[USRP-users] X3X0 SBX corrupted samples?

LEMENAGER Claude claude.lemenager at thalesgroup.com
Tue Oct 14 10:43:05 EDT 2014

Hello Marcus,

No changes with this other firmware. I am building UHD 003.007.003-RC1 for further tests.



Hello Marcus,

I am working at 950MHz (RF) sampling 25MHz.
One thing is curious: In grc I specify External for both Clock source and Time but when running I obtain:

-       References Initialized to internal sources
WARN: Sensor 'lo_locked' failed to lock within timeout on channel 0
... (other channels)
>From UHD-FFT example (QT), I obtain the same but the indicator 'lo_locked' is in locked state.
And more curiously, I use an Octoclock as external source, the PPS led is not synchronized between Octoclock and X310 (even between X310 despite the fact I set them to External References! (seems not to be aware from the settings)

With the respect of the images, I used the one of the 20 Aug 2014 (003.007.002-48) but have seen it exists one of 21 Aug-2014 (003.007.002-440) (dates from tags in directory). I will try with this one.

Thank you,


De : Marcus Müller [mailto:marcus.mueller at ettus.com]
Envoyé : jeudi 9 octobre 2014 15:39
À : usrp-users at lists.ettus.com
Objet : Re: [USRP-users] X3X0 SBX corrupted samples?

Hello Mr. Leménager,

the warning that the LO is not locked is severe in principle; are you using an external reference clock?
Could you paste the complete warning?

At which frequencies are you working?

On 09.10.2014 15:30, LEMENAGER Claude via USRP-users wrote:


I sample at least two channels (SBX 120) from one or multiple X310 boards each equipped with two SBX radio boards.

I uses NIUSRPRIO_PCIE==>UHD003.007.002 ==>Gnuradio 3.7.5 (built for this UHD under UBUNTU 14.04LTS).

The input is connected to a CW generator. The channels definition is A:0 B:0, antenna is RX2 in all cases.

The problems :

1)    I receive a warning concerning lo_locked no locked after timeout for each channel (I read a discuss where this fact was given)

2)    When I connect the A:0 channel on a gnuradio scope, this seems OK (I and Q parts). When I connect a B:0 channel (from any X310 board) I receive the CW wave plus spurious (sort of dirac through a filter) generally starting on Q channel but not only. This look like an erroneous sample (digitally speaking for example just an incorrect bit in the LSBs) before DDC. The spurious looks like periodic but the period seems to change with radio frequency (to confirm)

Did somebody encounters this problem?

If yes, is there a solution.

I plan to try to reproduce this (or to see if it's the same) with UHD directly accessed BY a C++ application.


Claude Leménager

P.S. Conclusion about preceding discussion (june) about PCIe interface: The HP PC on which I made my firsts experiences was equipped with one of the first generation PCIe chip. So it failed to interface with X310. I now uses a last generation pc and then there is no problem except for what I mention above. Thanks for support.


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