[BC] AM Stereo and Leonard Kahn

[Robert Orban]

At 06:55 PM 11/23/2010, Kyle Magrill wrote:
>The Crosley FM stereo system was an FM on FM system-as opposed to the
>suppressed carrier AM on FM ystem we have now. It's one disadvantage was that
>runing it meant that you had no space for SCAs-and since many FMs were running
>SCAs at the time, the system we have now was selected.

Moreover, the subcarrier was always on, even with no L-R modulation. 
This meant (IIRC) a 6 dB drop in the loudness of the L+R compared to 
monophonic transmission. Moreover, because the system used narrowband 
FM, it was necessary to truncate the higher-order Bessel sidebands of 
the subcarrier, producing a system with irreducible nonlinear 
distortion as part of the system specification. In short, the FM 
subcarrier introduced its own set of problems and it's likely that 
the FCC made the correct choice, particularly given the fact that the 
current system was scrutinized by more than just the FCC and as a 
result, was adopted almost everywhere internationally.