[BC] FM Stereo invention

[Dennis Cope]

Willie..

In the lab I got much better stereo separation with the TDM method over the
Matrix.  Especially in the receivers demux.  IMD and THD was also better.

Dennis
WESR, WCTG, NOAA



-----Original Message-----
From: broadcast-bounces at radiolists.net
[mailto:broadcast-bounces at radiolists.net]On Behalf Of WFIFeng at aol.com
Sent: Monday, February 19, 2007 12:30
To: broadcast at radiolists.net
Subject: [BC] FM Stereo invention


In a message dated 02/19/2007 12:15:10 PM Eastern Standard Time,
mark3xy at gmail.com writes:

> As most of you know, the FCC-approved stereo FM system was jointly
>  developed by GE and Zenith.  The difference was that Dr. Adler of
>  Zenith viewed it as a time-division-multiplex scheme (L and R
>  alternately sampled at a 38 kHz rate) while Tony Csicsatka at GE used
>  a matrix and balanced modulator to generate the L-R subcarrier.
>
>  He was undoubtedly a brilliant engineer.

The interesting thing is that both of these methods generate virtually the
same result! Some of those FM stereo generators on-a-chip use analog
switches at
38Khz to chop the L and R signals alternately. The end result is a
"standard"
stereo signal. Pretty slick "shortcut".

Willie...