[BC] AM Stereo

[Dave Hultsman]

My recollection is that Motorola even sued National Semiconductor that made the mutli-system chip used by Sony because it violated some of their patents.   Sony was the only major manufacturer that made at least two versions of their car radios with AM stereo and the two speaker portable stereo unit, the AM Stereo walkman and two AM Stereo Boomboxes .   When Motorola and Kahn bought suits or threatened Sony sold the remainder of the manufacture runs and didn't proceed on any additional AM stereo products.   Again if the FCC had picked any system initially, technology would have quickly evolved to solve any of the inherent problems.  AM was still a music service when all this started,  The Magnavox system was picked twice by the FCC based on their evaluations of all the systems.  The supposed problem was carrier cutoff on negative peaks.  Magnovox had solved that popping noise in their second generation chips.  Leonard Kahn and Double CSSB system was first to market and maybe should have got credit for that.  The Belar system was the earlier RCA AM system that came up a year or so before multiplex FM stereo was being discussed so it may have technically been earlier.  Dave Hershberger's  Harris system was fine but would really have required a major change in AM receivers that probably should have been done anyway,  synchronous detection.
 
The FCC several years later the Motorola System was mandated by congress. An attachment to an appropriations bill required that the FCC pick an AM Stereo system.  They chose the Motorola system but allowed anyone to use any system as long as it caused no interference to the Motorola C-Quam system.  This was essentially too late for the market place to do anything.  Many stations had already spent money on Kahn, Harris, Motorola and Magnavox.  I know that Continental replaced many Magnavox systems sold with the Motorola exciters. I wonder how many Kahn, Harris and Motorola Stereo units are now gathering dust. 
 
Dave Hultsman 
 
In a message dated 11/24/2010 10:04:49 A.M. Central Standard Time, bdoerle at mail.ucf.edu writes:
>Motorola could just as easily have manufactured
>> that chip.