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毕业设计 数字频率计设计,共24页,8270字。
内容摘要：本文介绍了数字频率计的基本原理以及工作过程。在电子技术中，频率是最基本的参数之一，并且与许多电参量的测量方案、测量结果都有十分密切的关系，因此频率的测量就显得更为重要。本文提出了一种采用以 Atmel公司的单片机(AT89C51)为主要部件的数字频率计测量的设计方法。该数字频率计电路简洁，软件潜力得到充分挖掘，低频段测量精度高，有效防止了干扰的侵入。独到之处体现在用软件取代了硬件。

关键词：数字频率计 单片机 周期信号

Design for digital frequency meter
Abstract: This paper describes the basic principles of digital frequency meter, as well as the working process. In electronic technology, the frequency is the most basic one of the parameters, and with a number of electrical parameters of the measurement program, measurement results are very close relations, and therefore the frequency of measurement becomes more important. There are several ways of measuring frequency, in which electronic counter measure the frequency with high precision, easy to use, quick measurements, and is easy to realize the advantages of automation of measurement process is an important means of frequency measurement. Electronic Counter Frequency Measurement There are two ways: First, the direct frequency measurement method, that is, the gate in a certain period of time measured the number of measured signal pulse; 2 is indirect frequency measurement method, such as cycle frequency measurement method. Direct frequency measurement method for high-frequency signals of frequency measurement, indirect frequency measurement method for low-frequency signals of frequency measurement. This paper presents a use of Altera’s CPLD (ATF1508AS), and Atmel’s microcontroller (AT89C51) a combination of the design method of digital frequency meter. The digital frequency meter circuit simplicity, the software is fully tap the potential of low-frequency measurements of high precision, effectively prevent the intrusion of interference. Reflected in the unique software to replace the hardware.

Key words: digital frequency meter Microcontroller EDA periodic signal
目 录
前言 1
一、数字频率计的概述 1
(一) 数字频率计的设计要求 1
(二) 数字频率计的基本工作原理 1
二、设计方案论证 2
(一) 直接测频法 2
(二) 倍频法 2
(三) 组合测频法 2
(四) 等精度测频法 3
三、数字频率计的实现 3
四、数字频率计的设计 5
(一) 系统硬件的构成 5
1. AT89C51 单片机及其引脚说明 5
2. 信号调理及放大整形模块 7
3. 时基信号产生电路 8
4.显示模块 9
(二) 系统软件的设计 13
五、实验结果和误差分析 14
六、结束语 16
附录1：数字频率计工作原理图 18
附录2：数字频率计PCB图 19
附录3：设计程序代码 20
参考文献 24