[BC] Crosley Stereo System...

[Burt I. Weiner]

The Crosley system with the AM (DSBSC) subcarrier was the only choice 
open that would fit a 15 kHz channel for the L-R in the bandwidth 
available. The BTSC TV audio system uses a compandered system to 
further reduce the noise in the L-R channel. Even though the L-R 
channel has a higher amplitude due to the DBX compandering, it still 
is ahead of the non-compandered system used for FM broadcast.

Besides, I use to have an old 10" Crosley TV.

Burt

At 10:00 PM 12/25/2005, you wrote:
> >From: DANA PUOPOLO <dpuopolo at usa.net>
> >
> >Nope!
> >
> >By far the best FM stereo system was an FM on FM system (Crosley?).
> >It only degraded the s/n by 6 db (as opposed to the 23 db 
> degradation the one
> >we have does). Its only problem was that it was incompatible with SCA's, and
> >the industry wanted that $$$ at the time.
> >
> >America's broadcast record of screwing up everything technical is
> >unblemished!
>
>Because the FM subcarrier in the FM/FM system was narrowband, there
>was not enough spectrum available for it without truncating the
>spectrum. This would have built nonlinear distortion into the system
>spec, which never could be improved by hardware improvements.
>
>The 6 dB loss you recall was _mono_ S/N because the FM subcarrier was
>always taking up baseband modulation even when there was no L-R
>energy. I don't recall the FM/FM's noise penalty in stereo, but it
>was a lot more than 6 dB because narrowband FM does not have the same
>SN advantage as wideband FM.
>
>The BTSC went through the same exercise comparing an FM/FM system
>(EIAJ) to a suppressed carrier AM system and once again, the
>suppressed carrier AM system proved superior. (This time, the
>subcarrier was companded to reduce the stereo SN penalty substantially.)
>
>We DID choose the right FM stereo system.
>
>Bob Orban

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California U.S.A.
biwa at earthlink.net
K6OQK