the insertion phase is 60 degrees for a 5 cm line; it is 120 degrees at 2000 MHz.
Operating Concepts TRL*/LRM* Calibration (ES Models Only) The TRM calibration technique is related to TRL with the difference being that it bases the characteristic impedance of the measurement on a matched ZO termination instead of a transmission line for the third measurement standard. Like the TRL thru standard, the TRM THRU standard can either be of zero length or non-zero length. The same rules for thru and reflect standards used for TRL apply for TRM.
Operating Concepts TRL*/LRM* Calibration (ES Models Only) specified to have zero delay, the reference plane will be established in the middle of the thru. The reflect standard may be used to set the reference plane instead of the thru provided the phase response (offset delay, reactance values and standard type) of the reflect standard is known and is specified in the calibration kit definition.
Operating Concepts GPIB Operation GPIB Operation This section contains information on the following topics: • local key • GPIB controller modes • instrument addresses • using the parallel port Local Key This key is allows you to return the analyzer to local (front panel) operation from remote (computer controlled) operation. This key will also abort a test sequence or hardcopy print/plot.
Operating Concepts GPIB Operation GPIB STATUS Indicators When the analyzer is connected to other instruments over GPIB, the GPIB STATUS indicators in the instrument state function block light up to display the current status of the analyzer. R = remote operation L = listen mode T = talk mode S = service request (SRQ) asserted by the analyzer System Controller Mode The SYSTEM CONTROLLER softkey activates the system controller mode.
Operating Concepts GPIB Operation Address Menu This menu can be accessed by pressing the SET ADDRESS softkey within the GPIB menu. In communications through the General Purpose Interface Bus (GPIB), each instrument on the bus is identified by a GPIB address. This decimal-based address code must be different for each instrument on the bus. This menu lets you set the GPIB address of the analyzer, and enter the addresses of peripheral devices so that the analyzer can communicate with them.
Operating Concepts GPIB Operation The GPIO Mode The GPIO mode turns the parallel port into a "general purpose input/output" port. In this mode the port can be connected to test fixtures, power supplies, and other peripheral equipment that might be used to interact with the analyzer during measurements. This mode is exclusively used in test sequencing.
Operating Concepts Limit Line Operation Limit Line Operation This menu can be accessed by pressing LIMIT MENU menu. LIMIT LINE within the system You can have limit lines drawn on the display to represent upper and lower limits or device specifications with which to compare the test device. Limits are defined in segments, where each segment is a portion of the stimulus span. Each limit segment has an upper and a lower starting limit value.
Operating Concepts Limit Line Operation If limit lines are on, they are plotted with the data on a plot. If limit testing is on, the PASS or FAIL message is plotted, and the failing portions of the trace that are a different color on the display are also a different color on the plot. If limits are specified, they are saved in memory with an instrument state. Edit Limits Menu This menu allows you to specify limits for limit lines or limit testing, and presents a table of limit values on the display.
Operating Concepts Knowing the Instrument Modes Knowing the Instrument Modes There are five major instrument modes of the analyzer: • network analyzer mode • tuned receiver mode • frequency offset operation (Option 089) Network Analyzer Mode This is the standard mode of operation for the analyzer, and is active after you press Preset or switch on the AC power. This mode uses the analyzer's internal source.
Operating Concepts Knowing the Instrument Modes Figure 7-46 Typical Test Setup for Tuned Receiver Mode Tuned Receiver Mode In-Depth Description If you press System INSTRUMENT MODE TUNED RECEIVER , the analyzer receiver operates independently of any signal source. The following features and limitations apply to the tuned receiver mode: • It is a fully synthesized receiver; it does not phase-lock to any source. • It functions in all sweep types.
Operating Concepts Differences between 8753 Network Analyzers Differences between 8753 Network Analyzers Table 7-3 Comparing the 8753A/B/C/D Feature 8753A 8753B 8753C 8753D 8753D Opt.
Operating Concepts Differences between 8753 Network Analyzers Table 7-4 Comparing the 8753D/E/ES Feature Fully integrated measurement system (built-in test set) 8753D 8753E 8753ES Yes Yes Yes +10 to −85 +10 to −85 +10 to −85 Auto/manual power range selecting Yes Yes Yes Port power coupling/uncoupling Yes Yes Yes Internal disk drive Yes Yes Yes Flash EPROM No Yes Yes Precision frequency reference (Option 1D5) Yes Yes Yes Frequency range - low end (in kHz) 30 30 30 Ext.
Operating Concepts Differences between 8753 Network Analyzers Table 7-4 Comparing the 8753D/E/ES Feature 8753E 8753D 8753ES Interfaces: RS-232, parallel, and DIN keyboard Yes Yes Yes User-defined preset Yes Yes Yes Non-volatile memory (in Kbytes) 512 2000 2000 110 dBa 110 dBa Dynamic range: 30 kHz − 3 GHz 110 dB Dynamic range: 3 GHz − 6 GHz 105 dB 105 dB 105 dB Yes Yes Yes Real time clock a a. 90 dB from 30 kHz to 50 kHz; 100 dB from 300 kHz to 16 MHz.
Operating Concepts Differences between 8753 Network Analyzers Table 7-5 Comparing the 8753D/E/ES Option 011 Network Analyzers Feature 8753D Option 011 8753E 8753ES Option 011 Option 011 Color display Yes Yes Yes Flat panel LCD No Yes Yes VGA output No Yes No Delete display (Option 1DT) No Yes No Test sequencing Yes Yes Yes Automatic sweep time Yes Yes Yes External source capability Yes Yes Yes Tuned receiver mode Yes Yes Yes Printer/plotter buffer Yes Yes Yes Harmo
8 Safety and Regulatory Information 8-1
Safety and Regulatory Information General Information General Information Maintenance Clean the cabinet, using a dry or damp cloth only. WARNING To prevent electrical shock, disconnect the analyzer from mains before cleaning. Use a dry cloth or one slightly dampened with water to clean the external case parts. Do not attempt to clean internally. Assistance Product maintenance agreements and other customer assistance agreements are available for Agilent Technologies products.
Safety and Regulatory Information General Information Table 8-1 Agilent Technologies Sales and Service Offices UNITED STATES Instrument Support Center Agilent Technologies Company (800) 403-0801 EUROPEAN FIELD OPERATIONS France Agilent Technologies France 1 Avenue Du Canada Zone D’Activite De Courtaboeuf F-91947 Les Ulis Cedex France (33 1) 69 82 60 60 Headquarters Agilent Technologies S.A. 150, Route du Nant-d’Avril 1217 Meyrin 2/ Geneva Switzerland (41 22) 780.
Safety and Regulatory Information Safety Symbols Safety Symbols The following safety symbols are used throughout this manual. Familiarize yourself with each of the symbols and its meaning before operating this instrument. CAUTION Caution denotes a hazard. It calls attention to a procedure that, if not correctly performed or adhered to, would result in damage to or destruction of the instrument. Do not proceed beyond a caution note until the indicated conditions are fully understood and met.
Safety and Regulatory Information Safety Considerations Safety Considerations NOTE This instrument has been designed and tested in accordance with IEC Publication 1010, Safety Requirements for Electronics Measuring Apparatus, and has been supplied in a safe condition. This instruction documentation contains information and warnings which must be followed by the user to ensure safe operation and to maintain the instrument in a safe condition.
Safety and Regulatory Information Safety Considerations Servicing WARNING No operator serviceable parts inside. Refer servicing to qualified personnel. To prevent electrical shock, do not remove covers. WARNING These servicing instructions are for use by qualified personnel only. To avoid electrical shock, do not perform any servicing unless you are qualified to do so. WARNING The opening of covers or removal of parts is likely to expose dangerous voltages.
Safety and Regulatory Information Safety Considerations CAUTION This product is designed for use in Installation Category II and Pollution Degree 2 per IEC 1010 and 664 respectively. CAUTION VENTILATION REQUIREMENTS: When installing the product in a cabinet, the convection into and out of the product must not be restricted. The ambient temperature (outside the cabinet) must be less than the maximum operating temperature of the product by 4° C for every 100 watts dissipated in the cabinet.
Safety and Regulatory Information Declaration of Conformity Declaration of Conformity 8-8
Index Numerics 2-port error corrections, performing, 6-42 4 Param Displays softkey, 1-18 A aborting a print or plot process, 4-33 absolute ripple test value, 1-89, 1-90 absolute power, 6-39 accuracy enhancement, 7-7, 7-37, 7-52 accurate measurements of electrically long devices cause of measurement problems, 5-8 improving measurement results, 5-8 activating averaging, 5-16 chop sweep mode, 5-13 display markers, 1-25 fixed markers, 1-29 limit test, 1-79 activating the bandwidth test, 1-94 active channel dis
Index calling the next measurement sequence, 2-29 capabilities mixer measurement, 2-3 capacitance, fringe, 6-6 cause of measurement problems, 5-8 center frequency, setting, 1-35 changing sequence title, 1-103 system bandwidth, 5-16 changing the ripple limits color, 1-89 channel coupling, 7-10 channel position softkey, 1-17 channel stimulus coupling, 7-14 characteristics of the filter, 1-69 characterizing a duplexer, 1-50 definitions, 1-50 procedure, 1-50 characterizing microwave systematic errors, 7-41 dev
Index viewing, 1-14 measurement data dividing by the memory trace, 1-20 subtracting memory trace, 1-20 viewing, 1-20 memory math functions, 1-19 memory trace viewing, 1-20 memory traces, 1-19 primary measurement dual channel mode with decoupled channel power, 1-14 dual channel mode with decoupled stimulus, 1-13 primary measurement channels, 1-12 viewing, 1-12 ratio measurements in channel 1 and 2, to, 1-20 display intensity, 1-21 display markers coupling, 1-31 uncoupling, 1-31 display markers, activating,
Index Channel Position softkey, 1-17 customizing, 1-17 viewing, 1-14 Freelance, using, 4-23 frequency segments, editing, 6-34 signals, deleting, 6-35 span, decreasing, 5-11 span, setting, 1-36 frequency bands adding, 1-86 changing, 1-85 deleting, 1-87 setting, 1-84 frequency drift, 5-5 frequency list sweep of 26 points, 2-28 frequency offset mode operation, 2-10 frequency offset mode, conversion compression, 2-39 frequency offset mode, conversion loss, 2-13 frequency offset operation, 7-84 frequency range,
Index reducing the averaging factor, 5-12 reducing the number of measurement points, 5-12 setting the auto sweep time mode, 5-12 setting the sweep type, 5-12 using external calibration, 5-13 using swept list mode, 5-10 viewing a single measurement channel, 5-13 widening the system bandwidth, 5-12 increasing test port input power, 5-15 incrementing the source frequencies, 2-31 in-depth sequencing information, 1-105 autostarting sequences, 1-106 commands completed before next sequence begins, 1-105 commands
Index M magnitude measuring, 1-7 measuring response, 1-7 maintaining testport output power during sweep retrace, 5-7 maintenance, 8-2 making a basic measurement, 1-4 choosing measurement parameters, 1-4 connecting required test equipment, 1-4 connecting the device under test, 1-4 error-correction, 1-5 frequency range, setting, 1-5 measurement, setting, 1-5 measuring the device under test, 1-5 outputting measurement results, 1-6 source power, setting, 1-5 making non-coaxial measurements, 6-49 fixtures, 6-49
Index viewing, 1-20 memory, display, 7-8 menu address, 7-79 analog in, 7-22 calibration kit, 7-57 conversion, 7-22 edit limits, 7-82 edit segment, 7-82 input ports menu, 7-23 offset limits, 7-82 segment, 7-16 S-parameter, 7-22 stepped edit list, 7-16 stepped edit subsweep, 7-16 swept edit list, 7-17 swept edit subsweep, 7-17 microprocessor, 7-4 microwave connector care, 5-3 microwave systematic errors, characterizing, 7-41 minimizing error when using adapters, 6-48 source and load mismatches, 2-4 minimum a
Index phase or group delay measurements, 2-34 phase linearity and group delay, 2-34 phase measurements, 2-34 places where you can save, 4-36 plot aborting a process, 4-33 plot files outputting from a PC to a plotter, 4-24 outputting from a PC to an HPGL compatible printer, 4-25 sending to the printer, 4-26 to output, 4-14 to view on a PC, 4-22 plot function, configuring, 4-10 plotting to a pen plotter, 4-12 plotting to an HPGL/2 compatible printer, 4-10 plot function, defining, 4-15 choosing display elemen
Index effect of spurious responses, 2-5 number of measurement points, 5-12 reducing recall time, 5-18 reducing trace noise, 5-16 activating averaging, 5-16 changing system bandwidth, 5-16 reduction, IF bandwidth, 7-36 reference plane and port extensions, 5-5 reflection measurements response and isolation error correction, 6-19 response error correction, 6-12 reflection measurements in time domain low pass, 3-16 interpreting the low pass response horizontal axis, 3-16 interpreting the low pass response vert
Index generating files in a loop counter example, 1-115 in-depth information, 1-105 jumps to itself, 1-112 limit test example, 1-117 loading from a disk, 1-104 loop counter example, 1-114 naming files, 1-103 printing, 1-105 purging from a disk, 1-104 running, 1-100 size, 1-106 stopping, 1-100 storing to disk, 1-104 sequencing special functions menu, 1-111 test, 1-98 servicing, 8-6 setting auto sweep time mode, 5-12 frequency range for time domain low pass, 3-15 gate, 3-35 setting ripple limits, 1-82–1-85 s
Index temperature drift, 5-5 terminology, TRL, 7-67 test bandwidth, 1-92–1-97 ripple limit, 1-82–1-91 test port coupling, 7-10 test port input power, increasing, 5-15 test sequencing, 1-98 changing the sequence title, 1-103 clearing a sequence from memory, 1-102 creating a sequence, 1-98 editing a sequence, 1-100 generating files in a loop counter example, 1-115 in-depth sequencing information, 1-105 inserting a command, 1-101 limit test example sequence, 1-117 loading a sequence from a disk, 1-104 loop co
Index I/O menu, 1-108 input decision making, 1-108 out menu, 1-111 output for controlling peripherals, 1-108 tuned receiver mode, 2-26, 2-28, 7-83 in-depth description, 7-84 test setup, typical, 7-83 two sources addressing and configuring, 2-29 two-port calibration, full, 7-55 two-port calibration, TRL*/LRM*, 7-55 two-port error model, 7-46 type-N connector sex clarifying, 6-4 types of error correction, 6-10 U uncoupling display markers, 1-31 understanding power ranges, 7-9 understanding S-parameters, 7-20
