Randall
  Something has confused me about the volksmeter or the SG sensor. For a passive sensor I always thought the response of the sensor dropped by (I forget the db slope) for frequencies below the natural frequency of the sensor. Therefore I would think the output would have to amplified accordingly for low frequencies. Is the noise amplified also? Is the drop-off mathematically known so the amplification can be correctly compensated? I didn't think a simple intergator in the output of the SG provided a simple flat response of output vs frequency.
  Regards
  Barry
  

Randall Peters  wrote:
  Recent discussions of force feedback have mentioned pendulums. I hope that these were thoughts directed only toward horizontal
instruments of the 'garden gate' variety (not what I call a pendulum); since I can't imagine a reason for ever wanting to go to
that degree of difficulty with a 'simple' pendulum such as in the VolksMeter. The direction of a simple static pendulum does
not migrate to any great extent. Its very low frequency response is determined by shape changes of the earth that do not exceed
tens of microradians. The exception to this claim applies only to the case of a detector with a very limited mechanical dynamic
range, such as a gap varying capacitive sensor. With the area-varying array used by the VoksMeter it is unlikely that force
balance or any other type of feedback should ever be needed.
Randall

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Randall
  
Something has confused me about the volksmeter or the SG sensor. For a passive sensor I always thought the response of the sensor dropped by (I forget the db slope) for frequencies below the natural frequency of the sensor. Therefore I would think the output would have to amplified accordingly for low frequencies. Is the noise amplified also? Is the drop-off mathematically known so the amplification can be correctly compensated? I didn't think a simple intergator in the output of the SG provided a simple flat response of output vs frequency.
  
Regards
  
Barry
  


Randall Peters <PETERS_RD@..........> wrote:
  
Recent discussions of force feedback have mentioned pendulums. I hope that these were thoughts directed only toward horizontal
instruments of the 'garden gate' variety (not
 what I call a pendulum); since I can't imagine a reason for ever wanting to go to
that degree of difficulty with a 'simple' pendulum such as in the VolksMeter. The direction of a simple static pendulum does
not migrate to any great extent. Its very low frequency response is determined by shape changes of the earth that do not exceed
tens of microradians. The exception to this claim applies only to the case of a detector with a very limited mechanical dynamic
range, such as a gap varying capacitive sensor. With the area-varying array used by the VoksMeter it is unlikely that force
balance or any other type of feedback should ever be needed.
Randall

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