User guide

In Manual mode, you can edit the automatically calculated frequencies. You can
also enter your own list of frequencies, with a minimum of two frequencies
specified. For example, you can jump between low and high jitter frequencies.
Enter the frequencies in Hz, separated by commas, for example:
2e4, 1.75e6, 6.334e5, ...
T I P
Press Apply if you want to keep the setting of frequencies for the current test run,
but if you still want to change the standard or BER specification. If all properties are
set as desired, press OK.
BER Specification
The Target Bit Error Ratio defines the pass/fail criteria of the jitter tolerance
compliance test. For every test point along the standard curve, the test is failed if
the measured BER lies above the Target Bit Error Ratio.
The Verification Method defines under which circumstances the measurement
proceeds from one frequency to the next. You can choose between two Verification
Methods:
Setting a Confidence Level is generally recommended. This ensures that neither
too few nor too many bits are captured. See also “Target BER” on page 449.
If you enable Absolute Bits/Errors, the measurement proceeds to the next jitter
frequency as soon as either the number of received bits or the number of errors is
reached.
N O T E
Ensure that you capture a number of bits that suffices to verify (with the desired
probability) that a measured point has a BER below the Target Bit Error Ratio.
The relax time allows the DUT to recover in case it has lost synchronization due
to an excessive high bit error rate. The next BER measurement starts after this
time has elapsed.
To run the Jitter measurements you need to make sure that Global Jitter, Sinusoidal
Jitter and Periodic Jitter are enabled.
Jitter Tolerance Tests 8
Agilent J-BERT N4903B High-Performance Serial BERT 465
Manual mode
Target Bit Error Ratio
Confidence Level
Absolute Bits/Errors
Relax Time
Optimal Measurement Setup