Frequency Converter (User Correction)
Menu Path:
The Center Frequency, marker readouts, and other frequency parameters and annotations so that they are correct relative to the input of the external converter. See Setting Up an 89640 with External Downconverter for an example setup using this feature.
is used to specify the frequency parameters of an external downconverter connected to the analyzer hardware. The VSA uses this correction data to adjust theAfter entering the user correction data, the VSA center frequency and bandwidth/span (
tab) can be set to match the downconverter.The
parameters apply to both I and Q channels of an I+jQ measurement channel.The following parameters are available in this section:
The
parameters are disabled (greyed-out) during recording playback.The settings in this section are remembered when the VSA is closed and restored when the VSA restarted.
When
is selected, the VSA is set by default to the specified . The trace data annotated measurement "Center" frequency is the specified . This reflects the fact that the external downconverter is tuned to the and produces an output at the . Select if the downconverter outputs a spectrum that is mirrored relative to the input.The measurement center frequency can be changed (see Changing Frequency Settings) within the limitations of the measurement hardware as well as the specified on the tab. When the measurement center frequency and span are changed, the measurement hardware is tuned within the IF range of the external downconverter. The displayed center frequency is changed appropriately, even though the is unchanged. This reflects the fact that a different portion of the bandwidth made available by the external converter is being looked at.
The measurement center frequency is limited to the
± ½ the , unless the measurement hardware limits are more restrictive. Spectrum displays are blanked outside the same limits.If
is selected while is in use, the fixed equalizer will select relative or absolute frequency mapping based on the tuning of the VSA hardware (i.e. at the converter IF frequency), not the displayed center frequency. If is selected while is in use, the delay is applied at the VSA input (i.e. at the converter IF frequency).See Also
Setting Up an 89640 with External Downconverter
I+jQ Measurement with External Downconverter