"Brenda Ann" wrote:


"Tony Meloche" wrote in message
...

Horse hockey. I'm not saying Leonard's suit didn't hamper the
reality of AM stereo, but if it had become a mainstream thing, "stereo
lo-fi" would have never held it's own against "stereo hi-fi" (FM).
[...]

Tony


There is absolutely no reason why AM stereo could not be just as high a
fidelity as FM stereo, and in fact was in many cases. What gives AM
broadcasting the characteristic 'telephone quality' sound it has is mostly
the receiver. There is some pre-transmitter processing to limit the
bandwidth used, but it doesn't need to be there for purposes of transmitting
the signal, only for purposes of limiting said bandwidth. In Portland, we
had several AMS stations with full frequency response (50-15K) just as FM.
And AMS signals didn't degrade the way FM does when in the downtown area or
on the 'dark side' of hills. Admittedly, AM signals can be noisier than FM
on the fringes, but they are better in hilly terrain for the most part than
FM.


In the brief period of broadcast stereo before FM multiplex stereo,
often one channel is carried on AM and the other on FM. I borrowed
one of those receivers in my college days and the AM performance was
astounding. Brenda Ann is right: Most AM receiver designs today
simply ignore fidelity as an issue.

--
Eric F. Richards

"Nature abhors a vacuum tube." -- Myron Glass,
often attributed to J. R. Pierce, Bell Labs, c. 1940