[BC] Is overprocessing illegal?

[Robert Orban]

At 09:24 PM 12/24/2006, Jerry Matis wrote:

>No. Practically all modern audio equipment will pass frequencies well beyond
>19 kHz. And in today's overprocessed, clipped, squashed, smashed, and
>deliberately distorted audio, there's likely to be lots of that, probably
>not intended to be heard, but the byproduct of the aforementioned
>overprocessing, clipping, squashing, smashing, and distorting audio. We
>would call them "artifacts" or "grunge", but if they pass into the
>composite signal, they would play hell with the stereo reception of said
>audio. The FM stereo system now in use was not designed to pass audio above
>about 15 kHz. So just filter it all out and be done with it.

Regardless of the amount of processing, all Orban FM processors effectively 
protect the pilot tone region and the SCA region (above 55 kHz, if one 
includes RBDS). This includes any spectrum introduced by composite 
limiting. Figs. 3-1 and 3-2 in the 8500 Operating Manual show typical 
measurements, which were made using the "maximum peak hold" mode of an FFT 
analyzer in "real-time" mode over a 10-minute observation period to catch 
even the most transient spectrum. If this measurement had been made with a 
swept spectrum analyzer and/or with video averaging, it would have looked 
even better.

I know that some other processor manufacturers (although not all) are also 
diligent in protecting the pilot tone and SCA regions.

Bob Orban