Thanks Tom,
I do have that article, and that circuit is similar to
the quasi-sync detector that I developed a couple of weeks ago. The appnote
that i have describes a design that I believe was created by one of the
application engineers at AD. This is a really cool circuit, because it is
optimized for 455kHz. I've got the board layout almost done...........maybe
later this week, I will have it built up.
I've bumped up the overload point on the receiver to 80,000uv, so it isn't
too bad now. Measured distortion with either the envelope detector or the
current version of the sync detector is .4% @ 300uV, but there is still
something I don't like about the sound of that sync detector. If I were to
try to market the receiver with the current sync detector, it would get shot
down by anybody who was unfortunate enough to buy it. Still more work to do
in this area. One fellow from Norway suggested that I have an I.F. output on
the radio, so that folks can use their own sync detector. I could do that,
but my goal is to design a sync detector that is better than anything else
on the market, regardless of price. Hopefully, I will be able to do it.

Pete

tom Holden wrote in message
om...
"Pete KE9OA" wrote in message [snip]
this into production, so the next step is to design a sync detector,
using
an Analog Devices AD607. The folks at AD were nice enough to send me a
workable application circuit, but unfortunately, this is going to
require a
four layer board, so I am not going to be able to etch the boards at
home
with this one. Not a bad thing in itself, but I am going to have a board
house do the prototype boards.

[snip]

Pete, here's an article on using the AD607 as a sync demod:
http://home.att.net/~wa1sov/technical/sync_det.html

73, Tom