Interface and control electronics for a bulk micromachined capacitive gyroscope

An interface and control electronics have been designed and implemented for a bulk micromachined capacitive gyroscope. The system is composed of an application-specific integrated circuit (ASIC) that implements the analog parts of the system and a field-programmable gate array (FPGA) chip that implements the digital signal processing part. Both the system architecture and details of the different circuit blocks will be discussed. The system utilizes phase coherent demodulation to resolve the final output signal. In a typical implementation, phase delay and phase noise in the clock generation cause the signal quality to degrade. A method for correcting these errors will be introduced. A prototype of a microelectromechanical gyroscope has been realized and characterized. The measurement results show that the gyroscope achieves 0.042°°/s/ Hz spot noise and 51.6-dB signal-to-noise ratio (SNR) over the 40-Hz bandwidth with a 100°°/s input signal.