Keysight M8195A User Manual page 85

Keysight M8195A Revision 2 – Arbitrary Waveform Generator User's Guide
the component # visible in this control. For example; for component #1 you
have certain values for Amplitude, Frequency and Phase. For component #2
you have other values for Amplitude, Frequency and Phase. Each component
has its individual values for Amplitude, Frequency and Phase.
 Frequency: The sinusoidal component's frequency is in Hertz (Hz).
 Amplitude: The amplitude of the current component is in Unit Intervals (UI)
peak-to-peak.

Phase: The initial phase is in sexagesimal degrees for the current component.
Random Jitter Section: Gaussian random jitter is defined in this section. Random jitter is
limited to some maximum value in every direction. Although the PDF (probability
distribution function) of the jitter profile follows accurately the Gaussian distribution, the
corresponding profile is implemented by embedding the timing deviations in the
synthesized waveform, so the same jitter profile will be repeated if the waveform is
generated continuously by looping the same segment. As a result, the statistical quality
of the jitter distribution will improve with longer waveform lengths. The following
controls are available:
 Bandwidth: The field controls the bandwidth of the random jitter profile
expressed in Hertz (Hz). Many receivers can handle random jitter depending
on its frequency contents. This is why jitter bandwidth can be limited. A low-
pass filter with a gentle roll-off is applied to the random jitter profile. In order
to save calculation time, filtering is done by creating a Gaussian random jitter
profile sampled at twice the user-set bandwidth and then resampled by
interpolating between samples. The result can be observed by executing
spectral jitter analysis in some jitter analysis tool such as the Keysight EZJIT.
 Amplitude: This is the rms (root-mean square) amplitude of the random jitter
(1 sigma) and is expressed in Unit Intervals (UI).

Crest Factor: This control allows for the random jitter profile clipping before
low-pass filtering. It is expressed in dB as a ratio between the maximum peak
and the rms value of the random jitter profile. For example: A crest factor of 0
dB corresponds to a peak-to-peak jitter of 2 times the rms value. A crest
factor of 6 dB corresponds to a peak-to-peak jitter of 4 times the rms value.
The Crest Factor corresponds to the level set by an ideal Gaussian distribution.
Once the signal is clipped, the rms value of the jitter is modified, so the actual
Crest Factor is different. However, for big enough values, ideal and actual rms
values are close, the larger the Crest Factor the closer they will be. A new
value is calculated until it falls within the legal limits. In this way, peaks in the
PDF do not show up, but the actual rms value is lower.
The actual crest factor will be higher than this setting as bandwidth limiting is
applied to the random jitter profile after clipping to make sure the desired
bandwidth is preserved.
DCD Section: Duty Cycle Distortion (DCD) jitter can be set in this section. There are two
types of impairments supported: "Classical" DCD, where there is a timing difference
between "marks" and "spaces" in the symbol sequence, and F/2 jitter, where the
duration of a symbol flips between two values from one symbol to the next. The
following controls are available:
 Amplitude: This is the peak-to-peak amplitude of the DCD jitter expressed in
Unit Intervals (UI).

Mode: This combo box allows for the selection of the "Classical" DCD or F/2
jitter mode.
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