[time-nuts] What is a Time-Nut grade Zero Crossing Circuit?

Bruce Griffiths bruce.griffiths at xtra.co.nz
Thu Jul 31 17:58:48 EDT 2008


Pete wrote:
> The JPL paper is here:  http://tycho.usno.navy.mil/ptti/1990/Vol%2022_20.pdf
>
> Pete Rawson
>   

Pete

You can usually do much better than that.
The Collins paper indicates how.

http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?isnumber=10665&arnumber=494304&type=ref 
<http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?isnumber=10665&arnumber=494304&type=ref>
(I know you have to purchase it or perhaps photocopy it. - but its well 
worth the effort)

I have extended the theory to include the case where the input noise 
spectral density is not the same for all finite gain limiter stages.
I also have a few spreadsheets which can be used to calculte the optimum 
gain distribution and corresponding filter bandwidths etc both for the 
restricted case that Collins analyses and the more general case.
The Collin's paper indicates how much better one can do with an 
optimised cascade of finite gain filtered limiter stages as opposed to 
the relatively conventional design in the Dick paper.

With high frequency signals one can use a bandpass filter at least for 
the first couple of low gain limiter stages.

Bruce




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