以AD为基础的交流毫伏表设计书毕业论文.docVIP

以AD637为基础的交流毫伏表设计 摘 要 在电量的测量中，电压，电流和频率是最基本的三个被测量。其中，电压量的测量最为经常。而且随着电子技术的发展，更需要测量弱电的电压，所以毫伏电压表就成为一种必不可少的测量仪器。另外，由于数字式仪器具有读数准确方便，精度高，误差小，灵敏度和分辨率高，测量速度快等特点，而倍受用户青睐The AD637-based exchange mV table design Abstract In the measurement of electricity, voltage, current and frequency is the most basic measurement of the three. Among them, the voltage measurement of the volume of the most often. In addition, with the development of electronic technology, but also the need for weak measurements of voltage, so mV voltage meter has become an indispensable instrument. In addition, as a result of digital equipment to facilitate accurate readings with high precision, small error, high sensitivity and resolution to measure the characteristics of speed, and greatly favored customers. MV of the system table to share as the core, low-power single-chip microcomputer-based MCS-51 controller, data acquisition system through data collection, the operator has a micro-amplifier and the attenuation of the relay output module, with attenuation enlarge analog signal processing, in which the signal all the way through the DC True RMS (RMS-DC) conversion, after 12 successive comparison fast A / D converter conversion AD574 chip, real-time analog to digital conversion for, calculated by the CPU and processed, by the Seven-Segment LED digital display, the ultimate realization of the measured value of the input signal voltage and frequency measurement value display. Key words Single-chip microcomputer Digital AC Millivol 目 录 摘 要 I Abstract II 1 绪论 1 2 单片机 2 2.1 单片机概述 2 2.2 单片机的内部结构 2 2.3 AT89C51简介 3 2.4 单片机最小系统 9 3 单元电路设计 10 3.1 衰减、放大倍数可调电路设计 10 3.2 真有效值直流(RMS-DC)变换电路设计 12 3.3 A/D模数转换单元设计 15 3.3.1 A/D转换器概述 15 3.3.2 逐次逼近式A/D原理及AD574芯片 15 3.4 直流稳压电源设计 20 3.4.1 单相桥式整流电路 20 3.4.2 桥式整流电路的技术指标 21 3.4.3 三端固定式集成稳压器 22 3.4.4 稳压电源电路 23 4 数码管LED及可编程接口芯片设计 24 4.1 LED数码管结构与原理 24 4.1.1 LED数码管结构种类 24 4.1.