AD_DA轉(zhuǎn)換器的設(shè)計(jì)及MATLAB仿真實(shí)現(xiàn)



摘    要

　　　隨著科學(xué)技術(shù)，特別是數(shù)字電子技術(shù)的迅速發(fā)展，使電子計(jì)算機(jī)從純計(jì)算機(jī)工具發(fā)展成為復(fù)雜的自動(dòng)控制系統(tǒng)的可信組成部分，依靠它對復(fù)雜的科學(xué)實(shí)驗(yàn)、生產(chǎn)過程實(shí)行自動(dòng)監(jiān)視、檢測及閉環(huán)控制。這樣，就完全需要數(shù)學(xué)系統(tǒng)來處理模擬信號(hào)，這種信號(hào)處理包括兩方面的內(nèi)容，一方面要將模擬信號(hào)轉(zhuǎn)換相應(yīng)的數(shù)字信號(hào)，才能送入數(shù)字系統(tǒng)（例如電子計(jì)算機(jī)）進(jìn)行算術(shù)的或邏輯的運(yùn)算，另一方面還經(jīng)常需要將數(shù)字系統(tǒng)處理后得到的數(shù)字信號(hào)在轉(zhuǎn)換成相應(yīng)的模擬信號(hào)，作為最后的輸出，去控制或驅(qū)動(dòng)執(zhí)行機(jī)構(gòu)執(zhí)行。

　　　自然界中存在的物理量，就起表現(xiàn)形式來看，可以分為模擬量和數(shù)字量兩種。模擬量的表現(xiàn)形式是連續(xù)的，數(shù)字量的表現(xiàn)形式則是不連續(xù)的(離散的)。這里所說的連續(xù)有兩個(gè)含義：隨時(shí)間是連續(xù)變化的，其數(shù)字也是連續(xù)可變的。自然界中絕大多數(shù)物理量都是連續(xù)變化的模擬量。例如：電壓、電流、時(shí)間、頻率、溫度、壓力、速度、流量等等。此外，各種非電量經(jīng)過傳感器轉(zhuǎn)換成的電壓或電流也是連續(xù)變化的模擬量。數(shù)字量則不具有這種連續(xù)變化的特點(diǎn)，它的數(shù)值只能一個(gè)單位地增加或減少。例如，放射性同位素物質(zhì)放射出來的射線粒子數(shù)，人口的數(shù)目等，就是數(shù)字量的具體例子。此外，晶體管的導(dǎo)通與截止，開關(guān)的通和斷等也可看作是數(shù)字量。

　　　隨著電子計(jì)算技術(shù)和數(shù)字系統(tǒng)在各個(gè)領(lǐng)域中的廣泛應(yīng)用，就需要將模擬量轉(zhuǎn)換成數(shù)字量，因?yàn)橹挥袛?shù)字量才能被計(jì)算機(jī)或數(shù)字系統(tǒng)識(shí)別。另一方面，在許多情況中，系統(tǒng)最后得到的數(shù)字結(jié)果又需要再變換為模擬量，用來通過執(zhí)行機(jī)構(gòu)去實(shí)行控制，或進(jìn)行必要的調(diào)整。因此就要求模擬量與數(shù)字量之間能相互進(jìn)行轉(zhuǎn)換。

　　　　關(guān)鍵詞：D/A轉(zhuǎn)換器；精密電阻網(wǎng)絡(luò)；解決時(shí)間

Abstract

　　　 With the rapid development of the science and technology, especially the digital electronic technology, the computer has evolved into the available part of the complex automatic control system from pure computer tool, and carried out the automatic monitoring, inspecting and closed-loop control by depending on its complex scientific experiment and production process. In this way, it completely needs math system to deal with analog signals. This kind of signal processing includes two aspects: on the one hand, transform the analog signals to the corresponding digital signals, in order to input the digital systems (such as the electronic computer) to perform arithmetic or logical operations; on the other hand, we often still need to convert the digital signals after the digital system handling into the corresponding analog signals as the final output, to control or drive the actuators' execution.

　　　The physical energy exists in nature, as for its forms, can be divided into two kinds: the analogue and digita. The orms of analogue is continuous, and the manifestation of the digita is discontinuous (discrete). Here there are two meanings about continuity：it is continuous and changeable with the time change , and its data is also continuous and changeable. The most physical energy in nature is the continuous and changeable analog energy. For example: voltage, current, time, frequency, temperature, pressure, velocity, flow and so on. Besides, various non-powers through the sensor into a voltage or current are continuously variable analogue. The digita does not have this continuous and changeable characteristics and its numerical only increase or decrease one by one unit. For example, the rays’ particle counts radiated by radioactive isotopes substances, the population number and so on, they are the specific examples. In addition, the transistor's conduction and cut off, on and off of the switch also can be considered as a kind of digita.

　　　As electronic computing and digital system wide application in various fields, it needs to convert the analog energy into digital energy, because only the digital energy can be identified by computer or digital system. On the other hand, in many cases, the numerical results finally out from the system still need to convert into the analog energy, in order to carry out control through the actuators, or make the necessary adjustment. Therefore, it requires the analogue and digita can convert one to another.

Key words: D/A converter; Precision resistor network; Solve time


目    錄

引  論 1

1  AD/DA轉(zhuǎn)換器的相關(guān)介紹 1

　　　1.1  AD/DA轉(zhuǎn)換技術(shù)的發(fā)展 1

　　　1.2  A/D轉(zhuǎn)換器  1

　　　1.3  D/A轉(zhuǎn)換器  3

2  A/D轉(zhuǎn)換器 5

　　　2.1  A/D 轉(zhuǎn)換器 5

　　　2.2  并行比較型A/D轉(zhuǎn)換器  6

　　　2.3  逐位逼近型A/D轉(zhuǎn)換器 7

3  D/A轉(zhuǎn)換器 11

　　　3.1  D/A轉(zhuǎn)換器的基本原理 11

　　　3.2  D/A轉(zhuǎn)化器的分類 12

4  AD/DA轉(zhuǎn)換器的MATLAB實(shí)現(xiàn) 17

　　　4.1  MATLAB的介紹 17

　　　4.2  A/D和D/A轉(zhuǎn)換器的MATLAB實(shí)現(xiàn) 18

結(jié)  語 23

主要參考文獻(xiàn) 24

附錄 25

　　　附錄一A/D轉(zhuǎn)換器的MATLAB實(shí)現(xiàn)程序及運(yùn)行結(jié)果 25

　　　附錄二D/A轉(zhuǎn)換器的MATLAB實(shí)現(xiàn)程序及運(yùn)行結(jié)果 28 -..