81250 Datasheet, PDF (11/64 Pages) Keysight Technologies – Agilent ParBERT 81250 Parallel Bit Error Ratio Tester

Output level measurement
This measurement performs an
automated sweep of the analyzer
threshold voltage at constant,
usually optimum, sample timing,
while it continuously measures
the BER. The result is displayed
in an unusual but intuitive way,
i.e. the threshold voltage (the
input parameter) is plotted on
the vertical axis and the BER
(the result), on the horizontal
axis (Figure 12a). A histogram
of BER versus threshold is
derived (Figure 12b) and is used
to calculate mean value and
standard deviation for one- and
zero-levels. Furthermore the Q-
factor can be derived from the
tail fitting operations of the
innermost (highest low-level and
lowest high-level) Gaussian
distributions of the BER
histograms (Figure 12c).
Figure 12a. BER versus threshold
Table 3. Output Level Measurements
Numerical Measurement
Results
High/low level
Mean level
Amplitude
Threshold margin
High/low level standard deviation
Peak to peak noise
Signal/noise ratio (rms & peak-to-peak)
Q-factor
Q-factor optimum threshold
Q-factor residual BER
Pass/fail
For all numerical results
Each one can be enabled individually
Graphical Result Displays
BER versus threshold
BER histogram versus threshold
Q-factor from BER versus threshold
Figure 12b. BER histogram versus threshold
Figure 12c. Q from BER versus threshold
ParBERT 812501M1 ain Overview
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