Operator's Manual SDAII Software
Serial Data Analysis II Software Operator's Manual © 2013 Teledyne LeCroy, Inc. All rights reserved. Unauthorized duplication of Teledyne LeCroy documentation materials other than for internal sales and distribution purposes is strictly prohibited. However, clients are encouraged to distribute and duplicate Teledyne LeCroy documentation for their own internal educational purposes. Serial Data Analysis II and Teledyne LeCroy are registered trademarks of Teledyne LeCroy, Inc.
Operator's Manual TABLE OF CONTENTS SDAII Overview Key Features Serial Data Analysis II Dialog Setting Up SDAII 2 2 2 3 Quick View Setting Up Quick View 4 5 Signal Inputs Set Up Signal Serial Data Inputs Signal Types Crossing Levels 6 6 7 7 7 Reference Clock Set Up Reference Clock Reference Clock Inputs Crossing Level Clock Timing 9 9 10 10 10 Clock Recovery Set Up Clock Recovery Bit Rate Reference Clock PLL Setup Clock Recovery Theory 11 11 11 11 12 14 Eye Measurements Eye Measure Dialog Set Up
Serial Data Analysis II Software SDAII Overview The new Serial Data Analyzer (SDAII) provides comprehensive measurement capabilities for evaluating serial digital signals. SDAII operates by processing a long signal acquisition. All jitter measurements and displays are based on times of successive edges for the signal only - nothing is relative to the trigger. As a result, they are not affected by trigger jitter.
Operator's Manual Setting Up SDAII Use the following steps to start your SDAII setup. 1. If you haven't done so already, touch Analysis → Serial Data on the menu bar. 2. On the Serial Data Analysis II dialog, place a checkmark in the Enable SDA box. 3. Touch the Setup Signal Inputs button to configure your signal input sources, crossing levels, and signal type. Note: Touch the Quick View button to quickly set up and view your serial data. 4.
Serial Data Analysis II Software Quick View The SDAIIQuick View shows the eye diagram, TIE track, bathtub curve, jitter histogram, NQ-scale, and jitter spectrum (with peaks annotated) in a single, summarized view. SDAII Quick View You must specify only the input signal for analysis. You can also specify the crossing level.
Operator's Manual Setting Up Quick View Follow these steps to set up Quick View. 1. If you haven't done so already, touch Analysis → Serial Data on the menu bar or touch the Serial Data Analyzer button on the Quick Access toolbar. 2. On the Serial Data Analysis II dialog, touch the Quick View button. The Signal Input(s) to be Analyzed pop-up window opens. 3. On the Serial Data Input(s) section, if you are using a differential probe, touch the 1 Input (or Diff. Probe) button.
Serial Data Analysis II Software Signal Inputs Set Up Signal On the Serial Data Analysis II dialog, touch the Setup Signal Input button to access the Signal Input dialog. Serial Data Input(s) section (1) lets you define the serial data input(s). If you are using a differential probe or if your signal is connected by one coaxial cable, you can select 1 Input (or Diff. Probe) and specify the input source in the Input1 box.
Operator's Manual Serial Data Inputs There are several scenarios for the configuration of the Seria Data Input(s) section. If you are using a differential probe or if your signal is connected by one coaxial cable, use the 1 Input (or Diff. Probe) button and select the input source. If you have a differential signal transmitted on two two coaxial cables or two single-ended probes., use the Input1-Input2 button and select the input channels used.
Serial Data Analysis II Software matically set on each acquisition. The value set is the selected percentage of the signal amplitude (which equals base - top). The Slope selector determines which edges are measured when "Clock" is selected in the Signal Type selector in the Signal dialog.. The choices for slope are Pos(itive), Neg(ative) or Both Select the choice that corresponds to the edge type that is used for clocking of the data in your device, or that is of interest in your analysis.
Operator's Manual Reference Clock Set Up Reference Clock An accurate reference clock is central to the measurements performed by SDAII. When the clock is recovered from data, the clock is defined from the locations of the data's crossing points in time. When a reference clock is used, the clock is defined from the locations of the reference clock's crossing points. Starting with zero, the clock edges are computed at specific time intervals relative to each other. Example: A 2.
Serial Data Analysis II Software Reference Clock Inputs The Reference Clock Input(s) section in the Ref. Clock Input dialog lets you define the clock input(s). You can choose Clock+ Only or Clock+ and Clock- .You can also define the upsample rate (when increasing the sampling rate of the clock signal). Crossing Level The Crossing level section of the Reference Clock Inputs dialog lets you set the voltage level where timing is measured for the reference clock.
Operator's Manual Clock Recovery Set Up Clock Recovery An accurate reference clock is central to any jitter measurement, including all the measurements performed by SDAIII-CompleteLinQ. The recovered clock is defined by the times at which the specified signal (either data or reference clock) crosses the specified threshold. Starting with zero, the clock edges are computed at specific time intervals relative to each other. A 2.5 GHz clock, for example, will have edges separated in time by 400 ps.
Serial Data Analysis II Software This section duplicates controls found elsewhere: the Use Explicit Clock Ref checkbox (serving the same function as the multiplexer switch on the SDAII dialog) and the Multiplier field (also found on the Ref Clock dialog). PLL Setup The PLL Setup section of the Clock Recoverydialog contains the controls to set the type and bandwidth of the digital PLL used in all SDAII measurements.
Operator's Manual PCI-EXPRESS There are four PCI-Express selections that meet the following standards: l PCI-Express Gen1 l PCI-Express Gen2 A l PCI-Express Gen2 B l PCI-Express Gen2 C DVI The DVI selection displays the DVI PLL dialog at the far right of the screen and follows the requirements of the DVI (Digital Video Interactive) and HDMI (High Definition Multimedia Interface) specifications.
Serial Data Analysis II Software l A damping factor below 0.707 provides an under-damped response that reacts more slowly to sudden changes in frequency; however, does not over-correct. The default value of 0.707 represents a critically damped response that provides the fastest reaction time without over-correcting. The second order PLL with a damping factor of 0.707 is specified in the serial ATA generation II document.
Operator's Manual SDA Edge Time Determination Clock recovery implementation in the SDA is shown in the following figure. This algorithm generates time values corresponding to a clock at the data rate. The computation follows variations in the data stream being tested through the use of a feedback control loop correcting each period of the clock by adding a portion of the error between the recovered clock edge and the nearest data edge.
Serial Data Analysis II Software The value of y is the correction value for the kth iteration of the computation and x is the error k k between the kth data edge and the corresponding clock edge. Notice that the current correction factor is equal to the weighted sum of the current error and all previous correction values. The multiplier value is set to one in the SDA, and the value of n is the PLL cutoff divisor set from the Serial Data Analysis IIdialog.
Operator's Manual Eye Measurements Eye Measure Dialog The Eye Measure dialog is the principal tool for setting up Eye diagrams. Click the Setup Eye Measurements button on the Serial Data Analysis II dialog to access the Eye Measure dialog. The Eye Modes section in the Eye Measure dialog lets you choose an eye mode, either Single Eye, Dual Eye Trans/Non-trans, Dual Eye Gated, Dual Eye FSB. The Masks section in the Eye Measure dialog lets you select different modes for the selected standard.
Serial Data Analysis II Software 7. Touch inside the X field and enter a value from 0 to 100%. As you enlarge the mask's margin, you lengthen the horizontal dimension, bringing the mask closer to the crossing points of your eye diagram. This reduces the amount of jitter that can still pass the eye. 8. Touch inside the Y field and enter a value from 0 to 100%. As you enlarge the mask's Y margin, you widen the vertical dimension, bringing the mask closer to the top and bottom of your eye diagram.
Operator's Manual Mask Testing Mask testing to either absolute or normalized masks can be performed with SDAIII-CompleteLinQ. You can determine where the signal has violated the mask, how many failures have occurred, and determine which particular UI is in violation. When selecting a Signal Type on the Signal tab for a serial data standard, the Mask section of the Eye Measure. Each standard has a set of required tests; some of the standards specify using a specific mask template.
Serial Data Analysis II Software Eye Saturation- Use the slider to increase or decrease eye saturation. The setting for saturation adjusts the color grading or intensity. Slide to the left to reduce the threshold required to reach saturation. Show Failures- Place a checkmark to show the mask failures. Mask failures are identified by contrasting color spots which appear anywhere the data intersects the mask template.
Operator's Manual Eye Parameters Dialog The Eye Parameters right-hand dialog lets you choose which parameters you want to show on the screen. You can also enter a slice width. The slice width is a percentage of the duration of a single bit (the part of the pattern over which the extinction ratio is measured). Setting a percentage value indicates how much of the central portion of the bit width to use. Both the Jitter Measurements and the Eye Parameters can be on at the same time.
Serial Data Analysis II Software Eye Height The eye height is a measure of the signal-to-noise ratio of a signal. The mean of the 0 level is subtracted from the mean of the 1 level as in the eye amplitude measurement. This number is modified by subtracting three times the standard deviation of both the 1 and 0 levels. The measurement provides an indication of the eye opening and is made on the central region (normally 20%, user changeable) of the UI (bit period).
Operator's Manual This measurement algorithm is best suited to eye diagrams that are rendered from optical rather than electrical signals. In the presence of inter-symbol interference and/or equalization, it may not give reasonable results. The Q factor is a measure of the overall signal-to-noise ratio of the data signal.
Serial Data Analysis II Software Eye Analysis Theory Eye diagrams are persistence maps, where each pixel in the map takes on a color that indicates how frequently a signal has passed through the time (within a UI) and voltage specified for that pixel. Theeye diagram shows all values a digital signal takes on during a bit period. A bit period (or UI) is defined by the data clock, so some sort of data clock is needed to measure the eye pattern.
Operator's Manual Eye Patterns SDAIImeasures eye patterns without using a trigger. This is done using the software clock recovery (discussed in Set Up Clock Recovery) to divide the data record into segments along the time values of the clock. For the purpose of dividing the time line into segments, the time resolution is essentially infinite. The samples occur at fixed intervals of 25 or 50 ps/pt (for 40 or 20 GS/s sampling rate).
Serial Data Analysis II Software Jitter Measurements Set Up Jitter Measurements Touch the Setup Jitter Measurements button on the Serial Data Analysis II dialog to access the Jitter Measure dialog. The SDAII jitter analysis follows a flow of events. The main Jitter Measure dialog shows the basic flow of the jitter analysis through a simple block diagram progressing from left to right. Each block in the diagram is also a button. Touching any of the buttons opens its corresponding right hand dialog.
Operator's Manual Pattern Analysis 1. First the data pattern is found. 2. Then, a DDj analysis is performed on the TIE trend. The average TIE is calculated for each DDj class. The DDj classes can be defined either by where the edge occurs in a repetitive pattern or by the N-bit sequence occurring prior to the edge. 3. From this analysis, a list of DDj values and populations is created for each classification made from step 1. 4.
Serial Data Analysis II Software Jitter Parameters The fit extrapolation for the NQ-scale model can be shown on the histogram for the NQ-scale model. The Rj+BUj jitter distribution with the analytical tail extrapolations is then convolved with the DDj distribution (found during the Pattern Analysis Step) to create the total jitter distribution. This is integrated to give the jitter CDF.
Operator's Manual Cutoff Freq (1) - Shown when any filter type is selected. Cutoff Freq (2) - Shown only when the Bandpass Filter Type is chosen. Pattern Analysis The DDj is measured by finding the average crossing time for each edge in the data pattern and comparing this to the nominal crossing time, based on the expected bit rate of the signal under test. This measurement requires a repeating data pattern to operate.
Serial Data Analysis II Software Length - Specify the length .. Auto Clear - Check this box to automatically clear the selections. Clear Sweeps - Click this button to clear sweeps. Repeating Pattern - Check this box to repeat the pattern. Min Patt. Reps. - Used to set the minimum number of repetitions of a pattern needed in the input waveform. A warning is shown if less than the minimum setting is provided. Auto Find Pattern - Check this box to automatically find the pattern.
Operator's Manual Show PLLTrack - Plots the jitter that the PLL is tracking out. This is relative to a ideal clock at the found bit rate. PLLTrack waveform shows the behavior of the PLL to track out low frequency jitter in your signal. It shows a waveform that includes, for each edge (real or virtual) in your signal, a measurement of the difference between (1) the expected arrival time of the edge, as determined by the PLL, and (2) the expected arrival time of the edge if the PLL was not turned on.
Serial Data Analysis II Software RjBUj Spectrum When displaying the RjBUj Spectrum, the spectral analysis takes the FFT of the RjBUjTrack (DDj removed). Note the Jitter Spectrum is showing magnitude; to get peak-to-peak jitter multiplied by 2.
Operator's Manual Peak Threshold Peak Threshold view enables you to know what peaks are viewed as Pj for downstream analysis. Spectrum with Threshold and Peak Annotation Pj Inv. FFT The Pj Inverse FFT turns a complex frequency view of the peak information into a simple time domain view of the users Pj (Periodic Jitter).
Serial Data Analysis II Software Jitter Histogram Analysis Two jitter histograms can be viewed in SDAII, the TIE histogram, which contains all sources of jitter, and the Rj+BUj histogram, which has the DDj removed. The integrated histogram or the CDF (cumulative distribution function) can also be viewed. The CDF can also be displayed in the more standard representation of a bathtub curve. Zoom in on any of the plots by touching the trace descriptor, and then selecting the zoom tab on the right side dialog.
Operator's Manual Jitter Parameters Touch the Jitter Parameters button on the Jitter Measurement dialog to display the Jitter Parametersdialog and select the parameters to display on the readout table. Dual-Dirac Spectral Rj+Dj CDF Fit - If Spectral is selected, then spectral analysis is used to determine a sigma value to fit the tails of RjBUjHist, and the positions of the right and left Gaussians, mu_left and mu_right are obtained from a best fit.
