[sdiy] (very OT?) Analog vs. Analogue - opinions needed

David G. Dixon dixon at interchange.ubc.ca
Sun Jul 5 04:55:27 CEST 2009

> Hasn't anyone built anything interesting recently to tell us about?

I built a second Multiplying Modulator (-2Q/4Q/+2Q multiplier with +, +/-,
and - polarity switches on both inputs) lastnight using a linearized 2164
instead of a 13700.  However, the design was a total disaster; I neglected
to put a follower on the modulating signal, forgetting that a simple active
rectifier (like a follower, but with a diode at the opamp output) doesn't
actually buffer anything.  Hence, the device did all sorts of strange
things.  Of course, my simulation did exactly those strange things, except
that I also neglected to run the simulation under those conditions.  Live
and learn!  That's what you get for being cocky!  At least I only have to
remake the board, but the panel is fine, and I'll be able to reuse all the

If only I'd used more silent vowels on all my words, like the British, I
could have avoided being such a dumbue-dumbue!

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