MEMS for the masses part 1: comparison to geophones in theory

Michael S. Hons and Robert R. Stewart

ABSTRACT

The operation of geophones, delta-sigma analog-to-digital converters and digital feedback MEMS accelerometers is explored. It is found that as long as nonlinearities in mechanical springs and electric and magnetic fields are negligible, the sensors should operate very much as predicted by their frequency responses. Since the frequency response to acceleration for a MEMS accelerometer is flat in acceleration and zero in phase, the geophone frequency response in acceleration can be used to produce geophone equivalent data from MEMS accelerometer data, or vice versa. When doing so, the noise added to the data by the recording system will be shaped along with the signal amplitudes.

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