LeCroy DDA 7 Zi series, Руководство оператора

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Operator's Manual
WP700Zi-OM-E-RevA
414
Control Values Description
first edge normalized to a unit interval for each N. DDsdev gives the standard
deviation for each edge relative to the first edge normalized to a UI for each N.
Length
(UI)
The
maximum N
value
This field displays the pattern length if Sync to Pattern is selected. Otherwise,
this is the maximum N value displayed in the plot.
Tx dens. 0.0 to 1.0
Transition density of the data stream. This control reads out the measured
transition density of the signal when the Find Pattern button is pressed. This field
is not used by the N-cycle plot.
Seq.
Type PRBS or
Pattern Selects whether the repeating pattern is a standard PRBS or a general pattern.
This control is only used when snyc to pattern is selected.
PRBS 5 to 15 When PRBS is selected, sets the length.
Find
Pattern
Pressing this button searches the signal for a repeating pattern and loads it into
the function when it is found. The Length (UI) and Tx dens. controls are then
updated.
Invert
Pattern
On/off Checking this box inverts the found pattern bit by bit.
Bit rate
The symbol rate of the signal under test. This value must be entered by the user
in order to set the nominal UI.
Avg Wfm On/off
Averages the N cycle plots measured on successive acquisitions. This is
especially useful for removing random effects from standard deviation plots.
Use PLL On/off
Use the software golden PLL to generate the reference clock for edge timing.
This setting is ignored when DDmean or DDsdev is selected.
Cutoff
Div. PLL cutoff
divisor When the PLL is selected, this control sets the loop bandwidth as a ratio of the
bit rate (loop BW = data rate/cutoff divisor).
Find
Level
When the level type is absolute, clicking this control finds the mean signal level.
Clear
Sweeps Pressing this button clears the sweeps that have been accumulated in the
averaging mode.
Htie to BER
This function takes as an input a histogram and converts it to one of 6 output waveforms. Normally, the histogram
contains a set of time interval error (TIE) measurements from which a total jitter measurement is desired. The
histogram should have a population of at least 100k and a minimum of 500 bins. The histogram should also be
completely contained on the instrument screen (it may be necessary to set the horizontal scale to do this). The
table below outlines the settings for this function.