[time-nuts] question Alan deviation measured with Timelab and counters

Charles Steinmetz csteinmetz at yandex.com
Sun Jan 18 01:00:02 EST 2015

Stephane wrote:

>>I need to make a squarer. I was hesitating between several methods 
>>: using a CMOS gate, but this will increase the flicker noise from 
>>what I've read, using an amplifier and clamping diodes or a fast 
>>comparator which might create some noise around the trigger 
>>point... Any recommendation there ?

The basic Wenzel design can be optimized with attention to a few 
details (see below).

Note that bias must be supplied to the LM329 (or whatever reference 
you use for the bases), which is not shown.  The 20v supply should be 
quiet.  The 1k emitter resistors can be replaced with quiet current 
sources, if you want to go to the trouble -- but with a quiet 20v 
supply, that should not be necessary (and designing quiet current 
sources is its own challenge).

I posted a variant of this circuit for 3v logic on 12/25/14, which 
you can find in the archive.  The power supply decoupling shown in 
that version (100uF tantalum + 1uF X7R ceramic + 10nF C0G or X7R 
ceramic) is superior to what is shown below).

Best regards,


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