用FPGA设计的等精度测量频率。频率的测量范围为1Hz-100MHz。可以测占空比，测时间间隔等。可测正弦波和方波。精度大于10e（-4）-Using FPGA to design the equal precision frequency measurement.Frequency of the measuring range is 1 hz- 100 MHZ.Can examine duty ratio, time interval measurement, etc.Sine wave an