基于单片机的数字频率计的硬件设计.doc

摘要 数字频率计是计算机、通讯设备、音频视频等科研生产领域不可缺少的测量仪器。它是一种用十进制数字显示被测信号频率的数字测量仪器。它的基本功能是测量正弦信号，方波信号及其他各种单位时间内变化的物理量。在进行模拟、数字电路的设计、安装、调试过程中，由于其使用十进制数显示，测量迅速，精确度高，显示直观，经常要用到频率计。传统的频率计通常是用很多的逻辑电路和时序电路来实现的，这种电路一般运行缓慢，而且测量频率的范围比较小。考虑到上述问题，本论文设计一个基于单片机技术的数字频率计。 本设计是基于 AT89C51单片机的系统，在设计中应用单片机的数字运算和控制功能实现了测频量程的自动切换，满足了时间要求和精度要求。ABSTRACT Digital frequency meter is the computer, communications equipment, audio, video and other essential areas of research and production of measuring instruments. It is a decimal figures show the number of the measured signal frequency measuring instruments. Its basic function is to measure the sinusoidal signal, square wave signals and other physical changes in unit time. During the simulation, digital circuit design, installation, commissioning process, due to the use of decimal numbers show that the rapid measurement, high precision, intuitive display, often use the frequency meter. Conventional frequency meter is usually a lot of logic circuits and sequential circuits to achieve, this circuit is generally slow, and the measurement frequency range is relatively small. Considering the above problem, this thesis to design a single chip technology based on digital frequency meter. The design is based on AT89C51 microcontroller frequency measurement system, the main circuit by the signal amplification achieved by shaping the pulse signal preprocessing circuit out, through the amplification into the pulse amplitude is large enough signal count timer microchip to realize the frequency counts and The dynamic scanning using single chip to measure the data sent to the digital display circuit displays. Application of microcontroller in the system design of digital computing and control functions to achieve the automatic switching of frequency measurement range to meet the time requirements and accuracy. Key Word：Frequency; Frequency Counter；AT89C51 目录 第1章 概述 0 1.1 课题研究背景 0 1.2 课题研究意义 1 第2章 总体方案设计 2 2.1 方案比较 2 2.2 方案论证 3 2.3 方案选择 3 第3章 系统硬件设计 4 3.1 信号放大电路 4 3.1.1 信号放