基于单片机的数模转换器设计

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1、摘要1.模拟信号的处理采用都是数字信号处理方式，AD;2.非线性；3.对非线性的数模转换提出了要求。在日常的小型工业现场设计和控制过程中，温度，压力，流量，电压和电流等模拟信号成为主要的被控参数，而这些参数大都具有非线性的特征；对现场这些需要控制的参数一般采用单片机构成的最小数据采集和处理系统对其进行采集和处理，以满足工业控制的要求。本论文结合经典的最小数据采集和处理系统，在此基础上，前向通道上仍旧使用模拟多路开关，A/D0809，80c51单片机对数据的采集和初步的数字化处理。论文中重点在后向通道的改进和设计上：通过采用软

2、件拟合的方法将非线性信号转换为线性电信号，在不占用硬件资源的情况下，较好的完成数字信号到模拟信号的关系转换。利用单片机的编程过程及后向放大电路实现对数据的拟合及放大使其最大程度的满足信号的平滑性和通用性。本论文重点在于后向通道的非线性数据的拟合过程和编程实现信号的拟合过程，实现控制信号的通用性和平滑性，完成本次的设计目的。关键词：单片机；数模转换器；非线性拟合；信号处理25目录1引言··························································41.1问题提出······

3、··············································41.2解决方案···················································51.3整体安排····················································62硬件系统电路设计··············································72.1系统硬件的总体设计·······························

4、··········72.2系统硬件电路组成···········································83非线性理论···················································133.1非线性理论介绍············································133.2数据拟合方法················25······························134软件系统设计··················

5、·······························144.1单片机软件设计············································154.2软件预处理················································164.3程序命令··················································175总结························································

6、·22参考文献·······················································23附录·························································24第一章引言251.1问题研究提出经典的基于单片机的数据采集和处理系统被广泛应用于现代工业生产现场，以及各种小型设备前向通道中的数据采集过程之中，该系统往往是对现场的温度、湿度、光照强度、电压和电流进行采集和控制，利用模拟多路开关和单片机以及一些外围的放大滤波电路进行参数的控制和处

7、理。在此过程中，单片机起在核心部件作用，连接模拟信号和数字信号，使整个处理过程既简单又高效，同时功率消耗不大，环境适应能力强，体积小，抗干扰能力强等诸多优点。在经典的采集系统中，单片机内部集成了数据的存储，数模转换，及程序设计和处理的过程。这次论文研究的重点就在于第一单片机中集成的数模功能的应用上，众所周知，数模转换原理，简单的说就是把单片机处理的数字信号转换成可以供机器使用的电压或者电流信号。现在简述下数模转换的原理：数模转换器是将输入的每一位二进制代码按其权值大小转换成相应的模拟量，然后将代表各位的模拟量相加，则所得的总

8、模拟量与数字量成正比，这样便实现了从数字量到模拟量的转换；（1.1）（1.2）数模转换器主要电路形式为权电阻网络和到T型电阻网络，实现数字量到模拟量的转化。在转化过程中，数模转换器有本身的分辨率，其值的计算方法为：(1.3)25分辨率越高转换时对输入量的微小变化的反应越灵敏，输入的数字量越