数字频率计的设计论文

中文题目：数字频率计的设计

外文题目：THE DESIGN OF DIGITAL FREQUENCY METER

毕业设计（论文）共 59 页（其中：外文文献及译文完成日期 2012年5月

13页） 图纸共1张

答辩日期 2012年6月

辽宁工程技术大学毕业设计

摘 要

随着电子信息产业的不断发展，信号频率的测量在科技研究和实际应用中的作用日益重要。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。首先，我们把待测信号经过放大整形，经三极管和施密特触发器把输入的信号转换为单片机能够识别的方波信号；然后把信号分成三路，这是为了测量的准确性，经四选一多路选择器通过单片机控制来选择把哪路信号送显示；最后经过单片机计算分析，将要显示的频率经驱动送入数码管显示。

本文从频率计的原理出发，介绍了基于单片机的数字频率计的设计方案，选择了实现系统得各种电路元器件，并对硬件电路进行了仿真。 关键字：单片机；频率计；测量

I

靳琳：数字频率计的设计

Abstract

With the development of electronic information industry, The measurement of signal frequency is becoming more and more important in Science and Technology Studies practical application .Traditional frequency meter is usually realized by logic circuit and sequence circuit. This circuit generally run slowly, and with small measurement range of frequencies. In view of the above problems, I design the digital frequency meter through SCM. Firstly, the signal to be measured is magnified and reshaped, when passing the transistor and Schmidt trigger, the signal is changed to square wave which can be recognised by SCM. Secondly, the signal is separated into three which is used to develop the precision; Multiplexer controlled by SCM is used to select the signal. At last, the frequency is drived by a driver.

The designment started from the schemic of the digital frequency meter , introducing the designing plan, selecting the component and simulating to the hardware circuit. Keywords: SCM; Frequency Meter; Measurement

II

目录

前言 .................................................................................................................. 1 1 概述 .............................................................................................................. 2 1.1 频率计的定义............................................................................................. 2 1.2 数字频率计设计的几种方案 ...................................................................... 2 1.3 几种方案的优劣讨论 ................................................................................. 3 2 系统硬件设计 ............................................................................................... 4 2.1 系统芯片介绍............................................................................................. 4 2.1.1 LM324 ...................................................................................................... 4 2.1.2 74HC14..................................................................................................... 6 2.1.3 74HC160................................................................................................... 7 2.1.4 CD4051..................................................................................................... 9 2.1.5 AT89C51 ..................................................................................................11 2.1.6 74HC138................................................................................................. 17 2.1.7 74HC244................................................................................................. 19 2.1.8 数码管 ................................................................................................... 20 2.2 系统的总体电路设计原理 ........................................................................ 23 2.2.1 系统的设计框图 .................................................................................... 23 2.2.2 数字频率计的设计原理 ......................................................................... 23 2.3 系统各部分电路功能的具体实现 ............................................................. 24 2.3.1 信号处理 ............................................................................................... 24

百度搜索“77cn”或“免费范文网”即可找到本站免费阅读全部范文。收藏本站方便下次阅读，免费范文网，提供经典小说综合文库数字频率计的设计论文在线全文阅读。