Chris Morriss wrote:

In message , Jeffrey D Angus
writes
Frank Dresser wrote:
I think the fact that the synchrodyne never became at all popular as an AM
radio detector in the tube era means something. If I recall correctly, I
read that synchrodyne detectors would howl until they sync'd. Also, the
phasing would have to be perfect to get good demodulation from normal double
sideband AM.

Now appearing on alt.binaries.pictures.radio

Syncrhodyne three tube receiver from the April 1951 edition of
Radio News.

Jeff


Many years ago, there was a series published in 'Wireless World' (might
even have been by John Linsley Hood) about the design of an AM
synchrodyne using transistors and linear ICs. It actually stripped off
the carrier from the incoming signal, and then limited and filtered this
to use as the source of the local oscillator. I believe the concept was
called 'Homodyne'.

Ppl should read all the old WW magazines on all articles about radio and audio.
There is a lot to read.


As far as I know, the audio quality was excellent, but it couldn't tune
a weak signal close to a powerful one as the powerful one always
succeeded in becoming the LO for the demodulator.

This might be unlikely with local stations, and if there was some selectivity
in the RF front end ahead of the real business.
So a two gang cap and double tuned pair of LC at RF is usefull



Here in the UK, AM audio is filtered to 5kHz before it gets to the
modulator, so you wouldn't get any increase in audio bandwidth.

Yuk,

Patrick Turner.



--
Chris Morriss