[time-nuts] HP 5316B External Reference

[Richard (Rick) Karlquist]

On 7/13/2020 6:26 AM, Wes wrote:
> Hi Magnus,
> 
> I did have the manual when I posed the original question but I had not 
> delved into the cal procedure until you mentioned it.  It seems to be a 
> bit complicated for what it does. I wonder how stable this is and how 
> often might it need to be repeated. Why they didn't use the external 
> reference more directly is a puzzle.
> 
> I appreciate your time in looking into this.
> 
> Regards,
> 
> Wes
> 
> 

I don't know the specific engineer who designed this injection
locking scheme, but IMHO it's a "too clever by half" sort of
thing (and that's being charitable).  Unfortunately, I encountered many 
examples of that in the 5334A, and other counters.  I took out around
a dozen of these "clever" circuits in the process of replacing the
5334A with the 5334B.  The engineers involved were outside their
lane as the saying goes; I actually talked to them about why they
designed the circuit in that way.  Didn't have a valid reason IMHO.
Just having been in that environment, I would be distrustful of the 5316 
design for anything important application like time nuts work.
Actually, I would be distrustful of any injection locking multiplier no 
matter who designed it.  Unfortunately, you can't conclude that
a design is good simply because it came out of HP.  In some ways,
it was disillusioning to go to work for HP and see what is
really going on.

Rick N6RK