一种从E1信号中提取时钟的全数字锁相环

An All-Digital Phase Locked Loop for Clock Recovery from E1 Signal

提出了一种从 E1信号中提取时钟的全数字锁相环。采用半脉宽移动技术设计数控振荡器 (DCO) ,使输出时钟占空比的误差小于 4%。经实验证实 ,在输入信号的频率范围为 2 .0 4 8MHz± 90 ppm且抖动满足 ITU- T G.82 3的情况下 ,该电路完全可以用于从 E1信号中提取时钟。采用数字锁相环对系统集成大有好处。

An all digital phase locked loop for clock recovery from E1 signal is presented.Half pulse width shift technique has been adopted for the circuit to achieve a duty cycle of 46% (min) and 54% (max).Hardware experiment demonstrates that the circuit can recover clock from E1 signal, and the performance can meet the ITU T G 823 recommendation.The signal frequency is between 2 048 MHz -90 ppm and 2 048 MHz +90 ppm