3.9. Reference In

The M81-SSM provides a reference input for acquiring external frequencies for use as a reference using a phase-locked loop (PLL). This reference can be used for lock-in measurements on any connected measure module. The maximum voltage limits of the Reference Input are +/- 10 V peak.

To configure the reference input, open the settings menu (top left corner of the screen). Then tap Reference configuration.

Figure 3.27 Reference configuration

For use by a lock-in measurement, see Reference Source.

Edge

The edge setting determines if the PLL is sensitive to the rising or falling edge of the reference input signal. If the edge is set to Rising, the positive going zero crossing of the reference signal will be regarded as zero degrees. If the edge is set to Falling, the negative going zero crossing of the reference signal will be regarded as zero degrees.

Interface Command: INPut:REFerence:EDGe