The issue about frequency measurement that one end of the differential clock to ground

The issue about frequency measurement that one end of the differential clock to ground

Troubleshooting (FAQ)

Summary

which probe can be used for special application.

Question

Can 53132A and a passive probe measure the frequency that one end of the differential clock to ground?

Answer

A passive (single-ended) probes are not recommended for differential measurements, and that a single passive probe cannot be used. A differential probe must be used instead. The reason is due to probe grounding. The 53132A chassis and input channels are referenced to earth ground. Connecting the (passive) probe to any ground point creates a ground return path which introduces transients in the measured signal. These transients can cause sporadic triggering and unpredictable signal behavior as the user has experienced. 

A differential probe is floating rather than referenced to ground, therefore no ground path which creates transients is present. There is no valid way to characterize the use of a passive probe.