Frequency Meter with Equal Precision Based FPGA + MCU

Abstract

Aiming at such disadvantages of traditional frequency measurement technology as low precision and small measurement range, the combination of FPGA and MCU is applied in this paper to realize equal precision frequency measurement. The system makes full use of advantages FPGA, which has high speed and multi-I/O port, and MCU which has good man-machine interface and flexible control function. By controlling the time of enable signal allowed frequency measurement equal to integer cycles of measured signal, the frequency measurement accuracy can keep constant in the whole measurement range. The frequency measurement range of meter is 0.1 Hz~ 50 MHz, and the accuracy of frequency measurement is 10-6 Hz. In addition to measuring frequency, the system also can detect the period, pulse width and duty ratio. The simulation and experimental results show that the frequency meter has such advantages as compact structure, small volume, high reliability and precision and wide frequency measurement range.