Pitch Extractor

[Scott Bernardi]

I'd like to include a pitch extractor in my new synth, and an article in
ElectroNotes 136 on using a Hilbert transform to remove upper harmonics
and emphasize the fundamental looks very interesting. The article was
more of an experiment than an actual module built. My Electronotes
subscription ran out soon after that issue (wish I had kept it up, now)
- does one of you that have a full set know if Bernie pursued that
subject in later issues? If so, I'd sure like to get my hands on a copy.

The Hilbert transform is realized by a 90 degree phase delay network
feeding a couple of multipliers hooked up as squarers.  What do people
use for multipliers?  AD633's seem very hard to locate; Arrow
Electronics has ICL8013's listed on their website. I'd like to use
something more accurate than OTA's, but also don't want to spend over
$10 per chip.

--
Scott Bernardi
sbernardi at home.net