Inst Spectrum (MB-OFDM)
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The (Instantaneous Spectrum) trace shows the frequency spectrum of the pre-demodulated time data. The time data is windowed and FFTed to create this trace.
If Pulse Search is Enabled, spectrum trace data is the results of the pulse search. If averaging is on, the does not show the effects of averaging. To see the effects of averaging, use the Spectrum trace data. If averaging is not on, this is identical to the Spectrum data.
The parameters Search Length, Result Length, Measurement Offset, and Measurement Interval affect the trace display (see Lengths, Intervals, and Offsets). In particular, these parameters set 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.) for the trace.
See Also
Available Trace Data (MB-OFDM)
