Hey John,
I have, The CV-157 uses that method in ADDITION to
a PLL. The Local Carrier has to be pretty close in phase
relationships to the sidebands or you get "Goofy" Audio.
It almost sounds like a "Flanging" effect. (Am I aging
myself?)
The CV-157 has the same drawbacks as his solid state
brothers except more so due to the motor tuned LO. He was
designed for fixed frequency operation between ship and
shore stations where everyone is "Dead Nuts" on freq.
I think the carrier filter is only 50 or 60 cy. wide.
You can read all about it here:
http://bama.edebris.com/manuals/military/cv157/ Back in the day when Radio Merlin 1 (a BBC affiliate)
was rockin' out on 9560/9895 kc I used it quite a bit. Not so
much anymore. It's a beautiful machine and I still have him.
Maybe yet another 2015 Resolution Hi!
73
/Dan
I dug this up in my old paper files. Seems like it could be useful, a synchronous detector that uses a narrow band filter for carrier instead of a PLL. Has anyone played with this for AM, better than envelope detector for fading effects? There may be some better chips than a CA3089 to do this.