日历时钟自动校准及调整

Regulating and Adjusting automatically the Calendar Clock

日历时钟时常跑快跑慢的现象普遍存在,经过日积月累,就会产生较大的误差。为了解决这一问题,我们设计了能够自动校准和调整运行速度的日历时钟。通过接收中央人民广播电台播出的中心频率为106.1MHz的调频信号,并解调出原来的音频调制信号,利用两个锁相环路分别跟踪800HZ和1600HZ的报时音频信号。锁相环路的输出引起单片机外部中断,中断程序排除干扰后完成对日历时钟的自动校准;并根据运行误差,对日历时钟芯片X1205内的数字微调寄存器和模拟微调寄存器进行微调补偿,实现其运行速度的自动调整。

The phenomenon that the calendar clock runs sometimes fast and sometimes slow exists generally, and the error increases as time passes. In order to solve this problem, we designed a calendar clock which can automatically regulate and adjust its run rate. It receives the FM signal with the central frequency of 106.1 MHz, which is broadcasted by the Centre People Broadcasting Station, demodulates it and recovers the original audio frequency modulation signal, and uses two phase-locked loops to trace audio frequency pips at 800 Hz and 1600 Hz respectively. The output of the phase-locked loop induces an interrupt on the exterior of the MCU, after the interrupt service routine eliminated the interference, the automatic regulation on calendar clock is realized. According to the run error, the inching compensation is done to the digital trimming register and the analog trimming register on the X1205 chip of the calendar clock, and the automatic adjustment on its run rate is realized.