[USRP-users] Rx/Tx Loopback

Rob Kossler rkossler at nd.edu
Wed Apr 1 23:35:04 EDT 2015


ok.  I'll try that.  Thanks.


Yes, the streams are going to the same physical device.  But no 1 PPS
input.  My intention is to use X310 internal PPS.  I think the GRC UHD
sink/source setting for clock source is "default".  I'm assuming that means
internal PPS.


On Wed, Apr 1, 2015 at 11:04 PM, Marcus D. Leech <mleech at ripnet.com> wrote:

>  On 04/01/2015 11:00 PM, Rob Kossler wrote:
>
>  I don't recall any error message with the low sample rate.  But, I was
> also using higher rates like 1 MS/s and 10 MS/s also.
>  Rob
>
>  May just be a buffering elasticity issue.
>
> Try putting something like a multiply-const block between them, with a
> constant of 1.0.  Just to put some buffering in place.
>
> These streams are going to the same physical device, yes?  And it has a
> 1PPS input?
>
>
>
>  On Wed, Apr 1, 2015 at 10:58 PM, Marcus D. Leech via USRP-users <
> usrp-users at lists.ettus.com> wrote:
>
>>   On 04/01/2015 05:57 PM, Rob Kossler via USRP-users wrote:
>>
>>   I would like to run a simple Rx to Tx loopback using gnuradio
>> companion with my X310.  The attached flowgraph contains two blocks, a UHD
>> source and UHD sink, which are directly connected to each other on each of
>> the 2 channels.
>>
>> When I run it, I get numerous "L" indications.  To me, this indicates
>> that I'm not delivering the samples to the Tx Streamer when it wants them.
>> Perhaps the start times for RX streaming and TX streaming need to be
>> specified?  If so, can this be done from GRC?
>>
>>  Thanks.
>>  Rob
>>
>>
>>   _______________________________________________
>> USRP-users mailing listUSRP-users at lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>
>>  The only thing I notice is that you've specified a really-low sample
>> rate, one which I'm thinking the X310 cannot support, did you get any error
>> messages
>>   to that effect when it's running.
>>
>>
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>>
>
>
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