Thanks in advance,

Suchita.

Is there a way to capture the demodulated IQ samples. I had captured IQ MeasTime trace earlier but after post analysis on MATLAB it seems to be the input signal. The Syms/Errs table gives the hard decision bits, I want to capture soft decision IQ samples. Please advise.

Thanks in advance,

Suchita.

Thanks in advance,

Suchita.

- If I plot the constellation generated by IQ Meas Time captured data, I see them to be all over the place as shown in the attached picture, 1samplesymbol.emf . I expect the constellation to be 16APSK which is what I see from the demodulated symbols on the VSA, please see attached IQMeasTime_TraceD.bmp.

Is there a method to offline process captured demodulated IQ samples to generate same constellation as generated by the demodulated symbols on the VSA.

- It appears that you have configured the demodulator to show you samples between the symbol pionts. If you wish the traces to show data only at the symbol times set Points Per Symbol to 1 (MeasSetup, Demod Properties, Format tab).

http://wireless.agilent.com/wireless/helpfiles/89600B/WebHelp/89600_CSH.htm#..//Subsystems/digdemod/content/dlg_digdemod_fmt_pointssym.htm- I am aware of that. I captured IQ Meas Time samples at both 1 Point/symbol and at 4 Point/symbol. 1samplesymbol.emf is what I am most interested in. That shows the plot of IQ Meas Time sample at 1 Point/symbol. IQMeasTime_TraceD.bmp just illustrates what I see on the VSA which I would like to reproduce offline using captured demodulated samples.

Edited by: Suchita on May 15, 2012 10:19 AM

This is more than 5 years old post but i suppose someone might still visit it.

I am facing the same problem. I have 16QAM demodulated symbols in VSA which i would want for post analysis in Matlab. I used two methods of extracting the data (actually 3 methods). One is directly saving the trace to .mat file. In matlab i wanted to analyze and there is no correlation b/w the transmitted symbols and the symbols from VSA, also the constellation looks weird.

Secondly i used the binblockread to read the data from buffer of VSA. reading from IQ of VSA i loose half of the symbols (with 1 point/symbol), when i read the buffer from Real and Imaginary (format) I get the all the symbols exactly same as that by saving the trace, but then again no correlation with the transmitted signal and weired constellation.

So my question is how to extract data (demodulated IQ ) from VSA to Matlab which should be exactly same as transmitted symbols. Any kind of help will be appreciated.

Thanks

IQ Meas Time does contain the IQ samples that are used to determine the bits that were transmitted.