信息产业用新光源

随着个人电脑的普及和信息网络的迅速发展。信息产业用的新光源得到进一步的开发和普遍应用。本文主要介绍背景照明光源的投射光学系统用的显示光源。这些光源为荧光灯，卤钨灯，短弧氙灯和金属卤化物灯等。文中还介绍了这些灯的特性和点灯线路。     

数据加密通信设备

“ィンタフュ-ス”83年5月第9卷第5期报道了一种数据加密通信设备—PC—80X。它接在数据线路终端上使变换规程的通用规程变换器具有机密保护功能。这种设备已经开始出售,每台70万日元。该设备的特点如下: (1)接在国际用户电报线路终端上可实现ASCⅡ代码(8单位)和波特点代码(Baud Dot Code)(5单位)之间的相互转换。(2)原来只能转发大写文字的信息也可以用5单位线路传送小写文字。     

试论闽台信息产业合作先行区建设的政策方向

本文在两岸三通大背景下，从战略规划、投资环境、合作、交流、创新、人才、信息平台、标准化、产业对接等方面提出了政策方向。指出：闽台信息产业具有很强的互补性，关键在于福建省如何把握信息产业发展规律，从我国信息产业总体布局出发，选择既满足国家信息产业发展战略的总体要求，又能够走出一条具有海西特色的高水平合作之路。当前情况下，闽台信息产业合作先行区应该把信息设备制造的技术创新放在优先位置，更应该把软件业、电子商务产业和信息服务业合作创新放在重中之重的位置。     

网络故障浅析

计算机网络就是利用通讯线路和通信设备．用一定的连接方法，将分布在不同地点的具有独立功能的多台计算机系统相互联结起来．在网络软件的支持下进行数据通信．实现资源共享的功能。除了计算机外，用于连接网络的硬件设备有光缆、光收发器、双绞线、路由器、交换机、网络适配器（网卡）等——造成网络不通的大部分原因都是这些设备出了故障。下面我们将对它们出现的故障进行简要的分析。     

基于线阵CCD的线路方向测量系统的开发

该系统硬件设备采用长距离准直激光光源、CCD图像传感器、旋转编码器、系统终端PC等器件,利用线阵CCD测量技术、数据处理技术、多信息传感融合技术等高新技术,能够对铁路路轨区段(长度≤200m)轨道几何形状进行高精度检测,将线路轨向测量结果直接数字化显示,为线路设备维修提供可靠的测量数据,解决了既有方法测量精度差、效率低的问题,能满足铁路工务系统作业要求、提高作业质量。     

光调制器的最近进展

光通信设备用的光调制器在作为电信号处理的信息与线路中传输的载波(光)之间,光调制起着“桥梁”的作用。所以,光调制所要求的共同条件,只是有效地利用光传输线路特性的宽带和高效率。光调制技术,大致可分为直接调制(通过改变光源激励状态进行调制)和外调制(对光源来说,另外采用调制器件进行调制)两种。近几年来,光纤维尤其是多模光纤维的     

GaN固体光源的进展

以GaN为代表的第三代半导体材料及器件的开发是新兴半导体产业的核心和基础,是信息产业前进的发动机,同时有可能改变人类照明光源的技术现状。本文对GaN固体光源的起源和发展做了回顾和展望,并给出几种可见光功率LED芯片的结构及其封装特点,最后指出在未来50年内,用GaN固体光源取代白炽灯照明将成为现实。     

信息安全与信息产业

信息产业中不仅是安全技术、安全产品等与信息安全有关,实际上,信息产业中的其他部分也都在不同程度上影响信息安全。因此我们考虑信息安全时决不能只考虑信息产业中的安全技术、安全产品等,而忽视信息产业的全局。事实上,任何信息系统都需要在各种信息产品(及服务)之上构建起来,因此提供这些产品和服务的信息产业就成为构建国家信息安全的物质基础。当然,不同的技术和产品对于信息安全的影响程度是不同的。一般说来,信息产业中的核心技术及其产品对于信息安全的影响远大于非核心技术及其产品,所以在美国这样的发达国家,信息产业中的核心技…     

稀有气体放电荧光灯及荧光粉

1.前言传真、PPC、图像扫描等信息机器的读出,除电曝光用光源及液晶显示用照明光,都广泛地使用荧光灯。在这些用途中,都要求对温度变化不敏感的光源,因为荧光灯自身发热及其它器件发热而引起机器内温度上升都可能影响荧光灯光源的光输出。近年来代之汞蒸汽灯的稀有气体放电灯(多数采用氙气体)被越来越多地用于信息机器光源。与普通荧光灯相比,稀有气体放电灯具有光输出对温度变化不灵敏、瞬时光通量稳定及响应速度快等优点,所以预期在     

国家计委推出加快信息产业发展政策

在日前召开的信息市场与国际合作研讨会上,国家计委主任陈锦华宣布了加快我国信息产业发展的几项重要方针政策.·在调整传统产业结构的同时,大力发展信息产业,努力提高信息产业在国民生产总值中的比重;·大力加强信息基础设施的建设,优先发展邮电通信业,积极采用国际先进技术与设备,建设光纤骨干工程,有重点、分层次地大力推进信息高速公路的建设;     

A Physically Based Fluorescent Lamp Model for a SPICE or a Simulink Environment

This paper describes a method of modeling fluorescent lamps. The lamp model can be implemented in all major circuit simulation software packages, an example has been given for SPICE and Simulink. The model is based upon a simplified set of physical equations that gives the model validity over a wider range of operating conditions than current fluorescent lamp SPICE models allow for. The model can be used to model any low-pressure mercury-buffer gas fluorescent lamps by entering key lamp parameters, length, radius, cold-spot temperature, and buffer gas fill pressure. If fill pressure is not known, a default value dependent on lamp radius is used. The model shows good agreement over a wide range of operating frequencies and lamp powers.      

Data on the Temperature Dependence of X-Band Fluorescent Lamp Noise Sources

This paper is concerned primarily with the performance of fluorescent lamps as microwave noise sources at 9,000 mc. In particular, it deals with the temperature dependence of the excess noise ratio of an 8-watt lamp running at a lamp current of 150 ma in a 10° E-plane holder. It was found that 1) the bulb temperature is much higher than that with a lamp current of 75 ma encountered in the 90° H-plane circuit investigated previously at 4,000 mc, hence the temperature coefficient of excess noise versus waveguide temperature obtained in the 4,000 mc circuit does not apply, 2) anomalous and unreproducible inversions in the temperature coefficient at these higher bulb temperatures have been observed, 3) these anomalies can be avoided by operating the bulb at lower temperatures, 40°C to 50°C, where the lamps appear to be just as uniform and stable and probably just as noisy as they are at 4,000 mc.     

A Novel Constant Power Control Circuit for HID Electronic Ballast

This paper presents a constant power control circuit for a three-stage high-intensity discharge (HID) electronic ballast. The three-stage electronic ballast is composed of a boost pre-regulator to achieve a high power factor, a DC/DC buck converter to regulate lamp current with constant lamp power, and a full-bridge inverter to drive the HID lamp with a low-frequency ac squarewave current. The buck converter operating in current mode utilizes current sense level-shift technique to achieve constant power output. The proposed constant power control circuit is easily designed and implemented for the three-stage HID electronic ballast. Finally, a laboratory prototype of a 70 W HID electronic ballast is implemented. The measured results show that the proposed ballast can be applied for various HID lamps with low lamp power variation (less than 0.6%).     

金属卤化物灯的高频点灯和放电稳定化

为了提高金属卤化物灯的光效，将该灯用电子镇流器在高频下燃点，观察到灯的不稳定性，称为音响共鸣现象。为了克服音响共鸣现象，介绍了四种稳定工作的方法：①在超音响共鸣的频率下工作；②在矩形波下工作；③采用适当的调制频率下工作；④采用三次谐波叠加高频正弦波点灯。本文介绍金属卤化物灯用电子镇流器、高频点灯和放电稳定化。     

Low Frequency Architecture for Multi-Lamp CCFL Systems With Capacitive Ignition

A low frequency architecture is proposed for driving parallel cold cathode fluorescent lamps (CCFLs) in large screen liquid crystal display (LCD) TV backlighting applications. Key to the architecture is a proposed capacitive coupling approach for aiding lamp ignition. A dc voltage is applied to the lamp electrodes while an ac voltage is applied to an external plate for capacitive coupling. The result is reliable, simultaneous ignition of parallel lamps with a required applied dc voltage near the lamp steady-state operating voltage. The complete system architecture includes a single high voltage converter, a pulse lamp ignition circuit, current control circuits and a single backlight controller. The topology is capable of driving a large number of parallel lamps with independent lamp current regulation, while avoiding ac coupling losses in steady-state operation and achieving significant reduction in reactive components when compared to typical high frequency ac ballast designs. Experimental results are presented for a system of four parallel 250 mm length lamps, demonstrating simultaneous parallel lamp ignition and dc current regulation.     

基于ADE7758的智能路灯节能控制系统的设计

介绍了利用ADE7758和AT89C55WD单片机设计智能路灯节能控制系统的硬件电路和软件功能描述,交流稳压采用补偿变压器稳压方式,如果在不同的地区,该系统还利用GPS定位模块根据不同地区、不同季节自动启停路灯,能有效的节约能源,减少照明灯具的损耗.     

Balanced Driving System for Multiple Cold-Cathode Fluorescent Lamps

A novel circuit with dual-high-voltage topology to drive cold-cathode fluorescent lamps (CCFLs) for liquid crystal display (LCD) backlight modules is proposed in this paper. In the proposed circuit topology, all the lamps are connected in series to alleviate the influence of parasitic capacitance induced between the lamps and the aluminum backplank. Balance lamp current and uniform light output can be achieved without using any current balancing circuit. The circuit topology is capable of driving arbitrarily even numbers of lamps with same lamp current while achieving significant reduction in size, weight, and cost. The circuit is verified by experimenting on a backlight module with four L-type lamps in a 19-inch LCD. The experimental results demonstrate the effectiveness and feasibility.      

Self-oscillating dimmable electronic ballast for fluorescent lamps

This letter presents a low-cost solution for converting the popularly adopted nondimmable electronic ballast circuit for fluorescent lamps with self-oscillating series resonant inverter into a dimmable one. The dimming function is achieved by increasing the switching frequency of the inverter from the natural frequency of the resonant tank, so that less energy is coupled to the lamp. Control of the switching frequency is based on deriving an adjustable dc current source from the inductor in the resonant tank to control the operating point of the saturable chokes for driving the switches in the inverter. The overall circuit does not require any integrated circuit. A 17-W prototype has been built and tested. Theoretical predictions have been verified with experimental results. The lamp can be dimmed to 10% of the full brightness.     

Acoustic-resonance-free electronic ballast for automotive HID lamps

A novel cost-effective and acoustic-resonance-free electronic ballast used to drive automotive high intensity discharging (HID) lamps that utilise a constant lamp power control scheme is proposed. The presented ballast is comprised of a buck-boost flyback converter to provide negative DC voltages and a half-bridge-type inverter to supply the lamp with low-frequency, square-wave AC voltage/ current. Owing to its low-frequency operation, no acoustic resonance occurs on the automotive HID lamps. Design guidelines and experimental results are demonstrated for a 35 Wautomotive HID lamp prototype ballast operating at 400 Hz switching frequency with battery input DC voltage of 12 V.     

Design and analysis of an IC-less self-oscillating series resonant inverter for dimmable electronic ballasts

This paper presents a low-cost solution of converting the popularly adopted nondimmable electronic ballast circuit for fluorescent lamps with self-oscillating series resonant inverter into a dimmable one. The dimming function is achieved by increasing the switching frequency of the inverter from the natural frequency of the resonant tank, so that less energy is coupled to the lamp. Control of the switching frequency is based on deriving an adjustable dc current source from the resonant inductor in the resonant tank to control the operating point of the saturable transformers for driving the switches in the inverter. The overall implementation does not require any integrated circuit. A 17-W prototype has been built and studied. Theoretical predictions have been verified with experimental results. The lamp can be dimmed down to 10% of the full power.