Mark Zenier ) writes:
In article ,
Pete KE9OA wrote:
"John S." wrote in message
roups.com...
Which radio...haven't heard that term.
I believe that Kiwa detector that went on eBay recently was of this design.
A guy I know who knows Craig a lot better than I do said that it used some
chip designed for VCRs. (My wild ass guess would be a Philips video IF
and detector chip with the synchro-phase circuit in it. TDA2540, TDA2541).
Mark Zenier Washington State resident
Are we talking what's no called "quasi-synchronous"?
Decades ago, Motorola had the MC1330 which was a mixer and a limiter
in one package, and intended as a quasi-synchronous detector in tv
sets.
I suspect if driven properly, the MC1350 IF amplifier would do it, since
the stage that is voltage controlled is just a "Gilbert Cell Mixer".
When the MC1496 Mixer (a "Gilbert Cell" long before the term was applied)
came out in the early seventies, there was an article in Ham Radio magazine
about it, I think by Roy Hejhall, and one of the examples was as a
"quasi-synchronous" detector, though I'm not sure if it explained it
as such or just as a fancy AM detector. Didn't even need a limiter, if
you fed a strong enough signal into it. The datasheet or application note
for the MC1496 includes the circuit.
Of course, there have also been examples of them based on FM detectors.
Many of those in ICs used a scheme that included a balanced mixer, and
of course it had the limiter, so all you had to do was hook it up.
Michael