【正文】 nfrared receiving device (photodiode. Transistor and PV) and the luminescence peak wavelength of light by the general ~ 0. 94μm. in the nearinfrared band, both of the spectrum is the coincidence to a good match, access to higher transmission efficiency and higher reliability. Commonly used infrared diode, and its shape is similar LED light emitting diodes, Its basic circuit shown in figure 2 2. The triode plans for the switch, when the base added a driving signal, Transistor saturated conduction infrared LED D is also Wizard Link, issued infrared (near infrared about μm). D. The 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 tra nsmission 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。 2 pulse width 1。絕大多數(shù)筆記本電腦和手機(jī)都配置紅外收發(fā) 器接口。 紅外收發(fā)器產(chǎn)品在可攜式產(chǎn)品中的應(yīng)用 作用 很大。具有兩個(gè)以上指令信號(hào)傳送通道的稱為多通道遙控系統(tǒng)。紅外遙控編碼脈沖是一組組連續(xù)的串行二進(jìn)制碼，對(duì)于一般的紅外收發(fā)系統(tǒng)，此串行碼作為微控制 器的遙控輸入信號(hào)，由其內(nèi)部 CPU 完成對(duì)遙控指令的解碼，對(duì)其他各種紅外遙控收發(fā)電子產(chǎn)品的設(shè)計(jì)者來(lái)說(shuō)，上述的微控制器內(nèi)部解碼出的遙控指令是不便于利用的。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)行電路實(shí)現(xiàn)各種指令的操作控制。 由 IRDA 協(xié)會(huì)的資料表明，國(guó)外公司的紅外收發(fā)器 產(chǎn)品起步較早，已經(jīng)形成了紅外收發(fā)器的配套生產(chǎn)產(chǎn)業(yè)鏈。從分析自然界中各種電磁波組成的波可知，波譜是由 ：射線，ｘ射線、紫外線、可見 光、紅外線、微波和無(wú)線波組成的。 其中如 Agilent 等公司還具有生產(chǎn)紅外收發(fā)器系列產(chǎn)品的能力，而 HP、 IBM 等大公司則專門為自己公司產(chǎn)品配備紅外收發(fā)器。 另外按芯片功耗大小又可以分為低功耗型和標(biāo)準(zhǔn)型兩類，低功耗型通常使用 3V電源，傳輸距離較近，約 030cm，標(biāo)準(zhǔn)型通常使用 5V電源，傳輸距離較遠(yuǎn)最少 1m以上 。 遙控收發(fā)系統(tǒng)一般由發(fā)射器和接收器兩部分組成。雖然在接收電路中加入多穩(wěn)態(tài)記憶電路 ,可以根據(jù)按動(dòng)發(fā)射器指令鍵的次數(shù) ,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)功能控制 ,但是這種狀態(tài)的改變是順序進(jìn)行的。 比如有 95％的筆記本電腦就安裝了紅外收發(fā)器接口 ,現(xiàn)在絕大多數(shù)手機(jī)上也配置紅外收發(fā)器接口。 本系統(tǒng)的設(shè)計(jì)目的是用紅外線作為傳輸媒質(zhì)來(lái)傳輸用戶的操作信息并由接收電路解調(diào)出原始信號(hào)，主要用到編碼芯片和解碼芯片對(duì)信號(hào)進(jìn)行調(diào)制與解調(diào)，其中編碼芯片用的是臺(tái)灣生產(chǎn)的 PT2262，解碼芯片是PT2272。s : Pulse said the two 0。 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, the receiving tube received from the reflected infrared before work. infrared munication basic tes infrared munication Principle Communication is the use of infrared wavelength of 900 nminfrared waves from 1000 to serve as an information carrier, through infrared technology between the two close munication and confidentiality of information transmitted. Infrared munication system structure include : part launcher, channel, the receiver part. Launcher source letter issued after the binary signal from the highfrequency modulated infrared LED sent, receiving device regard the reception of highfrequency signals from the infrared receiver tube after receiving further demodulation photoelectric conversion of the original information of a mass munication lose way. Afterwards the former Information received after receiving part of the drive circuit connected to the expected pletion of the various functions. To which the modulation coding style pulse width modulation (by changing the pulse width modulated signal PWM) and pulse modulation time (through change the pulse train interval time between the modulation signal PPM) two. infrared munication system elements (1) Launches : Currently there is a infrared wireless digital munications system sources of information including voice, data, images. Its methods of work for the launch of the receiver can be divided into different layout LOS way (LightofSight , intracardiac way), diffuse (diffuse) mode. LOS way directional, it has good channel characteristics such advantages, but the existence of a shadow effect. difficult to achieve roaming function. Roaming means the main features of nondirectional, and easy to implement roaming function, but its channel quality is better sometimes LOS way. Transmission of signals required for a few of (the sampling was quantified), the general need for baseband modulation, transmission, modulation, sometimes signal source coding, the abovedriven signals from photoelectric converter plete optical signal transmission. Infrared wireless digital munications system and its scope of workforfired power distribution, the quality of the munication. While using various methods to improve optical transmitter power, the other using spatial diversity, holographic films and so on so diffuse light for the launch of space optical power evenly distributed. (2) Channel : infrared wireless digital munication channel refers to the transmitters and receivers 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 digital munications in some occasions, poor quality, At this point needed to channel coding. Infrared wireless munication system, the optical signal reflection, light scattering and background noise and interference effects, Infrared wireless digital channel presence multipath interference and noise, This is to improve the quality and access for highspeed applications should be addressed. Infrared wireless digital munication channel often used by the major optical ponents, optical filter, condenser, their role is : plastic, filter, depending on the field transformation, the band division, the lens can be used as launchray focusing, the use