[BC] AM Stereo On A Mono Radio-FM Loudness

[RichardBJohnson at comcast.net]

Sure there were.

o discriminator --Invented by Edwin Armstrong.
o ratio detector --Invented by Edwin Armstrong.
o slope detector --published by Armstrong as a example 
o super-regenerative detector --Invented by Armstrong

What wasn't well defined in the original 50 MHz (W2XMN)
band was the IF (if any) to use.  Since Armstrong invented
the super-heterodyne receiver as well, he wanted to use
IF stages in his (RCA) receiver. However, the first
commercially successful FM receiver used a super-
regenerative detector. Later receivers used 21.5 MHz
IF amplifiers and still later, 10.7 MHz. The 21.5 MHz
IF amplifiers that later became the de-facto standard
of TV until color bandwidth forced the change to 41.25 MHz,
were developed because of a military radio development
which had become successful.

--
Cheers,
Richard B. Johnson
Read about my book
http://www.LymanSchool.org


 -------------- Original message ----------------------
From: "Jim Tonne" <tonne at comcast.net>
> 
> >> Somebody, maybe even Armstrong, himself, decided upon a
> >> deviation that could be handled with conventional receiver
> >> circuitry. 
> 
> There were no "conventional receiver circuits" then.
> 
> - JimT
> 
>