基于PMT的紫外光语音接收系统优化设计

针对以LED(发光二极管)为光源的紫外光通信系统中接收端紫外光信号较弱的问题,对基于PMT(光电倍增管)的紫外光语音接收系统提出了一套完整的优化设计方案,系统包括电流/电压变换、放大、滤波以及整形电路等,利用模块化设计思想完成了各部分电路的设计与实现,并进行了仿真和实验测试。结果表明,当光源采用1.6mW的紫外LED发射速率为4.8kbit/s的语音信号时,系统在10m半径范围内准视距条件下可以正确恢复出语音信号,话音清晰完整。     

在光电部件设计和生产中应用最广泛光电测量仪器

当前光纤已在远程通信中完全代替电缆,在数据通信中情况相似,甚至在大容量的局域网也使用光纤代替电缆,电缆光通信和传输的发射/接收部件的开发和测量主要依靠以电学测试仪器为基础的光电测试仪器.例如光信号源是利用电脉冲驱动的半导体激光二极管或发光二极管,光频谱分析仪是前端加有光电能转换和部分光学元件的电学频谱分析仪,光功率计是前端采用半导体充电二极管探头的电学功率计等.     

平板显示技术渴求新的测试方法

平板显示器中有源元件的参数测试与其他各类半导体器件的IC器件测试相同。然而,为了使液晶显示器(LCD)、有机发光二极管(OLED和发光聚合物(LEP)显示器件的测试精度和测试效率达到最佳,就需要对参数测试系统、电缆线路和测试方法作重大改进。     

LED点亮多彩照明——分析光度测量难点 改进LED的性能测试与评估

与白炽灯、荧光灯等传统光源相比,发光二极管(LED)具有寿命长、光效高、功耗低及便于维修等优点,因此目前全球生产和使用LED呈现急速上升的趋势,随之而来的是对LED性能的测试和评估逐渐被提上日程.     

分析光度测量难点改进LED的性能测试与评估

与白炽灯、荧光灯等传统光源相比,发光二极管(LED)具有寿命长、光效高、功耗低及便于维修等优点,因此目前全球生产和使用LED呈现急速上升的趋势,随之而来的是对LED性能的测试和评估逐渐被提上日程.     

适合初学者自制的晶体管测试仪

笔者利用发光二极管单向导电的特性制作了一台晶体管测试仪,该测试仪具有显示直观、携带方便等特点。该测试仪的原理图如图1所示。它能测试二极管、三极管、电容及线路的通断等,当电源电压提高到4.5V时还可对发光二极管进     

根据交流连续性排查电缆的单端故障

本文详细介绍了一个用于检测交流连续性的测试装置,该装置能够完成外部测试和维修工作。该电路可提供一个简单“通过／未通过”测试定位多芯电缆的故障。     

射频电缆组件组装工艺浅谈

近年来国内外射频电缆组件的发展很快,射频电缆组件的性能不断提高,对射频电缆组件组装工艺也提出了更高的要求.射频电缆组件组装过程多是手工操作,产品的一致性及性能很难控制,要求有良好的工艺保证,为此介绍了射频电缆组件组装工艺,包括电缆的裁剪及剥皮、内导体的连接、外导体的连接和电气性能的测试;探讨了在组装过程中应注意的问题,以及针对内导体焊接易出现虚焊问题进行研究.     

用统计方法分析维修记录

无论在何种ＣＡＴＶ网络中进行维修工作 ,都应有维修记录。维修记录的目的是给技术人员、管理人员提供网络系统的运行状况和各种元件设备维修更换的情况。维修记录是科学管理ＣＡＴＶ网络的基本依据 ,对日后的维修工作及系统改造升级有很大帮助。维修记录的内容可根据需要而定 ,一般有 :用户报修地点及时间 ,故障现象 ,设备、器件及电缆测试数据 ,维修处理情况 ,遗留问题 ,维修人员等。通过对纪录中具体内容进行统计整理、归纳 ,再按时间顺序做成各类故障统计表、设备器件更换表、电缆参数变化表和人员维修状况统计表等 ,应用统计方法去分析…     

某机载短波电台干扰无线电高度表的行为级仿真及分析

以电磁干扰测试试验为基础,利用ADS软件对高度表接收机系统进行行为级仿真,通过输出频谱判断干扰产生的原因,并采用了在低频电缆上加装阵列滤波器的解决方案。通过最终的电磁兼容性测试试验可以看出,这种分析电磁干扰机理的方法对实际工程问题有很大的参考价值。     

Degradation of light emitting diodes:a proposed methodology

Due to their long lifetime and high efficacy,light emitting diodes have the potential to revolutionize the illumination industry.However,self heat and high environmental temperature which will lead to increased junction temperature and degradation due to electrical overstress can shorten the life of the light emitting diode.In this research,a methodology to investigate the degradation of the LED emitter has been proposed.The epoxy lens of the emitter can be modelled using simplified Eyring methods whereas an equation has been proposed for describing the degradation of the LED emitters.     

Correlation of emission and electrical properties of gallium arsenide transistor structures

Transistor structures were fabricated in si-doped solution, grown GaAs. The p-n junction used as anl emitter was formed during the growth of the epitaxial layer employing amphoteric Si doping. The collector junction was made by a planar sulphur diffusion. The behavior of the emitted light and the collector current as a function of the emitter base current are observed. The degradation in quantum efficiency and transistor alpha is noted to be due to the same diode current component. The degradation of alpha due to emitter crowding at high current levels is directly exhibited.     

Degradation of light emitting diodes: a proposed methodology

Due to their long lifetime and high efficacy, light emitting diodes have the potential to revolutionize the illumination industry. However, self heat and high environmental temperature which will lead to increased junction temperature and degradation due to electrical overstress can shorten the life of the light emitting diode. In this research, a methodology to investigate the degradation of the LED emitter has been proposed. The epoxy lens of the emitter can be modelled using simplified Eyring methods whereas an equation has been proposed for describing the degradation of the LED emitters.     

A method for determining the emitter and base lifetimes in p-n junction diodes

A method is described that provides an experimental means for the first time to separate and determine the emitter and base lifetimes in a p-n diode after the junction has been fabricated. In the method, several static and transient measurements are analyzed using physical models of the diode characteristics. To illustrate the method, diffused silicon diodes are fabricated having substrate (base) impurity concentrations ranging from 10¹⁴to nearly 10¹⁷phosphorous atoms per cubic centimeter. The results show an emitter lifetime that is much smaller than the base lifetime in the diode having the highest base doping concentration. In this diode, the recombination current from the emitter is 65 percent of the recombination current from the base, demonstrating the significance of the emitter in governing the static current-voltage dependence. The importance of emitter recombination to the transient characteristics is also demonstrated. The paper emphasizes the techniques by which the base and emitter lifetimes are distinguished. It also demonstrates the need for carefully basing the quantitative analysis of the measurements on the underlying diode physics. The method described here applies not only to p-n diodes but also to junction solar cells and transistors.     

一种新型的微流体测量芯片的设计

介绍了一种新型的集成反熔丝和光敏二极管的微流体测量芯片的设计。将反熔丝发光二极管及光敏接收二极管集成到微流体装置可以通过结合集成电路技术和微加工技术来实现。这种新型的微流体芯片包括一个光敏二极管探测器,硅微通道和一个纳米级的反熔丝发光二极管。还介绍了反熔丝发光二极管的结构及工作原理、芯片的结构和制作方法、芯片的应用及其应用仿真。该芯片结合外流路装置可以检测流体的流速、通道中流体的吸收率、通道中流体在某介质中的折射参数以及液体中的气泡、微粒等。     

半导体激光器双波长光纤耦合模块的ZEMAX设计

为了发挥单管半导体激光器的优势,获得光纤耦合模块多波长、高功率、高亮度的光束输出,利用ZEMAX软件仿真模拟,设计了一种单管光纤耦合模块。此模块将32支输出波长分别为915 nm、975 nm,输出功率为15 W的单管半导体激光器,经过微透镜组快慢轴光束整形、空间合束、偏振合束、波长合束以及光束聚焦等一系列工艺后,耦合进芯径200 m、数值孔径0.22的光纤。模拟结果显示,光纤输出功率467.46 W,光纤前后耦合效率大于98.47%,总耦合效率高于97.39%,光功率密度高于12.86 MW/（cm2sr）,达到了泵浦激光器和功率型器件的性能要求。使用Solidworks软件设计了相应的底板结构,并结合ANSYS软件进行散热模拟分析,结果显示该模块散热性能良好,可行性较高。     

由OLED和复合光探测器构成的新型光耦合器

对以Al/Alq3/TPD/ITO/玻璃结构的有机/聚合物发光二极管(OLED)为发光器件,以光电二极管和双极晶体管构成的复合光探测器为光接收器件组成的光耦合器进行了实验研究.通过改变OLED上的偏压,获得光耦合器输出特性相应的变化.对实验结果进行了分析讨论.     

Emission from outside of the emission layer in state-of-the-art phosphorescent organic light-emitting diodes

The emission zone profile in an organic light-emitting diode was extracted by fitting the experimentally measured far-field angular electroluminescence spectrum of a purposely designed device. It is based on a thin 10 nm emission layer doped with the red emitting phosphor Ir(MDQ)₂acac. We find strong indications for light emission originating from outside of the emission layer, even though the device has electron and hole blocking layers. These are commonly assumed to completely confine the charge carrier recombination and hence the light emission to the emission layer. Since the calculated internal spectrum of the emission matches the emitter photoluminescence spectrum well, diffusion of the emitter molecules outside of the emission layer is hypothesized.     

Monolithic GaAlAs/GaAs infrared-to-visible wavelength converter with optical power amplification

A monolithic wavelength converter has been constructed in the GaAlAs alloy system which comprises a wide gap emitter phototransistor and a double heterojunction (DH) light emitting diode (LED) in a bifacial configuration. The liquid phase epitaxy (LPE)-grown structure is capable of efficiently converting IR light with λ < 870 nm into the red spectral range in conjunction with optical power amplification.     

高增益异质结光电晶体管的研制

利用液相外延技术研制出高增益InGaAsP/InP异质结光电晶体管(HPT)。入射光波长为1.256μm时,实现直流光增益为88.9,微分光增益为148,光谱响应范围为0.85～1.3μm。在外偏电压小于4V时暗电流小于10nA。