[USRP-users] E310 Rx Timeout with higher sampling rates

Voss, Nathan J VossN at battelle.org
Thu Apr 30 15:38:33 EDT 2015

I am running in native mode.

Running the 'rx_samples_to_file' application, I am able to get up to about 10Msps on the E310 before overflow issues arise. Definitely better than what I'm seeing in my own application, although I'm still surprised that it is capping out at only 10MHz when the advertised (analog) bandwidth is 56MHz. I'm also not seeing any 'Timeout' error codes from the sample application.

For the record, my command line is:
> rx_samples_to_file --args="master_clock_rate=56e6" --ant "RX2" --freq 315000000 --null --spb 512 --gain 25.0 --progress --type float

I am running the stock image that comes shipped with the E310. I have seen previous posts regarding updating the SD image to the 'Dizzy Beta' image. Would that potentially have anything to do with this issue? I've double checked my code for any obvious problems, and have confirmed that my 'rx_metadata' is set with no time_spec (which could cause delay before samples start) and also made sure that the stream is successfully started in continuous mode before I call recv().

Thanks again for your help.
From: mleech at ripnet.com [mleech at ripnet.com]
Sent: Thursday, April 30, 2015 3:09 PM
To: Voss, Nathan J
Cc: usrp-users at lists.ettus.com
Subject: Re: [USRP-users] E310 Rx Timeout with higher sampling rates

Are you running this native on the E310, or via "network mode"?

If native, try an "rx_samples_to_file" recording to /dev/null.  What sample-rate can you achieve, try different host-side data formats.

On 2015-04-30 14:45, Voss, Nathan J via USRP-users wrote:

I am in the process of porting code that was built and tested successfully on a USRP N200 to a USRP E310. The sampling rate is user-configurable, and we really need to support as large a bandwidth as possible. On the N200, my code worked fine for sampling rates up to ~15Msps, but on the E310 the same code is struggling to run over about 500Ksps.

When I set the sampling rate on the E310 above about 500Ksps, I initially get one or two 'O' overflow notifications, and then start to get timeout errors very frequently. My code is fairly simple, in that I'm calling 'usrp->recv()' in a pretty tight loop, very similar to the 'rx_samples_to_file' example. The timeout value I'm passing into the recv() call is currently 3.0 seconds, and my 'nsampls_per_buf' is typically 512.

Thanks for your help.
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