機(jī)械電子工程專業(yè)畢業(yè)論文—外文翻譯(紅外線遙控系統(tǒng))21239

1、譯 文學(xué) 院： 機(jī)械工程學(xué)院 專 業(yè)： 機(jī)械電子工程 學(xué) 號(hào)： 0840206126 姓 名： 指導(dǎo)教師： 2012年5 月 10 日紅外線遙控系統(tǒng)內(nèi)容摘要：目前在世界范圍內(nèi)被廣泛使用的一種無(wú)線連接技術(shù)是紅外線數(shù)據(jù)通信技術(shù)，其得到許多的軟硬件平臺(tái)支持。紅外收發(fā)器產(chǎn)品的特點(diǎn)有成本低，尺寸小，數(shù)據(jù)傳輸速度快，點(diǎn)對(duì)點(diǎn)ssl安全傳輸，防電磁干擾等，能夠?qū)崿F(xiàn)不同產(chǎn)品間快速、方便、安全地進(jìn)行信息交換和傳送，在近距離無(wú)線傳輸方面有著相當(dāng)明顯的優(yōu)勢(shì)。紅外遙控收發(fā)系統(tǒng)具有很強(qiáng)的實(shí)用意義，目前紅外收發(fā)器產(chǎn)品在便攜式產(chǎn)品中有著很大的應(yīng)用潛力。隨著紅外數(shù)據(jù)傳輸技術(shù)更加成熟、成本下降，紅外收發(fā)器在短距離通訊領(lǐng)域必將得到

2、更廣泛的應(yīng)用。設(shè)計(jì)本系統(tǒng)的目的是，用紅外線作為傳輸載體來(lái)攜帶用戶的操作信息并由接收電路接受并解調(diào)出原始操作信號(hào)，主要使用編碼芯片和解碼芯片對(duì)信號(hào)進(jìn)行調(diào)制和解調(diào)。其中編碼芯片使用的是pt2262，解碼芯片使用是pt2272，他們都由臺(tái)灣生產(chǎn)。其主要工作機(jī)理是：我們使用編碼鍵盤為pt2262輸入信息，輸入的信息被pt2262編碼并加載到38khz的載波上，并調(diào)制紅外發(fā)射二極管，輻射到空間。然后，接收系統(tǒng)接收到發(fā)射的信號(hào)并解調(diào)出原始信息。原始信號(hào)由pt2272進(jìn)行解碼，以此驅(qū)動(dòng)對(duì)應(yīng)的電路完成用戶的操作請(qǐng)求。關(guān)鍵字：紅外線；編碼；譯碼；lm386；紅外收發(fā)器。1 簡(jiǎn)介11 研究的背景及意義紅外數(shù)據(jù)通信

3、技術(shù)是目前世界范圍內(nèi)被廣泛采用的的一種無(wú)線連接技術(shù)，得到廣大的硬件和軟件平臺(tái)支持。其屬于一種通過(guò)數(shù)據(jù)電脈沖和紅外光脈沖之間進(jìn)行轉(zhuǎn)換從而實(shí)現(xiàn)無(wú)線數(shù)據(jù)接受和發(fā)送的技術(shù)。紅外收發(fā)器產(chǎn)品的特點(diǎn)有成本低，尺寸小，數(shù)據(jù)傳輸速度快，點(diǎn)對(duì)點(diǎn)ssl安全傳輸，防電磁干擾等，能夠?qū)崿F(xiàn)不同產(chǎn)品間快速、方便、安全地進(jìn)行信息交換和傳送，在近距離無(wú)線傳輸方面有著相當(dāng)明顯的優(yōu)勢(shì)。紅外收發(fā)器產(chǎn)品在便攜式產(chǎn)品中的應(yīng)用潛力巨大。目前，全世界有150,000,000臺(tái)設(shè)備采用了紅外技術(shù)，廣泛使用電子產(chǎn)品和工業(yè)裝備、醫(yī)療設(shè)備等領(lǐng)域。比如有95的便攜式電腦就安裝了紅外收發(fā)器接口,現(xiàn)在絕大部分手機(jī)上也配置了紅外收發(fā)器接口。隨著文檔數(shù)據(jù)交換

4、的普及，紅外數(shù)據(jù)通訊將使手機(jī)的數(shù)據(jù)傳輸越來(lái)越方便。隨著紅外數(shù)據(jù)傳輸技術(shù)越來(lái)越成熟、完善、低成本，紅外收發(fā)器在近距離通訊領(lǐng)域中將取得更為廣泛的應(yīng)用。本節(jié)首先闡明了紅外線收發(fā)集成電路設(shè)計(jì)課題的背景和重要性，進(jìn)而簡(jiǎn)明扼要地介紹了紅外數(shù)據(jù)通訊技術(shù)的特點(diǎn)和應(yīng)用方向以及紅外收發(fā)器產(chǎn)品的特點(diǎn)、國(guó)內(nèi)外現(xiàn)狀和發(fā)展趨勢(shì)，最后根據(jù)紅外遙控收發(fā)系統(tǒng)的實(shí)際應(yīng)用性確定了課題的設(shè)計(jì)目的。12 紅外遙控收發(fā)系統(tǒng)紅外遙控系統(tǒng)被劃分為單頻道遙控和多頻道遙控。只有一個(gè)指令信號(hào)傳輸通道的稱為單通道遙控系統(tǒng)，具有兩個(gè)以上指令信號(hào)傳輸通道的稱為多通道遙控系統(tǒng)。相對(duì)而言，單通道遙控一般來(lái)說(shuō)其發(fā)射器僅有一個(gè)指令鍵 ,接收器也只有一個(gè)執(zhí)行電路

5、。雖然在接收電路中加入可以根據(jù)按動(dòng)發(fā)射器指令鍵的次數(shù)的多穩(wěn)態(tài)記憶電路 ,使接收電路中的多穩(wěn)態(tài)記憶電路的狀態(tài)多次改變 ,實(shí)現(xiàn)多項(xiàng)功能的控制 ,然而這種狀態(tài)的改變是順序進(jìn)行的。如果我們要實(shí)現(xiàn)一項(xiàng)自由隨機(jī)控制 ,需要依靠采用多通道遙控系統(tǒng)來(lái)實(shí)現(xiàn)。多通道遙控可以實(shí)現(xiàn)對(duì)被控對(duì)象的多功能任意遙控。根據(jù)具體實(shí)際情況(如被控對(duì)象、操作要求及成本核算等)來(lái)決定選用幾個(gè)通道及何種控制方式。通常何情況下，紅外遙控收發(fā)系統(tǒng)由紅外遙控信號(hào)編碼發(fā)送器、紅外遙控信號(hào)接收器和解碼器（解碼芯片mcu）及其外部電路等三個(gè)部分組成。信號(hào)發(fā)送器用來(lái)產(chǎn)生紅外遙控編碼脈沖，驅(qū)動(dòng)紅外發(fā)射管輸出紅外遙控信號(hào)，而接收器則需要完成對(duì)信號(hào)的放大、

6、檢波、整波并解調(diào)出編碼脈沖。紅外遙控編碼脈沖是一組一組連續(xù)的，串行的二進(jìn)制碼，對(duì)于大多數(shù)的紅外收發(fā)系統(tǒng)，此串行碼可以用作微控制器的遙控輸入信號(hào)，完成對(duì)遙控指令的解碼是在cpu內(nèi)部，對(duì)于其它紅外遙控收發(fā)電子產(chǎn)品的設(shè)計(jì)者而言，前面提到的微控制器內(nèi)部解碼出的遙控指令是不易深入的。所以，人們利用紅外編碼芯片/解碼芯片及微控制器研制出許多種通用紅外遙控收發(fā)系統(tǒng)，在各種各樣的收發(fā)設(shè)備之間進(jìn)行紅外信號(hào)的傳輸。通常情況下遙控收發(fā)系統(tǒng)是由發(fā)射器和接收器這兩部分組成。發(fā)射器一般由方向鍵、指令編碼回路、激勵(lì)電路、驅(qū)動(dòng)電路、啟動(dòng)電路等幾部分組合而成。當(dāng)某鍵被按下時(shí) ,指令編碼回路產(chǎn)生對(duì)應(yīng)的指令編碼信號(hào) ,編碼指令信號(hào)

7、對(duì)載波進(jìn)行調(diào)制 ,通過(guò)驅(qū)動(dòng)電路進(jìn)行功率放大之后，通過(guò)發(fā)射電路向外發(fā)射已經(jīng)過(guò)調(diào)制的指令編碼信號(hào)。接收器一般由接收電路、放大電路、檢波電路、指令譯碼電路、驅(qū)動(dòng)電路、啟動(dòng)執(zhí)行電路等幾部分組合而成。接收電路接收發(fā)射器發(fā)射的已調(diào)制的編碼指令信號(hào) ,并對(duì)其進(jìn)行放大后送到解調(diào)電路。解調(diào)電路將送來(lái)的已調(diào)制的編碼信號(hào)進(jìn)行解調(diào) ,進(jìn)而還原為編碼信號(hào)。指令譯碼器將編碼指令信號(hào)進(jìn)行譯碼 ,最后由驅(qū)動(dòng)電路來(lái)驅(qū)動(dòng)執(zhí)行電路去實(shí)現(xiàn)各種各樣的指令的操作控制。13 紅外遙控收發(fā)器產(chǎn)品介紹1.3.1紅外遙控收發(fā)器產(chǎn)品的結(jié)構(gòu)和類型一般地紅外收發(fā)器依照工作模式和傳輸速率可分為四種類型：串行模式，最高傳輸速率為115.2kbps；中速率

8、模式：最高傳輸速率為0.567mbps和1.152mbps；高速率模式：最高傳輸速率為16mbps。此外按芯片能量功耗又可分成低功耗型和標(biāo)準(zhǔn)型兩種類型，低功耗型一般使用3v電源供電，傳輸距離較近介于0-30cm之間，標(biāo)準(zhǔn)型通常使用5v作為電源，傳輸距離較遠(yuǎn)，最少1m以上。1.3.2國(guó)內(nèi)外紅外遙控收發(fā)器現(xiàn)狀在紅外通信技術(shù)的早期發(fā)展階段，有幾個(gè)紅外通信標(biāo)準(zhǔn)，在不同標(biāo)準(zhǔn)之間紅外設(shè)備不能夠進(jìn)行紅外通信。為了使各種紅外設(shè)備能夠互相通信，在1993年，20多個(gè)大廠商發(fā)起成立了紅外數(shù)據(jù)協(xié)會(huì)（irda），統(tǒng)一了紅外通信的標(biāo)準(zhǔn)，也就是目前被廣泛采用的紅外數(shù)據(jù)通信協(xié)議及規(guī)范，也就所熟知的irda標(biāo)準(zhǔn)。自1993年

9、irda成立到今天，ird的會(huì)員已經(jīng)發(fā)展到150多個(gè)。irda的工業(yè)標(biāo)準(zhǔn)已經(jīng)獲得了廣泛的認(rèn)同和支持。已經(jīng)開(kāi)發(fā)出來(lái)的具備紅外通訊能力的設(shè)備已經(jīng)有一百多種。紅外模塊的年裝機(jī)數(shù)目已經(jīng)達(dá)到150000000套。盡管目前有同樣也屬于近距離無(wú)線通訊的藍(lán)牙技術(shù)，但紅外通訊技術(shù)憑借低廉的成本和廣泛兼容性的優(yōu)勢(shì)，紅外數(shù)據(jù)通訊在未來(lái)很長(zhǎng)一段時(shí)間內(nèi)仍舊會(huì)在短距離的無(wú)線數(shù)據(jù)通訊領(lǐng)域中扮演重要角色。1.3.3紅外收發(fā)器產(chǎn)品開(kāi)發(fā)趨勢(shì)對(duì)于各種各樣的紅外收發(fā)器產(chǎn)品，雖然傳輸速率、傳輸距離等特性不同，但紅外收發(fā)器產(chǎn)品一直朝著提高傳輸速率，增大傳輸距離，降低功率消耗，增大發(fā)射接收角度等方向發(fā)展。尤其是隨著技術(shù)發(fā)展和成熟，數(shù)據(jù)傳送

10、方式正朝著點(diǎn)對(duì)多點(diǎn)方向發(fā)展。所以紅外遙控收發(fā)器產(chǎn)品還有更加廣闊的發(fā)展前景。2 紅外通訊的知識(shí)21紅外線基礎(chǔ)知識(shí)2.1.1紅外線概述紅外線本質(zhì)上是一種電磁波。分析自然界中各種電磁波的組成可知，波譜是由 ：射線，射線、紫外線、可見(jiàn)光、紅外線、微波和無(wú)線電波組成。從構(gòu)成方式的觀點(diǎn)來(lái)看，它們之間似乎沒(méi)有關(guān)系，但如果按照它們的波長(zhǎng)依次進(jìn)行排列，我們會(huì)發(fā)現(xiàn)無(wú)處不在的可見(jiàn)光只占了整個(gè)波譜中0.38m-0.76m長(zhǎng)的這么一點(diǎn)范圍，而和可見(jiàn)光相鄰的紅外線 （包括遠(yuǎn)紅外線、中紅外線和近紅外線外）卻占了波譜中0.76m-1000m的一大段。其中，微米波長(zhǎng)范圍內(nèi)又包括了紫外光 、可見(jiàn)光、近紅外、中紅外 、遠(yuǎn)紅外、微波

11、。由上面的分析可知，紅外線是一種十分豐富的波譜資源，目前它己廣泛地應(yīng)用在生產(chǎn)、生活、軍事、醫(yī)療等多方面，例如紅外加熱、紅外線醫(yī)療、紅外線通信、紅外攝像、紅外遙控等。紅外線遙控只是紅外線眾多應(yīng)用中的一部分，目前廣泛應(yīng)用在家用電器中的彩色電視遙控器、錄像機(jī)遙控器、 vcd遙控器、高保真音響遙控器等，它使這些電器用具的控制變得十分簡(jiǎn)單方便。2.1.2紅外線特性紅外線介于可見(jiàn)光和微波之間，因此它具有相鄰波段的波的某些特性。在靠近紅外區(qū)的地方，它比鄰可見(jiàn)光，所以具有可見(jiàn)光的某些特性，如直線傳播、反射、折射、散射、衍射、可被某些物體吸收以及能夠通過(guò)透鏡將其聚焦等。在遠(yuǎn)離紅外區(qū)的地方，它比鄰微波區(qū)，因此它具

12、有微波的某些特性，如較強(qiáng)的透射能力和可以貫穿某些不透明物質(zhì)等。在自然界中，不論任何物體，也不論其自身是否發(fā)光 （指可見(jiàn)光）， 只要其溫度超過(guò)絕對(duì)零度 （-273），都會(huì)一刻不停地向周圍輻射紅外線。只不過(guò)是溫度較高的物體輻射較強(qiáng)的紅外線，溫度低的物體輻射較弱的紅外線。因此紅外線普遍存在于自然界，又叫做熱輻射線簡(jiǎn)稱熱輻射。紅外線攝像、紅外線夜市、熱電電紅外探測(cè)以及某些導(dǎo)彈的瞄準(zhǔn)等就是利用紅外線的這一特性工作的。紅外線和可見(jiàn)光比較起來(lái)的另一個(gè)特性是色彩的豐富多樣。因?yàn)榭梢?jiàn)光的最長(zhǎng)波長(zhǎng)是最短波長(zhǎng)的數(shù)倍（780nm-380nm），所以也叫作一倍頻程。而紅外線的最長(zhǎng)波長(zhǎng)是最短波長(zhǎng)的1倍，而紅外線的最長(zhǎng)波長(zhǎng)

13、是最短波長(zhǎng)的10倍，也就是10倍頻程。所以，如果可見(jiàn)光能用7色光表現(xiàn)，那么紅外線便能夠用70種顏色表現(xiàn)，展示了豐富的色彩。紅外線的透霧性能好，這是它的又一個(gè)特性。由于紅外線不可 見(jiàn),因此對(duì)環(huán)境色彩影響很小。紅外線的波長(zhǎng)遠(yuǎn)小于無(wú)線電波的波長(zhǎng) ,所以紅外線遙控不會(huì)影響鄰近的無(wú)線電設(shè)備。另外波長(zhǎng)小于 1.5m 的近紅外光 ,在透明大氣中的傳播特性要比可見(jiàn)光好得,并且由于它靠近可見(jiàn)光的紅光附近 ,他的直線傳播、反射、折射和被物質(zhì)吸收等物理特性與可見(jiàn)光非常類似。因此 ,它可以使用與可見(jiàn)光類似的聚焦透鏡等光學(xué)裝置。由于紅外線遙控不能像無(wú)線電遙控那樣可以穿過(guò)障礙去控制被控制對(duì)象 ,因此在設(shè)計(jì)家用電器的紅外線

14、遙控器時(shí) ,不必和無(wú)線電遙控一樣 ,給每一套(發(fā)射器和接收器)不同的遙控頻率或編碼(不然的話,就會(huì)干擾妨礙鄰居的家用電器) ,所有相似產(chǎn)品的紅外線遙控器 ,允許有相同的控制頻率或編碼 ,而不會(huì)出現(xiàn)遙控信號(hào)“串門”的問(wèn)題。紅外線遙控的普及帶來(lái)了很大的便利。紅外線不可見(jiàn) ,具有很好的隱蔽性和保密性 ,因此 ,被廣泛地應(yīng)用于防盜、警戒等安全保衛(wèi)裝置。紅外線遙控具有結(jié)構(gòu)簡(jiǎn)單、低成本、防干擾能力強(qiáng)、可靠的工作性能等一系列優(yōu)點(diǎn) ,特別適合近距離遙控、特別是室內(nèi)遙控的控制方式。2.1.3紅外發(fā)光二極管特性紅外線不可見(jiàn)，肉眼眼是無(wú)法察覺(jué)。電子技術(shù)中是利用紅外發(fā)光二極管（俗稱紅外發(fā)光二極管）來(lái)產(chǎn)生紅外線。紅外遙

15、控收發(fā)是利用近紅外光搭載波長(zhǎng)為 0.76m1. 5m的遙控指令。使用近紅外光作為遙控光源 ,是因?yàn)槟壳凹t外發(fā)光二極管與紅外接收器件(光敏二極管、三極管及光電池) 的發(fā)光與接受光峰值波長(zhǎng)一般為 0.8m0. 94m ,在鄰近紅外光的波段內(nèi) ,二者的光譜恰好重合 ,可以很好地匹配 ,可獲得比較高的傳輸效率和比較高的可靠性。通常用的紅外發(fā)光二極管，外形和發(fā)光二極管led相似，它的基本電路如圖2-2所示。如圖三極管作為賄賂開(kāi)關(guān)，當(dāng)基極加上驅(qū)動(dòng)信號(hào)，三極管飽和導(dǎo)通，紅外發(fā)光管d也正向?qū)üぷ?，發(fā)射紅外光（近紅外線約0.93m）。d的管端電壓降約1.4v，工作電流通常為1020ma。為了適應(yīng)不同的工作電壓

16、要求，d端回路中常串有限流電阻為紅外發(fā)光二極管限流。當(dāng)發(fā)射電路發(fā)射紅外線去控制相應(yīng)的受控裝置時(shí)，控制的距離正比于d的發(fā)射功率。為了增大紅外線的控制距離，紅外發(fā)光二極管 d應(yīng)工作于工作電流是脈動(dòng)的脈沖狀態(tài)。因?yàn)槊}動(dòng)光（調(diào)制光）的有效傳送距離與脈沖的最大峰值電流成正比例，所以只需盡量增大峰值電流ip，就可以加大紅外光的發(fā)射距離。ip增加是一種降低脈沖責(zé)任周期,這是壓縮脈沖寬度一些電視紅外遙控控制,其紅外發(fā)光的脈沖責(zé)任周期約1/4-1/3；對(duì)于一些電氣產(chǎn)品紅外遙控器，他們的占空比是1/10。減小脈沖占空比也可以使小功率紅外發(fā)光二極管的發(fā)射距離明顯增加。普通的紅外發(fā)光二極管，功率分為小功率（1mw10

17、mw）、中等功率（20mw50mw）和大功率（50mw100mw以上）三大類。在使用不同功率的紅外發(fā)光二極管時(shí)，應(yīng)配置相應(yīng)功率的驅(qū)動(dòng)電路。由圖2-2中指出的，只需在驅(qū)動(dòng)管上加上一定頻率的脈沖電壓，紅外發(fā)光二極管就能產(chǎn)生調(diào)制光。紅外線發(fā)射與接收有兩種方式，一種是直射式，第二種是反射式。直射式意思是發(fā)光管和接收管相對(duì)安置于發(fā)射與受控物的兩邊，中間有一定距離；反射式則是發(fā)光管和接收管并列一起，通常接收管始終無(wú)光照，只是在發(fā)光管發(fā)出的紅外光遇到反射物的時(shí)候，接收管收到反射的紅外線才工作。22紅外通信基本原理2.2.1紅外通信技術(shù)的工作原理紅外通信技術(shù)是利用波長(zhǎng)介于900nm-1000nm的紅外波為信息

18、的載體，通過(guò)紅外技術(shù)實(shí)現(xiàn)兩點(diǎn)間的近距離秘密信息交換和信息的傳送。紅外通信系統(tǒng)組成結(jié)構(gòu)包含:發(fā)射器，信道，接收器。發(fā)射器把信源發(fā)出的二進(jìn)制信號(hào)經(jīng)過(guò)高頻調(diào)制后，通過(guò)紅外發(fā)光二極管發(fā)送出去，接收器把接收的紅外高頻信號(hào)通過(guò)接收管接收后經(jīng)光電轉(zhuǎn)換再解調(diào)為原始信息的一種通信傳輸方式。再接收到原始信息后，可在接收部分連接驅(qū)動(dòng)電路以完成預(yù)期的各種功能。其中對(duì)信息的的編碼調(diào)制方式有脈寬調(diào)制（改變脈沖寬度調(diào)制信號(hào)pwm）與脈時(shí)調(diào)制（改變脈沖串之間時(shí)間間隔調(diào)制信號(hào)ppm）兩種。2.2.2紅外通信系統(tǒng)原理（1）發(fā)射器：當(dāng)前己有紅外無(wú)線數(shù)字通信系統(tǒng)的信息源為語(yǔ)音、數(shù)據(jù)、圖像等。它的工作方式按發(fā)射 器 接 收器的布局方式

19、不劃分為los方式(light-of-sight，內(nèi)部方式)，擴(kuò)散(diffuse)方式。los方式具有方向性，它有信道特性好等優(yōu)點(diǎn)，但有“影子”效應(yīng)，很難用于實(shí)現(xiàn)漫游功能的實(shí)現(xiàn)。漫游方式意味著非方向性，能夠易于實(shí)現(xiàn)漫游功能，但它的信道質(zhì)量有時(shí)比不上los方式。傳輸?shù)男盘?hào)需要經(jīng)數(shù)化(采樣量化)，通常需要進(jìn)行基帶調(diào)制、傳輸調(diào)制，有時(shí)還需要進(jìn)行信號(hào)源壓縮編碼，由上所得電信號(hào)驅(qū)動(dòng)光電變換電路完成紅外光信號(hào)發(fā)射。紅外無(wú)線數(shù)字通信系統(tǒng)的工作范圍與光發(fā)射器的功率空間分布、通信質(zhì)量有關(guān)系。一方面采用各種方法提高光發(fā)射功率，另外一方面采用空間分集、全息漫射片等使其光發(fā)射器的光功率在空間均勻分布。（2）信道：紅

20、外無(wú)線數(shù)字通信的信道通常指的是信號(hào)傳送器與接收器之間的空間。由于有自然光線及人工光源等背景干擾光信號(hào)的混入，信號(hào)源頭和端設(shè)備中電光學(xué)噪聲與干擾的影響，紅外無(wú)線數(shù)字通信在某些場(chǎng)合質(zhì)量較差，這個(gè)時(shí)候還需加入信道編碼。在紅外無(wú)線通信系統(tǒng)中，由于光信號(hào)的反射、散射及背景噪聲與干擾的影響等，紅外無(wú)線數(shù)字信道中存在多條干擾及噪聲，這是在提高信道質(zhì)量及進(jìn)行高速率應(yīng)用時(shí)需要解決的難題。紅外無(wú)線數(shù)字通信信道中經(jīng)常使用的光學(xué)元件主要有光學(xué)濾光片、聚光鏡等，其作用是:整形、濾波、變換視場(chǎng)、劃分頻段等；例如可用透鏡對(duì)發(fā)射光進(jìn)行聚焦，利用光學(xué)濾光片濾除散光，利用透鏡擴(kuò)大光接收機(jī)的接收范圍，還能利用光學(xué)元件進(jìn)行鏈路的頻分

21、復(fù)用等。在紅外無(wú)線通信信道中光噪聲包括:自然噪聲(陽(yáng)光)和人為干擾(熒光燈光)等，可以通過(guò)調(diào)制傳輸技術(shù)和加入濾光片等來(lái)解決。（3）接收器：為了去除噪聲及碼間干擾，信道中的光信號(hào)由光接收器來(lái)實(shí)現(xiàn)光電之間的變換。紅外無(wú)線數(shù)字通信系統(tǒng)接收器包括光接收機(jī)部分和后面的取樣、濾波、判決、量化、平衡和譯碼部分。紅外無(wú)線光接收機(jī)常采用電子放大器，并要求這些放大器帶寬大、增益高、噪聲低、干擾小、頻率響應(yīng)與信道脈沖響應(yīng)能夠匹配。為了去除低頻噪聲及人為干擾需要使用帶通濾波器。為了獲得大的光接收機(jī)工作范圍及瞬時(shí)視場(chǎng)，通常使用球形光學(xué)透鏡。2.2.3紅外通信特點(diǎn)無(wú)線通信包含多種方式，通過(guò)紅外光進(jìn)行通信具有如下特點(diǎn)：頻率

22、高，波長(zhǎng)短，所發(fā)射的能量集中在空間傳送時(shí)衰減小，能夠保證信號(hào)的有效傳送；紅外線不可見(jiàn)，機(jī)密性強(qiáng)，選擇它為信息載體，裝置工作時(shí)會(huì)有視覺(jué)污染，對(duì)人體無(wú)害；傳播范圍沒(méi)有限制，沒(méi)有頻率干擾問(wèn)題，同無(wú)線電波方式比較，不需要對(duì)頻譜資源問(wèn)題向相關(guān)部門進(jìn)行申請(qǐng)和登記，易于落實(shí)實(shí)施；具有良好的方向性，當(dāng)傳送設(shè)備和紅外接收端口排成直線，左右偏差在15度以內(nèi)時(shí)，紅外裝置工作效果最好；紅外線不能穿過(guò)或繞過(guò)人和物體，在進(jìn)行數(shù)據(jù)傳輸時(shí)，光路不能被阻斷；現(xiàn)今發(fā)射和接收紅外信號(hào)技術(shù)已經(jīng)比較成熟，有元件體積小，成本低，制作簡(jiǎn)單、易于產(chǎn)生和調(diào)制等優(yōu)勢(shì)。2.3紅外通信編碼基礎(chǔ)知識(shí)通常情況下，紅外遙控收發(fā)器將信號(hào)(二進(jìn)制脈沖)調(diào)制在

23、38khz的載波上，在經(jīng)過(guò)緩沖放大后送到紅外發(fā)光二極管，轉(zhuǎn)化為紅外光信號(hào)發(fā)射出去。二進(jìn)制脈沖的形式多樣，其最常用的是脈寬調(diào)變碼(脈沖寬度調(diào)制碼)和ppm碼(脈沖位置調(diào)制碼）。前者以寬脈沖為1，窄脈沖為0。后者脈沖寬度相同，但是碼位的寬度不一樣，碼位寬的代表著1，碼位窄的代表著0。遙控編碼脈沖信號(hào)（如ppm碼）一般由引導(dǎo)碼、系統(tǒng)碼、系統(tǒng)反碼、功能碼、功能反碼等組成。引導(dǎo)碼也叫初始碼，由寬度為9ms的高電平和寬度為4.5ms的低電平組成（不同的遙控系統(tǒng)在高低電平的寬度上有一定區(qū)別），遠(yuǎn)程編碼用來(lái)標(biāo)記脈沖信號(hào)的開(kāi)始。系統(tǒng)碼也稱為識(shí)別碼，它用來(lái)表示遙控系統(tǒng)的種類，以此區(qū)別其它遙控系統(tǒng)，防止各遙控系統(tǒng)的

24、錯(cuò)誤動(dòng)作。功能碼也叫腳本碼，它具有相應(yīng)的控制功能，接收機(jī)中的單片機(jī)可根據(jù)功能碼的數(shù)值完成各種操作。系統(tǒng)反碼與功能反碼分別是系統(tǒng)碼與功能碼的反碼，反碼的引入是為了能在接收端校對(duì)傳輸過(guò)程中是否產(chǎn)生了差錯(cuò)。為了改進(jìn)抗干擾性能表現(xiàn)和降低電源功耗，將上述的遙控編碼脈沖對(duì)頻率為38khz(周期26.3ms)的載波信號(hào)進(jìn)行脈幅調(diào)制(pam），經(jīng)過(guò)緩沖放大后，送到紅外發(fā)光管，將遙控信號(hào)發(fā)射出去。地址碼和數(shù)據(jù)碼都使用用寬度不同的脈沖來(lái)表示，兩個(gè)窄脈沖表示“0”；兩個(gè)寬脈沖表示“1”；一個(gè)窄脈沖和一個(gè)寬脈沖表示“f”，表達(dá)的是地址碼的“懸空”?？梢悦黠@看到，紅外遙控發(fā)射器發(fā)出的紅外編碼，上半部分是一組一組的字碼，

25、每組字碼之間被同步碼隔開(kāi)。下半部分是被放大的一組字碼：一個(gè)字碼由12位ad碼（地址碼和數(shù)據(jù)碼，如8位地址碼加4位數(shù)據(jù)碼）組成，每個(gè)ad位用兩個(gè)脈沖來(lái)表示：兩個(gè)窄脈沖意思是“0”；兩個(gè)寬脈沖意思是“1”；一個(gè)窄脈沖和一個(gè)寬脈沖意思是“f”即地址碼的“懸空”。pt2262每次發(fā)射至少4組字碼，pt2272只有連續(xù)兩次檢測(cè)到相同的地址碼加數(shù)據(jù)碼才會(huì)把數(shù)據(jù)碼中的“1”進(jìn)行驅(qū)動(dòng)相應(yīng)的數(shù)據(jù)輸出端成為高電平并驅(qū)動(dòng)vt端同步成為高電平。infrared remote control systemabstract：red outside data correspondence the technique be

26、currently within the scope of world drive extensive usage of a kind of wireless conjunction technique, drive numerous hardware and software platform support. red outside the transceiver product have cost low, small scaled turn, the baud rate be quick, point to point ssl, be free from electromagnetis

27、m thousand raos etc. characteristics, can realization information at dissimilarity of the product fast, convenience, safely exchange and transmission, at short distance wireless deliver aspect to own very obvious of advantage .along with red outside the data deliver a technique more and more mature,

28、 the cost descend, red outside the transceiver necessarily will get at the short distance communication realm more extensive of application.the purpose that design this system is transmit customers operation information with infrared rays for transmit media, then demodulate original signal with rece

29、ive circuit. it use coding chip to modulate signal and use decoding chip to demodulate signal. the coding chip is pt2262 and decoding chip is pt2272. both chips are made in taiwan. main work principle is that we provide to input the information for the pt2262 with coding keyboard. the input informat

30、ion was coded by pt2262 and loading to high frequent load wave whose frequent is 38 khz, then modulate infrared transmit dioxide and radiate space outside when it attian enough power. the receive circuit receive the signal and demodulate original information. the original signal was decoded by pt227

31、2, so as to drive some circuit to accomplish customers operation demand.keywords: infrared dray；code；decoding；lm386；red outside transceiver1 introduction1.1 research the background and significance infrared data communication technology is the world wide use of a wireless connection technology, by t

32、he many hardware and software platforms supported. is a data through electrical pulses and infrared optical pulse switch between the wireless data transceiver technology.infrared transceiver products with low cost, small, fast transmission rate, the point-to-point transmission security, not subject

33、to electromagnetic interference and other characteristics that can be achieved between the different products, rapid, convenient and safe exchange and transmission, in short distance wireless transmission have a very distinct advantage.infrared transceiver products in the portable product of a great

34、 role. at present, the worlds 150 million piece of equipment used infrared technology in electronic products and industrial equipment. medical equipment and other fields widely used. for example, 95% of the notebook computers on the installation of infrared transceiver interface the majority of the

35、cell phone is also the allocation of infrared transceiver interface. with the exchange of quantitative data, infrared data communications will enable cell phone data transmission more convenient. with infrared data transmission technology matures, perfect, low costs, infrared transceiver in short di

36、stance communications will be more widely applied. this chapter first describes the infrared transceiver ic design issues to the background and significance. then briefed the infrared data communications technology features and applications, and infrared transceiver product characteristics, domestic

37、 and international situation and development trend of the last under infrared remote transceiver system in practical application to establish a task of design orientation.1.2 infrared remote control transceiver systeminfrared remote control system is divided into single-channel and multi-channel rem

38、ote control. only a command signal transmission channel, called single-channel remote control system; with more than two instructions signal transmission channel known as a multi-channel remote control system. relatively simple single-channel remote control, in general, only a launcher directive key

39、 receivers and only one circuit implementation. while in the receiving circuit to add more stable memory circuits that can be activated commands to launch a number of key, so that the receiver circuit multistable memory circuit repeatedly to change the state, to realize many of the functional contro

40、l, but such a state of change is the order. if we are to achieve an arbitrary control, resort to the use of multi-channel remote control system. multi-channel remote control can be realized by the object of arbitrary multi-function remote control. as for the choice of several routes and what control

41、 methods, according to the actual situation (such as object, operational requirements and cost accounting, etc.) to decide. general infrared remote transceiver system by infrared remote control transmitter signal coding, infrared remote control signal receivers and decoders (or decoder chip mcu) and

42、 the external circuit consisting of three parts. signal transmitter remote control code used to generate pulses of infrared emission-driven output infrared remote control signal, receiver completion of the remote control signal amplification and detection, plastic and demodulation encoding pulse. in

43、frared remote control coded pulse is going to obtain a continuous serial binary code, and for most of the infrared transceiver system, this serial code as micro-controller of the remote control input signals from the internal cpu completion of the remote control instruction decoder, on the other inf

44、rared remote control transceivers, the designers of electronic products, the internal micro-controller of the remote control decoder directive is not accessible. therefore, people are using infrared encoder / decoder chip and microcontroller developed various generic infrared remote transceiver syst

45、em, in various equipment infrared signals between the transceiver.remote transceiver system generally transmitters and receivers is composed of two parts. launchers from the general direction keys, coded instructions circuit modulation circuit, driving circuit, firing circuit of several parts. when

46、pressed a key, the directive coding circuit, in the corresponding instructions encoded signal, the encoder signal to the carrier modulation, driven by the power amplifier circuit after circuit fired from the field after firing instructions coded modulation signals. general receiver by the receiving

47、circuit, the amplifier circuit, demodulation circuits, instruction decoder circuit, driving circuit, circuit implementation of several parts. receiving circuit will launch vehicles have been coded modulation signal receiving instructions from, and to enlarge evacuation demodulation circuit. demodula

48、tion circuit will have the coding modulation signal demodulation, namely, reduction of signal coding. the instruction decoder to the encoder signal decoding, driven by the final circuit to drive the implementation of various instructions circuit to control the operation.1.3 infrared remote control t

49、ransceiver product profiles1.3.1 infrared remote control transceiver product structure and type 待添加的隱藏文字內(nèi)容2currently infrared transceiver in accordance with the mode of transmission rate and can be divided into four categories : serial mode, the highest rate of 115.2 kbps; medium-speed model : the h

50、ighest rate of 0.567 mbps and 1.152mbps; high-speed mode : the maximum rate of 16 mbps.also according to the size chip power consumption can be divided into low-power consumption and standard two categories, low-power type normally used 3 v power supply, transmission distance closer to about 0 - 30c

51、m, which is commonly used standard 5v power supply, transmission distance away at least 1m above.1.3.2 infrared remote control transmitters of the status quo at home and abroadinfrared communication technology in the development stage and there are several infrared communication standards, between d

52、ifferent standards for infrared equipment can not infrared communication. to have all the infrared equipment to interoperability in 1993 by more than 20 large manufacturers initiated the establishment of an infrared data association (irda) unified the infrared communication standards , which is curr

53、ently widely used in infrared data communication protocols and standards, also known as the irda standard.since 1993 irda since the establishment of the infrared data association members have developed to more than 150. irda standards of the industry has been widely recognized and supported. has bee

54、n developed with the infrared communications equipment have been as many as 100 species. ir module, installed capacity has reached 150 million sets. although there is also a short distance wireless bluetooth technology, but in infrared communication technology low cost and broad compatibility advant

55、ages, infrared data communication in the future will still be a very long time inherent short-range wireless data communications fields play an important role.1.3.3 infrared transceiver product development trendin various infrared transceiver products, although the transmission rate, transmission di

56、stance and other characteristics, but infrared transceiver products has been towards improving the transmission rate, increase the transmission distance and lower power consumption, expanding launch reception angle of development. in particular, as the technology development and maturity, the means

57、of transmission is moving in the direction of point-to-multipoint. therefore infrared remote control transceiver products have broader prospects for development.2 infrared communication of knowledge2.1 infrared ray foundation knowledge2.1.1 infrared outlined infrared is actually a kind of electromag

58、netic wave. from the analysis of various natural component of the electromagnetic wave reflected spectrum is :-ray, x-ray, ultraviolet, visible, infrared, microwave and radio wave. from the viewpoint of form, and they did not seem to, but if the wavelength in descending order, and we will find him all the only visible light spectrum of the entire 0.38 m - 0.76m so long little area, and adjacent to the visible light and infrared (including the far infrared, mid-infrared and near infrared foreign) accounts for the spectrum of 0.76 m - 1000m of a major. which micron waveleng