说明：  FPGA设计中几个基本问题的分析及解决 多时钟系统，时钟设计，时钟歪斜，门控时钟，毛刺信号及其消除，FPGA中的延时设计，FPGA设计应注意的其它问题
(FPGA design analysis of a few basic questions and solve multi-clock system, clock design, clock skew, clock gating, and the elimination of burr signal, FPGA design of the delay, FPGA design should pay attention to other issues)