[time-nuts] Looking for a Counter

Hal Murray hmurray at megapathdsl.net
Thu Oct 6 21:26:21 UTC 2011

> I'm actually looking a similar problem.. I want to set up an experiment  to
> characterize a bunch (several dozen?) of cheap XOs over temperature  and
> time and power cycles. I'm not looking for 1e-15 adev at 100 seconds  kind
> of performance: maybe more like 1E-6 or 1E-7 ADEV.

I'd like something like that.  I suspect other nuts would too.  Please let us 
know if you find anything interesting.

My first thought was to use a bunch of tvb's picPETs backwards.  :)  Feed 
them all the same PPS and clock each one with one of the clocks you want to 
test.  But that requires a serial port per XO.  Maybe you have an old 
many-input serial box in the junk bin, but I'm always short of them.

How about a PIC/AVR listening on a serial port and driving a big mux?  You could probably power it and a HC151 from a modem control pin.  A PCB would be mostly connectors.  If you are going to make a PCB, you might as well wire up any unused PIC pins to various connectors.

Or use USB...  A USB to parallel port chip avoids the PIC.

These are my opinions, not necessarily my employer's.  I hate spam.

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