MOTM

I made the "frequency mixer with op amps" that appeared in EDN some 
time ago.  I used the Tellun MUUB-4 pcb as a daughter card for a MOTM-
890 mixer that I recently purchased from the August sale.  I used two 
of the 5 inputs for the frequency multiplier and normalled the output 
to input 5.  It works pretty neat and functions as a full wave 
rectifier with only a single input.

Schematics and photos at
http://modularsynthesis.com/modules/DJB-FM/djb-fm.htm

Dave