A Demodulation Technique for the Sensing Circuit of a MEMS Gyroscope

This paper deals with the design of a digital sensing interface for a MEMS gyroscope. In such devices, the information regarding the angular rate Omega(Z)(t) experienced by the sensor is contained in a suppressed carrier- dual side band (SC-DSB) signal, which has Omega(Z)(t) as modulating component. Hence, a demodulation must be carried out in order to retrieve a measurement of the angular rate. The demodulation process presented in the paper consists of a quantization stage of the SC-DSB signal, which is performed with a three-level band-pass Delta Sigma converter followed by a digital demodulation of the Delta Sigma bit-stream with a given digital sequence. Several simulation results are reported to evaluate system performances.