本设计以AT89S52单片机为核心充分利用硬件资源设计的一种频率计，该频率计首先将被测信号放大整形处理，变成满足单片机I/O口接受的TTL/ CMOS 兼容信号从单片机的T1输入口输入直接累加脉冲数，将单片机内部定时器定时为1S，这时累加的脉冲数即为被测信号的频率。最后经单片机处理送至lcd液晶显示屏显示。-This design with AT89S52 MCU as the core design make full use of the hardware resources of a kind of frequency meter, the frequency meter will first measured signal amplification plastic processing, become meet SCM I/O port to accept TTL/CMOS compatible signal directly　MCU T1 input port input accumulative pulse number, MCU internal timer timing for 1 s, then the number of pulses accumulation is the measured signal frequency. Finally by the single chip to the LCD display shows.