[time-nuts] FE5680A square-wave output

bob grant bobgrant at fastmail.fm
Mon Feb 13 23:08:52 UTC 2012

I'm not that fond of the way in which 10MHz is made available on a DB9.
But there's a vacant site for an AC161 on the FE5680 PCB to perform a /6 
operation from the 60MHz crystal. To good an opportunity to miss up....

Here is some pics of the mod.


There is scant decoupling here, and it shows up as 6 blips in 
high/low signal levels whenever there is a signal transition.

I needed to add a tantalum, X7R, C0G and a small piece of FR4 with Cu
The output is on a RG178 SMA pigtail. 

Series termination worked best with 47R and 330R in parallel delivering
a reasonably nice 5V signal.

Earlier you may recall the "Why a 10MHz sinewave?" thread, and for those 
there are component sites for 390p and 1uH which make a wide bandpass

Have fun

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