Maker Pro
Maker Pro

Acoustic sound emanation from electric circuit components

P

Peteris Krumins

Jan 1, 1970
0
Hello,

I am writing a document for school on how different forms of energy
emanated from the computer systems can be used to analyse the data
being processed by the computer system.

Currenly I am writing about acoustic sound emanation from the computer.
Here is the source of information which I am describing in more detail:
http://www.wisdom.weizmann.ac.il/~tromer/acoustic/

The thing I cannot understand is what creates the acoustic sound which can
be used for analysis.
Is it the great amount of transistors in the CPU, or as I found in other
sources, bad quality condensers? Or the quality does not matter? Do all
condensers emanate acoustic sound? What about transistors, can
they actually emanate sound?

Thanks in advance.
 
W

wavelength

Jan 1, 1970
0
Peteris Krumins said:
Hello,

I am writing a document for school on how different forms of energy
emanated from the computer systems can be used to analyse the data
being processed by the computer system.

Currenly I am writing about acoustic sound emanation from the computer.
Here is the source of information which I am describing in more detail:
http://www.wisdom.weizmann.ac.il/~tromer/acoustic/

The thing I cannot understand is what creates the acoustic sound which can
be used for analysis.
Is it the great amount of transistors in the CPU, or as I found in other
sources, bad quality condensers? Or the quality does not matter? Do all
condensers emanate acoustic sound? What about transistors, can
they actually emanate sound?

Thanks in advance.

Hiyas :),

In regards to your question >The thing I cannot understand is what
creates the acoustic sound which can
be used for analysis.


The primary source of the Sounds of computers are the Mechanical parts.
Which, for example, are floopy drives, hard drives, fans, speakers,
keybpards, CD and DVD units etc. Electronic parts { including condensers },
in general, do not make any sounds unless they are being ' fried ' ;).

Best

:)
 
U

Uncle Al

Jan 1, 1970
0
Peteris said:
Hello,

I am writing a document for school on how different forms of energy
emanated from the computer systems can be used to analyse the data
being processed by the computer system.

Currenly I am writing about acoustic sound emanation from the computer.
Here is the source of information which I am describing in more detail:
http://www.wisdom.weizmann.ac.il/~tromer/acoustic/

The thing I cannot understand is what creates the acoustic sound which can
be used for analysis.
Is it the great amount of transistors in the CPU, or as I found in other
sources, bad quality condensers? Or the quality does not matter? Do all
condensers emanate acoustic sound? What about transistors, can
they actually emanate sound?

Current flow creates magnetic fields, then Lenz' law. Voltage
stress. Stuff moves in response to changing fields - e.g.,
transformer hum. Keyboard strikes may give you impulses. Almost
everything in a computer is near- or multi-GHz square waves with their
very high frequency harmonics. One doubts any information processing
yeidls even ultrasonic acoustic signals carrying information -
including sum/difference beats. Circuit elements that move will
mechanically fail from fatique. The only part you want to hum is the
quartz crystal that locks the board frequency (if there is one).

Look for EM emissions. That is how the alphabet soup of jackbooted
Federal agencies listens in on what you do. Only a fool would go
wireless (computer or telephone).
 
P

Peteris Krumins

Jan 1, 1970
0
Hiyas :),

In regards to your question >The thing I cannot understand is what
creates the acoustic sound which can
be used for analysis.

The primary source of the Sounds of computers are the Mechanical
parts.
Which, for example, are floopy drives, hard drives, fans, speakers,
keybpards, CD and DVD units etc. Electronic parts { including
condensers }, in general, do not make any sounds unless they are being
' fried ' ;).

Did you take a look at the link I posted? It says they managed to record
the sound (2.5kHz - 40kHz) which came from the electric parts.
 
G

Gareth

Jan 1, 1970
0
wavelength said:
Hiyas :),

In regards to your question >The thing I cannot understand is what
creates the acoustic sound which can
be used for analysis.


The primary source of the Sounds of computers are the Mechanical parts.
Which, for example, are floopy drives, hard drives, fans, speakers,
keybpards, CD and DVD units etc. Electronic parts { including condensers },
in general, do not make any sounds unless they are being ' fried ' ;).

Yes, I would have thought so too and I haven't noticed the capacitors in
my computer making any noise, but some researchers think differently:

"The sounds made by capacitors on motherboards might, in theory, give
attackers code-breaking clues in much the same way electro-magnetic
leakage or power fluctuations can be used in so-called "side-channel"
attacks on secure systems"

see:

http://www.theregister.co.uk/2004/05/11/sounds_yield_crypto_clues/

Gareth.

PS condensers are more usually called capacitors.


--
 
J

Jan Panteltje

Jan 1, 1970
0
Hello,

I am writing a document for school on how different forms of energy
emanated from the computer systems can be used to analyse the data
being processed by the computer system.

Currenly I am writing about acoustic sound emanation from the computer.
Here is the source of information which I am describing in more detail:
http://www.wisdom.weizmann.ac.il/~tromer/acoustic/

The thing I cannot understand is what creates the acoustic sound which can
be used for analysis.
Is it the great amount of transistors in the CPU, or as I found in other
sources, bad quality condensers? Or the quality does not matter? Do all
condensers emanate acoustic sound? What about transistors, can
they actually emanate sound?

Thanks in advance.
Any component that can move a tiny bit or has parts of it that can move
could create sound.
Often it is transformers (because the magnetic field moves magnetic parts or
windings even), capacitors (because of piezzo electric effect for example),
transistors I dunno, never noticed :).
Transistors do change (move) microscopic amounts due to heating and cooling,
but such fast heating and cooling that vibrations in the audio range would
come from it .. I dunno, maybe if you had an ultra sensitive microphone.
Strongest noise in a PC comes from the fan(s).
Next is the harddisk and floppy drive, the movement of the disk, and the
positioning of the disk arm (very fast, milliseconds) makes a lot of noise.
Floppies are worse (stepper motor head seek).
Of cause 48 x speed CDROM drives and DVD drives add a lot of fun too.
And, on top of that, PCs do have a speaker.
beep beep
JP
 
M

Michael Varney

Jan 1, 1970
0
Uncle Al said:
Current flow creates magnetic fields, then Lenz' law. Voltage
stress. Stuff moves in response to changing fields - e.g.,
transformer hum. Keyboard strikes may give you impulses. Almost
everything in a computer is near- or multi-GHz square waves with their
very high frequency harmonics. One doubts any information processing
yeidls even ultrasonic acoustic signals carrying information -
including sum/difference beats. Circuit elements that move will
mechanically fail from fatique. The only part you want to hum is the
quartz crystal that locks the board frequency (if there is one).

Look for EM emissions. That is how the alphabet soup of jackbooted
Federal agencies listens in on what you do. Only a fool would go
wireless (computer or telephone).

Today there has been periodic power outages near where I live. The lights
go out and I hear an awful racket outside, like a deep vibrating thrum. Car
alarms go off and my cats run in terror.
Inductive spikes can be a bitch.
 
W

wavelength

Jan 1, 1970
0
Peteris Krumins said:
Did you take a look at the link I posted? It says they managed to record
the sound (2.5kHz - 40kHz) which came from the electric parts.


Hiyas :),


On the link .................

One thing that you might keep in mind is that a square wave contains a
huge number of frequencys. See Fourier Analysis. A Perfect square wave
contains a Infinite number of frequencys. ' Square ' waves are the defacto
signal in a computer. These frequencys will ' find ', and stimulate
the mechanical resonances of the system. And with Sensitive equipment could
be detected.

They are VERY weak though unless they find resonances in which case the
part is actually oscillating. No intensity information was given - only
spectral.

It would be interesting to see the spectral content of the lines in more
detail to see how sharp they are. In the part where chill spray is sprayed
notice how the lines more or less return to their original positions as the
system returns to its original state. The band is from the ' noise like '
sound of the spray itself - ie random noise.

There are better ways to ' eavesdrop ' though if that what the goal is
though ...........



Best

:)
 
C

crynwulf

Jan 1, 1970
0
Peteris said:
Hello,

I am writing a document for school on how different forms of energy
emanated from the computer systems can be used to analyse the data
being processed by the computer system.

Currenly I am writing about acoustic sound emanation from the computer.
Here is the source of information which I am describing in more detail:
http://www.wisdom.weizmann.ac.il/~tromer/acoustic/

The thing I cannot understand is what creates the acoustic sound which
can be used for analysis.
Is it the great amount of transistors in the CPU, or as I found in other
sources, bad quality condensers? Or the quality does not matter? Do all
condensers emanate acoustic sound? What about transistors, can
they actually emanate sound?

Thanks in advance.
All electronic parts change shape slightly when passing a current. This
shape change is the source of the noise. Transformers are the worst.
Capicators are next. Capicators consist of two metalic conductors separated
by an insulator. When charged, the plates attract each other and compress
the insulator layer. When discharged, they relax and the insulato expands.
No, you won't be able to hear the noise from a cap, but you might be able
to measure it. Caps also emit some em that can be turned into (amplifed)
sound by nearby metal parts, such as the chassis of a desktop. If you can
get close enough to measure this sound, you probably should just tap onto
the CPU leads and log it directly.
 
T

The Ghost In The Machine

Jan 1, 1970
0
In sci.physics, Peteris Krumins
<[email protected]>
wrote
Hello,

I am writing a document for school on how different forms of energy
emanated from the computer systems can be used to analyse the data
being processed by the computer system.

Currenly I am writing about acoustic sound emanation from the computer.
Here is the source of information which I am describing in more detail:
http://www.wisdom.weizmann.ac.il/~tromer/acoustic/

The thing I cannot understand is what creates the acoustic sound which can
be used for analysis.
Is it the great amount of transistors in the CPU, or as I found in other
sources, bad quality condensers? Or the quality does not matter? Do all
condensers emanate acoustic sound? What about transistors, can
they actually emanate sound?

Thanks in advance.

Who needs transistors? :) Dunno about modern TV sets but when I was
younger I could hear the very high-pitched squeal of what probably
was a transformer being abused by a 15,750 Hz sawtooth. :) Not
sure if my hearing is good enough anymore.

As it is, the actual sound might be an artifact of a magnetic
covering being vibrated by electric currents. Then again, one
could get lucky and have noisy power lines because of too few
bypass caps; the noisy power might show up in the sound output,
for example -- my new computer has that problem, although it's
not noticeable unless I turn up the volume on my speakers. However,
what you're mentioning is a microphone and/or other monitoring
device that's not listening to the speakers.

Of course, there is the possibility that the microphone is
directly picking up the electromagnetic radiation as well.

You mention low-quality condensers (caps). Since capacitors store
energy by distorting the electric field of the surface of the
dielectric they'd probably make low-quality piezoelectric
transducers as well -- and they might make a bit of noise.

I can't say for sure, but it's a bit like EEGs in that one can
get a general idea of the activity of the system by listening
to the noise (on my system at least, I can hear each keyclick
as I type in, although I also hear other noises, and I can
make a bunch of noise if I do things with my browser -- even
moving the mouse makes interesting noises).
 
R

Rich Grise

Jan 1, 1970
0
Gareth said:
Yes, I would have thought so too and I haven't noticed the capacitors in
my computer making any noise, but some researchers think differently:

"The sounds made by capacitors on motherboards might, in theory, give
attackers code-breaking clues in much the same way electro-magnetic
leakage or power fluctuations can be used in so-called "side-channel"
attacks on secure systems"

see:

http://www.theregister.co.uk/2004/05/11/sounds_yield_crypto_clues/

If you believe that they're spying on you by analyzing the various
acoustic sounds from piezo effects and magnetorestrictive effects
and so on, then you'd better wear your aluminum foil hat at all
times.

Cheers!
Rich
 
Top