Re: [Discuss-gnuradio] New external clock board for USRP

[Alexander Chemeris]

On Fri, Sep 25, 2009 at 04:36, David I. Emery <address@hidden> wrote:
> On Fri, Sep 25, 2009 at 12:00:34AM +0400, Alexander Chemeris wrote:
>> Power will be taken from USRP 6V, clock output will be SMA to
>> connect to USRP directly. Frequency control will be accessible
>> over RS-232 (aka COM-port) with simple text-based protocol. We're
>> going to use ATMega for this. Ideally we want tighter integration
>> with USRP, so it can be controlled via the same USB connection,
>> so you can control clocks right from GnuRadio. But to date we can't
>> figure out how to do this cleanly. All suggestions are welcome.
>
>        Have you any sense of how much additional phase noise - sampling
> clock jitter - the ATMega will introduce compared to the TXCO Matt uses ?
> This impacts SNR... especially with  higher nyquist n subsampling.

We don't use ATMega for clock generation, it's used to control precise
generator and as interface to PC only.

-- 
Regards,
Alexander Chemeris.