利用XILINX的SPARTAN-3A系列的XC3S200A的FPGA为载体，以VHDL为系统逻辑描述的表达方式，完成的数字频率计的设计。-SPARTAN-3A XILINX the use of the FPGA family XC3S200A to vector to the system Logic VHDL descr iption expressions, completed the design of Digital Frequency Meter.