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Old October 12th 06, 12:21 AM posted to comp.sys.ibm.pc.hardware.storage,alt.comp.hardware,sci.electronics.equipment,rec.radio.amateur.misc
kony kony is offline
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First recorded activity by RadioBanter: Oct 2006
Posts: 27
Default How detect if MP3 player is recording in your room? [OT]

On Wed, 11 Oct 2006 16:49:05 -0500, "Matthew Hicks"
wrote:


"kony" wrote in message
.. .
On Wed, 11 Oct 2006 00:38:03 -0500, "Ken Maltby"
wrote:


You know how an IC gives off heat in relation to how
hard it is working, ("constant current" is a myth) heat is
only one part of the electromagnetic spectrum.


No, constant current is a fact. The IC draws constant
current in many MP3 players and does not substantially
change it's heat output unless entirely turned off or put to
sleep which is an entirely separate mode of player
operation, not momentary in use like with a CPU.


No, contsant current isn't a fact. When an IC sends outputs the signals on
the traces are switching and unless the same data is flowing you will see
different currents depending on what data is bieng sent and what was sent
before. Resistance can also change.



The signals are fairly constant, encoded bits regardless of
whether there's silence or not. My argument is not whether
the mere presences of signals can be deteced, but rather
there is a significant enough difference in signal to detect
with sound input versus silence (in the room).

Claiming you will see different currents based on the data
is easy with the gear open and measurement by wire. Trying
to find whether there is an unknown device present or not is
not quite same situation.