Signal inputs, Set up signal, Setup signal inputs – Teledyne LeCroy SDA II User Manual
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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. If you are using two single-ended probes or two coaxial cables, you can
select Input1-Input2 and specify the input sources to use when calculating the differential signal. For
more information, see
Crossing Level section (2) lets you to set the voltage level at which the signal timing is measured. The
crossing level is set separately for the data and clock signals (if an external clock is selected) and can either
be an absolute voltage or a percentage of the signal amplitude via the relative selection. You can also con-
figure a hysteresis level, and between positive, negative and both edge types for when the "Clock" Signal
Type is selected. The Crossing Level section on this dialog is for the data signal. For more information, see
.
Signal Type section (3) lets you choose a standard signal type. The signal type you choose automatically
sets the nominal bit rate for the selected standard, and populates the Mask Type selector in the Eye
dialog. For more information, see
Noise Settings includes settings that are used by the vertical noise measurements toolkit. Settings
include the Sample Phase, which determines where in the unit interval the sample is taken for the noise
measurement. Also, see
How to Order SDAIII-CompleteLinQ Capabilities
for information on which prod-
ucts include the vertical noise analysis capabilities.
NOTE:
l
Many of the measurements in SDAIIrequire both a high sampling rate and long memory to com-
pute jitter and vertical noise accurately.
l
Lower sampling rates can result in less accurate jitter measurements, and short record lengths can
give incomplete eye patterns or jitter and noise displays that diverge.
l
For best results, acquire waveforms with at least 100,000 unit intervals, and of >100 iterations of
the pattern. See
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