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HI!
What I want to do is take a signal from like a tape
recorder or something like that and amplify it to a
frequency above the range of human hearing. I know it
won't be audible, (I don't WANT it to ba audible :-)
but I want it to be THERE. I don't care if rats can
hear it LOL.
I don't have a lot of recources, so I need to find an
alternative that doesn't rely upon a recording studio.
I don't have access to one. I need to be able to
achieve that effect easier and more affordably.
It's for a paper for a class.
Thanks a lot!
Sonci

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sonic,

What I want to do is take a signal from like a tape
recorder or something like that and amplify it to a
frequency above the range of human hearing. I know it
won't be audible, (I don't WANT it to ba audible :-)
but I want it to be THERE. I don't care if rats can
hear it LOL.

So what you want is not amplification but conversion.
The signal will probably already have enough signal
level. What will you do with the converted signal,
That's what we are trying to get you to say.
Will it be connected to a supersonic transducer?
If this is ordinary audio it could be converted but
it would be a somewhat complex process. Fixed
frequencies are easily converted in radio to
new higher frequencies. But complex audio is not
so easy to convert that way.

Jim

We call it ultrasonic here. Supersonic is used to describe speed.
:)

What about this:

Use the same modulation technique as stereo FM radio. As I
understand it, FM stereo is achieved using SSB modulation at audio
frequencies. The carrier or as it is refered to in FM stereo the
pilot signal is 19KHz. I think the L-R is shifted up above 19KHz and
the L+R is below 19KHz. That way a mono receiver is simpler since
all it has to do is low pass the signal to get L+R. All you want is
the signal above 19KHz or whatever carrier you choose. You have a
different application so you don't require L and R separation. The
low frequencies and the carrier can be low pass filtered and
removed. I think I have schematics for just such a thing but it is
not a beginners project. You will need very good understanding of
analog electronics and good construction skills.

What other kinds of projects have you built?

HI!
If you could email the schematics, that would be
great!
Thanks a ton!

--- manifold <manifold_1@...> wrote:

We call it ultrasonic here. Supersonic is used to
describe speed.
:)

What about this:

Use the same modulation technique as stereo FM
radio. As I
understand it, FM stereo is achieved using SSB
modulation at audio
frequencies. The carrier or as it is refered to in
FM stereo the
pilot signal is 19KHz. I think the L-R is shifted
up above 19KHz and
the L+R is below 19KHz. That way a mono receiver is
simpler since
all it has to do is low pass the signal to get L+R.
All you want is
the signal above 19KHz or whatever carrier you
choose. You have a
different application so you don't require L and R
separation. The
low frequencies and the carrier can be low pass
filtered and
removed. I think I have schematics for just such a
thing but it is
not a beginners project. You will need very good
understanding of
analog electronics and good construction skills.

What other kinds of projects have you built?



--- In Electronics_101@y..., Jim Purcell
<jpurcell@w...> wrote:

sonic,

What I want to do is take a signal from like a

tape

recorder or something like that and amplify it

to a

frequency above the range of human hearing. I

know it

won't be audible, (I don't WANT it to ba audible

:-)

but I want it to be THERE. I don't care if rats

can

hear it LOL.

So what you want is not amplification but

conversion.

The signal will probably already have enough

signal

level. What will you do with the converted

signal,

That's what we are trying to get you to say.
Will it be connected to a supersonic transducer?
If this is ordinary audio it could be converted

but

it would be a somewhat complex process. Fixed
frequencies are easily converted in radio to
new higher frequencies. But complex audio is not
so easy to convert that way.

Jim

__________________________________________________
Do You Yahoo!?
Find a job, post your resume.

Here are the links but after thinking about it more, this will not
work either. All this does is produce a signal that get fed to the
VCO. Therefor there is no frequency shift of the orginal signal
there is just AM modulation of the 19KHz signal. Maybe this will
work and I am missing something.

o Is one of the results of mixing the two signals a frequency
shifted verstion of the audio signal? Maybe someone who knows more
about SSB transmission can help.

My brain is tired today and I can't remember very much. Check out
thes links anyway. The circuit looks good and the designer has done
a good job with available parts. If you can't read the postscript
files, get ghost script or if anyone is interested I think I
converted the postscript files to pdf and may still have them
somewhere.


(old ciruit, easier
to read)

HI!
What I want to do is take a signal from like a tape
recorder or something like that and amplify it to a
frequency above the range of human hearing. I know it
won't be audible, (I don't WANT it to ba audible :-)
but I want it to be THERE. I don't care if rats can
hear it LOL.
I don't have a lot of recources, so I need to find an
alternative that doesn't rely upon a recording studio.
I don't have access to one. I need to be able to
achieve that effect easier and more affordably.
It's for a paper for a class.
Thanks a lot!
Sonci

Not exactly an easy task. As suggested in some other posts you would need a
suppressed-carrier balanced modulator to produce 2 ultrasonic sidebands
having the same spectral relationships as the original audio, and then a
filter with one side very steep to reject the unwanted sideband and any
residual 'carrier' frequency. It is possible to construct such a circuit,
but a bit tricky to adjust it without the right test equipment.

What is the desired result or effect you're after? Or, what is the
objective of the paper you're writing?


Steve H.

hi sonci,

i feel u can generate any frequency by using a small code
just type
main()
{
sound(freq);// fil the value what u need to generate.
}

note: in Turbo c help if u find the chicken died bcoz of 10 HZ
generated by the industry in australia.

so u can have a try in genrating without any hardware.
Micro Mangal


--- In Electronics_101@y..., Steve <73227.1605@c...> wrote:

HI!
What I want to do is take a signal from like a tape
recorder or something like that and amplify it to a
frequency above the range of human hearing. I know it
won't be audible, (I don't WANT it to ba audible :-)
but I want it to be THERE. I don't care if rats can
hear it LOL.
I don't have a lot of recources, so I need to find an
alternative that doesn't rely upon a recording studio.
I don't have access to one. I need to be able to
achieve that effect easier and more affordably.
It's for a paper for a class.
Thanks a lot!
Sonci

Not exactly an easy task. As suggested in some other posts you

would need a

suppressed-carrier balanced modulator to produce 2 ultrasonic

sidebands

having the same spectral relationships as the original audio, and

then a

filter with one side very steep to reject the unwanted sideband and

any

residual 'carrier' frequency. It is possible to construct such a

circuit,

but a bit tricky to adjust it without the right test equipment.

What is the desired result or effect you're after? Or, what is the
objective of the paper you're writing?

Steve H.