紅外線遙控系統(tǒng)外文翻譯

1、<p><b>　　譯 文</b></p><p>　　學(xué) 院： 機(jī)械工程學(xué)院 </p><p>　　專 業(yè)： 機(jī)械電子工程 </p><p>　　學(xué) 號： 0840206126 </p><p>　　姓 名： 楊武俊 </p>&

2、lt;p>　　指導(dǎo)教師： 沈澤洪 </p><p>　　江 蘇 科 技 大 學(xué)</p><p>　　2012年5 月 10 日</p><p><b>　　紅外線遙控系統(tǒng)</b></p><p>　　內(nèi)容摘要：目前在世界范圍內(nèi)被廣泛使用的一種無線連接技術(shù)是紅外線數(shù)據(jù)通信技術(shù)，其得到許多的軟硬件

3、平臺支持。紅外收發(fā)器產(chǎn)品的特點有成本低，尺寸小，數(shù)據(jù)傳輸速度快，點對點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，在近距離無線傳輸方面有著相當(dāng)明顯的優(yōu)勢。紅外遙控收發(fā)系統(tǒng)具有很強(qiáng)的實用意義，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)域必將得到更廣泛的應(yīng)用。</p><p>　　設(shè)計本系統(tǒng)的目的是，用

4、紅外線作為傳輸載體來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，主要使用編碼芯片和解碼芯片對信號進(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)射的信號并解調(diào)出原始信息。原始信號由PT2272進(jìn)行解碼，以此驅(qū)動

5、對應(yīng)的電路完成用戶的操作請求。</p><p>　　關(guān)鍵字：紅外線；編碼；譯碼；LM386；紅外收發(fā)器。</p><p><b>　　1 簡介</b></p><p>　　1．1 研究的背景及意義</p><p>　　紅外數(shù)據(jù)通信技術(shù)是目前世界范圍內(nèi)被廣泛采用的的一種無線連接技術(shù)，得到廣大的硬件和軟件平臺支持。其屬于一種

6、通過數(shù)據(jù)電脈沖和紅外光脈沖之間進(jìn)行轉(zhuǎn)換從而實現(xiàn)無線數(shù)據(jù)接受和發(fā)送的技術(shù)。</p><p>　　紅外收發(fā)器產(chǎn)品的特點有成本低，尺寸小，數(shù)據(jù)傳輸速度快，點對點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，在近距離無線傳輸方面有著相當(dāng)明顯的優(yōu)勢。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)

7、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)傳輸越來越方便。隨著紅外數(shù)據(jù)傳輸技術(shù)越來越成熟、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。</p><p>　　本節(jié)首先闡明了紅外線收發(fā)集成電路設(shè)計課題的背景和重要性，進(jìn)而簡明扼要地介紹了紅外數(shù)據(jù)通訊技術(shù)的特點和應(yīng)用方向以及紅外收發(fā)器產(chǎn)品的特點

8、、國內(nèi)外現(xiàn)狀和發(fā)展趨勢，最后根據(jù)紅外遙控收發(fā)系統(tǒng)的實際應(yīng)用性確定了課題的設(shè)計目的。</p><p>　　1．2 紅外遙控收發(fā)系統(tǒng)</p><p>　　紅外遙控系統(tǒng)被劃分為單頻道遙控和多頻道遙控。只有一個指令信號傳輸通道的稱為單通道遙控系統(tǒng)，具有兩個以上指令信號傳輸通道的稱為多通道遙控系統(tǒng)。相對而言，單通道遙控一般來說其發(fā)射器僅有一個指令鍵 ,接收器也只有一個執(zhí)行電路。雖然在接收電路中加入可

9、以根據(jù)按動發(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 ,實現(xiàn)多項功能的控制 ,然而這種狀態(tài)的改變是順序進(jìn)行的。如果我們要實現(xiàn)一項自由隨機(jī)控制 ,需要依靠采用多通道遙控系統(tǒng)來實現(xiàn)。多通道遙控可以實現(xiàn)對被控對象的多功能任意遙控。根據(jù)具體實際情況(如被控對象、操作要求及成本核算等)來決定選用幾個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)由紅外遙控信號編碼發(fā)送器、紅外遙控信號接收器和解碼器（解碼芯

10、片MCU）及其外部電路等三個部分組成。信號發(fā)送器用來產(chǎn)生紅外遙控編碼脈沖，驅(qū)動紅外發(fā)射管輸出紅外遙控信號，而接收器則需要完成對信號的放大、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，完成對遙控指令的解碼是在CPU內(nèi)部，</p><p>　　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

11、令編碼回路、激勵電路、驅(qū)動電路、啟動電路等幾部分組合而成。當(dāng)某鍵被按下時 ,指令編碼回路產(chǎn)生對應(yīng)的指令編碼信號 ,編碼指令信號對載波進(jìn)行調(diào)制 ,通過驅(qū)動電路進(jìn)行功率放大之后，通過發(fā)射電路向外發(fā)射已經(jīng)過調(diào)制的指令編碼信號。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)動電路、啟動執(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 ,并對其進(jìn)行放大后送到解調(diào)電路。解調(diào)電路將送來的已調(diào)制的編碼信號進(jìn)行解調(diào) ,進(jìn)

12、而還原為編碼信號。指令譯碼器將編碼指令信號進(jìn)行譯碼 ,最后由驅(qū)動電路來驅(qū)動執(zhí)行電路去實現(xiàn)各種各樣的指令的操作控制。</p><p>　　1．3 紅外遙控收發(fā)器產(chǎn)品介紹</p><p>　　1.3.1紅外遙控收發(fā)器產(chǎn)品的結(jié)構(gòu)和類型</p><p>　　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；中速率模式：最高傳輸

13、速率為0.567Mbps和1.152Mbps；高速率模式：最高傳輸速率為16Mbps。</p><p>　　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。</p><p>　　1.3.2國內(nèi)外紅外遙控收發(fā)器現(xiàn)狀</p><p>　　在紅外通信

14、技術(shù)的早期發(fā)展階段，有幾個紅外通信標(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多個大廠商發(fā)起成立了紅外數(shù)據(jù)協(xié)會（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)。</p><p>　　自1993年IRDA成立到今天，IRD的會員已經(jīng)發(fā)展到150多個。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)開發(fā)出

15、來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，紅外數(shù)據(jù)通訊在未來很長一段時間內(nèi)仍舊會在短距離的無線數(shù)據(jù)通訊領(lǐng)域中扮演重要角色。</p><p>　　1.3.3紅外收發(fā)器產(chǎn)品開發(fā)趨勢</p><p>　　對于各種各樣的紅外收發(fā)器產(chǎn)品，雖然傳輸速率、傳輸距

16、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)傳送方式正朝著點對多點方向發(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。</p><p><b>　　2 紅外通訊的知識</b></p><p>　　2．1紅外線基礎(chǔ)知識</p><p>　　2.1.1

17、紅外線概述</p><p>　　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，ｘ射線、紫外線、可見光、紅外線、微波和無線電波組成。從構(gòu)成方式的觀點來看，它們之間似乎沒有關(guān)系，但如果按照它們的波長依次進(jìn)行排列，我們會發(fā)現(xiàn)無處不在的可見光只占了整個波譜中0.38μm-0.76μm長的這么一點范圍，而和可見光相鄰的紅外線 （包括遠(yuǎn)紅外線、中紅外線和近紅外線外）卻占了波譜中0.76μm-1

18、000μm的一大段。其中，微米波長范圍內(nèi)又包括了紫外光 、可見光、近紅外、中紅外 、遠(yuǎn)紅外、微波。</p><p>　　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

19、使這些電器用具的控制變得十分簡單方便。</p><p>　　2.1.2紅外線特性</p><p>　　紅外線介于可見光和微波之間，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，它比鄰可見光，所以具有可見光的某些特性，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)，因此它具有微波的某些特性，如較強(qiáng)的透射能力和可以貫穿某

20、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 （指可見光）， 只要其溫度超過絕對零度 （-273℃），都會一刻不停地向周圍輻射紅外線。只不過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，又叫做熱輻射線簡稱熱輻射。紅外線攝像、紅外線夜市、熱電電紅外探測以及某些導(dǎo)彈的瞄準(zhǔn)等就是利用紅外線的這一特性工作的。</p><p>　　紅外線和可見光比較起來的另一

21、個特性是色彩的豐富多樣。因為可見光的最長波長是最短波長的數(shù)倍（780nm-380nm），所以也叫作一倍頻程。而紅外線的最長波長是最短波長的1倍，而紅外線的最長波長是最短波長的10倍，也就是10倍頻程。所以，如果可見光能用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，這是它的又一個特性。</p><p>　　由于紅外線不可 見,因此對環(huán)境色彩影響很小。紅外線的波長遠(yuǎn)小于無線電波

22、的波長 ,所以紅外線遙控不會影響鄰近的無線電設(shè)備。另外波長小于 1.5μm 的近紅外光 ,在透明大氣中的傳播特性要比可見光好得,并且由于它靠近可見光的紅光附近 ,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光非常類似。因此 ,它可以使用與可見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線電遙控那樣可以穿過障礙去控制被控制對象 ,因此在設(shè)計家用電器的紅外線遙控器時 ,不必和無線電遙控一樣 ,給每一套(發(fā)射器和接收器)不同的遙

23、控頻率或編碼(不然的話,就會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 ,而不會出現(xiàn)遙控信號“串門”的問題。紅外線遙控的普及帶來了很大的便利。紅外線不可見 ,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 ,特別適合近距離遙控、特別是室內(nèi)遙控的控制方式。</p><p>

24、　　2.1.3紅外發(fā)光二極管特性</p><p>　　紅外線不可見，肉眼眼是無法察覺。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）來產(chǎn)生紅外線。紅外遙控收發(fā)是利用近紅外光搭載波長為 0.76μm～1. 5μm的遙控指令。使用近紅外光作為遙控光源 ,是因為目前紅外發(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一般為 0.8μm～0. 94μm ,在鄰近紅外光的波段內(nèi) ,二者的

25、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。</p><p>　　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關(guān)，當(dāng)基極加上驅(qū)動信號，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0.93μm）。D的管端電壓降約1.4V，工作電流通常為10－20mA。為了適應(yīng)不同的工作電壓要求，D端回路中常串有限流電阻為紅外

26、發(fā)光二極管限流。</p><p>　　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，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的脈沖狀態(tài)。因為脈動光（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τ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

27、-1/3；對于一些電氣產(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（1mW—10mW）、中等功率（20mW－50mW）和大功率（50mW－100mW以上）三大類。在使用不同功率的紅外發(fā)光二極管時，應(yīng)配置相應(yīng)功率的驅(qū)動電路。由圖2-2中指出的，只需在驅(qū)動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。</p><p&

28、gt;　　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，通常接收管始終無光照，只是在發(fā)光管發(fā)出的紅外光遇到反射物的時候，接收管收到反射的紅外線才工作。</p><p>　　2．2紅外通信基本原理</p><p>　　2.2.1紅外通信技術(shù)的工作原理</p>&

29、lt;p>　　紅外通信技術(shù)是利用波長介于900nm-1000nm的紅外波為信息的載體，通過紅外技術(shù)實現(xiàn)兩點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。</p><p>　　發(fā)射器把信源發(fā)出的二進(jìn)制信號經(jīng)過高頻調(diào)制后，通過紅外發(fā)光二極管發(fā)送出去，接收器把接收的紅外高頻信號通過接收管接收后經(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)

30、動電路以完成預(yù)期的各種功能。其中對信息的的編碼調(diào)制方式有脈寬調(diào)制（改變脈沖寬度調(diào)制信號PWM）與脈時調(diào)制（改變脈沖串之間時間間隔調(diào)制信號PPM）兩種。</p><p>　　2.2.2紅外通信系統(tǒng)原理</p><p>　?。?）發(fā)射器：當(dāng)前己有紅外無線數(shù)字通信系統(tǒng)的信息源為語音、數(shù)據(jù)、圖像等。它的工作方式按發(fā)射 器 接 收器的布局方式不劃分為LOS方式(Light-of-Sight，內(nèi)部方式

31、)，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，但有“影子”效應(yīng)，很難用于實現(xiàn)漫游功能的實現(xiàn)。漫游方式意味著非方向性，能夠易于實現(xiàn)漫游功能，但它的信道質(zhì)量有時比不上LOS方式。傳輸?shù)男盘栃枰?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，有時還需要進(jìn)行信號源壓縮編碼，由上所得電信號驅(qū)動光電變換電路完成紅外光信號發(fā)射。紅外無線數(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

32、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。</p><p>　　（2）信道：紅外無線數(shù)字通信的信道通常指的是信號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的混入，信號源頭和端設(shè)備中電光學(xué)噪聲與干擾的影響，紅外無線數(shù)字通信在某些場合質(zhì)量較差，這個時候還需加入信道編碼。在紅外無線通信系統(tǒng)中，由于光信號的反射、散射及背景噪聲與干擾的影響等，紅外無線數(shù)

33、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)用時需要解決的難題。紅外無線數(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、劃分頻段等；例如可用透鏡對發(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)行鏈路的頻分復(fù)用等。在紅外無線通信信道中光噪聲包括:自然噪聲(陽光)和人為干擾(熒光燈光)等，可以通過調(diào)制傳輸技術(shù)和加入濾光片等來解決。<

34、/p><p>　?。?）接收器：為了去除噪聲及碼間干擾，信道中的光信號由光接收器來實現(xiàn)光電之間的變換。紅外無線數(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)工作范圍及瞬時視場，通常使用球形光學(xué)透鏡。<

35、;/p><p>　　2.2.3紅外通信特點</p><p>　　無線通信包含多種方式，通過紅外光進(jìn)行通信具有如下特點：</p><p>　　·頻率高，波長短，所發(fā)射的能量集中在空間傳送時衰減小，能夠保證信號的有效傳送；</p><p>　　·紅外線不可見，機(jī)密性強(qiáng)，選擇它為信息載體，裝置工作時會有視覺污染，對人體無害；<

36、/p><p>　　·傳播范圍沒有限制，沒有頻率干擾問題，同無線電波方式比較，不需要對頻譜資源問題向相關(guān)部門進(jìn)行申請和登記，易于落實實施；</p><p>　　·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，紅外裝置工作效果最好；</p><p>　　·紅外線不能穿過或繞過人和物體，在進(jìn)行數(shù)據(jù)傳輸時，光路不能被阻

37、斷；</p><p>　　·現(xiàn)今發(fā)射和接收紅外信號技術(shù)已經(jīng)比較成熟，有元件體積小，成本低，制作簡單、易于產(chǎn)生和調(diào)制等優(yōu)勢。</p><p>　　2.3紅外通信編碼基礎(chǔ)知識</p><p>　　通常情況下，紅外遙控收發(fā)器將信號(二進(jìn)制脈沖)調(diào)制在38KHz的載波上，在經(jīng)過緩沖放大后送到紅外發(fā)光二極管，轉(zhuǎn)化為紅外光信號發(fā)射出去。二進(jìn)制脈沖的形式多樣，其最常用的

38、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。</p><p>　　遙控編碼脈沖信號（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)程編碼用來標(biāo)記脈沖信號

39、的開始。系統(tǒng)碼也稱為識別碼，它用來表示遙控系統(tǒng)的種類，以此區(qū)別其它遙控系統(tǒng)，防止各遙控系統(tǒng)的錯誤動作。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傳輸過程中是否產(chǎn)生了差錯。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頻率為38KHz(周期26.3ms)的載波信號進(jìn)行脈幅調(diào)制(PAM），經(jīng)過緩沖放大后，送

40、到紅外發(fā)光管，將遙控信號發(fā)射出去。</p><p>　　地址碼和數(shù)據(jù)碼都使用用寬度不同的脈沖來表示，兩個窄脈沖表示“0”；兩個寬脈沖表示“1”；一個窄脈沖和一個寬脈沖表示“F”，表達(dá)的是地址碼的“懸空”。</p><p>　　可以明顯看到，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，每組字碼之間被同步碼隔開。下半部分是被放大的一組字碼：一個字碼由12位AD碼（地址碼和數(shù)據(jù)碼，如

41、8位地址碼加4位數(shù)據(jù)碼）組成，每個AD位用兩個脈沖來表示：兩個窄脈沖意思是“0”；兩個寬脈沖意思是“1”；一個窄脈沖和一個寬脈沖意思是“F”即地址碼的“懸空”。</p><p>　　PT2262每次發(fā)射至少4組字碼，PT2272只有連續(xù)兩次檢測到相同的地址碼加數(shù)據(jù)碼才會把數(shù)據(jù)碼中的“1”進(jìn)行驅(qū)動相應(yīng)的數(shù)據(jù)輸出端成為高電平并驅(qū)動VT端同步成為高電平。</p><p>　　Infrared R

42、emote Control System</p><p>　　Abstract：Red outside data correspondence the technique be currently within the scope of world drive extensive usage of a kind of wireless conjunction technique, drive numerous

43、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 electromagnetism thousand Raos etc. characteristics,

44、can realization information at dissimilarity of the product fast, convenience, safely exchange and tran</p><p>　　The purpose that design this system is transmit customer’s operation information with infrared

45、 rays for transmit media, then demodulate original signal with receive 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. Bot

46、h chips are made in Taiwan. Main work principle is that we provide to input the information for the PT2262 with coding keyboard. The input information was coded by PT2262 and loading to </p><p>　　Keywords: I

47、nfrared dray；Code；Decoding；LM386；Red outside transceiver</p><p>　　1 Introduction</p><p>　　1.1 research the background and significance </p><p>　　Infrared Data Communication Technolo

48、gy is the world wide use of a wireless connection technology, by the many hardware and software platforms supported. Is a data through electrical pulses and infrared optical pulse switch between the wireless data transce

49、iver technology.</p><p>　　Infrared transceiver products with low cost, small, fast transmission rate, the point-to-point transmission security, not subject to electromagnetic interference and other character

50、istics 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.</p><p>　　Infrared tra

51、nsceiver products in the portable product of a great role. At present, the world's 150 million piece of equipment used infrared technology in electronic products and industrial equipment. medical equipment and other

52、fields widely used. For example, 95% of the notebook computers on the installation of infrared transceiver interface the majority of the cell phone is also the allocation of infrared transceiver interface. With the excha

53、nge of quantitative data, infrared data communicatio</p><p>　　This chapter first describes the infrared transceiver IC design issues to the background and significance. then briefed the infrared data communi

54、cations technology features and applications, and infrared transceiver product characteristics, domestic and international situation and development trend of the last under infrared remote transceiver system in practical

55、 application to establish a task of design orientation.</p><p>　　1.2 Infrared Remote Control Transceiver System</p><p>　　Infrared remote control system is divided into single-channel and multi-c

56、hannel remote 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.

57、Relatively simple single-channel remote control, in general, only a launcher directive Key receivers and only one circuit implementation. While in the receiving circuit to add more stable memory circuits tha</p>&

58、lt;p>　　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

59、 of several parts. When 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 fir

60、ed from the field after firing instructions coded modulation signals. </p><p>　　1.3 infrared remote control transceiver product profiles</p><p>　　1.3.1 infrared remote control transceiver produc

61、t structure and type </p><p>　　Currently 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-sp

62、eed model : the highest rate of 0.567 Mbps and 1.152Mbps; High-speed mode : The maximum rate of 16 Mbps.</p><p>　　Also according to the size chip power consumption can be divided into low-power consumption a

63、nd standard two categories, low-power type normally used 3 V power supply, transmission distance closer to about 0 - 30cm, which is commonly used standard 5V power supply, transmission distance away at least 1m above.<

64、;/p><p>　　1.3.2 infrared remote control transmitters of the status quo at home and abroad</p><p>　　Infrared communication technology in the development stage and there are several infrared communic

65、ation standards, between different 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 establi

66、shment of an Infrared Data Association (IRDA) unified the infrared communication standards , which is currently widely used in infrared data communication protocols and standards, al</p><p>　　Since 1993 IRDA

67、 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 been developed with the infrared communicati

68、ons 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

69、low cost and broad compatibility advantages, </p><p>　　1.3.3 Infrared Transceiver product development trend</p><p>　　In various infrared transceiver products, although the transmission rate, tra

70、nsmission distance 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

71、 angle of development. In particular, as the technology development and maturity, the means of transmission is moving in the direction of point-to-multipoint. Therefore infrared remote control transceive</p><p

72、>　　2 Infrared communication of knowledge</p><p>　　2.1 infrared ray foundation knowledge</p><p>　　2.1.1 infrared outlined </p><p>　　Infrared is actually a kind of electromagnetic

73、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

74、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 μm - 0.76μm so long little area, and adjacent to the visible light and infrared (including t

75、he far infrar</p><p>　　From the above analysis shows that infrared is a very rich spectrum resources, it currently has in production, life, military, medical, and other aspects have been widely used, such as

76、 infrared heating, medical infrared, infrared communication, infrared camera, infrared remote control, and so on. Infrared remote control is the many applications of infrared part of the current household appliances wide

77、ly used in TV remote control, VCR remote control, VCD remote control, high-fidelity audio remote</p><p>　　2.1.2 infrared properties</p><p>　　Infrared lies between visible light and microwave a w

78、ave, it is with certain clinical characteristics of the wave. In the near-infrared, visible light and its adjacent, it is visible in certain characteristics, such as straight-line transmission, reflection, refraction, sc

79、attering, diffraction, can be certain objects and can be absorbed through the lens of their focusing. In the far-infrared region, owing to its neighboring microwave, it has some characteristics of microwave, If a strong

80、penetra</p><p>　　Infrared and visible light compared to another characteristic of a variety of colors. As the longest wavelength of visible light is a wavelength of the shortest times (780 nm-380 nm), So is

81、called an octave. And infrared wavelength is the longest shortest wavelength of a times, and the longest wavelength infrared is the shortest wavelength of 10 times, that is, 10 octave. Therefore, if visible light can be

82、expressed as seven colors, infrared may performance 70 colors, showing the rich colors. In</p><p>　　Because not visible to the infrared, it has little effect on the environment. By the wave infrared rays tha

83、n the long wavelength radio waves, infrared remote control will not affect the nearby radio equipment. Another wavelength of less than 1.5μm near infrared light, transparent atmosphere in the visible light transmission c

84、haracteristics much better than, because it close to the visible edge of the red light, linear transmission, reflection, refraction and absorption material and the physical </p><p>　　2.1.3 infrared diode cha

85、racteristics </p><p>　　Infrared is not visible, people here are not aware of. Electronic technology is used infrared light emitting diode (also known as the IR emission diode) to generate infrared. Infrared

86、remote control transceiver is using near-infrared transmission control instructions 0.76μm wavelength of ~ 1. 5μm. Near-infrared remote control as a light source, because there infrared light emitting diodes and infrared

87、 receiving device (photodiode. Transistor and PV) and the luminescence peak wavelength of light </p><p>　　When the circuit diagram of the infrared emission control corresponding to the controlled device, the

88、 control of the distance and D is proportional to the transmitting power. In order to increase the distance of infrared control, infrared diode D should work on the pulse state that work is the lifeblood of current. Beca

89、use pulse light (optical modulation) the effective transmission distance and pulse is proportional to the peak current, only maximize peak current Ip, will increase the infrared d</p><p>　　Infrared transmitt

90、er and receiver in the way the two kinds of straight, and the second is reflective. Luminescence pointed straight pipe and tube receiver placed in a relatively controlled and fired on the two ends, a certain distance awa

91、y from the middle; Reflective means luminescent tube and pipe parallel with the receiving peacetime, without always receiving tube light, luminescence only in possession of the infrared light reflected from encountered,

92、the receiving tube received from the refle</p><p>　　2.2 infrared communication basic tenets </p><p>　　2.2.1 infrared communication Principle </p><p>　　Communication is the use of in

93、frared wavelength of 900 nm-infrared waves from 1000 to serve as an information carrier, through infrared technology between the two close communication and confidentiality of information transmitted. Infrared communicat

94、ion system structure include : part launcher, channel, the receiver part.</p><p>　　Launcher source letter issued after the binary signal from the high-frequency modulated infrared LED sent, receiving device

95、regard the reception of high-frequency signals from the infrared receiver tube after receiving further demodulation photoelectric conversion of the original information of a mass communication lose way. Afterwards the fo

96、rmer Information received after receiving part of the drive circuit connected to the expected completion of the various functions. To which the modulation c</p><p>　　2.2.2 infrared communication system eleme

97、nts</p><p>　　(1) Launches : Currently there is a infrared wireless digital communications system sources of information including voice, data, images. Its methods of work for the launch of the receiver can b

98、e divided into different layout LOS way (Light-of-Sight , intracardiac way), diffuse (diffuse) mode. LOS way directional, it has good channel characteristics such advantages, but the existence of a "shadow" eff

99、ect. difficult to achieve roaming function. Roaming means the main features of non-directional, </p><p>　　(2) Channel : infrared wireless digital communication channel refers to the transmitters and receiver

100、s in the space between. Due to natural light and artificial light sources such as light signals in the context of intervention, and the source - Electrical Equipment, The optical noise and disturbances, infrared wireless