Abstract: In order to meet the requirements of hardware engineers for high precision and high bandwidth frequency measurement instruments, a high precision cymometer based on FPGA is designed. The frequency meter consists of peripheral voltage following circuit and serial communication circuit, frequency divider module, frequency measurement module and serial communication module on FPGA. The Cyclone IV chip of Altera company is used as the control core. Firstly, the signal to be measured is stabilized and isolated by voltage follower, and then the stabilized signal is connected to the frequency divider module. The frequency divider module divides the frequency signal into low-frequency and high-frequency signals with the limit of 1 kHz, and uses periodic frequency measurement method and pulse counting method to measure the frequency of low-frequency signal and high-frequency signal respectively. The measured frequency data can be uploaded to the upper computer through the serial port in real time. After testing, the frequency meter can achieve 1 Hz accuracy, 200 MHz frequency measurement bandwidth and multi-channel detection.

Key words: cymometer, high precision, FPGA, high bandwidth