[time-nuts] question Alan deviation measured with Timelab and counters
csteinmetz at yandex.com
Sun Jan 18 01:00:02 EST 2015
>>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).
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