In a message dated 12/10/2007, gmvoeth@........... writes:

I have a  vertical setup with a sensor that seems to have a sensitivity of 
1.5 to 2  volts per inches per second and I can see a magnitude 4 about 6 
degrees away.  or so it seems. I am using heavy damping to allow me to use a single 
bandpass  filter to equalize the freq response of a one hertz geophone 
somewhere  between 4 seconds and 2 Hz.
 
Hi Geoff,
 
    You need to use negative impedance input to get  broad band response from 
a geophone by heavy damping to mostly cancel out the  internal resistance. 
You then need a very low noise 1/f amplifier to give you a  flat to velocity 
response.

    The technique is dscribed with references at 
_http://www.lennartz-electronic.de/MamboV4.5.2/downloads/Seismometers.pdf_ 
(http://www.lennartz-electronic.de/MamboV4.5.2/downloads/Seismometers.pdf) 
 
    Regards,
 
    Chris Chapman



   





In a message dated 12/10/2007, gmvoeth@........... writes:
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  vertical setup with a sensor that seems to have a sensitivity of 1.5 to 2=20
  volts per inches per second and I can see a magnitude 4 about 6 degrees aw=
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  or so it seems. I am using heavy damping to allow me to use a single bandp=
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  filter to equalize the freq response of a one hertz geophone somewher=
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  between 4 seconds and 2 Hz.
 
Hi Geoff,
 
    You need to use negative impedance input to get=
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broad band response from a geophone by heavy damping to mostly cancel out th=
e=20
internal resistance. You then need a very low noise 1/f amplifier to give yo=
u a=20
flat to velocity response.

    The technique is dscribed with references at http://www.lennartz-electronic.de/MamboV4.5.2/downloads/Seismometers.p=
df
 
    Regards,
 
    Chris Chapman