[time-nuts] sine to square wave circuits - performance data?

Attila Kinali attila at kinali.ch
Wed Oct 4 17:11:09 EDT 2017

On Wed, 4 Oct 2017 16:47:22 -0400
Bob kb8tq <kb8tq at n1k.org> wrote:

> >> Driving a 5V powered CMOS gate with 5.5V p-p does a pretty good job ….
> > 
> > If you have this much signal, yes. Not everyone has the luxury of an
> > steady +19dBm input signal. Part of the reason why I am looking into
> > this is because I wanted a squaring circuit that can work down to +2dBm,
> > where, so I have been told, CMOS gates do not work well anymore.
> > 
> You don’t need 19 DBM to put 5.5V into a gate. A broadband transformer
> or a matching network and 0 DBM will do just fine. Neither one is terribly
> hard to come by. Neither one takes up much board space.

Right.. given that CMOS gates have a very high input impedance,
this works. The only thing that needs to be done is proper limiting
of the signal in order not to destroy the gate (ie two Schottky diodes).

			Attila Kinali

It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
                 -- Miss Matheson, The Diamond Age, Neil Stephenson

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