Xilinx的modelsim　仿真库！里面有许多库函数，对于ｖｌｏｇ或ｖｈｄｌ编程有很多好的源代码可以剪切！-Xilinx modelsim simulation library! There are many libraries, vlog or VHDL programming a lot of good source code can shear!

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.

PLL 时钟模块　　Quartus II平台的简单设计实例　附仿真波形-PLL clock module Quartus II platform attached to a simple design example simulation waveforms