[USRP-users] Problem Streaming Receive Samples without Deconstructing USRP Object Every Time

Robert Palumbo palumr at gmail.com
Thu Feb 2 20:12:39 EST 2012


Not sure if this helps to narrow down what probably sounds like a
pretty generic problem, but upon re-constructing the USRP object,
while I can receive samples on the first stream command, it takes two
to three stream commands before I get the full number of samples I've
requested. So, it looks like the packets are being dropped somewhere.
Has anyone seen this before?

On Thu, Feb 2, 2012 at 12:47 PM, Robert Palumbo <palumr at gmail.com> wrote:
> Hello,
>
> I am currently using the USRP N210 (rev. 4) and integrating the UHD
> (release 003.003.001) function calls into a GUI interface for ease of
> use. I've modified the FPGA code for the transmit path for pulsed
> transmission, but the receive path is completely intact and untouched.
> Everything is working great, as far as configuring the general
> settings (frequency, subdevice specification, data rate, etc.), but
> I'm having problems receiving samples with a stream command.
>
> My problem is that when I construct the USRP object, issue a stream
> command after configuring the general settings, and subsequently make
> a 'recv' call, the call to recv always fails with an error code
> ERROR_CODE_TIMEOUT in the receive metadata. However, if I configure
> the general settings, deconstruct and reconstruct the USRP object
> (i.e. restart the GUI), then issue a stream command, it works fine
> with no problem.
>
> Has anyone out there seen this type of behavior before, or has any
> suggestions? It seems to happen regardless of what streaming mode I
> issue. Within the stream_cmd, I am using the 'stream_now=true' flag,
> followed by the 'issue_stream_cmd'.
>
> If it matters, within my program I pass the usrp object as arguments
> to lower level functions, which are just wrappers around sequences of
> UHD calls.
>
> Any help would be much appreciated.
>
> Thanks,
>
> Rob
>
> --
> Robert A Palumbo
> palumr at gmail.com



-- 
Robert A Palumbo

Systems Engineer
Integrated Defense Systems
Raytheon Company
www.raytheon.com

+1 (978).376.7321 (cell)
palumr at gmail.com




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