Re: [Discuss-gnuradio] [USRP-users] N210s MIMO feature testing as in the Application Note Synchronization and MIMO updated kb

[Jawad Seddar]

Hi Naceur,

I think this question has more to do with GNU Radio and GRC than with USRPs per say, so I added the GNU Radio mailing list.

I'll try and answer some of your questions.

1/ Your WX GUI looks old and ugly indeed. I've never had this issue before.

But WX widgets are "deprecated" and not recommended for use. You should be using the QT GUI widgets which look much nicer :D

2/ You can do a phase shift with the Multiply const block. 

Just set the constant to cos(phi) + 1j * sin(phi) where phi is your phase shift.

You can even put the phase "phi" in a QT range (I believe that's the correct name) so you can change your phase shit from a slider on the GUI.

(One caveat here, you need to import cos and sin to use them. Just add an import block and put "import numpy as np" then in your Multiply const block set the constant to np.cos(phi) + 1j * np.sin(phi))

3/ I'm not sure what you mean or if I have the answer to this one.

Hope this helps,

Jawad

2016-07-29 0:31 GMT+02:00 El Ouni, Naceur (IntlAssoc) via USRP-users <address@hidden>:

Hello usrp-users,

 

I am trying to test the MIMO capability of two N210s connected. I kept the 2 N210s connected through Ethernet to my Ubuntu 14.04 machine.

Following the Application Note on synchronization and MIMO, I generated two GNU Radio flowgraphs: non-MIMO.grc

 

 

and MIMO.grc:

 

 

Some questions arise here: 1/ did the WX GUI Scope Sink changed or what ? the document shows something like

However I am getting I guess an “uglier” version

 

 

2/ I am not able to find a phase shift block in the gnu radio palette. Does delay or Freq. Selective IQ Correction do the same function ?

Or is there any other block that may allow me to phase correct thw two uhd_sources signals.

 

3/ Apart from a consideration of Host-Radio data rate, how does connecting both MIMO-connectd USRPs with Ethernet cables or not affect my data paths, alignments of streams.

 

My ultimate goal is to be to show a pair of coherent receivers as show in the note

 

 

 

Thanks and Regards,

 

Naceur El Ouni

NIST - Wireless Networks Division (673)

100 Bureau Dr. Building 222-A218

Gaithersburg, MD 20899

(301) 975-3353

 

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