Modeling and simulation of a capacitive micro-accelerometer system

Capacitive Micro-Accelerometer digital feedback system was developed using the theory of second-order Σ-Δ modulator. The second-order mechanical gauge outfit behaves as two integrators in second-order Σ-Δ modulator and the number of bits of the quantizer is 1 bit. Continuous-time model of the gauge outfit was transformed to discrete-time model based on the IIR theory and the quantizer linear model was established using the LMS arithmetic. Therefore the quasi-linear discrete model was derived. The simulation results shown that the micro-accelerometer system was a low pass system and it had linear phase characteristic approximately in the low frequency band. The simulation results also displayed that the second order noise shaping was performed in the system which made the noise transfer to higher frequency band. Finally the accelerometer system was simulated with the sine signal input, and the results validated that the output and the input are consistent.