AnsweredAssumed Answered

OQPSK signal - E4437B and 89441A

Question asked by Tardz on Oct 27, 2017
Latest reply on May 17, 2018 by jcresp
  • Comment • 1

Hi,

   I would like to do a test with OQPSK signal, I used an E4437B (PN9 sequence, gaussian filter, alpha 0.5, OQPSK modulation type) and I used a 89441A to see constellation (see picture). Setup for demodulation is no filter for measurement and gaussian filter with alpha 0.5 for reference. Another try with RECTangular filter, there are more than four grouping of points ... what's wrong with my setup. I suppose that EVM measurement with 89441A is incorrect.

 

Thanks

Yves

jcresp
jcresp Employee May 17, 2018 1:54 PM
Correct Answer

Hello Tardz,

 

Here is a FAQ on using the Keysight 89400 Series analyzer to demodulate an offset QPSK signal.

 

Here is also a link on "10 Steps to a Perfect Digital Modulation Measurement" that can also help.

 

Finally, this application note includes a sections on: modulation accuracy, troubleshooting with error vector measurements, etc.

 

Best

See the reply in context

Attachments

No one else had this question

Outcomes