一种通用精确同步源的设计与实现

Design and implementation of a general-purpose precise sync source

针对同步控制和采样对高精度同步信号源的需求,给出了一种同步源的设计原理与实现方法。以"CPLD+单片机"作为控制器件,依据自适应控制的原理对恒温晶振的时钟信号和GPS的秒脉冲(pulsespersecond,PPS)进行参数辨识和自适应处理,获得了频率可设定的高精度同步时钟信号。该方案消除了采用PPS信号或晶振作为同步时钟时,由于受干扰和晶振存在不确定漂移等因素对同步精度造成的影响。实验结果表明,该方案是可行的,并特别适合应用于远程分布式测控系统中。

A design scheme of a general-purpose precise sync source is presented to meet the demand of the synchronous control and sampling for high-precision sync source. According to the adaptive control principle, output parameters of oven controlled crystal oscillator and the pulses per second (PPS) signals of GPS are identified and processed by using the CPLD and single-chip microcomputer. Therefore, a high-precision sync clock signal with settable frequency is formed. Compared with the solution of using the PPS signal or crystal oscillator as the sync clock, this scheme eliminates the negative effects on the sync precision imposed by the interference and the uncertain drift of the crystal oscillator. Experimental results show that the scheme is feasible, and especially suitable to the remote distributed measurement and control system.