数字频率计可以实现0.1---50khz的频率测试，小于1000时采用测周法，大于1000时自动转为计数法，最大误差小于千分之一，基本保持在万分之一之内。试验板采用12Mhz晶振，74164静态数码管显示，CD4051信号调理输入TTL方波信号。-Digital frequency meter can achieve 0.1--- 50khz frequency of testing, measuring less than 1000 weeks of method used, more than 1000 automatically to count, the maximum error is less than one thousandth, keeping within one ten thousandth . Test board with 12Mhz crystal, 74,164 static digital display, CD4051 signal conditioning input TTL square wave signal.