简易频率计的设计

分类号UDC 单位代码10644

密级公开学号2008050248

学士学位论文

简易频率计的设计

The design of simple frequency counter

论文作者：聂德军

指导教师：伍世云

系

别：物理与工程技术系

专业：电子科学与技术

提交论文日期：年月日

论文答辩日期：年月日

学位授予单位：四川文理学院

中国 达州

2012 年月

摘要

频率是电子技术领域中最基本的参数之一，在许多测量方案以及测量结果中都会涉及到频率测量的相关问题，频率精确测量的重要性显而易见。

在本设计中就介绍了频率测量的原理以及一种简易频率计的制作方法。由于待测信号未知，它有可能是正弦波，有可能是三角波，也有可能是方波。通过施密特触发器把待测信号转换为可以计数的脉冲信号，再由单片机计数输出到合适的电子显示元件以十进制显示出来。

本文重点介绍了以AT89C52单片机为对系统各个部件的控制来实现整个电路的信号频率采集、测量、转换数据、以及显示最终结果的功能，结合外围电子电路得以频率和周期的测量，并用十进制数字来显示被测信号的频率和周期。本数字频率计的硬件部分是采用PROTEUS ISIS绘制的，PROTEUS和KEIL联合做系统仿真，软件部分的单片机控制程序的编写使用的是C语言本。本系统的最大优点就是它结构简单易懂，制作起来也并不算麻烦，其缺点就是容易受自身电路元件以及周围环境的影响，从而导致测量结果与实际值的偏差。

关键词：单片机AT89C52 电路原理频率测量周期测量

I

ABSTRACT

Frequency is one of the basic parameters in the field of electronic technology, many measurement programs, as well as measurement results are related to the frequency measurement, and frequency of accurate measurement of obvious importance.

In this design on a frequency measurement principle and method of making a simple frequency meter. The test signal is unknown, it may be a sine wave, there is a triangle wave, there may be a square wave. Converted to a test signal through the Schmitt trigger pulse signal can count, count by the microcontroller output to the appropriate electronic display elements displayed in decimal.

This paper focuses on AT89C52 microcontroller for control of the system in various parts of to achieve the entire circuit signal frequency acquisition, measurement and conversion data, and display the final results feature, combined with the external electronic circuit can be frequency and period of measurement, and use decimal numbers to display of the measured signal frequency and period. The digital hardware part of the frequency meter using the PROTEUS the ISIS draw, the PROTEUS, and KEIL do system simulation software part of the microprocessor control program written using C language in this. The biggest advantage of this system is its structure is simple, the production is not too troublesome, the drawback is vulnerable to its own circuit elements, as well as the surrounding environment, resulting in the deviation of measurement results and the actual value.

Keywords: SCM AT89C52 circuit schematic frequency measurement cycle measurement

II

目录

目录

摘要 ............................................................... I ABSTRACT ............................................................ I I 第一章绪论.. (1)

1.1频率计应用概述 (1)

1.2数字频率计系统介绍 (2)

1.2.1课题研究的目的和意义 (2)

1.2.2国内外数字频率计的研究现状 (2)

第二章数字频率计的设计 (4)

2.1设计的任务和要求 (4)

2.2总体框架和测量方案 (4)

2.2.1 测量方法论证 (6)

2.2.2 计时方案选择 (9)

第三章硬件电路的设计及仿真 (10)

3.1整体电路介绍 (10)

3.2信号整形电路 (10)

3.3单片机最小系统设计 (12)

3.4施密特触发器整形仿真与功能仿真 (13)

3.5显示方案 (17)

3.5.1 LED方案 (17)

3.5.2 LCD1602方案 (17)

第4章软件设计 (19)

4.1软件编程思想 (19)

4.2主要程序段及软件流程图 (19)

4.2.1频率周期测量流程图 (19)

4.2.2总流程图 (20)

结论 (22)

参考文献 (24)

致谢 (24)

附：程序代码 (26)

III