LeCroy DDA 7 Zi series, Operator'S Manual

Page: 417 / 544

Operator's Manual
WP700Zi-OM-E-RevA
416
Jitter Filter Function
The jitter filter function generates a time sequence of jitter measurements that are filtered by the selected band-
pass filter. Low-pass and high-pass frequencies are set in the function’s menu. You must enter the bit frequency
(data rate) to set the sampling rate for the digital filter. This function is only valid when operating on the TIETrend
trace generated by the SDA. The low frequency corner is limited by the record length (longer records are required
for lower cutoff frequencies). If an invalid lower cutoff frequency is chosen, the filter reverts to low-pass.
Bit Frequency 100 kHz to 4.5 GHz The bit rate of the signal under test
Low Pass
Frequency Set by record length and sample rate (bit
rate) The lower corner frequency of the band-
pass filter
High Pass
Frequency Set by record length and sample rate (bit
rate) The upper corner frequency of the band-
pass filter
Slice2Persist
The Include virtual edges checkbox must be checked in
the TIE@lvl parameter dialog to include both transition
and non-transition edges in the eye pattern.
The Slice2Persist function takes as its input a data waveform and a clock signal. The clock must consist of a
sequence of time values that increase at the nominal unit interval for each successive sample. For example, a 2.5
Gb/s bit stream should have a clock input consisting of the numbers 0, 4e-10, 8e-10, 12e-10, …, which increase
at a 400 ps per UI rate. The clock signal is derived from the output of the TIE@lvl parameter, which contains a
sequence of adjustment values that are added to the nominal bit period for each UI. These correction values allow
the TIE@lvl parameter to act as a phase locked loop. The web edit setup is shown below.