Hello turbot,
All of the data in your display is useful. You could discard half of
the data if the spectrum was symmetric around the Y-axis. However, your
data appears between 0 and 10 MHz and appears to be symmetric about
some point in between. All of this frequency data is useful.
I am not clear what you mean when you say that you want to "index the
bandwidth due to the measurement setting". Are you saying that you'd
like to change the span of the power spectrum? Could you please clarify
what you are trying to accomplish?
Matt Anderson
Hardware Services Marketing Manager
National Instruments