学海网

课程设计 简易频率计的设计，共20页,7944字。
摘 要
随着电子科学技术的迅猛发展，人们对测量的精度和准确度的要求也越来越高。电子测量成为许多科技人员必须掌握的一门技术。测量仪器各种各样，其中频率计是很常用的一种测量仪器。
频率与许多电参量的测量方案和测量结果有着一些密切的关系。因此频率的测量就显得更为重要了。测量频率的方法有许多种,其中电子计数器具有使用方便、测量速度快、精度高、以及便于实现测量过程自动化等诸多优点，是频率测量的重要手段之一。
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。
本次的课程设计是利AT89C51单片机T0的计数功能和T1的定时功能来完成１S内对输入的信号波形的个数进行计数，计数的结果通过74LS48译码器，最后由4位静态数码管显示出来，显示的结果就是输入信号的频率。

关键词　单片机　译码器　数码管　静态显示
Abstrct

With the rapid development of electronic science and technology, people measurement precision and accuracy requirements are getting higher and higher. Electronic Measurement of many scientific and technical personnel must master a technique. Variety of measuring instruments, which is a very commonly used frequency meter as a measuring instrument.
Frequency and number of electrical parameters and measuring the results of the measurement program has a number of closely related. Therefore, the frequency Measurement becomes more important. Measuring frequency There are many ways in which electronic counter with a easy to use, measurement speed, high precision and easy to achieve the measurement of process automation, and many other advantages, is the frequency of Important means of measurement.
Digital frequency meter is the computer, communications equipment, audio, video and other essential areas of scientific research and production measurements Equipment. It is measured using the decimal figures show that the number of signal frequency measuring instruments. Its basic function is to measure sinusoidal signal, square wave signals and a variety of other changes in physical quantities per unit time.Conducting analog, digital circuit design, installation, commissioning process, due to its use decimal number display, measuring the rapid, precise Is indeed high, showing an intuitive, often use the frequency counter.
This course is designed Lee AT89C51 microcontroller T0 and T1 count function of the timing function to complete 1S input signal waveform within the number of counted, count resulted in the adoption 74LS48 decoder, the last by four static digital tube display , which showed the result is the input signal frequency.

Key words： SCM, a static decoder digital tube display
目 录
摘 要 I
Abstrct II
引 言 1
1设计思想及原理 2
1.1设计思路 2
2系统硬件电路的设计 3
2.1系统控制电路 3
2.1.1关于AT89C51功能及其引脚说明 3
2.1.2 信号调理及放大整形模块 5
2.1.3显示器的选择 6
2.2单片机定时/计数器 6
2.2.1方式寄存器TMOD 6
2.2.2定时/计数器的工作方式 7
3 系统程序的设计 8
3.1 频率计主程序流程图 8
3.2 子程序的设计 9
3.2.1 中断服务子程序 9
3.2.2 软件计数器子程序 10
3.3.3 动态显示子程序 10
4源程序清单 11
5总结 13
6致谢 14
7 参考文献 15
附录A总体电路图. 16