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Re: [Discuss-gnuradio] Mulitple USRP Stream Confusion
From: |
Daigle, Andrew - 1008 - MITLL |
Subject: |
Re: [Discuss-gnuradio] Mulitple USRP Stream Confusion |
Date: |
Wed, 1 Oct 2014 12:54:30 +0000 |
Hello Martin,
Thanks for the response.
I should have mentioned that the subdev spec was set to A:A B:A because I am
using the basic RX boards. Trying "0:A 0:B" instead gives the following error:
"0:A is not a valid rx subdevice specification on mboard 0. possible values
are: [A:AB, A:BA, A:A, A:B, B:AB, B:BA, B:A, B:B]."
Your suggestion to set the channel as 0,1,2,3 seemed to work perfectly (not
sure how I missed that) as now I am getting four complex shorts out of my setup
(an example of what is now in the buffer is shown below):
(-3,-2)(3,0)(-1,0)(1,0)
(2,-1)(0,0)(-3,0)(-2,0)
(3,5)(1,0)(-1,0)(-1,0)
(4,-2)(-4,0)(-1,0)(2,0)
In getting the channels to stream however, I ran across another strange
occurrence. After looking at the FFT data it appears as though the following
commands only set the frequency of the first channel:
uhd::tune_request_t tune_request(freq);
usrp->set_rx_freq(tune_request);
Channels 1,2, and 3 all show single peaks centered at 0 Hz in the FFT window. I
was able to correct this by directly setting the frequency of each channel
independently (as shown below) , but I was under the impression that when you
create the usrp devices to begin with it should apply commands across all
channels?
uhd::tune_request_t tune_request(freq);
usrp->set_rx_freq(tune_request, 0);
usrp->set_rx_freq(tune_request, 1);
usrp->set_rx_freq(tune_request, 2);
usrp->set_rx_freq(tune_request, 3);
Thanks again! This is really a great product and I look forward to getting more
acquainted with what it can do.
-Andrew
________________________________________
From: address@hidden address@hidden on behalf of Martin Braun address@hidden
Sent: Tuesday, September 30, 2014 5:04 PM
To: address@hidden
Subject: Re: [Discuss-gnuradio] Mulitple USRP Stream Confusion
Hey Andrew,
First, that subdev seems off -- I'd assume it's something like "A:0
B:0"? Next, I'm not even sure what you mean you set the channels to
"0,1" on both devices. You should have 1 streamer, with a channel
setting of "0,1,2,3". The 'args' string seems correct.
Does this help?
M
On 30.09.2014 13:01, Daigle, Andrew - 1008 - MITLL wrote:
> Hello!
>
> I am having trouble trying to create a continuous stream of complex
> shorts from multiple (2) X310 USRPs (each running 2 channels) over a
> single 1gigE switch (at a very low sampling rate); currently it appears
> as though I can only stream from one USRP at a time and I can't seem to
> figure out why. I should note I don't have this problem running each
> USRP on its own dedicated network (but unfortunately that won't be
> possible moving forward).
>
> To date, I have been using the rx_multi_samples example provided with
> UHD (source 003.007.002). I don’t seem to have any issue connecting to
> both USRPs and setting the parameters via the args=”addr0=192.168.10.2,
> addr1=192.168.10.3” command. It is just that when I call rx_stream->recv
> only the lights on the USRP which was listed first in args turn on. The
> subdev spec and channel selection for each USRP is set to "A:A B:A" and
> "0,1" and the incoming data from rx_stream is two channels of complex
> shorts (not 4 like I would expect from 2 USRPs).
>
> Do I have to initiate the streams differently or am I missing something?
>
> Thanks!
>
> -Andrew
>
>
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> Discuss-gnuradio mailing list
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