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

James Humphries james.humphries at ettus.com
Mon Mar 21 11:09:04 EDT 2016


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> 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, רועי 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
> >
> >
> >
> > _______________________________________________
> > USRP-users mailing list
> > USRP-users at lists.ettus.com
> > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
> >
>
>
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