[USRP-users] E310 - Maximal rate for rx_samples_to_file example

Kyle A Logue kyle.a.logue at aero.org
Mon Mar 21 12:22:57 EDT 2016


Roy,


I have successfully used the following higher sample rates on an E310:

  *   6 MSPS in 2 second intervals to Metafile on PNY Turbo Performance 64GB UHS-3 SD Card
  *   16 MSPS in 170ms intervals to /var/volatile/tmp every 2 seconds, then moved to SD Card

Trying to get data off via Ethernet is a fool's errand, so don't bother. I haven't tested the newest Sandisk Extreme Plus SD Cards, but they may be faster.


Kyle Logue · The Aerospace Corporation · ETG-DCID · Senior MTS · 310.336.3038 · kyle.logue at aero.org<mailto:kyle.logue at aero.org>

________________________________
From: USRP-users <usrp-users-bounces at lists.ettus.com> on behalf of James Humphries via USRP-users <usrp-users at lists.ettus.com>
Sent: Monday, March 21, 2016 08:09
To: Claudio Cicconetti
Cc: USRP-users at lists.ettus.com
Subject: Re: [USRP-users] E310 - Maximal rate for rx_samples_to_file example

Hi Roy,

In addition to Claudio's suggestion, keep in mind that a 1MHz sampling rate is already approaching the max write speed of the micro-sd card. It may not be able to sustain those write speeds for very long.

At 1 MS/s,

1 MS/s * 4 bytes/float * 2 floats/sample = 8 MB/s.

This doesn't consider that the OS is also loaded from the SD card and may be consuming some time reading/writing to the SD card as well.

-Trip

On Mon, Mar 21, 2016 at 9:10 AM, Claudio Cicconetti via USRP-users <usrp-users at lists.ettus.com<mailto:usrp-users at lists.ettus.com>> wrote:
Dear Roy,
Did you try the --null option? It will do everything except storing the
samples, just in case you suspect the issue may have something to do
with the actual writing part.

Best regards,
Claudio

On 03/21/2016 11:37 AM, ???? via USRP-users wrote:
> Hi,
>
> What is the maximal sampling rate possible for sampling to a file without getting overflows (E310)?
>
> I ran the rx_samples_to_file example on the E310 with the default sampling rate (1MHz), and after about a minute I started getting overflows ("O"s).
>
> Additional info:
>
>
> 1.       The E310 image is "fido-rfnoc-test" (http://files.ettus.com/e3xx_images/alpha/fido-rfnoc-test/)
>
> 2.       The FPGA image is "uhd-images_003.010.rfnoc-282-gab4e9eaa" (http://files.ettus.com/binaries/images/)
>
> 3.       The "rx_samples_to_file" example was cross-compiled from "rfnoc-devel" branch (https://github.com/EttusResearch/uhd/tree/rfnoc-devel), following the instructions in http://files.ettus.com/manual/page_usrp_e3x0.html#e3x0_sdk.
>
> 4.       The micro SD card is UHS speed class 1 (10MB/s).
>
> Thanks,
> Roy
>
>
>
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