积分式数字电夺表设计.doc

积分式数字电压表设计 九江学院学士学位论文 PAGE 6 PAGE 7 摘 要 随着电子科技的发展，电子测量成为广大电子工作者必须掌握的手段，对测量的精度和功能的要求也越来越高，而电压的测量甚为突出，因为电压的测量最为普遍。同时随着微电子技术的迅速发展和超大规模集成电路的出现，特别是单片机的出现，正在引起测量控制仪表领域的新的技术革命。 A/D转换电路是数据采集系统中的重要部分，也是计算机应用系统中一种重要的功能接口。目前市场上有两种常用的A/D转换芯片，一类是逐次逼近式的，如AD1674，其特点是转换速度较高，功率较低。另一类是双积分式的，如ICL7135，其特点是转换精度高、抗干扰能力强。但高位数的A/D转换器价格相对较高。本文介绍的一种基于单片机的高精度、双积分型转换电路，具有电路体积小、成本低、性价比高、结构简单、调试容易和工作可靠等特点，有很好的实际应用价值。 本设计在参阅了大量前人设计的数字电压表的基础上利用单片机技术结合LM339以及采用模拟开关CD4051构建一个测量范围达0-750V。本文首先简要介绍了积分式数字电压表的主要组成部分及原理，然后详细介绍了硬件系统和软件系统的设计，并给出了硬件电路的各部分电路的设计及原理以及软件算法。 关键词： 电压测量；LM339；模拟开关；单片机 Integral design of digital voltmeter Abstract With the development of electronical scientific technology, electronic measurement become a technic that everyone of engaging electronical had to master it. What’s more, the measurement accuracy and functional equirements are getting higher and higher, and the voltage measurement is best important. At the same time as the rapid development of microelectronics technology and the emergence of ultra-large-scale integrated circuits, In particular the emergence of MCU, is causing the field of measurement and control instruments of the new technological revolution. A/D converter circuit is an important part of the data acquisition system, is also an important function of interface of the computer application system. At present there are two common A/D conversion chip on the market. one is successive approximation type, such as the AD1674, characterized by high conversion, a lower power,; and the other is a two-integral type, such as the ICL7135, characterized by high precision conversion, and strong interference capability, But the high number of A/D converter is relatively expensive. This article describes a microcomputer-based high-precision, dual integral conversion circuit, with circuit size and low cost, cost-effective, simple structure, easy and reliable debugging and so on, have a good practical value. The design of a large number of our predecessors in the see-d