简单易懂的可配置dpll的VHDL代码。用于时钟恢复后的相位抖动的的滤波有非常好的效果， 而且能参数化配置pll的级数。 已通过测试。 -Straightforward configuration VHDL code dpll. Very good results for the clock recovery phase jitter filtering, and can be parameterized configuration pll series. Has been tested.