Karl,

Thanks for the detailed explanation.Things are becoming a little clearer
about pendulums picking up acceleration, velocity and displacement. 

At 01:59 PM 10/30/99 -0700, Karl wrote:
>Another 2¢...  The following is what I think I know about this stuff.
>Please tell me if I am off base on any of it.  


>You can use a mechanical system with a relatively large spring constant
>(not much deflection for a given acceleration), but the feedback system has
>to be that much better (to keep the loop gain high) at all frequencies of
>interest.  Check some numbers and see how it measures up.  I'd be happy to
>crunch some numbers if anyone is interested.

That would be a big help. What information would you need for the number
crunching?

>
>By the way, the VBB system normally produces a velocity output, but the
>current through the feedback coil is proportional to acceleration, and that
>signal can be used as well.

Yes, but does the output at that point have a flat freq. response to
acceleration above the period of the pendulum or does it fall of at the
12db/octave or 6db/octave rate?

-Larry Cochrane
Redwood City, PSN
 

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