[USRP-users] Local Oscillator Lock Problem

Josh Blum josh at ettus.com
Sat Jun 2 13:32:09 EDT 2012



On 06/02/2012 10:15 AM, Simon HB9DRV wrote:
> Hi,
> 
>  
> 
> With the WBX board there are random frequencies at which the LO doesn't
> lock, for example 72 MHz and 98 MHz. What's annoying is that when the LO
> isn't locked the returned data isn't too excellent L
> 
>  
> 
> I'm testing the lock status every second, problem is independent on
> bandwidth, antenna, RF gain. I do not have MIMO, GPS or any fancy stuff,
> just a WBX in a N210 and my software. CPU is not overloaded.
> 
>  
> 
> Please look at these two screenshots, both with a 10MHz bandwidth,
> 
>  
> 
> ftp://ftp.ham-radio.ch/common/sdr-radio/pics/98MHz.png (98MHz) lock is
> on/off/on/off
> 
> ftp://ftp.ham-radio.ch/common/sdr-radio/pics/100MHz.png (100MHz) lock is on
> always.
> 
>  
> 
> So are there known center (LO) frequencies to avoid?
> 
>  

What version of UHD are you using?

If you installed from unstable aka the master branch, there is a known
issue tuning below the clock rate; introduced when implementing phase
synchronization for the WBX.

I recommend in the meantime using a release installer or something from
the maint branch. Or if not that, staying > 100 MHz in the meantime when
using WBX with USRP N-series.

-josh




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