On Sun, 15 Oct 2006 02:08:05 -0500, "Ken Maltby"
wrote:



1) A specific, exact scenario.

2) A method for discriminating recording MP3 players from
everything else, in the exact scenario. Not some vague
concept of detecting semiconductors, a mere HF signal or
anything else that is not unique to a multitude of different
MP3 players.

3) A device that can reliably use that method in that
scenario.

#2 is the linchpin, #3 may indeed be possible after #2 is
resolved to #1. So it is with any purpose built device.

All this proves is that you have not read or understood
my earlier posts. I described the way actual devices
operate to detect any device that is detecting audio.

You made a suggestion that was not resolvable to a
difference in operation of an MP3 player. With a constant
current and constant bitrate output, you'd essentially be
suggesting that from a distance you can discriminate which
bits are flowing on the bus to the memory, in what is likely
a shielded case. I find this highly unlikely.


It
shouldn't be hard to realize that any device that is
responding to a pattern of sound is a threat.

Sure, but even ignoring the issue of whether it's feasible
to have test sound patterns at all, we don't have any
evidence a digitally recording MP3 player will have a
detectable response in particular scenarios, if in any at
all.

For a
recorder, of any kind, to record the audio in a room
it must detect it, and amplify the detected signal.

The recorder does not necessarily need amplification prior
to digitization, it is commonly a single chip solution that
would not have to output to headphones either in this use.


These processes can be detected, if this processing
matches the on and off timing of a known pattern
of sound, (which you control) you can isolate the
device. (Your "2" above.)

"IF" the process existed, and "IF" the detection device was
suitable sensitive, and "IF" the scenario allowed proximity,
then perhaps it's possible. None of these three IFs can be
assumed yet.




I hope you aren't going to say that while this type
of detector can detect that there is a device
responding to the sound in the room, and help you
locate it; this hasn't identified the device as an MP3
recorder.

Not at all, I'm going to say the device won't detect the MP3
player recording at all in most scenarios, that it might
detect "something" electronic is in the room but that's all,
it won't ID it as an MP3 player nor that it is responding to
sound in the room. "Maybe" if you had it right up against
the recorder, but do you expect that scenario?

I would think even you realize that it is
of no importance what the device is, that is responding
to the audio pattern, it would need to be considered
a live threat.

You're drifting down a tangent that has not yet been
reached. I never argued that a detected response to an
audio pattern wasn't suspicious enough to draw a conclusion
about the operation of a device.

It still doesn't get us where we need to be, to detect a
recording MP3 player reliably and discriminate it from other
non-recording electronic devices. This is not the same as a
tape recorder.

"kony" wrote in message
...
On Sun, 15 Oct 2006 02:08:05 -0500, "Ken Maltby"
wrote:



1) A specific, exact scenario.

2) A method for discriminating recording MP3 players from
everything else, in the exact scenario. Not some vague
concept of detecting semiconductors, a mere HF signal or
anything else that is not unique to a multitude of different
MP3 players.

3) A device that can reliably use that method in that
scenario.

#2 is the linchpin, #3 may indeed be possible after #2 is
resolved to #1. So it is with any purpose built device.

All this proves is that you have not read or understood
my earlier posts. I described the way actual devices
operate to detect any device that is detecting audio.

You made a suggestion that was not resolvable to a
difference in operation of an MP3 player. With a constant
current and constant bitrate output, you'd essentially be
suggesting that from a distance you can discriminate which
bits are flowing on the bus to the memory, in what is likely
a shielded case. I find this highly unlikely.


I was suggesting no such thing. I find your idea that an
ungrounded MP3 recorder has any significant shielding,
very unlikely. The recorder to be a threat and to respond
to sound must let sound waves through, even if it is a
contact microphone/sensor/transducer, and they require
significant amplification in their operation.

It is not necessary to know "which bits are flowing on
the bus to the memory", the detection takes place before
that is even an issue.

If you are going to pretend you understand how the
device I described operates, try to approach it from
a different angle than; finding a way it couldn't work,
then deciding that is what I must be describing.


It
shouldn't be hard to realize that any device that is
responding to a pattern of sound is a threat.

Sure, but even ignoring the issue of whether it's feasible
to have test sound patterns at all, we don't have any
evidence a digitally recording MP3 player will have a
detectable response in particular scenarios, if in any at
all.

So now you doubt that it's possible to generate a
controlled pattern of sound? (You wouldn't be
responsible for Rap "Music", would you?)

I'm no giving you "evidence". But I must have missed
your "evidence" that the device I described doesn't
work. Evidence is something besides your opinion,
or your interpretation of High School Physics and needs
to be based in proven limitations.

Try the following:
http://www.testequipmentdepot.com/ra...ipment/rf1.htm
it's the cheapest way to even start to examine this issue with
an attempt to establish some "evidence", you should be able to
detect some response from a recording device. This is nothing
like the device I was describing, but if you can see a result with
this, even you would have to admit that much more sophisticated
devices can do what I've described.


For a
recorder, of any kind, to record the audio in a room
it must detect it, and amplify the detected signal.

The recorder does not necessarily need amplification prior
to digitization, it is commonly a single chip solution that
would not have to output to headphones either in this use.

Almost all audio detectors/sensors require amplification,
and those that don't, carry a significant bias current that
gets modulated, more than enough to be detectable with
modern equipment.


These processes can be detected, if this processing
matches the on and off timing of a known pattern
of sound, (which you control) you can isolate the
device. (Your "2" above.)

"IF" the process existed, and "IF" the detection device was
suitable sensitive, and "IF" the scenario allowed proximity,
then perhaps it's possible. None of these three IFs can be
assumed yet.


Isn't it fortunate that no one needs your agreement that it's
possible, to make and use such devices.


I hope you aren't going to say that while this type
of detector can detect that there is a device
responding to the sound in the room, and help you
locate it; this hasn't identified the device as an MP3
recorder.

Not at all, I'm going to say the device won't detect the MP3
player recording at all in most scenarios, that it might
detect "something" electronic is in the room but that's all,
it won't ID it as an MP3 player nor that it is responding to
sound in the room. "Maybe" if you had it right up against
the recorder, but do you expect that scenario?


I say that such devices can detect any device that is
responding to a supplied audio signal pattern. Any
device that is detecting the audio pattern. They can
detect anything electronic, that generates electrical
noise or signal when it detects acoustical energy.

There is a great deal more some of these devices
can do in the hands of a skilled operator/analyst.

It looks like we have established that you are going
to just deny the possibility. You can believe what
you wish, it has no impact on reality what so ever.


I would think even you realize that it is
of no importance what the device is, that is responding
to the audio pattern, it would need to be considered
a live threat.

You're drifting down a tangent that has not yet been
reached. I never argued that a detected response to an
audio pattern wasn't suspicious enough to draw a conclusion
about the operation of a device.

It still doesn't get us where we need to be, to detect a
recording MP3 player reliably and discriminate it from other
non-recording electronic devices. This is not the same as a
tape recorder.

You have been provided a description of how these devices
can do just that, your only answer seems to be that you don't
believe a device could work as I described. You provide no
explanation (much less evidence) of why it couldn't work.

You seem intent on saying "No they can't work." I know
that they most certainly do work. What point is there in
further argument, on that basis?

Luck;
Ken

On Sun, 15 Oct 2006 09:32:39 -0500, "Ken Maltby"
wrote:


You made a suggestion that was not resolvable to a
difference in operation of an MP3 player. With a constant
current and constant bitrate output, you'd essentially be
suggesting that from a distance you can discriminate which
bits are flowing on the bus to the memory, in what is likely
a shielded case. I find this highly unlikely.


I was suggesting no such thing. I find your idea that an
ungrounded MP3 recorder has any significant shielding,
very unlikely.

Define significant. Many have grounded copper foil in them.
It's not as though this is a high powered device to begin
with, though, and would commonly have to be detected at a
distance.

The recorder to be a threat and to respond
to sound must let sound waves through, even if it is a
contact microphone/sensor/transducer, and they require
significant amplification in their operation.

No, you are thinking of older devices. There needs be no
amplification prior to the digitization chip which can run
at constant current, very low voltage and no easily
detectable response to room noise from a distance.

We might consider it mere coincidence that it is recording
something, because the means to that end are different than
in a recording device with a different (end) medium and
analog amplification.




It is not necessary to know "which bits are flowing on
the bus to the memory", the detection takes place before
that is even an issue.

You mean "IF" it could, it would.



If you are going to pretend you understand how the
device I described operates, try to approach it from
a different angle than; finding a way it couldn't work,
then deciding that is what I must be describing.

I'm not going to pretend anything, I'm suggesting you are
not describing an MP3 player in recording mode.

All the rest of your supportive argument hinges on being
able to detect a signal that may not exist at all, or in
cases where it does, are not sufficient strenth to measure
at any distance. Remember it is not enough to find one
particular MP3 player, nor a dissimilar device like a tape
recorder, that can be detected- it has to be effective
against the entire class of devices, or at the very least
the common ones available on the market.

"kony" wrote in message
...
On Sun, 15 Oct 2006 09:32:39 -0500, "Ken Maltby"
wrote:


You made a suggestion that was not resolvable to a
difference in operation of an MP3 player. With a constant
current and constant bitrate output, you'd essentially be
suggesting that from a distance you can discriminate which
bits are flowing on the bus to the memory, in what is likely
a shielded case. I find this highly unlikely.


I was suggesting no such thing. I find your idea that an
ungrounded MP3 recorder has any significant shielding,
very unlikely.

Define significant. Many have grounded copper foil in them.
It's not as though this is a high powered device to begin
with, though, and would commonly have to be detected at a
distance.

Still consumer electronics do not have very good shielding.
Hence it would be a very minor task to detect the sampling clock of the
recorder in question. And most of the times the sampling rate is specified
by the MFG.


The recorder to be a threat and to respond
to sound must let sound waves through, even if it is a
contact microphone/sensor/transducer, and they require
significant amplification in their operation.

No, you are thinking of older devices. There needs be no
amplification prior to the digitization chip which can run
at constant current, very low voltage and no easily
detectable response to room noise from a distance.

You still have the sampling rate, which requires a clock at that rate, so at
a minimum that clock can be detected.
And most designs would include an amplification stage prior to digitization,
as the levels from most mics will not be sufficient, and also to add
isolation between the input stages.

On Sun, 15 Oct 2006 19:21:08 -0800, "Dana"
wrote:


"kony" wrote in message
.. .
On Sun, 15 Oct 2006 09:32:39 -0500, "Ken Maltby"
wrote:


You made a suggestion that was not resolvable to a
difference in operation of an MP3 player. With a constant
current and constant bitrate output, you'd essentially be
suggesting that from a distance you can discriminate which
bits are flowing on the bus to the memory, in what is likely
a shielded case. I find this highly unlikely.


I was suggesting no such thing. I find your idea that an
ungrounded MP3 recorder has any significant shielding,
very unlikely.

Define significant. Many have grounded copper foil in them.
It's not as though this is a high powered device to begin
with, though, and would commonly have to be detected at a
distance.

Still consumer electronics do not have very good shielding.

Doesn't have to be *very good*, only has to further reduce
emissions which likely weren't at a level high enough to
discriminate recording mode even without the shield.

Hence it would be a very minor task to detect the sampling clock of the
recorder in question.

That does not indicate it is an MP3 player, let alone
recording. There is no one "sample clock" common to all MP3
players.

most of the times the sampling rate is specified
by the MFG.


Manufacturer of the chip, yes, not the MP3 player, and
"spec" really means, hardware support as it can't be
selected at random like with most computers running soft
codecs. Even so, this rate is not usually a separate
oscillator, the chip itself has a clock that can also vary
per chip. It is certianly not something that remains
constant over all MP3 players, and not a signal that appears
only when set to recording mode.



The recorder to be a threat and to respond
to sound must let sound waves through, even if it is a
contact microphone/sensor/transducer, and they require
significant amplification in their operation.

No, you are thinking of older devices. There needs be no
amplification prior to the digitization chip which can run
at constant current, very low voltage and no easily
detectable response to room noise from a distance.

You still have the sampling rate, which requires a clock at that rate,

No, it does not. Clock rates are divisible or multiplied
these days, and these rates are often common to process
sizes, or current targets, not a specific functional
requirement. In other words, it's a safe bet you cannot
detect a recording MP3 player with a universal "sampling
rate" detection scheme, even before considering they won't
all necessaril record at the same rate, further lacking
consideration for any possiblity of variable rate or spread
spectrum.

so at
a minimum that clock can be detected.
And most designs would include an amplification stage prior to digitization,
as the levels from most mics will not be sufficient,

Sufficient for hearing through earbuds, no, that'd be amp'd.

Sufficient for a microchip DESIGNED to use a mic input to
digitize MP3? It would be an incredibly poorly designed
chip if it had to have a preamp tacked on after the mic.

and also to add
isolation between the input stages.

You are thinking old-school multi-stage, possibly even
discrete audio designs. All-integrated single chip MP3
players (recording) isn't directly applicable.

"kony" wrote in message
...
On Sun, 15 Oct 2006 19:21:08 -0800, "Dana"
wrote:


"kony" wrote in message
.. .
On Sun, 15 Oct 2006 09:32:39 -0500, "Ken Maltby"
wrote:


You made a suggestion that was not resolvable to a
difference in operation of an MP3 player. With a constant
current and constant bitrate output, you'd essentially be
suggesting that from a distance you can discriminate which
bits are flowing on the bus to the memory, in what is likely
a shielded case. I find this highly unlikely.


I was suggesting no such thing. I find your idea that an
ungrounded MP3 recorder has any significant shielding,
very unlikely.

Define significant. Many have grounded copper foil in them.
It's not as though this is a high powered device to begin
with, though, and would commonly have to be detected at a
distance.

Still consumer electronics do not have very good shielding.

Doesn't have to be *very good*, only has to further reduce
emissions which likely weren't at a level high enough to
discriminate recording mode even without the shield.

And most consumer electronics are not very well shielded, hence it is a snap
to pick up their emissions with off the shelf test equipment.


Hence it would be a very minor task to detect the sampling clock of the
recorder in question.

That does not indicate it is an MP3 player,

So what. It still indicates the presence of a device that can record the
persons converstaion, and that is what is required. It can be a dictation
device some other kind of recorder, it would still be detected.


most of the times the sampling rate is specified
by the MFG.


Manufacturer of the chip, yes, not the MP3 player

All you need is the chip, and usually the OEM will list what the chip MFG
states anyway.

and
"spec" really means, hardware support as it can't be
selected at random like with most computers running soft
codecs. Even so, this rate is not usually a separate
oscillator,

Usually you have an external clock needed to feed the codec. That clock can
be detected as well.




The recorder to be a threat and to respond
to sound must let sound waves through, even if it is a
contact microphone/sensor/transducer, and they require
significant amplification in their operation.

No, you are thinking of older devices. There needs be no
amplification prior to the digitization chip which can run
at constant current, very low voltage and no easily
detectable response to room noise from a distance.

You still have the sampling rate, which requires a clock at that rate,

No, it does not.

Without a sampling rate, there will be no conversion of analog to digital.
You have to take so many samples of the analog signal.

so at
a minimum that clock can be detected.
And most designs would include an amplification stage prior to
digitization,
as the levels from most mics will not be sufficient,

and also to add
isolation between the input stages.

On Sun, 15 Oct 2006 20:31:16 -0800, "Dana"
wrote:


Doesn't have to be *very good*, only has to further reduce
emissions which likely weren't at a level high enough to
discriminate recording mode even without the shield.

And most consumer electronics are not very well shielded, hence it is a snap
to pick up their emissions with off the shelf test equipment.


"Most" don't have any shield at all. MP3 players, commonly
do. Further, "most" consumer devices have an order or two
of magnitude, more active parts in them and use far more
power, stronger emissions.

Further, detecting a very faint signal is not the same thing
as having a strong enough detection and valid discrimination
method between recording MP3 players and all other consumer
electronics. Remember that we are not just trying to detect
that some "thing" using electricity is present, it has to be
identifed in function and is not just one device buy a
multitude of different MP3 player (or other digital
recorders too if you want to consider all types) recorders.

You will have to find a specific commonality, not just a
vague generalization, to discriminate them. Even this much
is premature- that commonality would have to exist which has
not in itself been established.




Hence it would be a very minor task to detect the sampling clock of the
recorder in question.

That does not indicate it is an MP3 player,

So what. It still indicates the presence of a device that can record the
persons converstaion,

No it does not. Did you think nothing but MP3 players have
clocks, or that all MP3 players have the same clock rate?
Neither is true.

and that is what is required. It can be a dictation
device some other kind of recorder, it would still be detected.

No, in some cases you might detect some devices, but it'd be
random, you'd far more often detect non-recording or devices
completely incapable of recording and wouldn't detect some
actually recording. In other words, random and useless.




most of the times the sampling rate is specified
by the MFG.


Manufacturer of the chip, yes, not the MP3 player

All you need is the chip, and usually the OEM will list what the chip MFG
states anyway.

You'll need ALL of the chips in existence, and you'd find
some are not putting out enough noise to be detected in a
typical scenario. Maybe if you put a scanner up against the
device. Is that really useful? If you had the device out
already, no further scanning is needed at all unless you
have far-fetched idea like if the MP3 recorder were built
into a shoe-heel or a clock, etc. Even then, it's a matter
of scenario. If that scenario doesn't allow getting the
scanner close enough to find the shoe is a source, you'll
never even know it was suspicious there was a noisey shoe.

I've gone off on a tangent though, for our purposes an MP3
player should be considered what is bought off the shelf.
OEMs do not "list what the chip MFG states". Most often you
have to tear open the specific player and examine it
yourself, or rely on reports from someone else who has.



and
"spec" really means, hardware support as it can't be
selected at random like with most computers running soft
codecs. Even so, this rate is not usually a separate
oscillator,

Usually you have an external clock needed to feed the codec. That clock can
be detected as well.

Again you are thinking of older electronics, today's
player/recorders are highly integrated. That doesn't mean
ALL devices will have a different or undetectable, or
indistinuishable clock signal, but it does mean you don't
have a commonality that allows detection as an MP3 player,
let alone one recording.


No, it does not.

Without a sampling rate, there will be no conversion of analog to digital.

The existence of a sampling rate does not suggest it is
always the same rate nor that it is measureable in any
particular scenario.

You have to take so many samples of the analog signal.

Yes, but this does not lead to any of the other conclusions.