数字频率计设计论文（cpld+vhdl编程） 毕设论文.docVIP

数字频率计的研究 Digital frequency of research 学 生: 专 业：电子信息工程 班级 学号： 指导 教师： 学 院: 电子信息工程 摘 要 本设计采用的数字频率计是专门用于测量信号频率的装置，并用十进制显示，它具有测量迅速、精度高、技术方便等优点。它不仅可以测量正弦波、方波和尖脉冲信号的频率，而且还能对其它多种物理量进行测量。系统用MSC—51单片机作为控制核心，门控信号由定时计数器产生，但由于单片机的技术频率有采用限，所以需要高频信号进行硬件分频处理，AT89C51完成运算、控制及显示功能；为克服通用数字电路集成度低、电路安装布局不便的缺点，采用CPLD完成逻辑处理功能，使电路大为简化；用模拟输入通道实现信号的自动增益控制计较宽的测频范围 关键词: CPLD 频率计 AT89C51 VHDL MSC—51 ABSTRACT Digital frequency meter is used to measure the signal frequency devices, and decimal number display. Digital frequency is a kind of traditional measuring instrument, widely used in teaching, factories and schools in the company. It not only can measure sine pulse, and pointed the pulse signal frequency, it can also on other measure multi-physical quantity. Such as mechanical vibration frequency, rotating speed of the rotation, etc., to convert, and then use frequency signal measurement program. This design USES digital frequency meter is used to measure the signal frequency devices, and that, it has the decimal measurement, high precision and fast technology convenience etc. It not only can measure sine pulse, and pointed the pulse signal frequency, but also to other measure multi-physical quantity. System using MSC - 51 SCM as control core, door control signals generated by timing counter, but because the technology is adopted MCU frequency, so need high frequency signal processing, hardware, control and complete AT89C51 display function, To overcome the common digital circuit, low installation layout integration circuit faults, using the inconvenience of logic function, complete CPLD greatly simplified the circuit, In analog input signal channel of automatic gain control of the wide range of frequency measurement care Keyword: CPLD frequency meter AT89C51 VHDL MSC - 51 目 录 第一章 绪 论 1 1.1引言 1 1.2 发展前景 2 第二章 设计技术方案要求 3 2.1技术指标及要求 3 2.2方案论证 3 第三章 测量原理 5 3.1频率测量模块 5 3.1.1直接测频法 5 3.1.2 组合测频法 6 3.1.3 倍频法 6 3.1.4 等精度测频法 6 3.2周期测量模块 8 3.2.1周期