AS-1 Damping Adjustment

The images below show how a lift-test calibration of an AS-1 instrument changes as the damping is adjusted.  In order to determine the damping ratio, I simultaneously recorded the output of the AS-1 coil with the AS-1 black box amplifier and AmaSeis as well as with a 1000x gain amplifier attached to a DATAQ 158UP ADC and recorded with WinDaq.  To reduce the high-frequency noise that is picked up by the AS-1 coil, an 80uF capacitor was connected in parallel with the coil.

Chris Chapman has designed an amplifier circuit for this purpose.

*Damping ratio computed using this page:  http://www.jclahr.com/science/psn/damping/

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