Signal Track (Frequency)
The VSA can change the center frequency automatically to track an input channel's drifting signal. The Signal Track check box enables and disables this feature. For baseband multi-channel VSA configurations, specify which input channel to track: Channel 1, Channel 2, Channel 3, ..., Channel X (where X is the channel number).
If the VSA Center Frequency is changed, is disabled.
- Multiple Input Channel Configurations:
- Multiple channel drop-down list channel selection (Channel 2, Channel 3,..., Channel X) is only available when a multiple Input Channel measurement configuration is specified (select menu ).
- is not available for or configurations.
- Signal Tracking Limitations: Signal tracking is only available for Vector and Analog Demod measurement types with Averaging OFF. Also, signal tracking is not useful when using the trace format.
- Specifying the Center Frequency: For multi-channel configurations, the Frequency is applied to ALL channels. Different center frequencies cannot be specified on a per channel basis.
Better results can be achieved if a window with good frequency characteristics is used, such as a Gaussian or Hanning window, in that order.
Signal Tracking Implementation
When signal tracking is selected, the VSA adjusts the value of the VSA Center Frequency so that the largest measured signal is centered in the current frequency span. The effect of signal tracking is similar to repeatedly using the feature to determine the frequency of the largest measured signal and then using the Copy Marker to Center Frequency feature to copy the Peak Marker frequency to the VSA Center Frequency (Right click in the trace, select Peak and then Right click in the trace, select Copy Marker to Center Frequency.
In some cases, is on, but the VSA cannot set the frequency to the correct value. This happens when the frequency is set to and signal tracking is turned on. cannot change the and the VSA is limited in where it can set the frequency.
