说明：  PLL system LPF/PFD/VCO/Divider model in Matlab,在Matlab中将PLL系统的各个模块模型话，便于分析整个PLL的环路稳定特性，锁定时间等…… 附录中包含完整的Matlab code
(PLL system LPF/PFD/VCO/Divider model in Matlab, the Matlab will PLL system model of each module, the easy analysis of the whole PLL loop stability characteristics, lock time ... ... the appendix contains a complete Matlab code)