基于STC89C52的高精度数字相位测量方法设计

Measure method design of high-accuracy digital phase place based on STC89C52

通过过零检相来获取两信号过零点时间间隔,采用脉冲填充法与单片机相结合的测量电路,计算出时间间隔的脉冲个数,进而求得相位差值;引入锁相倍频电路,使基准填充脉冲能随着信号频率的变化而变化,从而消除了频率变化引起的误差;利用数据选择器对采样通道切换,实现了零点漂移的补偿;以STC89C52高速单片机和相位检测电路为核心实现该系统,相位测量误差限于±0.02°.

Obtains time interval of two signals passing zero point by over zero examining phase, calculates the quantity of pulse of the time interval by measurement circuit combining the pulse pack methoed with one-chip computer, gets the phase place difference. Introduction of the double frequency circuit of phase-locked makes the benchmark pack pulse change with signal frequency, thus eliminates the error caused by frequency change. Switches the sampling passway by data selector, realizes the compensation for zero point excursion. Taking STC89C52 high-speed one-chip computer and phase place exemining circuit as core realizes this system, the measurement precision of phase place is ± 0.02°.