A Standalone Programmable Signal Processing Unit for Versatile Characterization of MEMS Gyroscopes

This paper reports a stand-alone signal processing and control unit designed to provide flexible characterization of MEMS vibratory gyroscopes. The unit consists of a programmable 32-bit 150 MIPS DSP controller, 16-bit 1 MSPS digital-to-analog and 18-bit analog-to-digital interface circuits, and signal conditioning electronics. The multi-channel analog-to-digital interface is optimized for detection of small electrical signals typical for MEMS devices. Digitally controlled conditioning of analog signals allows for high-resolution differential digitization of a wide range of detection signals. The digital-to-analog interface circuit produces a wide range of DC and AC voltages needed for actuation and detection in gyroscopes; a single 5 V supply is used to power the board. The DSP controller allows easy MATLAB/Simulink programming and execution-time data exchange. Performance of the board was experimentally characterized using an anti-phase driven rate gyroscope with multi-degree of freedom sense mode. Using 16-bit conversion, the measured capacitance-change equivalent resolution is 27 aF/radicHz . Due to its flexible architecture, the unit is easily customizable for stand-alone and computer controlled operation of a variety of dynamic MEMS.