关键词: 电场式时栅, 信号处理, 时间测量, 多相时钟采样

Abstract: This paper proposes a new method for measuring the phase change of electric field time-grating signals. This method uses the characteristics that the frequency of the time-grating induction signal is fixed and the signal returns to the initial phase point after the phase shift of 2π. The counter based on the high frequency pulse is used as the time measuring ruler, and the full range measurement of the ruler is equal to the periodic change time of the induction signal. The time scale is then subdivided by multiple phase clock sampling. When the phase of the signal moves periodically, the corresponding reading on the ruler changes periodically. Based on the inherent characteristics of the time-grating induction signal, this method avoids the measurement errors caused by the inconsistency of the time reference, signal skew and edge jitter in the construction of the entity reference signal, and also avoids the limitation of the sampling performance of the multi-phase clock, which further improves the measurement stability and resolution. By designing a time-grating signal processing system based on FPGA, a feasibility test of the optimized scheme is carried out on a 120-pole electric field circular time-grating sensor. The stability of the sensor reaches 0.405′′, which is nearly 3 times higher than before. The theoretical resolution and actual resolution are 0.135′′ and 0.54′′, which are about 2 times higher than before.