All-Digital High-Resolution Frequency Measurement SoC for Rapid MEMS Readouts

This work proposes an all-digital on-chip digital Frequency measuring system (FMS) that is intended to replace conventional low-resolution measuring instruments. The method of measurement is a two-step process with a coarse estimate followed by a fine resolution frequency estimation from three DFT samples using the Candan method. We describe the design, and performance evaluation, as a high-resolution rapid frequency measurement system, particularly for high-precision MEMS applications. The proposed FMS has been synthesized, implemented and verified on a Xilinx ZYNQ XC7Z020-1CLG400C SoC. The ASIC implementation of the SoC on a 65nm CMOS technology reveals that the design consumes 120 mW power at a 100 MHz clock while providing sub-5 ppm resolution with a readout time of 5.7 mu s, suitable for MEMS applications with bandwidth up to 10 MHz.