Signal demodulation of automaticblock with audio frequencyshift modulated track circuits was implemented with phase-locked loop (PLL) technique and a singe chip microcomputer.
利用锁相环(LL)窄带跟踪特性，与单片机结合，实现自动闭塞系统移频信号解调。
2
The article analyses the frequency security & stability of signal generator circuit of dispatching equipment of automaticblock with frequencyshift, and an optimum design scheme is concluded.