Re: [Discuss-gnuradio] Clock synchronization B210

[Martin Braun]

On 08/29/2014 12:02 AM, Sharath Ananth wrote:
> Hello all,
> 
>  I am using the B210 without an external 10MHz clock and without a GPSDO
> mounted. As expected I see a frequency and sampling time error on the
> captured samples. Once this sampling time error is estimated, I would
> like to remove this in hardware by changing the sampling clock by a
> small amount. 
> Similarly once the frequency error is estimated, I would like to remove
> this in hardware by changing the LO frequency by a small amount.
> 
> How can this be achieved in GRC? Is this by calling UHD_tune_req() in
> one of my custom blocks with the correct offset? Will this call modify
> the setting in the UHD source block already present in GRC

You can change the offsets in software, if that's what you're looking
for. A tune request does not know about these offsets, if you set an LO
offset, it will tune such that the LO is not on DC.

So, the easiest way is to imply subtract the offset from your actual
target frequency. Same goes for the master_clock_rate