基于MSP430单片机的低频授时码接收器设计

Design of low frequency time-code receiver based on MSP430

针对传统计时设备存在计时累积误差和校准时间困难等缺点,以MSP430低功耗单片机为控制核心,设计了一种低频授时码接收系统。该系统由磁棒天线接收授时码信号,经过选频放大和滤波处理后,送至单片机进行信号解码,依此来校准和更新系统时钟。通过分析授时码编码格式的特点,设计了一套信号解码算法,并针对低频授时码信号容易受到电磁干扰的现象,采用低通滤波电路和数字滤波相结合的方法,有效地提高了系统的抗干扰能力。实验测试表明,系统能通过自动校时功能实现与国家授时中心标准时间的同步,也可以在需要时启动强制校准时间功能,以消除时间的累积误差,定时精度可以达到1 s。

Aiming at the shortcomings of the traditional timing equipment of the timing accumulating error and the difficulty of calibration,a low frequency code-timing receiving system which is using MSP430 MCU as the control core is designed.The system receives the timing code signal from the ferrite rod antenna,and after being subjected to frequency selective amplification and filtering processing,it is sent to the single chip microcomputer for signal decoding,thereby calibrates and updates the system clock.The characteristics of timing code coding format are analyzed,and a set of signal decoding algorithms is designed.The low frequency timing code signal is susceptible to electromagnetic interference.The anti-interference ability of the system is effectively improved by combining active low-pass filter circuit and digital filtering.The experimental test shows that the system can synchronize with the national time center standard time through the automatic calibration function,and can also start the forced calibration when needed to eliminate the accumulated error of time,and the timing precision can reach 1 s.