[BC] LPFM's, now, reliable remote closures

[Mark Humphrey]

On 9/7/06, Tom Bosscher <tom at bosscher.org> wrote:
>
>     With all the advances in our broadcast technology, we still seem to
> lack an easy way to get four to eight contact closures in the audible
> region. I still would like to see someone come up with a box (puleez,
> don't make it a card for one more cpu in the rack), that would use the
> tone sequence like CBS/NBC/ABC used 20 years ago. Audible, yes, but very
> quiet.

There's a way to do this "in-band" and keep the tones inaudible, but
it probably infringes on Arbitron's PPM patents.

Basically, the tone frequencies would be chosen dynamically, such that
they are masked by program content.  They could be injected 20 dB down
(like the Arbitron codes) and nobody would notice.   This kind of
stuff is easy to do with DSP.

Mark