摘 要 频率测量是电子学测量中最为基本的测量之一。频率计主要是由信号输入和放大电路、单片机模块、分频模块及显示电路模块组成。AT89C51 单片机是频率计的控制核心，来完成它待测信号的计数，译码，显示以及对分频比的控制。利用它内部的定时/计数器完成待测信号频率的测量。在整个设计过程中，所制作的频率计采纳外部分频，实现 10Hz-500kHz 的频率测量，而且可以实现量程自动切换流程。以 AT89C51 单片机为核心，通过单片机内部定时/计数器的门控时间，方便对频率计的测量。其待测频率值使用 LCD 液晶显示器显示，并可以自动切换量程。本次采纳单片机技术设计一种数字显示的频率计，具有测量准确度高，响应速度快，体积小等优点。关键词：周期测频法，单片机控制，软硬件结合。ABSTRACTFrequency measurement is the most basic measurement in Electronic field. Frequency meter is mainly composed of a signal input and an amplifying circuit, SCM module, frequency module and a display circuit module. AT89C51 MCU is the control core frequency of dollars to complete its count of the signal under test, decoding, display and control of the frequency division ratio. Using its internal timer or counter to complete the signal of the under test cycle / frequency of measurement. Throughout the design process, periodic measurement of the frequency meter application and the corresponding mathematical treatment to achieve 1Hz ~ 500 KHz frequency measurements, and can automatically switch the flow to achieve scale. To the core of AT89C51 micro-controller, with the MCU internal timer / counter gate time, it can be easier for frequency measurement. The use of microcomputer technology to design a digital display of frequency meter, have a measurement of high accuracy, fast response, small size and so on.KEYWORDS: The cycle frequency measurement, Single chip control, The combination of hardware and software.目 录1 绪 论............................................
