介绍了锁相环PLL的实现原理，可以为VHDL实现PLL提供参考。-introduced PLL PLL The principle for VHDL PLL reference.

数字鉴相器,数字锁相环频率合成系统FPGA的实现,很有借鉴价值-Digital phase detector, digital PLL frequency synthesizer system FPGA realization of referential value