Michael Dunn wrote:

Hello fellow radionuts (radionauts?). For some reason, I've decided
to design and build an FM tuner. Just to see if I can make a good one
I guess. A few questions have presented themselves:

-PLL or quadrature (IC) decoding?


-Stereo decoding: single IC or "discrete"?


-Throw in SCA! Why not? PLL?


-Anyone in S Ontario (KW) area?


-I'm still having a hard time figuring out AFC. I can see how I might
do it with a PLL - the DC error voltage being used to pull the LO to
the correct frequency. How was it done in the old days? ;-) If I
could design not only AFC, but also automatic tuning of an RF
preselector and perhaps even an antenna tuner, that would be tres cool.



All thoughts greatly appreciated.

Michael Dunn
VA3SSP
mdunn @at@ cantares.on.ca
Tech museums: http://www.cantares.on.ca/museums.htm
Design portfolio: http://www.cantares.on.ca/portfolio/

You can also use the signal from a quadrature decoder, whether IC's or
tube -- and there's a clever game you can play to make a gyrator out of
a pin-toad, which is how you pull the LO around if you're doing it with
tubes, etc.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com