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
> 

       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 
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