EVM Measurement of Recorded Data Using ADS

[sajan09]

This may be a very basic question, but I am a beginner.

I have my demodulated I and Q channel data from my reciever. Can I use ADS software to do Error Vector Magnitude Calculations.

Thanks in advance

 

[pancho_hideboo]

Can I use ADS software to do Error Vector Magnitude Calculations.

Basically yes.

What modulation do you use ?

If your modulation is simple one such as QPSK, you can evaluate EVM by Post Processing only.
http://edocs.soco.agilent.com/display/ads2009/const+evm()#constevm()-1106089

But your modulation is complex, you have to rely on measurement by Run Time Processing not Post Processing for synchronization and identification of constellation.
Here you have to use Ptolemy or VSA89600 for evaluation of EVM.

http://edocs.soco.agilent.com/display/ads2009/EVM
http://edocs.soco.agilent.com/display/ads2009/EVM+WithRef
http://edocs.soco.agilent.com/display/ads2009/WMAN+EVM

http://edocs.soco.agilent.com/display/ads2009/VSA+89600+Sink

Do you have VSA89600 or its interface license for ADS ?

If you have VSA89600, you don't have to use ADS.

Don't mix up Simulation(=Run Time Processing) with Post Processing.
They are completely different phase.
About Post Processing, see http://www.designers-guide.org/Forum/YaBB.pl?num=1264511244

 

[sajan09]

Thanks for your reply.

Yes I am using QPSK.

This command const_evm() I have to use it in the data display window?

And I can port any data to give it as input, I mean I and Q channel data?

Thanks for your reply in advance

 

[pancho_hideboo]

Yes I am using QPSK.
This command const_evm() I have to use it in the data display window?

Yes. But it requires reference QPSK signal as input.
So you have to create reference signal using Ptolemy or Analog/RF domain simulator such as envelope analysis or transient analysis.

And I can port any data to give it as input, I mean I and Q channel data?

Yes.

 

[sajan09]

Thanks a lot for your replies. They were very helpful.