Agilent 71501D Eye-Diagram Analysis User’s Guide
© Copyright Agilent Technologies 2002 All Rights Reserved. Reproduction, adaptation, or translation without prior written permission is prohibited, except as allowed under copyright laws. Agilent Part No. 70874-90023 Printed in USA May 2002 Agilent Technologies Lightwave Division 3910 Brickway Boulevard, Santa Rosa, CA 95403, USA Notice. The information contained in this document is subject to change without notice. Companies, names, and data used in examples herein are fictitious unless otherwise noted.
General Safety Considerations General Safety Considerations This product has been designed and tested in accordance with the standards listed on the Manufacturer’s Declaration of Conformity, and has been supplied in a safe condition. The documentation contains information and warnings that must be followed by the user to ensure safe operation and to maintain the product in a safe condition. Install the instrument according to the enclosure protection provided.
General Safety Considerations CAUTION Fiber-optic connectors are easily damaged when connected to dirty or damaged cables and accessories. The Agilent 71501D’s front-panel input connector is no exception. When you use improper cleaning and handling techniques, you risk expensive instrument repairs, damaged cables, and compromised measurements. Before you connect any fiber-optic cable to the Agilent 71501D clean it thoroughly.
Contents 1 Getting Started Steps for Setting Up Eye-Diagram Analysis 1-4 2 Application Tutorials Tutorial 1: Measure Eye-Parameters 2-4 Tutorial 2: Measure in Optical Power Units 2-8 Tutorial 3: Measure Extinction Ratios on Low-Level Signals 2-10 Tutorial 4: Measure Laser Turn-on Delay 2-13 Tutorial 5: Use Software Filters 2-15 Tutorial 6: Test to Industry Standards 2-19 Tutorial 7: Default and Custom Mask or Limit Line Testing 2-23 Tutorial 8: Display the Data Pattern 2-27 Tutorial 9: Constructing a Low-P
Contents 5 Specifications and Characteristics Vertical Specifications 5-3 Input Channel Specifications 5-4 Trigger Specifications 5-5 Trigger Specifications 5-6 Horizontal Specifications 5-7 Declaration of Conformity 5-8 Contents-2
1 Getting Started
Getting Started Getting Started with the Eye-Diagram Analyzer Getting Started with the Eye-Diagram Analyzer In this chapter, you will find information on the following topics: • • • • • • Steps for Setting Up Eye-Diagram Analysis 1-4 Step 1. Connect the Equipment 1-12 Step 2. Load the Personality 1-16 Step 3. Complete the Installation Using the Screen Instructions Step 4. Set Up the Measurement Conditions 1-22 Optional Step.
Getting Started Getting Started with the Eye-Diagram Analyzer The custom keypad The eye-diagram analyzer comes with a custom keypad that snaps into the front panel of 70004A displays. The keypad gives you quick access to common instrument functions. (Each of these functions can also be accessed using the normal softkey menus.) If you have the custom keypad, practice using it. You will find that the time required, for many of the procedures in this book, will be significantly reduced.
Getting Started Steps for Setting Up Eye-Diagram Analysis Steps for Setting Up Eye-Diagram Analysis 1 Connect the equipment. 2 Load the eye-diagram personality. 3 Complete the installation using the self-guided screens. 4 Set up the measurement conditions. Connect the Equipment You can connect the equipment in three possible configurations: • With 70841A/B pattern generator and 70311 clock source modules. This is the preferred configuration.
Getting Started Steps for Setting Up Eye-Diagram Analysis Note When used with an 71612A/70843, the system requires a manual configuration. Set Up the Measurement Conditions Select from eye, eyeline, and pattern modes Use the Setup menu’s diagram softkey to select from one of three measurement modes: eye, eyeline, and pattern.
Getting Started Steps for Setting Up Eye-Diagram Analysis Eye Mode The eye mode displays traces using individual dots in a manner that is similar to conventional sampling oscilloscopes.
Getting Started Steps for Setting Up Eye-Diagram Analysis Eyeline Mode : Eyeline mode displays continuous traces.
Getting Started Steps for Setting Up Eye-Diagram Analysis Pattern Mode Pattern mode displays the actual PRBS data stream bits. This mode uses the pattern trigger which allows the display to show the same portion of the data stream from sweep to sweep. Mask/limit lines provide pass/fail testing Mask/limit lines are displayed geometric shapes that define the acceptable limits and shape of an eye-diagram. The following figure shows a mask. Use masks for pass/fail testing and as an aid to error analysis.
Getting Started Steps for Setting Up Eye-Diagram Analysis Apply software filters in eyeline mode In eyeline mode, user frequency corrections can be applied to the data to simulate a hardware transmission filter. The eye-diagram analyzer comes with several Bessel-Thomson filters. These files are on the 71501D memory card. Refer toChapter 9, “Agilent 70820A: User Corrections” and Chapter 11, “Agilent 70820A: Memory Cards, Disks, and RAM”for information on user-corrections.
Getting Started Steps for Setting Up Eye-Diagram Analysis Three sweep selections are available • single • continuous • stopped With the continuous selection, sweeps occur as soon as the selected triggering conditions are met and repeat continuously as long as the trigger conditions are met. The source of the trigger reference is selected using the Setup menu’s CH2 softkey. The following table shows the reference used when using an Agilent 7084X pattern generator. Table 1-1.
Getting Started Steps for Setting Up Eye-Diagram Analysis These softkeys can also be used to specify an optical-to-electrical responsivity conversion between the source and input channels. As a result, the display shows optical units referenced to the input of the optical-to-electrical converter. Channel and marker readouts change to watts/div. Also, the CH1 EXT ATTEN softkey changes to read CH1 RSPVTY (responsivity). Autoranging The Trg,Cal menu’s autorng ON OFF softkey turns on or off autoranging.
Getting Started Steps for Setting Up Eye-Diagram Analysis Step 1. Connect the Equipment 70841A/B Pattern Generator and 70311A Signal Generator Modules 1 If you are using 70841A/B pattern generator and 70311A signal generator modules with your eye-diagram analyzer, install them into an MMS mainframe as shown in the following figure.
Getting Started Steps for Setting Up Eye-Diagram Analysis 2 If you are using 70841A/B pattern generator and 70311A signal generator modules with your eye-diagram analyzer, connect cables to the instruments as shown in the following graphic. • If you are using a clock source other than an 70311A, make sure that the signal generator and 70820A microwave transition analyzer module share the same frequency reference. Use the 10 MHz REF connectors on the rear panel of the 70820A.
Getting Started Steps for Setting Up Eye-Diagram Analysis Front-Panel Cable Connections Cables: SMA to SMA (Channel 1) p/n 8120-4948 SMA to SMA (Channel 2) p/n 8120-4948 SMB to SMB (10 MHz Reference) p/n 8120-5025 Miscellaneous: 3.5 mm (f) to 2.
Getting Started Steps for Setting Up Eye-Diagram Analysis Laser and Optical- If you have access to a laser and an optical-to-electrical converter, use the to-Electrical connections shown in the following figure. To protect the input connectors, Converter use adapters between the cables and the connectors. The laser is the device being tested. Cables: SMA to SMA (Channel 1) p/n 8120-4948 SMA to SMA (Channel 2) p/n 8120-4948 SMB to SMB (10 MHz Reference) p/n 8120-5025 Miscellaneous: 3.5 mm (f) to 2.
Getting Started Steps for Setting Up Eye-Diagram Analysis Connections without a Laser Source and Converter If a laser source and optical-to-electrical converter are not available, use the alternate connection shown in the following figure. In this case, the pattern generator’s data output is displayed. An electrical device could be inserted between the pattern generator and the eye-diagram analyzer. Step 2.
Getting Started Steps for Setting Up Eye-Diagram Analysis If the Program Failed to Load The program has failed to load if one of the following occurs: • The message Please wait... Loading 70874 never shows. • The left-side softkeys match those shown in the following figure. “Manually Load the Personality” on page 1-17 70820A Module’s Main Menu Manually Load the Personality 1 Insert the 70874A eye-diagram memory card into the front-panel card slot.
Getting Started Steps for Setting Up Eye-Diagram Analysis 3 If the screen does not resemble the above figure, press: msi:, HP-MSIB CARD, prev menu DISPLAY, Mass Storage, msi, MEMORY CARD MENU The list of files should now be displayed. 4 Turn the front-panel knob to highlight the file "AUTOST" and then press: LOAD FILE If you load the "70874" file by mistake, the message 7386 memory overflow may be displayed.
Getting Started Steps for Setting Up Eye-Diagram Analysis Step 3. Complete the Installation Using the Screen Instructions • If the displayed screen looks like the figure on the left side of this page, your system has been previously configured. Press CONT and then continue with "Step 4. Connect the front-panel cables". However, if you wish to reconfigure your system, press RECNFIG, and continue with the following explanation of the self-guided screens.
Getting Started Steps for Setting Up Eye-Diagram Analysis First Self-Guided Screen 3 Use the following self-guided screen to indicate the 10 MHz frequency reference used. Press INTERNL if the 70820A module is used as the reference. Press EXTERNL if the clock source is used as the reference.
Getting Started Steps for Setting Up Eye-Diagram Analysis 4 The following screen should be displayed. Notice that the eye-diagram analyzer’s left-side Setup menu is selected. 5 If you have not already connect the cables to the instruments’ front panels, follow the instructions shown. Otherwise, proceed with “If you have not already connect the cables to the instruments’ front panels, follow the instructions shown.
Getting Started Steps for Setting Up Eye-Diagram Analysis the instruments’ front panels, follow the instructions shown. Otherwise, proceed with “If you have not already connect the cables to the instruments’ front panels, follow the instructions shown. Otherwise, proceed with “If you have not already connect the cables to the instruments’ front panels, follow the instructions shown. Otherwise, proceed with .” on page 1-21.” on page 1-21.” on page 1-22.” on page 1-22. Step 4.
Getting Started Steps for Setting Up Eye-Diagram Analysis Note Using the CLOCK OUT trigger signal provides faster data acquisition for eyediagrams. If the amplitude of the trigger signal is too large, an over-range message is displayed. If a message is displayed, reduce the amplitude of the signal; use an external attenuator, and enter the value using CH2 EXT ATTEN. Select the Pattern Generator Settings 6 If an 70841A/B pattern generator is used, press READ PAT GEN.
Getting Started Steps for Setting Up Eye-Diagram Analysis Controlling an 70841A/B Pattern Generator When using the 70311A clock source (below 3 Gb/s): This section explains how to display the menus for the 70841A/B pattern generator. The display can be assigned to control either the eye-diagram analyzer or the 70841A/B pattern generator. Note If the eye-diagram analyzer is configured with a non 70841 pattern generator, you must manually set the trigger level.
Getting Started Steps for Setting Up Eye-Diagram Analysis 70841A/B appears. c Press ADJUST ROW, and rotate the knob to move the box to the row where the 70841A/B appears. d Press ASSIGN BOTH. 4 Use the displayed softkey menus to set the pattern generator to the desired settings. For an example, refer to the paragraph "Configure the data signal" in Chapter 2, “Application Tutorials”.
Getting Started Steps for Setting Up Eye-Diagram Analysis 3 Turn the display off and select trace one by pressing: Traces, display ON|OFF OFF, select:, TR1 Move the Measurement Plane To move the measurement plane, press: Trg,Cal, CH1 EXT ATTEN and enter the attenuation on channel 1 input. Optional Step.
Getting Started Steps for Setting Up Eye-Diagram Analysis 3 The eye-diagram is now ready for use.
Getting Started Steps for Setting Up Eye-Diagram Analysis
2 Application Tutorials
Application Tutorials Application Tutorials Application Tutorials This chapter contains nine tutorials that introduce important eye-diagram analyzer features. The tutorials should be performed in the order listed. To create the data signal, you will need a pseudo-random binary sequence (PRBS) pattern generator. Refer to “Configure the Data Signal” on page 2-2 before you start the tutorials.
Application Tutorials Application Tutorials Clock Freq: 2.
Application Tutorials Tutorial 1: Measure Eye-Parameters Tutorial 1: Measure Eye-Parameters The eye-diagram analyzer performs automatic eye measurements in eye mode. This mode is similar to that of conventional sampling oscilloscopes; the display shows individual dots. View the Signal 1 To view the signal, press: INSTR PRESET, Traces, persist, VARIABL This turns the persistence mode on. Refer to Chapter 3, “Eye-Diagram Analyzer Reference” for an explanation of the available persistence modes.
Application Tutorials Tutorial 1: Measure Eye-Parameters Example of a Large Overshoot Resulting from Laser Bias Perform an Offset Calibration This calibration procedure removes any offset that may be present in the optical-to-electrical converter. This is sometimes referred to as the "dark" level. The offset calibration ensures accurate measurements of the laser’s one and zero levels. 4 Turn the laser off. (If you are measuring the pattern generator directly, disconnect the input signal at channel 1.
Application Tutorials Tutorial 1: Measure Eye-Parameters Enabling this function approximately doubles the measurement time. 8 Perform the eye measurement by pressing: MEASURE EYE After a brief period of time, the display should look like the following figure. Refer to Chapter 3, “Eye-Diagram Analyzer Reference” for definitions of each measurement listed on the screen.
Application Tutorials Tutorial 1: Measure Eye-Parameters Example Extinction Ratio Measurement 10 Change the amount of data used for the histograms by pressing: NUMBER SAMPLES and enter the # of samples A larger value gives more accuracy, but increases the data acquisition time.
Application Tutorials Tutorial 2: Measure in Optical Power Units Tutorial 2: Measure in Optical Power Units The analyzer display has the ability to show optical units referenced to the input of the optical-to-electrical converter. This changes the channel and marker readouts to watts/div. 1 Set the analyzer to a known state by pressing: INSTR PRESET, Trg,Cal, CH1 EXT ATTEN responsivity value, V/Watt For example, the following figure shows 350 V/Watt entered.
Application Tutorials Tutorial 2: Measure in Optical Power Units 2-9
Application Tutorials Tutorial 3: Measure Extinction Ratios on Low-Level Signals Tutorial 3: Measure Extinction Ratios on LowLevel Signals Repeatable extinction ratio measurements can be made on low-level signals. This is accomplished by applying a filter to the signal.
Application Tutorials Tutorial 3: Measure Extinction Ratios on Low-Level Signals Autoscaled Display of Low-Level Signal 4 Turn filtering on by pressing: Setup, eyefltr ON OFF ON Perform an Offset Calibration This calibration procedure removes any offset that may be present in the optical-to-electrical converter. This is sometimes referred to as the "dark" level. The offset calibration ensures accurate measurements of the laser’s level. 5 Turn the laser off.
Application Tutorials Tutorial 3: Measure Extinction Ratios on Low-Level Signals Measure the Extinction Ratio 8 To measure the extinction ratio, press: Measure, NUMBER SAMPLES and enter 20000, EXTINCT RATIO Refer to the following figure.
Application Tutorials Tutorial 4: Measure Laser Turn-on Delay Tutorial 4: Measure Laser Turn-on Delay On-screen markers can be used to measure both amplitude and time separation in eye-diagrams. The compatible modes for markers are eye, eyeline, and pattern.
Application Tutorials Tutorial 4: Measure Laser Turn-on Delay Laser Overshoot and Turn-On Delay
Application Tutorials Tutorial 5: Use Software Filters Tutorial 5: Use Software Filters This tutorial enables a software filter. The filter is designed with user frequency corrections. User frequency corrections can be used for: • Removing the effects of frequency response roll-off due to the optical-toelectrical converter and cables. • Simulating hardware filters recommended for laser transmitter evaluation, such as 4th-order Bessel- Thomson filters.
Application Tutorials Tutorial 5: Use Software Filters User-Corrections Applied to the Data Change to Eyeline Mode 1 Set the analyzer to a known state by pressing: INSTR PRESET, Traces, persist, VARIABL and enter 5, diagram, EYELINE Notice the level of the laser overshoot, and the turn-on delay, varies from sweep to sweep, dependent on the previous pattern of ones and zeros.
Application Tutorials Tutorial 5: Use Software Filters Eyeline Display Showing Laser Overshoot Load the Software Filter 2 Place the 70874A memory card in the front-panel card slot. 3 Display the catalog of files on the memory card by pressing: Mass Storage 4 Turn the front-panel knob to highlight the file "a_bt248832". 5 Load the file into user-corrections by pressing: LOAD FILE This file simulates a 4th-order Bessel-Thomson filter with a cutoff at threequarters of the bit rate.
Application Tutorials Tutorial 5: Use Software Filters 7 Turn the autoscale function on by pressing: Traces, AUTO-SCALE The display should look like the following figure. Notice that the laser overshoot is no longer visible, due to the filtering effect of the user-corrections in the 71501A.
Application Tutorials Tutorial 6: Test to Industry Standards Tutorial 6: Test to Industry Standards Masks allow you to test eye-diagrams against industry standards. The eye-diagram analyzer provides built-in masks for testing the major SONET/SDH transmission rates. Compatible modes are eye and eyeline.
Application Tutorials Tutorial 6: Test to Industry Standards Turn Mask Testing On 6 Turn mask testing on by pressing: Masks, test ON OFF ON This resets the error counters. Errors for the standard specifications show up beside the M1 screen annotation for mask violations, and beside L2 and L3 for upper and lower limit violations, respectively. Notice that in this case, violations are occurring due to too much overshoot.
Application Tutorials Tutorial 6: Test to Industry Standards Stop on and Display Trace Errors The eye-diagram analyzer has the ability to stop data acquisition when a mask violation occurs. The number of traces or errors that stop this data acquisition can be specified. In addition, if you are in eyeline mode, you can separately display the traces that have caused an error.
Application Tutorials Tutorial 6: Test to Industry Standards test ON OFF ON The instrument stops sweeping after two error traces have been accumulated. Refer to the following figure. Note that for this figure, errors occur due to overshoot on a zero-to-one transition.
Application Tutorials Tutorial 7: Default and Custom Mask or Limit Line Testing Tutorial 7: Default and Custom Mask or Limit Line Testing The 70820A menus allow you to create and display up to eight limit lines and masks at one time. Five default mask/limit-line shapes are provided for your use: • hexagon • square • equilateral triangle • inverted equilateral triangle • flat line You can stretch, shrink, or move any mask. It is also easy to add additional points or delete unneeded points from any shape.
Application Tutorials Tutorial 7: Default and Custom Mask or Limit Line Testing Create a Mask or Limit Line 1 Set the analyzer to a known state by pressing: INSTR PRESET, Setup, BIT INTVL and enter 1.5, Traces, persist, VARIABL, PERSIST SWEEPS and enter 8 MENU, page 1 of 2, Analyze, masks, limits, define shapes, type: • If you want to create a mask, press MASK. • If you want to create a limit line, press UPPER LIMIT or LOWER LIMIT.
Application Tutorials Tutorial 7: Default and Custom Mask or Limit Line Testing Stretch, Reduce, or Move the Mask 11 To stretch, reduce or move the mask by press: prev menu, scale X|Y or offset X|Y Add a Mask Margin 12 Press the left-side Masks softkey.
Application Tutorials Tutorial 7: Default and Custom Mask or Limit Line Testing Display the Error Trace 23 Display a mask and begin testing as described in this section, and then press: err trc ON|OFF ON Erase a Mask or Limit Line 24 Select the mask or limit line you wish to erase by pressing: MENU, page 1 of 2, Analyze, masks, limits, define shapes, edit SELECT the number of the mask or limit line to be erased 25 Erase the mask by pressing: delete shapes , DELETE CURRENT Remove all Displayed Masks 26 Remo
Application Tutorials Tutorial 8: Display the Data Pattern Tutorial 8: Display the Data Pattern The eye-diagram analyzer can display the data pattern. This is done by selecting the pattern mode and triggering the display trace update on the pattern trigger. This insures the trace on the screen remains the same from sweep to sweep. In this mode, trace averaging can be used for more repeatable measurements on noisy signals.
Application Tutorials Tutorial 8: Display the Data Pattern Example Pattern Mode Display Add Time Delay 6 Add time delay by pressing: Setup, DELAY Each push of the step keys (⇓ and⇑) gives a change in delay equal to exactly one bit. This technique can also be used to step the X offset of the mask one bit at a time, to check for mask violations at each bit position. 7 Disconnect the RF cable from the pattern generator’s TRIGGER OUT connector and connect the cable to the CLOCK OUT connector.
Application Tutorials Tutorial 8: Display the Data Pattern 8 Set channel 2 by pressing: CH2 is:, CLK OUT Notice that the diagram softkey annotation no longer indicates pattern mode, and a note is displayed on the screen as shown in the following figure.
Application Tutorials Tutorial 9: Constructing a Low-Pass Filter from a Transfer Function Tutorial 9: Constructing a Low-Pass Filter from a Transfer Function This procedure builds a fourth order Bessel-Thomson filter characterizing SONET/SDH transmitters operating at 2.48832 Gbit/sec. The filter is loaded into channel 1 user-correction data.
Application Tutorials Tutorial 9: Constructing a Low-Pass Filter from a Transfer Function 3 Turn the display off by pressing: Traces, select:, TR1, display ON OFF OFF 4 Build the equation by pressing: select:, TR2, input:, build eqn, CLR - END, SEL|EDT SEL 5 Turn the front-panel to highlight the j operand, and then press: INSERT Continue using this technique to construct the trace equation shown in the following figure. Enter numbers using the front-panel numeric keypad.
Application Tutorials Tutorial 9: Constructing a Low-Pass Filter from a Transfer Function 6 Build the trace equation shown in the following figure by pressing: RETURN, select:, TR3, input:, build eqn, CLR - END, SEL|EDT SEL Build the trace equation. Notice the cursor has wrapped to the following line. Be sure to include the last two right parenthesis characters shown on the last line.
Application Tutorials Tutorial 9: Constructing a Low-Pass Filter from a Transfer Function 10 Set the marker on 1.86224 GHz using the knob or numeric keypad.
Application Tutorials Tutorial 9: Constructing a Low-Pass Filter from a Transfer Function 14 Highlight "UCORR1" using the knob.
Application Tutorials Tutorial 9: Constructing a Low-Pass Filter from a Transfer Function 16 To store the filter to a memory card, press: States, more 1 of 2, mass storage 17 If the mass-storage device needs to be selected, refer to “Saving to Mass Storage” on page 3-34.
Application Tutorials Tutorial 10: Create a Vertical Histogram Tutorial 10: Create a Vertical Histogram This tutorial creates a vertical histogram on data taken from a sine wave. The procedure, however, works for any type of waveform. Select the Histogram Type 1 Display a trace to perform statistical analysis on. 2 Display the histogram menu by pressing: page 1 of 2, Analyze, histogm 3 Select the trace to perform the statistical analysis on by pressing: trace: Use the knob to select the desired trace.
Application Tutorials Tutorial 10: Create a Vertical Histogram 6 Enter the number of samples to be taken for the histogram by pressing: prev menu, NUMBER SAMPLES, # of samples, ENTER The default number of samples taken is 1000. 7 To draw the vertical histogram, press: SINGLE ACQUIRE Data will be acquired once.
Application Tutorials Tutorial 10: Create a Vertical Histogram Perform Statistical Analysis The range of sample points used to calculate the mean and standard deviation is the full screen. 9 To change the limits, press: other, UPPER LIMIT, LIMIT→ 0%-100%, new upper limit value, ENTER, LOWER LIMIT, LIMIT→ 0%-100%, new lower limit value, ENTER Notice the values of the limit-line positions are indicated at the top of the display.
Application Tutorials Tutorial 10: Create a Vertical Histogram 10 To display a line indicating the location of the mean, press: results, MEAN, The mean and standard deviation values are also shown.
Application Tutorials Tutorial 10: Create a Vertical Histogram 11 To display a line indicating the location of the standard deviation, press: STD DEV
Application Tutorials Tutorial 11: Create a Horizontal Histogram Tutorial 11: Create a Horizontal Histogram This tutorial creates a horizontal histogram on data taken from a sine wave. The procedure, however, works for any type of waveform. Select the Histogram Type 1 Display a trace to perform statistical analysis on.
Application Tutorials Tutorial 11: Create a Horizontal Histogram 6 Enter the number of samples to be taken for the histogram by pressing: prev menu, NUMBER SAMPLES, # of samples, ENTER The default number of samples taken is 1000. 7 To draw the horizontal histogram, press: SINGLE ACQUIRE Data will be acquired once.
Application Tutorials Tutorial 11: Create a Horizontal Histogram Perform Statistical Analysis The range of sample points used to calculate the mean and standard deviation is the full screen. 9 To change the limits, press: other, UPPER LIMIT, LIMIT→ 0%-100%, new upper limit value, ENTER, LOWER LIMIT, LIMIT→0%-100%, new lower limit value, ENTER Notice the values of the limit-line positions are indicated at the top of the display.
Application Tutorials Tutorial 11: Create a Horizontal Histogram 10 To display a line indicating the location of the mean, press: results, MEAN The mean and standard deviation values are also shown.
Application Tutorials Tutorial 11: Create a Horizontal Histogram 11 To display a line indicating the location of the standard deviation, press: STD DEV 2-45
Application Tutorials Tutorial 11: Create a Horizontal Histogram
3 Eye-Diagram Analyzer Reference
Eye-Diagram Analyzer Reference Eye-Diagram Analyzer Reference Eye-Diagram Analyzer Reference In this chapter, you will find information on the following topics: • • • • • • • • • • • • • • Performing Eye-Diagram Measurements 3-3 Generating Histograms 3-7 Masks and Limit Lines 3-9 Eye-Diagram Menu Maps 3-12 Agilent 70820A Menus 3-14 Controlling the Display 3-16 Calibrating the Eye-Diagram Analyzer 3-23 Displaying Traces 3-25 Using Markers 3-30 Applying Mask Testing 3-31 Saving to Mass Storage 3-34 Creatin
Eye-Diagram Analyzer Reference Performing Eye-Diagram Measurements Performing Eye-Diagram Measurements To perform the automatic eye-diagram measurements, use the Measure menu. With the exception of extinction ratio, these measurements must be performed in eye mode. Automatic Measurements The Measure menu’s top two softkeys automatically start measurements: • EXTINCT RATIO • MEASURE EYE • Use the EXTINCT RATIO softkey to automatically compute the extinction ratio in eye or eyeline modes.
Eye-Diagram Analyzer Reference Performing Eye-Diagram Measurements Use the NUMBER SAMPLES softkey for this purpose. • Use the MEASURE EYE to initiate a number of automatic histogram measurements on an eye-diagram. • Use the r/f tim ON OFF softkey to enable rise time and fall time measurements during the measure eye routine. This approximately doubles the measurement time. • Use the UPPER THRSHLD and LOWER THRSHLD softkeys to set the upper and lower edges for rise time and fall time measurements.
Eye-Diagram Analyzer Reference Performing Eye-Diagram Measurements Crossing Level This measurement is the amplitude that the one level and zero level cross. It also expresses the level as a percentage of the mean one level and mean zero level difference. Eye Width This measurement is the eye width determined from the bit period and the eye jitter. On the eye, the edges are defined to be the left crossing point plusthree sigma and the right crossing point minus-three sigma.
Eye-Diagram Analyzer Reference Performing Eye-Diagram Measurements For Optimum Performance The 70820A module should be configured to: • Control the RF source over the communications bus. • Share the same frequency reference as the RF source. Channels Versus Traces The 70820A module has two input channels, four traces, and four trace memory registers. • Channels are used to measure input signals. • Traces are used to display measurement results. • Trace memory registers can be used as a third channel.
Eye-Diagram Analyzer Reference Generating Histograms Generating Histograms The 70820A can perform statistical analysis on any displayed trace. After creating a vertical or horizontal histogram of the trace data, the display can show mean and standard deviation values of the histogram. Histogram analysis is performed using the Histogram menu.
Eye-Diagram Analyzer Reference Generating Histograms When generating histograms, you must perform the following basic steps: 1 Select a trace. 2 Select histogram type. 3 Enter the number of samples. 4 Set limits for acquired data. 5 Acquire the data. 6 Establish limits for statistical analysis. 7 View the mean and standard deviation. Histogram data can be acquired once using the SINGLE ACQUIRE softkey or continuously updated using the CONT ACQUIRE softkey. Press other for this additional menu.
Eye-Diagram Analyzer Reference Masks and Limit Lines Masks and Limit Lines Masks and limit lines allow you to test the shape (time or frequency versus amplitude) of a displayed response. Masks are closed polygon shapes. Limit lines are lines. Traces or measurement points that penetrate a mask or cross a limit line result in testing errors.
Eye-Diagram Analyzer Reference Masks and Limit Lines A Limit Line Displayed on Screen Because you can perform repetitive testing of response shapes, masks and limit lines are ideal for pass/fail testing on production lines. You create, save, recall, and edit limit lines using the masks, limits menu. Access this menu using the left-side Analyze softkey. Since masks and limit lines are treated similarly, in this chapter, most references to masks applies equally to limit lines.
Eye-Diagram Analyzer Reference Masks and Limit Lines Testing Responses Once you’ve created a mask or limit line, set the following conditions for testing: • Trace to which testing is applied. • Violations defined as traces or measurement points. • Testing ends after a set number of errors. • Testing ends after a set number of traces. Use the test ON|OFF softkey to start testing. Testing stops whenever one of the following events occurs: • A set number of trace sweeps. • A set number of violations.
Eye-Diagram Analyzer Reference Eye-Diagram Menu Maps Eye-Diagram Menu Maps The two menu maps in this section graphically represent the eye-diagram analyzer’s softkey menus.
Eye-Diagram Analyzer Reference Eye-Diagram Menu Maps Traces, Measure, Markers, Masks, and Mass Storage Menus 3-13
Eye-Diagram Analyzer Reference Agilent 70820A Menus Agilent 70820A Menus This section discusses the softkey menus for the 70820A microwave transition analyzer module. To learn about the eye-diagram analyzer’s menus, refer to “Eye-Diagram Menu Maps” on page 3-12. These menus provide additional features useful for running the eye-diagram analyzer. You will find the preview feature discussed in this chapter very useful.
Eye-Diagram Analyzer Reference Agilent 70820A Menus The Left-Side Softkeys Use the softkeys located on the left side of the display to access the twelve major menus. These softkeys are shown in two pages. Press page 1 of 2 to view the second page of softkeys. When the 70820A module first turns on, the Main menu is automatically selected.
Eye-Diagram Analyzer Reference Controlling the Display Controlling the Display To Control the Number of Bits Displayed The Setup menu’s BIT INTVL softkey allows you to select the number of bits that will be displayed on the screen. The horizontal time scale automatically changes to the appropriate setting. Use DELAY to enter time delay. The amount of delay is entered in bits. Use this feature, in pattern mode, to view different portions of the PRBS waveform.
Eye-Diagram Analyzer Reference Controlling the Display To Improve the Sensitivity in Eyeline Mode In eyeline mode, additional eye filtering can be applied to improve the measurement sensitivity. This can be an advantage when measuring extinction ratios on low-level signals. Use the eyefltr ON OFF softkey to apply the filter. When the pattern repetition frequency is greater than 10 MHz, internal filtering is applied that provides a 20 dB signal-to-noise improvement.
Eye-Diagram Analyzer Reference Controlling the Display To learn more about these files and about creating and applying user-corrections, refer to “Tutorial 5: Use Software Filters” on page 2-15. User-Correction Files File Name File Data a_bt248832 4th order Bessel- Thomson filter for 2.48832 Gbit/sec transmission. a_bt_62208 4th order Bessel- Thomson filter for 622.08 Mbit/sec transmission. a_bt_15552 4th order Bessel- Thomson filter for 155.52 Mbit/sec transmission.
Eye-Diagram Analyzer Reference Controlling the Display 4 Load the file by pressing: LOAD FILE The file is loaded when user-corrections loaded is displayed on the screen. 5 Turn the user correction function on by pressing: Trg, Cal, more 1 of 2, usr cor ON|OFF ON.
Eye-Diagram Analyzer Reference Controlling the Display User-Corrections Applied to the Data To View 70820A Menus Press MENU. To Return to the Jitter Analyzer (or Eye-Diagram Analyzer) Press USER. To Preview Programming Commands Press MENU, Config, more 1 of 3, preview ON|OFF ON To View the Firmware Date Code If the eye-diagram analyzer’s menus are not displayed, load the program as explained in Chapter 1, “Getting Started”. For a demonstration of the Preview function, press persist ON|OFF.
Eye-Diagram Analyzer Reference Controlling the Display To View the Date and Time There are two clocks that can be displayed on the screen: the display’s clock and the 70820A module’s clock. You can control whether the clocks are displayed, the indicated time, and the display format. When the mainframe is turned on, the display sets the clock in the 70820A module. This causes both clocks to indicate the same time.
Eye-Diagram Analyzer Reference Controlling the Display 3 To select US or European display format, press US|EURO US or: US|EURO EURO 4 To change the time or date, press: set clock Enter the new value in the same format as displayed. Control the Display’s Clock 1 Press DISPLAY, Misc, clock • If you want to turn the clock display on and off, press CLOCK DISPLAY. • If you want to select US or European display format, press US/EURO. • If you want to change the time or date, press set clock.
Eye-Diagram Analyzer Reference Calibrating the Eye-Diagram Analyzer Calibrating the Eye-Diagram Analyzer Note For information on user-corrections and instrument calibration data, refer to “Agilent 70820A User-Corrections” on page 3-49 and refer to “Agilent 70820A Calibration” on page 3-61. To Compensate for dc Offsets An offset calibration routine is provided that allows the eye-diagram analyzer to compensate channel 1 for any external or internal dc offsets.
Eye-Diagram Analyzer Reference Calibrating the Eye-Diagram Analyzer 1 Connect a low-loss cable between the front-panel CALIBRATOR OUTPUT and channel 1 connectors. 2 To calibrate the IF, press: MENU, page 1 of 2, Calib, IF calib, CAL CH1 The calibration routine takes about 30 minutes to complete. 3 Disconnect the cable from channel 1, and connect it to the channel 2 connector. 4 Repeat the above procedure for channel 2.
Eye-Diagram Analyzer Reference Displaying Traces Displaying Traces Four Traces can be Displayed The Traces menu’s select: softkey allows you to display and control up to four traces. The scaling, reference positions, and reference levels of each trace can be separately adjusted. To automatically adjust the trace scale factor and reference level for optimum display, simply press AUTO-SCALE. Signals are autoscaled once when the softkey is pressed and not on a continual basis.
Eye-Diagram Analyzer Reference Displaying Traces To Position and Scale Each Trace The selected trace can be positioned vertically on the display. This is accomplished using the REF LEV|POS softkey to enter both the reference position and reference level. The reference position (POS) is entered as a percentage of the vertical display. The top of the screen is 100%. The bottom of the screen is 0%. The reference level (REF LEV) is the amplitude value at the reference position.
Eye-Diagram Analyzer Reference Displaying Traces The Averaging Submenu Average trace 1 by pressing: Traces, average, AVERAGE SWEEPS and enter the number of sweeps used for running average, average ON|OFF ON Four Persistence Modes are Available The eye-diagram analyzer offers four trace persistence selections.
Eye-Diagram Analyzer Reference Displaying Traces The Persistence Submenu Infinite Monochrome Persistence With infinite monochrome persistence ( INFINIT), traces accumulate on the display until persistence is turned off or the display is cleared using the Setup menu’s CLEAR DISPLAY softkey. Press OFF to turn off infinite monochrome persistence. Variable Monochrome Persistence With variable monochrome persistence ( VARIABL), older traces become dimmer as new traces are acquired.
Eye-Diagram Analyzer Reference Displaying Traces 1 green 2 cyan (light blue) 3 purple 4 rose 5 yellow This persistence works best with high values of N, typically values of 50 through 100. In this mode, no softkeys can be pressed until after EXIT GRADING is pressed. Monochrome Grading Persistence Monochrome grading persistence ( MONO GRADING) works just like color grading except that a given pixel increases in intensity instead of color each time a dot falls on it.
Eye-Diagram Analyzer Reference Using Markers Using Markers Use this menu to activate the four available line markers: X1, X2, Y1, and Y2. Markers allow you to measure or compare portions of the displayed waveform. For example, you can use markers to measure the peak-to-peak difference in a laser’s turn-on time as measured on the eye-diagram’s crossing point. Use the front-panel knob or numeric keypad to position each displayed marker on the screen.
Eye-Diagram Analyzer Reference Applying Mask Testing Applying Mask Testing Use the Masks menu to display and control mask testing. Built in standard masks for the more common SONET/SDH transmission rates are provided. To learn how to create your own custom masks, refer to Chapter 2, “Application Tutorials”. Test Results are Displayed During mask testing, mask violations are displayed in the lower portion of the display.
Eye-Diagram Analyzer Reference Applying Mask Testing Automatic Alignment Scales the Mask The MASK ALIGN softkey, located under the Masks menu, automatically aligns and scales a default mask to the data per the SONET/SDH standards. This is accomplished using histograms and is best done in eye mode for faster and more evenly distributed data acquisition. Eye mode provides a more even statistical distribution of high and low data.
Eye-Diagram Analyzer Reference Applying Mask Testing The Mask Setup Submenu 3-33
Eye-Diagram Analyzer Reference Saving to Mass Storage Saving to Mass Storage Use the Mass Storage menu, to save and recall files to a mass storage device. The mass storage device is normally a memory card that has been inserted into the front-panel card slot. You can also store data to a GPIB disk drive, and to internal random-access memory (RAM) disk, refer to “Selecting and Formatting Memory” on page 3-34.
Eye-Diagram Analyzer Reference Saving to Mass Storage as long as the card’s battery has sufficient power. You should change the battery every two years using the procedure in this section. Refer to “To Change a Memory Card Battery” on page 3-39. RAM memory cards have a write-protect switch, on the end which is not inserted into the display’s card slot. If this switch is slid toward the edge of the card (marked "SAFE"), no changes may be made to the card’s content.
Eye-Diagram Analyzer Reference Saving to Mass Storage GPIB Disk Drives Measurement data and files can be saved on an external GPIB disk drive. The disk drive must be a 3.5 inch, CS80 compatible, such as an 9122. To use the drive, you must connect it and enter its GPIB address using DISPLAY menu softkeys. The procedure in this section shows you how to do this. You will need to know the disk drive’s GPIB address, unit number, and volume number. The GPIB address is represented by a digit from 1 through 7.
Eye-Diagram Analyzer Reference Saving to Mass Storage Initializing (formatting) a memory card CAUTION The following steps erase any files stored on the card. 1 If the memory card is new and needs to be formatted, press: MENU, page 1 of 2, States, more 1 of 2, mass storage, more, FORMAT 2 To use the LIF format, press: FORMAT as LIF 3 To format as DOS, press: FORMAT as DOS To Use an Internal RAM Disk 1 To invoke Instrument BASIC, press: USER If the eye-diagram personality is loaded, press USER again.
Eye-Diagram Analyzer Reference Saving to Mass Storage 4 Enter the disk drive’s unit number by pressing: UNIT NUMBER This number is typically a 0 or 1. Zero usually indicates the disk drive’s left side slot. 5 Enter the disk drive’s volume number by pressing: VOLUME NUMBER The volume number should be left at the default value of zero for floppy disk drives.
Eye-Diagram Analyzer Reference Saving to Mass Storage To Change a Memory Card Battery The memory card’s battery is a lithium commercial CMOS type, part number CR 2016. The memory card should be installed when the battery is removed. If the battery is removed while the card is not installed, all data in the card will be lost. Store memory-card files on another device before changing the battery, when extra care is appropriate. 1 Install the memory card into the 70004A display.
Eye-Diagram Analyzer Reference Saving to Mass Storage Working with Files Files are identified by a prefix and a name. The eye-diagram analyzer assigns a prefix according to the type of data, as shown in the following table. You enter the file name. When cataloged, the file listings show the file’s data type and size in bytes.
Eye-Diagram Analyzer Reference Saving to Mass Storage To Duplicate a Memory Card Instrument BASIC provides the ability to mass copy all the files from one memory card to another memory card. This allows you to easily reproduce copies without having to copy the files one at a time. Use the following steps: 1 Refer to “To Use a Memory Card” on page 3-36 to select the memory card for use. 2 Insert the memory card with the files into the front-panel card slot. 3 Press USER.
Eye-Diagram Analyzer Reference Saving to Mass Storage 6 Issue the following Instrument BASIC command to copy the files from the RAM disk to the new card: COPY "*:MEMORY,0,0" TO ":EXTERNAL,904" To Catalog all Files Use this procedure to catalog default memory. To select default memory, refer to “Selecting and Formatting Memory” on page 3-34. 1 If you plan to catalog the files on a memory card, insert the card in the frontpanel card slot.
Eye-Diagram Analyzer Reference Saving to Mass Storage Entering a File Name without a Keyboard a Turn the front-panel knob to move the character-select cursor. b Press SELECT CHAR to enter a character at the character-select cursor. c Press the numeric keypad to enter numbers or a minus sign. d The INSERT or ... softkey determines the action of the SELECT CHAR softkey. Choices are INSERT a character, REPLACE an existing character, or DELETE a character.
Eye-Diagram Analyzer Reference Saving to Mass Storage To Erase all Files CAUTION This procedure erases all files stored in default memory. To erase all files in default memory, press: MENU, page 1 of 2, States, more 1 of 2, mass storage, more, FORMAT To Change the Prefix 1 To modify the prefix, press: MENU, page 1 of 2, States, more 1 of 2, mass storage, more, CHANGE PREFIX Enter the desired text.
Eye-Diagram Analyzer Reference Saving to Mass Storage To Erase a Custom Prefix 1 To erase a custom prefix, press: MENU, page 1 of 2, States, more 1 of 2, mass storage, more, CHANGE PREFIX Repeatedly press the ⇓ step key until the cursor is located at the start of the custom text. 2 Clear the text by pressing: CLEAR TO END, ENTER LINE To Save an Instrument State 1 Set the eye-diagram analyzer to the desired settings. 2 Insert a ROM card into the front-panel card slot.
Eye-Diagram Analyzer Reference Saving to Mass Storage To Save a Mask/ Limit Line File 1 Display the Mass Storage menu by pressing: States, more 1 of 2, mass storage If the mass-storage device needs to be selected, refer to “Selecting and Formatting Memory” on page 3-34. 2 Enter the file name by pressing: save, save misc, SAV MSK LIM Use the softkeys, knob, numeric keypad, and step keys to enter the file name.
Eye-Diagram Analyzer Reference Creating Copies of the Display Creating Copies of the Display Often, it is important to create hard copies of the display for reports or records. A copy of the display can be printed on any Hewlett-Packard graphics printer. These printers support the Hewlett-Packard PCL printer language and include the following: • ThinkJet • PaintJet • LaserJet Note The printer must have an GPIB interface.
Eye-Diagram Analyzer Reference Creating Copies of the Display 4 Select the print option by pressing: ←, copy options, COPY IS PRT/PLT PRT 5 Create the print by pressing: USER, PRINT To Create a Plot Hard copies can be produced on an Hewlett-Packard plotter if the eye-diagram analyzer is in pattern mode. Plots cannot be produced in eye or eyeline modes. 1 Connect the plotter to the display via an GPIB cable.
Eye-Diagram Analyzer Reference Agilent 70820A User-Corrections Agilent 70820A User-Corrections User corrections provide a convenient method for modifying the display of input signals. Some of the applications for user-corrections include the following: • Filtering input signals to simulate the effects of circuit design. • Compensating for frequency and phase response of external probes. • Compensating for frequency and phase response of external test setups.
Eye-Diagram Analyzer Reference Agilent 70820A User-Corrections Example User-Corrections User corrections always contain at least two default lines of data, as shown in the following figure. While these two lines of data cannot be removed, you can modify their magnitude or phase values. New lines of data are easily added. Each line of data consists of FREQuency, MAGNitude, PHASE, and path to next FREQ fields.
Eye-Diagram Analyzer Reference Agilent 70820A User-Corrections Default Data Enter user-correction data by: manually using front-panel keys or storing the results of a sweep to user-correction memory.
Eye-Diagram Analyzer Reference Agilent 70820A User-Corrections To Delete a Channel’s UserCorrections 1 Delete a channel’s user-corrections by pressing: MENU, page 1 of 2, Calib, user corr 2 Select the desired channel by pressing: CH1|CH2 3 Delete the selected channels user-corrections by pressing: other, DELETE ALL 4 To delete all corrections, press: CONFIRM DEL ALL 5 To cancel the deletion process, press: ABORT DEL ALL Entering and Editing User-Corrections The User Correction menu provides softkeys for e
Eye-Diagram Analyzer Reference Agilent 70820A User-Corrections The following two figures show the effect of selecting linear slope and flat types. The trace graphically shows the filter. With the exception of the path to next FREQ field, the data in each filter is identical.
Eye-Diagram Analyzer Reference Agilent 70820A User-Corrections To Enter a Line of Data 1 Enter a line of data by pressing: MENU, page 1 of 2, Calib, user corr, SEL|EDT SEL New lines are added just above the highlighted line. Use the front-panel knob or arrow keys to highlight any field of the line which is to be below the new inserted line.
Eye-Diagram Analyzer Reference Agilent 70820A User-Corrections To Edit a Line of Data 1 To edit a line of data, press: MENU, page 1 of 2, Calib, user corr, SEL|EDT EDT Use the front-panel knob, step keys, or numeric keypad to change the displayed value.
Eye-Diagram Analyzer Reference Agilent 70820A User-Corrections To Copy UserCopy user correction to an alternate channel by pressing: Correction to MENU, page 1 of 2, Calib, user corr, other, copy to CH2 Alternate Channel If channel 2 data is selected, the softkey reads copy to CH1. Viewing User-Correction Data This section explains how to assign user-correction data to a trace. This allows you to view the data graphically.
Eye-Diagram Analyzer Reference Agilent 70820A User-Corrections To View UserCorrections 1 To view user-corrections, press: MENU 2 To enter the Traces menu, press: Traces 3 Select a trace, and then press: input: 4 Use the front-panel knob to scroll the menu bar to UCORR1, as shown in the following figure. UCORR1 sets the trace to user-correction data for channel 1. UCORR2 sets the trace to user-correction data for channel 2. 5 Press the RETURN softkey.
Eye-Diagram Analyzer Reference Agilent 70820A User-Corrections 7 Set the frequency scale of the user-correction trace: • If the microwave transition analyzer is set for a frequency sweep, use the Main menu’s START and STOP softkeys. • If the microwave transition analyzer is set for a time sweep, press the Main menu’s SEC/DIV softkey, and enter the sweep time to set the stop frequency. The formula to determine the sweep time is provided at the beginning of this section.
Eye-Diagram Analyzer Reference Agilent 70820A User-Corrections Saving, Recalling, and Cataloging User-Correction Files User-correction data can be saved in files and recalled for later use. This section shows you how to accomplish this task using the 70820A module’s mass storage menu. (You can also save, recall, and erase user-correction files using the eye-diagram analyzer’s Mass Storage menu.) The files are saved to default memory.
Eye-Diagram Analyzer Reference Agilent 70820A User-Corrections To Recall a UserCorrection File 1 To recall a user-correction file, press: MENU, page 1 of 2, States, more 1 of 2, mass storage If the mass-storage device needs to be selected, refer to “Selecting and Formatting Memory” on page 3-34. 2 Rotate the front-panel knob to select (highlight) the desired file.
Eye-Diagram Analyzer Reference Agilent 70820A Calibration Agilent 70820A Calibration Use the Calibration menu to perform the following tasks: • Match delay between channels. • Initiate an instrument self-test routine. • Turn off RF correction. • Calibrate the IF. • Verify the calibrator signal. The Calibration Menu The automatic IF calibrations documented in this section ensure accurate measurements using the eye-diagram analyzer.
Eye-Diagram Analyzer Reference Agilent 70820A Calibration The Calibration Menu Turning Off RF Correction The microwave transition analyzer module applies RF correction factors to all measurements. These correction factors are loaded into nonvolatile memory at the factory . You can prevent the use of RF correction factors during measurements. Note Eyeline and pattern modes are required. RF corrections can only be applied in eyeline and pattern modes. RF corrections must be off in eye mode.
Eye-Diagram Analyzer Reference Agilent 70820A Calibration Matching Delay Between Channels Significant delays can occur between the signals on channel 1 and channel 2 when the electrical lengths of external cabling varies. This results in a phase offset between the two channels. The microwave transition analyzer module offers the capability to add delay to either channel 1 or channel 2. The following figure shows added delay on channel 2.
Eye-Diagram Analyzer Reference Agilent 70820A Calibration Trace 2 Delay Compensated To Delay a Channel Automatically compensate channel 2 by pressing: MENU, page 1 of 2, Calib, chan skew, AUTO SKEW Calibrating the IF The microwave transition analyzer module provides separate automatic IF calibration routines for channel 1 and channel 2. Each requires approximately 30 minutes to run.
Eye-Diagram Analyzer Reference Agilent 70820A Calibration Note Warm up time Allow the microwave transition analyzer module to warm up for at least one hour before performing a calibration. To Calibrate the IF 1 Connect a low-loss cable between the front-panel CALIBRATOR OUTPUT and channel 1 connectors. 2 To calibrate the IF, press: MENU, page 1 of 2, Calib, IF calib, CAL CH1, CAL CH1 The calibration routine takes about 30 minutes to complete.
Eye-Diagram Analyzer Reference Agilent 70820A Calibration Viewing the Calibration Data The ability to view the IF calibration data is mainly intended for service purposes. However, the procedures in this section show you how to view the data. To View IF Correction Data Traces 1 Display the Traces menu by pressing: MENU, Traces 2 Turn on both trace 1 and trace 2. Set the input to trace 1 as channel 1. Set the input to trace 2 to channel 2.
Eye-Diagram Analyzer Reference Agilent 70820A Calibration To View Hardware Response Traces 1 Display the traces menu by pressing: MENU, Traces 2 Turn on both trace 1 and trace 2. Set the input to trace 1 as channel 1. Set the input to trace 2 to channel 2.
Eye-Diagram Analyzer Reference Agilent 70820A Calibration 7 To display the various hardware responses, press: page 1 of 2, SHOW CAL Use the front-panel step keys to scroll through the various hardware responses.
Eye-Diagram Analyzer Reference Agilent 70820A Calibration 5 To view the data for channel 1, press: CH1 CAL INFO 6 To view the data for channel 2, press: CH2 CAL INFO 7 To view additional pages of information, continue pressing: CH1 CAL INFO or CH2 CAL INFO Performing a Self-Test You can initiate an automatic self-test routine that checks the internal condition of all major circuits. The self-test takes approximately 30 seconds to run.
Eye-Diagram Analyzer Reference Agilent 70820A Calibration To Turn the Calibrator Signal On To turn the calibrator signal on, press: To Change the Calibrator Frequency and Amplitude To change the calibrator frequency and amplitude, press: MENU, page 1 of 2, Calib, cal signal, cal sig ON|OFF ON MENU, Calib, cal signal, FREQ, (156 Hz–5 MHz), AMPL, (0–4)
4 Programming Commands
Programming Commands Programming Commands Programming Commands This chapter documents programming the eye-diagram analyzer. Note You will find the preview feature discussed in this chapter very useful. It displays the programming command corresponding to the response received when most softkeys are pressed. You will find information on the following commands in this chapter.
Programming Commands Introduction Introduction Before communicating with the eye-diagram analyzer application, the Instrument BASIC system must be queried for the name of the program and told we wish to communicate with this program. The following example shows how to do this.
Programming Commands Introduction PROG:WAIT? query to indicate when the 70874C has paused. Then, retrieve the response using the PROG:STR? query. Use PROG:STATe to continue program execution. (Notice the lower case letter e in PROG:STATe. This indicates the this letter can be entered in either upper or lower case.) The following example shows how to return the results of eye measurement. Notice that the MEAS command does not use the Param variable.
Programming Commands Introduction BIT The BIT command string sets the instrument’s time scale (seconds-per-division) to a value which corresponds to the number of bits specified in the Param variable. Values of Program Variables Variable Example Data Type Value Command string BIT Param floating-point number example: 3.5 Response string DONE OUTPUT Mta;"PROG:NUMB ’Param’,3.
Programming Commands Introduction Example OUTPUT Mta;"PROG:STR ’Command’,’CLEAR’" OUTPUT Mta;"PROG:WAIT?" ENTER Mta;A$ OUTPUT Mta;"PROG:STR? ’Response’" ENTER Mta;Response$ OUTPUT Mta;"PROG:STAT CONT" DEFAULT The DEFAULT command string copies the default masks specified in the Param variable.
Programming Commands Introduction DELAY The DELAY command string sets the displayed delay value to the number of bits specified in the Param variable. Values of Program Variables Variable Example Data Type Value Command string DELAY Param floating-point number example: 2.75 Response string DONE OUTPUT Mta;"PROG:NUMB ’Param’,2.
Programming Commands Introduction Values of Program Variables Variable Command Data Type string DIAGRAM string EYE EYELINE PATTERN string DONE Param Response Example Value OUTPUT Mta;"PROG:STR ’Param’,’EYELINE’" OUTPUT Mta;"PROG:STR ’Command’,’DIAGRAM’" OUTPUT Mta;"PROG:WAIT?" ENTER Mta;A$ OUTPUT Mta;"PROG:STR? ’Response’" ENTER Mta;Response$ OUTPUT Mta;"PROG:STAT CONT" EXTIN The EXTIN command string performs an extinction ratio measurement.
Programming Commands Introduction Example OUTPUT Mta;"PROG:STR ’Command’,’EXTIN’" OUTPUT Mta;"PROG:WAIT?" ENTER Mta;A$ OUTPUT Mta;"PROG:STR? ’Response’" ENTER Mta;Response$ OUTPUT Mta;"PROG:STAT CONT" MARGIN The MARGIN command string sets the margin percentage limit for margin mask testing. Load the Param variable with a floating-point number that specifies the percentage over standard mask to test. The range of margin is 0 to 100 percent.
Programming Commands Introduction Values of Program Variables Variable Command Param Response Example Data Type Value string MARMSK string ON OFF string DONE OUTPUT Mta;"PROG:STR ’Param’,’ON’" OUTPUT Mta;"PROG:STR ’Command’,’MARMSK’" OUTPUT Mta;"PROG:WAIT?" ENTER Mta;A$ OUTPUT Mta;"PROG:STR? ’Response’" ENTER Mta;Response$ OUTPUT Mta;"PROG:STAT CONT" MEAS The MEAS command string performs the following eight measurements on the eye: 1 mean 1 level 2 mean 0 level 3 eye height 4 crossing level 5 ey
Programming Commands Introduction Values of Program Variables Variable Value Command string Param There are no parameters for this command. Response Example Data Type string MEAS example: 25.1 14.2 9.67 2.23 8.91 4.5 2.11 6.7 OUTPUT Mta;"PROG:STR ’Command’,’MEAS’" OUTPUT Mta;"PROG:WAIT?" ENTER Mta;A$ OUTPUT Mta;"PROG:STR? ’Response’" ENTER Mta;Response$ OUTPUT Mta;"PROG:STAT CONT" PERSIST The PERSIST command string controls persistence displays.
Programming Commands Introduction Values of Program Variables Variable Command Data Type string PRESIST string INF VAR COLGRAD MONOGRAD OFF string DONE Param Response Example Value OUTPUT Mta;"PROG:STR ’Param’,’COLGRAD’" OUTPUT Mta;"PROG:STR ’Command’,’PERSIST’" OUTPUT Mta;"PROG:WAIT?" ENTER Mta;A$ OUTPUT Mta;"PROG:STR? ’Response’" ENTER Mta;Response$ OUTPUT Mta;"PROG:STAT CONT" QUIT The QUIT command string causes the eye-diagram personality to terminate.
5 Specifications and Characteristics
Specifications and Characteristics Specifications and Characteristics Specifications and Characteristics This chapter contains specifications and characteristics for the 71501C and 70874C Jitter and Eye Diagram Analyzer. Definitions of Terms The distinction between specifications, characteristics, typical performance, and nominal values is described as follows: • Specifications describe warranted performance over the temperature range 0°C to +55°C (unless otherwise noted).
Specifications and Characteristics Vertical Specifications Vertical Specifications Table 5-1. Vertical Specifications Bandwidth (–3 dB): 20 GHz (extended BW off) 40 GHz (extended BW on) dc accurachy (±5° C from cal): The larger of ±2% of signal ampltiude or 500 µV The larger of ±1% of signal ampltiude or 500 µV (typical) Noise floor (at 1 GHz): <1.
Specifications and Characteristics Input Channel Specifications Input Channel Specifications CAUTION Input channels RF INPUT 1 and RF INPUT 2 are dc coupled. Table 5-2. Input Channel Specifications Operation input range: <±320 mB (including dc offset) Maximum safe input voltage without damage: ±2 V pk-pk Number of input channels: 2 Input connectorsa 2.4 mm (male) Nominal input impedance: 50 Ω Programmable dc offset: ±320 mV a. Includes two 2.4 mm (f) to 3.5 mm (f) adapters.
Specifications and Characteristics Trigger Specifications Trigger Specifications Table 5-3. Trigger Specifications Operation input range: (including dc offset) <±320 mV Maximum safe input voltage without damage ±2 Vpk-pk Number of input channels: 2 Input connectors:a 2.4 mm (male) Nominal input impedance: 50 Ω Programmable dc offset: ±320 mV a. Includes two 2.4 mm (f) to 3.5 mm (f) adapters.
Specifications and Characteristics Trigger Specifications Trigger Specifications Table 5-4. Trigger Specifications Trigger sensitivity (dc - 40 GHz): 65 mV pk-pk (typical) Jitter: <2.
Specifications and Characteristics Horizontal Specifications Horizontal Specifications These specifications are for the eye diagram analyzer only. Table 5-5.
Specifications and Characteristics Declaration of Conformity Declaration of Conformity
Index Numerics 0 level description, 3-4 1 Level description, 3-4 10 MHz reference, 1-11 70820A calibration, 3-61 70820A clock control, 3-21 70820A connections, 1-13 70820A menus, 3-14 70820A user-corrections, 3-49 70841A/B pattern generator, 1-24 A accessories, 1-15 accessories required, 1-14 add time delay, 2-28 additional margin testing, 2-20 Agilent 70820A menus, 3-14 ALIGN command, 4-4 align mask, 3-32 amplitude and phase transitions, 3-5 analysis, eye-diagram, 1-2 application tutorials, 2-2 apply use
Index create print, 3-47 crossing level description, 3-5 custom keypad, 1-3 custom mask or limit line testing, 2-23 custom prefix, 3-45 D data pattern display, 2-27 data signal configuration, 2-2 data, user-corrections, 3-20 date and time viewing, 3-21 date code of firmware, 3-20 dc offset compensation, 3-23 default and custom mask or limit line testing, 2-23 DEFAULT command, 4-6 definition INSTR PRESET key, 1-11 definitions 0 level, 3-4 1 level, 3-4 crossing level, 3-5 extinction ratio, 3-4 eye height, 3
Index eye-diagram analyzer reference, 3-2 eye-diagram analyzer, calibrating, 3-23 eye-diagram menus, 3-12 eyeline software filters, 1-9 eyeline mode, 1-5, 1-7, 2-13 F fails, program loading, 1-17 fast amplitude and phase transitions, 3-5 features of modes, 1-5 fiber optics care of, 1-iv file prefixes, 3-40 files user-correction, 1-9, 3-18 files, catalog, 3-42 files, change prefix, 3-44 files, custom prefix, 3-45 files, erase, 3-43 files, recall, 3-43 filter, from a transfer function, 2-30 filter, laser ov
Index markers turned on, 2-13 markers, menus, 3-13 MARMSK command, 4-9 mask align, 3-32 mask and limit lines, 1-8 mask margins, 3-32 mask or limit line creation, 2-24 mask or limit line editing, 2-24 mask setup menu, 3-33 mask testing applying, 3-31 modes available, 1-5 masks and limit lines, 3-9 masks and limit lines description, 3-9 masks displayed on screen, 3-9 masks, menus, 3-13 mass storage, 3-34 mass storage, menus, 3-13 matching delay between channels, 3-63 mean fall time description, 3-5 mean rise
Index printing, 3-47 PROG STR? to read response, 4-3 program failed to load, 1-17 program variables, values, 4-5 programming commands, 4-2 programming commands, preview, 3-20 Q QUIT command, 4-12 R RAM disks, 3-35 read response, PROG STR?, 4-3 rear-panel connections, 1-13 recall files, 3-43 recall, mask or limit line, 3-46 recall, user-correction file, 3-60 reference, 10 MHz, 1-11 reference, eye-diagram analyzer, 3-2 repetitive and non-repetitive signals, 3-5 restore the factory instrument preset, 1-27 r
Index trigger level, manually set, 1-25 trigger source, 1-22 trigger, menus, 3-12 turn calibrator signal on, 3-70 turning off RF correction, 3-62 tutorials application, 2-2 constructing a low-pass filter from a transfer function, 2-30 create a horizontal histogram, 2-41 create a vertical histogram, 2-36 default and custom mask or limit line testing, 2-23 display the data pattern, 2-27 extinction ratios on low-level signals, 2-10 eye-parameters, 2-4 measure laser turn-on delay, 2-13 measurement in optical p
