有直接注入信号锁相环的跟踪捕捉性能分析

ANALYSIS FOR THE SYNCHRONOUS TRACKING AND CAPTURE IN PLL OF THE INPUT SIGNAL DIRECTLY INJECTED

从Alder方程出发,分析计算了有直接注入信号的一阶与二阶锁相环路的捕捉和同步跟踪带宽,表明:注入信号的作用是等效于提高了环路的直流增益,从而改善了环路的同步跟踪及捕捉性能。

The experimental results in [1] was shown that if a part of the input signal directly injected to the VCO, the synchronous tractly bandwidth and synchronous capture bandwidth will extended effectively. Further, in this paper from Adler's equation the bandwidth of the tracking and capture of the first and second order PLL are analysed. It is shown that the action of the injected signal is equivalent to the increment of the total loop gain, hence the characteristic of tracking and capture will be improved.