用VHDL实现数字频率计,1. 时基产生与测频时序控制电路模块2. 待测信号脉冲计数电路模块3.锁存与译码显示控制电路模块4.顶层电路模块. -Using VHDL digital frequency meter, 1. Time-base generation and frequency measurement timing control circuit module 2. Analyte signal pulse counting circuit module 3. Latch and