[hpsdr] Gibraltar fanning out clock and 1pps to HORTON/CASMIR/MERCURY/..

[Bob McGwier N4HY]

Agreed and Achim was being conservative.  I know from work done with 
Hambly and Clark that we can do MUCH better than sub-100 ns, with care,  
single digit nsec.

Bob




Eric Blossom wrote:

>***** High Performance Software Defined Radio Discussion List *****
>
>On Mon, Jul 10, 2006 at 03:41:52PM +0200, Achim Vollhardt wrote:
>  
>
>>***** High Performance Software Defined Radio Discussion List *****
>>
>>Dear HPSDR group,
>>I would like to remind people about the coherent system approach Bob and
>>others mentioned some while ago:
>>
>>IF we manage to derive all signal path clocks from a single source
>>(let's assume a 10 MHz GIBRALTAR for now), this system will be able to
>>PRECISELY time any recorded signal to the sub-100 ns level!
>>    
>>
>
>Coherent processing will be very useful.  However, sub-100 ns is way
>too sloppy if you're dealing with 100 MHz sampling clocks.  That could
>be 10 samples!  Accounting for aperture jitter at those rates, the
>specs get even tighter.
>
>It seems to me that for any serious coherent processing, clock
>distribution is *not* going to happen across the ATLAS bus, but rather
>through equal length coax or LVDS/LVPECL in some kind of star configuration.
>
>If I'm wrong, please set me straight, and explain to me how you plan
>on handling a system with say 4 MERCURY's, or 4 HORTONs for that matter.
>
>Eric, K7GNU
>  
>


-- 
Robert W. McGwier, Ph.D.
Center for Communications Research
805 Bunn Drive
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