1）能够测量正弦波、三角波、锯齿波、矩形波等周期性信号的频率； 2）能直接用十进制数字显示测得的频率； 3）频率测量范围：1HZ~10KHZ切量程能自动切换； 4）输入信号幅度范围为0.5~5V，要求一起自动适应； 5）测量时间：T〈=1.5S；6）用CPLD/FPGA可编程逻辑器件实现 -1) capable of measuring the frequency of the sine wave, triangle wave, sawtooth wave, rectangular wave periodic signal　2) the direct use of decimal digits to display the measured frequency　3) Frequency measuring range: 1HZ ~ 10KHZ cut range can be automatically switched　a) input signal amplitude range of 0.5 ~~ 5V requirements with automatic adaptation　5) Measurement time: T < = 1.5S　6) CPLD/FPGA programmable logic devices