Re: Speech sensors?

[msantos@etse.urv.es]

> Does anyone out there more knowledgable than me (and that's not hard) 
> know if the following 
> technique is for real or is an urban myth: that industrial-espionage type 
> sensors exit which can reconstruct an internal conversation from the 
> remotely-sensed vibrations of a room window?
> If it is genuine, how is it done in practice?
> Cheers and Christmas Greetings to all
> Margaret Mazzolini
Hi all,
I saw a demonstration some weeks ago on a tv talk-show. 
I didn't doubt it was really working. It consisted of
a laser which had to be pointed directly to the source
you want to listen to. Any obstacle in between makes
the system to fail.
They didn't explain in more detaiil how it works. 
My guess is that it's based on the doppler effect measuring
phase shifts of the bounced ray which returns to th system.
If I remember well, it was said that the max. working distance
from the noise source was about 200 meters.

But I don't know f.i. how clear that way can distinguish 
between other
sources of noise. I'm thinking in a great city, with a lot
traffic noise, the neighbour with his 150W Hi-Fi system at
full throttle, and so on.

Any one knows something about that system?

Regards,
msantos@etse.urv.es


MErry Christmas & happy new year