Signal processing for MEMS capacitive transducers

摘要

The circuitry processes sense signals generated by MEMS capacitive transducers, particularly microphones, to compensate for distortion in the sense signals, possibly due to large-value input signals. The circuitry has a signal path between an input 204 for receiving the sense signal and an output 205. Compensation circuitry 206, 207 is configured to monitor the signal at a first point along the signal path and generate a correction signal Scoff; and modify the signal at at least a second point along said signal path based on said correction signal. The correction signal is a function of the value of the signal at the first point so as to introduce compensation components into the output signal that compensate for distortion components in the sense signal. The first point may be before or after the second point. The monitoring may be performed in an analogue or a digital part of the signal path the modification may be applied in an analogue or a digital part of the signal path.