A New Phase Difference Measurement Method and Its Implementation Based on FPGA

Abstract

Phase difference is an important parameter and its measurement has been widely used in many fields. The common measurement method is to convert the phase difference measurement to time difference measurement by reshaping and timing (or counting) technology. This method can work well when the two signals after being reshaped have same duty cycle, otherwise the measurement is incorrect. A method to measure phase difference based on multi-parameters has been proposed in this paper. The new method utilizes four time difference parameters to overcome the disadvantage of the original single parameter method, and employs signal synchronization and multicycle measuring to increase measuring accuracy. Based on the principle of the proposed phase difference measurement method, the implementation circuit based on FPGA has been designed. Measuring experiments have been performed under conditions of different duty cycles, different phase differences and different frequencies of the counted impulse in Quartus II6.0 simulation environment. The experiment results illustrate the new method performs more measuring accuracy even when the duty cycle and phase difference of rectangular waves change in a large range. With the frequency of the counted impulse is more than 8 times to that of the measured signal, the measurement error can be less than 0.01 degrees.