Hi,

I run the demo signal from VSA software (80211a_64QAM.sdf) and I save the trace as Matlab mat format without saving header (see attachment).

Next, I import the mat file into matlab and plot the psd for the signal but I couldn't get the same waveform as in VSA software (see attachment). Since the span is 31.25MHz in VSA, I use 40MHz (31.25*1.28) as sample rate in Matlab.

I use the following Matlab commands to import the mat file and plot PSD:

IQData=importdata('11a.mat');

hp = spectrum.periodogram('hamming');

hpopts = psdopts(hp,IQData);

sampleRate=40e6;

set(hpopts,'Fs',sampleRate,'SpectrumType','twosided','centerdc',true);

hpsd = psd(hp,IQData,hpopts);

figure; plot(hpsd);

Please help me to understand why the spectrum looks difference between VSA and matlab.

Thanks,

Philip

I run the demo signal from VSA software (80211a_64QAM.sdf) and I save the trace as Matlab mat format without saving header (see attachment).

Next, I import the mat file into matlab and plot the psd for the signal but I couldn't get the same waveform as in VSA software (see attachment). Since the span is 31.25MHz in VSA, I use 40MHz (31.25*1.28) as sample rate in Matlab.

I use the following Matlab commands to import the mat file and plot PSD:

IQData=importdata('11a.mat');

hp = spectrum.periodogram('hamming');

hpopts = psdopts(hp,IQData);

sampleRate=40e6;

set(hpopts,'Fs',sampleRate,'SpectrumType','twosided','centerdc',true);

hpsd = psd(hp,IQData,hpopts);

figure; plot(hpsd);

Please help me to understand why the spectrum looks difference between VSA and matlab.

Thanks,

Philip

In the VSA the Channel 1 spectrum trace is an FFT of the Channel Time trace after windowing selected by the user is performed.

This message does not indicate the trace that was saved from the VSA.

Regards -