Keysight Technologies N5171B EXG, Руководство пользователя

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332 Keysight EXG and MXG X-Series Signal Generators User’s Guide
BERT (Option UN7)
Bit Error Rate Tester–Option UN7
and the Spcl Pattern Ignore Off On softkey is set to On , then all of the consecutive 0’s or 1’s are
ignored. Select either 0’s or 1’s as the data to ignore by using the Spcl Pattern 0’s 1’s softkey. The
following figure shows an example of the special pattern ignore function.
Figure 12-11 Pattern Ignore Function Example
The 160 or more ignored bits can be anywhere in the PN sequence. The signal generator ignores
these bits as error, but they are counted in the PN sequence bit count.
Pass/Fail Judgement
There are two pass/fail judgement update modes: cycle end and fail hold. With cycle end selected,
either pass or fail judgement is made for the results of each measurement cycle. With fail hold
selected, the fail judgement is retained whenever a failure occurs during one loop of BERT repeat
measurements. Fail hold mode allows you to determine when a failure occurs at least once during
an entire cycle of measurements.
Repeat Measurements
When the Cycle Count softkey is set to more than 1, the synchronization performed before the start
of each measurement is only executed the first time; then it keeps track of the clock signal and the
PRBS generation for the incoming data. This function can reduce the total time for BERT
measurements. Also, once synchronization is established, it is retained even if the BERT
measurement result degrades. You may wish to adjust the signal level to find a specific BERT value.
However, once synchronization is lost in a repeat sequence, it will not be restored until the initiation
of a new sequence. The following figure shows an example of the repeat measurements.
Figure 12-12 Repeat Measurements Example