Re: [Discuss-gnuradio] USRP2 Maximum througput

[Sharif Shaher]

Hi Matt,

Thanks so much for the response.  I will try usrp2_fft
as you say.  One other comment, I understand your point
about the sound card, but I would have expected audio overruns
or underruns, not that the usp2_wfm_rcv.py would not run.
I guess I am wrong on that?

Also, I dont believe usrp2_rx_cfile.py sends data anywhere
except a file.  Regardless, I will try urp2_fft...thanks so much.

Sharif
----- Original Message ----- 
From: "Matt Ettus" <address@hidden>
To: "Sharif Shaher" <address@hidden>
Cc: <address@hidden>
Sent: Wednesday, February 10, 2010 1:11 PM
Subject: Re: [Discuss-gnuradio] USRP2 Maximum througput


> On 02/10/2010 09:37 AM, Sharif Shaher wrote:
> > Hello,
> > I am trying to test my maximum achievable throughput from our USRP2
> > to my host PC. The easiest way for me to do this is to invoke,
> > let say, usrp2_wfm_rcv.py. The ADC sample rate in usp2_wfm_rcv.py
> > is set to 100Ms/sec, and the decimation rate is set to 312 for a net
> > sample rate of 320 KS/sec. This configuration works fine, I have no
> > overruns. However when I change the decimation rate to 10, let's say,
> > usrp2_wfm_rcv.py returns a number of errors. Additionally, when I
> > run usrp2_rx_cfile.py (to dump data to a file) and set the decimation
> > to 10 or below, although I dont get any errors, it does not work. Setting
> > the decimation to 312 works just fine. Does anyone have any idea if
> > there is some limitation as to how little I can decimate and if so is
> > there a way to get around this. The USRP2 advertises 50MSamp/sec max
> > throughput, is there some other way I can validate this. Does anyone
> > know what the maximum throughput might be (is it 50Msamp/sec), assuming
> > my PC is not a bottleneck?
> > Thanks,
> > Sharif
>
>
> The problem you are having is that the data from the USRP2 is being fed 
> into your soundcard after processing.  So if you change the decimation to 
> 10, it means you are trying to feed many megasamples per second into a 
> soundcard and it won't do that.
>
> If you want to see how fast you can use your usrp, use usrp2_fft.py, which 
> shows the spectrum.  It has a place to put in the decimation ratio, so you 
> can try 4 to 512.
>
> Matt