Preferred Input Domains (Input)

Menu Path:Input > Capture

The Preferred Input Domains parameters control the input domain preferences for a measurement and provides a means of reloading a meaurement to apply changes made to enabled input domain selections.

The Preferred Input Domains parameters are:

Time (always allowed): Includes time domain inputs as a possible input domain. This checkbox is grayed out because it is always allowed (VSA compatible analyzer hardware connectivity always supports Time domain acquisitions). There are several ramifications for using time domain inputs:
- The frequency limits are restricted to what the data source can provide as Span in the Vector measurement. See Multiband Measurements for more information.
  
  The frequency limits are restricted to what the data source can provide as Span in the Vector measurement.
- Several functions are disabled, such as IF Dither.
- The RBW Resolution Band Width (RBW or ResBW): specifies the minimum frequency bandwith that two separate frequency spectra can be resolved and viewed seperately. For FFT (digital) based VSA's the process is equivalent to passing a time-domain signal through a bank of bandpass filters, whose center frequencies correspond to the frequencies of the FFT bins. For a traditional swept-tuned (non-digital) spectrum analyzer, the resolution bandwidth is the bandwidth of the IF filter which determines the selectivity., VBW, and Sweep settings are limited by the maximum capture duration supported by the data source.
Power Spectrum: Includes Power Spectrum as a possible input domain, depending on the connected hardware and the measurement configuration.
All (no input domain restriction): Selects both Time and Power Spectrum to be included as possible input domains. Disabling Power Spectrum would cause All to be disabled.
Active Input Domain: Shows detail about the current input domain for the measurement. This would typically be Time for Vector and modulation analysis measurements, and either Time or Power Spectrum for Power Spectrum measurement.
Change Input Domain: Reloads the measurement according to the enabled input domain selections.