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Originally Posted by JimmyM Well if it ever becomes widespread, I'm sure there will be laws governing its usage. I don't think you'd be able to use it for subliminal advertising, just like subliminal advertising is outlawed in films, TV and music. However, it will probably be allowed as an advertising tool, so you might want to get used to the idea. |
Two things:
1) Norris' device is based on the non-linearity of transmission of ultrasonic frequencies through air. In effect, the air demodulates the desired signal (the sound) from the ultrasonic carrier. Norris' contribution is the development of an efficient way to do this. It's actually a very old idea and phenomonon that was difficult to realize practically. Norris demonstrated his devices some years back at a meeting of the Acoustical Society of America. He was not very forthcoming with the details of its operation other than to explain that he had developed a "pre-processor" to condition the signal to make near-optimal use of the non-linear effects upon which the technique relies.
2) About 30 years ago, subliminal advertising was shown to be nonsense. THERE IS NO SUCH THING AS SUBLIMINAL PERCEPTION!
(For those of you out there who might not believe me, I really don't care to dredge up this nonsense here. The so-called "subliminal perceptions" are a result of entangling response biases with sensitivity-- all quite well accounted for by signal-detection theory.)
