410 Keysight EXG and MXG X-Series Signal Generators User’s GuideUsing BERT for N5172B/82B with Option UN7Bit Error Rate Testand the Spcl Pattern Ignore Off On softkey is set to On, then all of the consecutive 0’s or 1’s areignored. Select either 0’s or 1’s as the data to ignore by using the Spcl Pattern 0’s 1’s softkey. Thefollowing figure shows an example of the special pattern ignore function.Figure 16-11 Pattern Ignore Function ExampleThe 160 or more ignored bits can be anywhere in the PN sequence. The signal generator ignoresthese bits as error, but they are counted in the PN sequence bit count.Pass/Fail JudgementThere 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 holdselected, the fail judgement is retained whenever a failure occurs during one loop of BERT repeatmeasurements. Fail hold mode allows you to determine when a failure occurs at least once duringan entire cycle of measurements.Repeat MeasurementsWhen the Cycle Count softkey is set to more than 1, the synchronization performed before the startof each measurement is only executed the first time; then it keeps track of the clock signal and thePRBS generation for the incoming data. This function can reduce the total time for BERTmeasurements. Also, once synchronization is established, it is retained even if the BERTmeasurement 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 initiationof a new sequence. The following figure shows an example of the repeat measurements.Figure 16-12 Repeat Measurements Example
