I've built precision rectifiers using op-amps, in the past. While they do
sound very good, they don't eliminate the selective fading that is present
with any other envelope detector.
I once built a version of a crystal radio that used this type of detector. I
used a textbood circuit that had diodes in the feedback loop of an op-amp.

Pete

"N9NEO" wrote in message
oups.com...
Is anyone here interested in collaborating on a small pc board with a
precision detector and an elliptic filter? and maybe even a small
amplifier too. This would be a retrofit to existing radio. I have
heard it is almost as good as a sync detector- better than some. I
have heard others say it is smoke and mirrors so I expect to get to the
truth here.

I am looking for two other people to help out. Board will cost you
maybe 30 bucks. I use PCB express. You get three small boards no silk
no solder mask for about 60bucks. I am in-between consulting jobs now,
so that I have a little time but watching my funds. I think with smd
parts maybe only half a board is needed so that each will cost even
less.


Idea has been around for quite some time but recently brought to my
attention by Terry. I am looking at that Redsun RP2100 unit as the
platform to run with.

regards,
NEO