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plotting VSA output in Matlab

Question asked by feilip on May 22, 2014
Latest reply on Jun 25, 2014 by tabbott
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  

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