User guide

This graph shows the absolute values of the derivative of the bit error rates over
the thresholds (dBER/dTh). It visualizes the data that forms the basis for the
calculations of the level and noise values.
The graph provides a special marker that allows you to estimate the data
distribution by approximating it by means of a Gaussian normal distribution.
The Output Levels measurement provides a third graphical display: the Q from BER
versus Threshold graph. This graph refers to the Q-factor calculations. For details
on these calculations see “QBER vs. Threshold Graph” on page 275 and
“Understanding the Q-Factor Results” on page 282.
Output Levels - Reference
The Output Levels measurement returns the results in a graphical and in a
numerical form. The following sections provide explanations of the measured
parameters and the display options that are specific to this measurement.
Additionally, some information is provided to explain the theoretical background
behind.
The properties of the Output Levels measurement can be specified on the various
tabs of the Properties dialog box.
Parameters Tab
N O T E
If you modify the parameters on this page, you have to rerun the measurement to
update the results.
Set the criteria for moving to the next sample point:
•
Number of Compared Bits
After this number of compared bits, the measurement stops for the current
sample point and moves to the next one.
•
Number of Errors
6 Advanced Analysis
270 Agilent J-BERT N4903B High-Performance Serial BERT