Why not just FM it - with a voltage to frequency converter, assuming you
could get the resolution you are seeking. The old Qindar telemetry
systems worked like that and they worked well, before the days of
digital.
A sound card can do frequency conversion.
Another idea, check the web for a program called "hamcom" I remember it
had an audio spectrum analyzer that used a zero crossing detector on the
serial port.
Bob

ChrisAtUpw@....... wrote:

> In a message dated 05/05/01, travis5765@............ writes:
>
>
>>        I was wondering if it was possible to Amplitude Modulate,
>> with
>> the seismometer signal, a carrier of an arbitrary audio frequency of
>>
>> about 10Khz and input it into the SoundBlaster at the back of your
>> computer. Then doing something fancy with software like peak
>> averaging
>> then plotting it.
>
>       Sure you can do this in principle, but you would need to
> intercept the
> raw digital data before it got recorded or you would end up with files
> of MB
> per minute. You need just a few Hz for recording. The noise level
> would need
> to be checked. Amplitude modulated carrier signals will get past the
> input
> filter OK, so long as the carrier itself is >20 Hz and < 15 KHz. My
> choice
> would be about 1 KHz. Processing the signal could keep your CPU just a
> bit
> busy. Sounds to me like the hard way to do it.
>
>       Regards,
>
>       Chris Chapman


Why not just FM it - with a voltage to frequency converter, assuming you
could get the resolution you are seeking. The old Qindar telemetry systems
worked like that and they worked well, before the days of digital.

A sound card can do frequency conversion.

Another idea, check the web for a program called "hamcom" I remember
it had an audio spectrum analyzer that used a zero crossing detector on
the serial port. 

Bob
ChrisAtUpw@....... wrote:
In a message
dated 05/05/01, travis5765@............ writes:

 
      
I was wondering if it was possible to Amplitude Modulate, with

the seismometer signal,
a carrier of an arbitrary audio frequency of

about 10Khz and input it
into the SoundBlaster at the back of your

computer. Then doing something
fancy with software like peak averaging

then plotting it.

     
Sure you can do this in principle, but you would need to intercept the

raw digital data before
it got recorded or you would end up with files of MB

per minute. You need just
a few Hz for recording. The noise level would need

to be checked. Amplitude
modulated carrier signals will get past the input

filter OK, so long as the
carrier itself is >20 Hz and < 15 KHz. My choice

would be about 1 KHz. Processing
the signal could keep your CPU just a bit

busy. Sounds to me like
the hard way to do it.
     
Regards,
     
Chris Chapman