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Due to the disadvantage of low precision in frequency measurement for the silicon micro-resonant sensor, a frequency meter based on field-programmable gate array (FPGA) is designed according to the principle of periodic frequency measurement. The rising edge of the standard signal is counted in a signal period to be measured, the frequency and period of the signal to be measured are roughly calculated. According to this, the rising edge of the standard signal is re-counted so that the frequency of the signal to be measured can be accurately measured. The measured frequency signal is sent to PC through RS-232, and the frequency value can be displayed and stored in real time. The experimental result shows that the relative error of 1 Hz to 2 MHz square wave signal measured with this frequency meter can reach the magnitude of 10-7. The frequency meter is used to measure the resonant frequency output from the closed-loop self-excited measuring circuit of the resonant sensor. The frequency signal is stable within 1 Hz.