pancho_hideboo
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Hi.
I have the following instruments.
(1) Sweep Type Spectrum Analyzer (2) Real Time Spectrum Analyzer (3) Vector Signal Analyzer (4) Vector Network Analyzer (5) Scalar Network Analyzer
IFFT of Spectrum Analyzer data gives you an autocorrelation function.
But if you want to get impulse response, you have to rely on vector network analyzer not spectrum analyzer. And most vector network analyzer have IFFT ability as option. Vector network analyzer have frequency offset ability which make it possible to treat frequency conversion device such as mixer.
Unless you measure output from vco, where you don't need signal generator as signal input to DUT, you can't use vector signal analyzer. If you measure vco, you can see I(t)+j*Q(t) directly using vector signal analyzer. But if you measure DUT's response drived by signal generator, you can't use vector signal analyzer. Even though you connect 10MHz reference_out of Signal generator to reference_in of vector signal analyzer, phase are never constant against frequency sweep. So it is very difficult to evaluate a phase difference of input and output of DUT.
Also current vector signal analyzer don't have a tracking signal output ability to control signal generator. If my memory is correct, Agilent old VSA89400 had this ability.
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