About Frequency
The parameters on the Frequency tab are used to configure the frequency parameters for a measurement.
Depending on whether the Show Center/Span check box is selected or cleared, frequency parameters in the tab and X-axis annotation on traces are expressed in terms of either:
and : X-axis is annotated with Center and Span.
or
and : X-axis is annotated with Start and Stop frequencies.
Full span measurements view the entire available frequency spectrum on one display. Alternately, smaller slices of the frequency spectrum may be viewed.
Any number of different spans can be selected and positioned by specifying their start and stop frequencies or by specifying a center frequency and span size.
Changing one parameter causes other parameters to change. For example, changing start causes span and center to change. The following table shows how Start, Stop, Center, and Span interact:
If changed... |
affects these... |
Does not affect |
---|---|---|
Start |
Span & Center Time Data (changes to Zoom mode) |
Stop |
Stop |
Span & Center |
Start |
Center |
Start & Stop |
Span |
Span |
Start & Stop Time Data (changes to Zoom mode) |
Center |
An exception occurs when changing one parameter would set another to an invalid value. For example, if the
Frequency is changed so that with the current the Frequency would be less than 0, the VSA adjusts the so that the Frequency is valid.See Also