cellphone question
 

If I leave my cell phone near my computer speakers I will hear occasional
buzzing, clicking, etc. Before the phone begins to ring, I hear a
dah..dah.daahhhhh. I know this is RF interference being picked up by the
amplifier in the speaker. If one were to record this sound with a
microphone at 11 or 22Khz, would it be possible to obtain any information
(usable signal) from the recorded audio?
Thanks,

cellphone question
 

"Mike Muderick" wrote in message
news:smoSf.18848$wH5.9595@trnddc02...
If I leave my cell phone near my computer speakers I will hear occasional
buzzing, clicking, etc. Before the phone begins to ring, I hear a
dah..dah.daahhhhh. I know this is RF interference being picked up by the
amplifier in the speaker. If one were to record this sound with a
microphone at 11 or 22Khz, would it be possible to obtain any information
(usable signal) from the recorded audio?
Thanks,



If you could then clean up the audio into a reasonable digital waveform, in
the right format, and somehow then get it into a cellphone provider's
software package, then I guess that you could, but I'm not sure that it
would tell you anything useful. AFAIK, it's just a response from the phone,
to the question
" OI !! Are you still there ? Yes ? OK, let's set up a channel 'cause I'm
about to ring you " or something along those lines, sent by the last cell
that the phone had become registered on. Perhaps others on here know a lot
more about it, but I think that's something like I remember reading it.

Of course, what you're hearing may not be a data stream as such, at all. It
may just be as a result of the phone's RF output frequency hopping about all
over the place on some kind of spread spectrum scheme. Again, others here
might be able to give a better answer on that.

Arfa