At 12:30 AM 10/7/96 -0700, cypherpunks@count04.mry.scruznet.com wrote:
PSE/VSE etc relys on a random 8-14 hz fm modulation appearing in the the 3rd formant band of the voice... the Dektor PSE retailed for approximately 5k in the early 1970's the hagoth hs-2 was the early 80;s for 2k ..
The technical details look vaguely familiar, but I probably last read them two decades ago. It doesn't sound like it would be too complicated to implement, with ordinary phase-lock loops, switched-capacitor filters, and other analog building blocks.
I bought 2 VSE units based on a new chip for 89.95 apiece recently... this was on an article appearing in popular electronics in 1995
I'll have to look that up. Was it a DSP or some analog implementation? Most importantly, does it seem to WORK?
no software as of yet and it would be probably a FFT or DFT based algorithm running on a sound blaster DSP(hardware DSP only) or as software on a fast 150 Mhz + pentium I can give the basic facts known... it is a truth detector only(not a lie detector), background music shows up a stress... and scrubbing the modulation shows up as constant stress or "possible decption"
Yes, it occurs to me that a vocorder-type compression/decompression of the voice would, effectively, remove FM modulation by averaging out short-term variations in voice frequencies.
truth is indicated by the modualtion showing up randomly over small increments of time... the effect is caused by microscopic tremors of the larynx when the speaker is relaxed and truthful the larnyx is relaxed and the random modulations show up,(or the speaker believes what he is saying to be the truth, when lying or under stress the larybx tightens and the random modulations disappear indicating stress... it would be nice to have it in software... to run on a laptop soundboard and spread to the net as widely as pgp...
I think it's particularly revealing that the TV networks don't try to use it. They're supposed to be looking for an edge, something to make the news seem more interesting. The political establishment would see the publicizing of this as going beyond an unwritten limitation on the media. Jim Bell jimbell@pacifier.com