谐振式传感器高精度频率测量技术研究*

Research on high precision frequency measurement technology of resonant sensor

摘要:

随着 MEMS 振梁加表、振梁压力传感器等谐振式传感器精度的提高，对频率测量精度的要求也随之提高。 现有的测频技术通常采用单片机内置的输入捕获及中断功能，与实际需求的测量精度差距较大。提出一种基于 FPGA 的高精度频率测量方案，在 5ms 的采样间隔下实现 1ppm 的相对频率测量精度，满足高精度谐振式传感器的精度要求。

Abstract:

With the improvement of the accuracy of the resonant sensors such as MEMS vibration beam accelerometer and vibration beam pressure sensor, the requirement of the frequency measurement accuracy is also improved. The existing frequency measurement technology usually uses the function of input capture and interrupt built in the MCU, which can not guarantee the timing constraints, and have a large gap with actual demand of measurement accuracy. In this paper, a high-precision frequency measurement scheme based on FPGA is proposed. The scheme achieves the relative frequency measurement accuracy of 1ppm under the sampling interval of 5ms, which meets the accuracy requirements of high-precision resonant sensor.