本系统是基于CPLD和单片机的一种用于信号频率周期、时间间隔和占空比测量的数字频率计，系统由AGC（自动增益控制）电路、宽带放大电路、高速比较电路实现有效值10mV/频率100MHz和处理显示部分组成，其中AGC电路实现幅度自动增益控制使放大后的信号幅度在一定的范围内保持一致，比较电路将前级电路输出的信号转换成CPLD,利用等精度测频原理，实现闸门时间1S的高精度测量。单片机通信处理数据并显示，数据表明，系统精度达到发挥部分要求。(This system is a CPLD microcontroller for signal frequency and period, time interval and the duty ratio of digital frequency measurement meter based on the system by the AGC (automatic gain control) circuit, amplifier circuit, high speed broadband comparison circuit to achieve effective value of 10mV/ 100MHz and the frequency of processing components, including AGC circuit control signal after amplification is consistent within a certain range of amplitude automatic gain circuit compares the former circuit output signal is converted into CPLD, using precision frequency measurement principle, realizes high accuracy time gate 1S. SCM communication processing data and display, data show that the system precision to play a part of the requirements.)