【正文】 pressure drop of about V and the current general for 1020mA. To adapt to the working voltage of the D loop resistance often as a series of infrared diode current limit resistance. When the circuit diagram of the infrared emission control corresponding to the controlled device, the 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. Because 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 distance. Ip increase is a way to reduce the pulse duty cycle, that is pressed pulse width τ some TV infrared remote control, its infrared luminescence of the pulse duty cycle of about 1/41/3。 with more than two instructions signal transmission channel known as a multichannel remote control system. Relatively simple singlechannel 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 that can be activated mands 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 control, But such a state of change is the order. If we are to achieve an arbitrary control, resort to the use of multichannel remote control system. Multichannel remote control can be realized by the object of arbitrary multifunction remote control. As for the choice of several routes and what control 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 the external circuit consisting of three parts. Signal transmitter remote control code used to generate pulses of infrared emissiondriven output infrared remote control signal, receiver pletion of the remote control signal amplification and detection, plastic and demodulation encoding pulse. Infrared 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 microcontroller of the remote control input signals from the internal CPU pletion of the remote control instruction decoder, on the other infrared remote control transceivers, the designers of electronic products, The internal microcontroller 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 system, In various equipment infrared signals between the transceiver. Remote transceiver system generally transmitters and receivers is posed of two parts. Launchers from the general direction keys, coded instructions circuit modulation circuit, driving circuit, firing circuit 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 fired from the field after firing instructions coded modulation signals. General receiver by the receiving 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. Demodulation 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. infrared remote control transceiver product profiles infrared remote control transceiver product structure and type Currently infrared transceiver in accordance with the mode of transmission rate and can be divided into four categories : Serial mode, the highest rate of Kbps。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)據碼，如 8 位地址碼加 4 位數(shù)據碼）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 ” 。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生 了 差錯。 遙控編碼脈沖信號（ 如 PPM 碼） 一般 由 引導碼 、系統(tǒng)碼、系統(tǒng)反碼、功能碼、功能反碼等組成。 紅外通信編碼基礎知識 通 常 情況下， 紅外遙控 收發(fā)器 將信號 (二進制脈沖 )調制在 38KHz 的載波上， 在經過緩沖放大后送 到 紅外發(fā)光二極管，轉化為紅外 光 信號發(fā)射出去。 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 相關部 門進行 申 請和登記，易于 落實 實施 ； 為了獲得大的光接收機工作范圍及瞬時視場，通常使用球形光學透鏡。 （ 3）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。由于有自然光線及人工光源等背景干擾光信號的混入，信號源頭和端設備中電光學噪聲與干擾的影響，紅外無線數(shù)字通信在某些場合質量較差，這個時候還需加入信道編碼。傳輸 的信 號 需要 經數(shù)化 (采樣 量 化 )， 通常需要 進行 基 帶調制、傳輸調制 ， 有時還 需要 進行信號源壓縮編碼 ，由上 所得電信號驅動光 電變換電路完成 紅外 光信號發(fā)射。 （ 1）發(fā)射器：當前己有紅外無線數(shù)字通信系統(tǒng)的信息源為語音 、數(shù)據、圖像等。 紅外通信系統(tǒng) 組成結構 包含 :發(fā)射器，信道， 接收器 。由圖 22 中指出的，只需在驅動管上加上一定頻率的脈沖電壓，紅外發(fā)光二極管就能產生調制光。 Ip 增加是一種降低脈沖責 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)光的脈沖責任周期約 1/41/3；對于一些電氣產品紅外遙控器，他們的占空比是 1/10。為了適應不同的工作電壓要求， D 端回路中常串有限流電阻為紅外發(fā)光二極管限流。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 m～ 0. 94μ m ,在鄰近紅外光的波段內 ,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。紅外線遙控具有結構簡單、低成本、防干擾能力強、可靠的工作性能等一系列優(yōu)點 ,特別適合近 距離遙控、特別是室內遙控的控制方式。因此 ,它可以使用與可見光類似的聚焦透鏡等光學裝置。紅外線的透霧性能好，這是它的又一個特性。 紅外線和可見光比較起來的另一個特性是色彩的豐富多樣。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。紅外線遙控只是紅外線眾多應用中的 一部分，目前廣泛應用在家用電器中的彩色電視遙控器、錄像機遙控器、 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單方便。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。 紅外收發(fā)器產品 開發(fā)趨勢 對于各種各樣的紅外收發(fā)器產品，雖然傳輸速率、傳輸距離等特性不同，但紅外收發(fā)器產品一直朝著提高傳輸速率，增大傳輸距離，降低