[time-nuts] Fury Realhamradio listing

Dr Bruce Griffiths bruce.griffiths at xtra.co.nz
Sun Apr 29 01:20:03 EDT 2007


SAIDJACK at aol.com wrote:
> They can get 0.1ns resolution on the printout because of  averaging. I don't 
> know what their native granularity is.
>  
> Single shot resolution may not have such a significant  impact since the GPS 
> used in the Z3801A is so much worse than the  M12+.
>  
> Our resolution is more coarse than 100ps, but our inherent GPS noise is  very 
> significantly lower than the Z3801. Resolution of 100ps with a peak to peak  
> noise of 100ns or more is not as good as peak to peak noise of 31ns with  RMS 
> noise of <10ns.
>  
> So even if they have true 100ps hardware resolution (I somehow doubt  it 
> since an expensive 54132A only has 150ps resolution) then that's more than  two 
> orders of magnitude less than their sawtooth noise - does it really matter  at 
> that point?
>   
Said

Obtaining 100ps resolution, particularly when one is only making 1 
measurement per second, is relatively easy and inexpensive to do with a 
few discrete components.

Obtaining much better than 150ps resolution is somewhat more difficult 
when using the technique employed by the HP53131/2 in its CMOS gate array.

Bruce




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