:CRECovery:LBWTuning:TORelock

Command Syntax

:CRECoveryN:LBWTuning:TORelock {ON | OFF}

Where N identifies slot number {1:8} which is associated with clock recovery module.

Description

When locking clock recovery, Loop Bandwidth Tuning increases the accuracy of the Target LBW (Loop Bandwidwith) setting. Loop bandwidth tuning calculates the loop gain on live input data to arrive at an improved loop bandwidth setting. This feature is recommended when performing measurements that are sensitive to loop bandwidth, such as TDECQ.

When Tune on Relock is selected, loop bandwidth tuning is selected to be appended to the normal clock recovery relock algorithm. In other words, when you select Tune on Relock, loop bandwidth tuning is not applied until the next time that clock recovery is relocked. Use the :CRECovery:RELock command to initiate a relock. Be aware that enabling this setting increases the time needed for the clock recovery to lock. For example, it could add an additional 3 or 4 seconds when locking the clock recovery. By default, Tune on Relock is turned off.

In the following situations, Loop Bandwidth Tuning may not result in reliable adjustment in which case, turn off this feature:

• Degraded input signals
• Low-amplitude input signals

Use the :CRECovery:LBWTuning:STATus? query to confirm that the tuning has been applied.

When clock recovery is locked, changes to any of the following loop bandwidth settings will invalidate the loop bandwidth tuning and the tuning status will become untuned:

• Target LBW setting (:CRECovery:LBANdwidth)
• Loop characteristics (peaking) (:CRECovery:LSELect and :CRECovery:LSELect:AUTomatic)
• Equalization Level setting (:CRECovery:ELEVel)
• Enable High Gain setting (N1078A DCA-M with optical input data) (:CRECovery:EHGain)