基于单片机的频率计设计.doc

I -基于单片机的频率计设计摘 要随着数字电子技术的发展,很多工程中都会涉及到频率测量，如用振弦式方法进行力的测量、时间测量、速度测量速度控制等因此，频率测量成为一项越来越普遍的工作，测频原理和测频方法的研究正受到越来越多的关注本系统以 AT89C52 单片机为核心，通过单片机内部定时/计数器的门控时间，实现对频率的测量当一个信号输入时，系统对其进行放大整形后分频处理，分频之后再选择合适信号输入到单片机进行测试，从而显示出这个信号的频率大小经过测试，在给定信号下利用 protues 仿真，得到误差极小的测量结果，且可根据输入频率自动切换测频档位实际电路的验证效果证明该频率计价格低廉、精度较高、工作稳定可靠关键词：频率计；单片机；分频片机的频率计设计- II -Design of frequency meter based on single-chip computerABSTRACTWith the development of digital electronic technology, many projects involve frequency measurement, such as force measurements made with vibrating string type method, time, speed measurement and speed control, etc. Therefore, frequency measurement become an increasingly common work, frequency measuring principle and method research is being more and more attention.AT89C52 as the core, this system by single chip microcomputer internal timer/counter, door control time, realize the frequency measurement.When a signal is input, the system of frequency division processing after amplification plastic, then frequency division to choose appropriate signal input to the single chip microcomputer test, which showed the signal frequency.After the test, using protues simulation under a given signal,getting the minimal error measurement results, and can automatically switching frequency measuring gear according to the input frequency.The practical circuit validation results prove that: the frequency meter, low cost, high precision, stable and reliable work.Keywords：frequency meter；single-chip computer；frequency division- III -目录引 言 .........................................................................................................................................1第 1 章 绪论 .............................................................................................................................21.1 频率计概述 .................................................................................................................21.2 频率计的发展现状及研究趋势 .................................................................................21.3 数字频率计的种类 .....................................................................................................3第 2 章 系统总体设计 ...............................................................................................................42.1 系统设计要求 ...............................................................................................................42.2 测频方法 .......................................................................................................................42.3 系统设计思路 ...............................................................................................................42.4 系统设计框图 ...............................................................................................................4第 3 章 系统硬件设计 ...............................................................................................................63.1 单片机模块 ...................................................................................................................63.1.1 AT89C52 介绍 .....................................................................................................63.1.2 单片机引脚分配 .................................................................................................73.1.3 复位电路 .............................................................................................................73.1.4 定时/计数器 ........................................................................................................73.2 电源模块 .......................................................................................................................83.2.1 电源变压器 .........................................................................................................93.2.2 整流电路 .............................................................................................................93.2.3 滤波电路 .............................................................................................................93.2.4 稳压电路 ...........................................................................................................103.2.5 电源模块原理图 ...............................................................................................103.3 放大整形模块 .............................................................................................................103.3.1 与非门 74LS00 .................................................................................................113.3.2 放大整形模块原理图 .......................................................................................113.4 分频模块 .....................................................................................................................113.4.1 分频器 74LS161 芯片 ......................................................................................123.4.2 多路选择器 74LS151 芯片 ..............................................................................123.4.3 分频模块原理图 .....................................................................。