[Discuss-gnuradio] Re: Discuss-gnuradio Digest, Vol 53, Issue 53

[Jonas]

> On Thu, Apr 26, 2007 at 02:48:34PM -0400, Kevin Rudd (Contractor) wrote:
>   
> > Thanks for the suggestion.  I dove into the TCP code to try and figure out
> > what it was doing.  I found my problem.  I have to use the following read
> > command...
> >
> > data  = pnet(con, 'read', 1000, 'SINGLE', 'NATIVE');
> >
> > Now I notice that matlab seems to be lag behind the USRP.  So, maybe matlab
> > is not the best path to process the data in realtime.  I am curious what the
> > best data rate someone has sustained using a TCP connection.
> >     
>
> TCP on GigE can do upwards of 100MB/s ;)
>
>   
> > If I get it up and going, I will post my code and a howto so others can
> > stream data to and from MATLAB in real time.
> >     
>
> Thanks.
>
> Eric
>   
Hi Kevin,

I'm never directly sending samples to and from Matlab (for my 
application Matlab is too slow and can't keep up with the USRP). 
Instead, in Matlab I generate my waveform first, and then use Matlab's 
built in FTP to send the file to the USRP server computer. To generate 
the file that I send, I use write_float_binary.m 
(gnuradio-core\src\utils\). The resulting ".dat" file can then be used 
directly with a regular GNU Radio file source.

I wouldn't be surprised if the USRP overflows that you are seeing are 
attributed to Matlab's inability to keep up (assuming you are going from 
the USRP to Matlab).

Jonas

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