背景光光伏效应对屏蔽-光伏空间孤子的影响

在光伏晶体两端外加一恒定的直流偏压，背景光的光伏效应对形成屏蔽-光伏孤子的空间电荷场没有影响，但对晶体中的电流有影响.如果外电源的电动势是恒定的，则背景光的光伏效应与外电路的电阻协同起作用，可以通过晶体两端的电压降影响晶体中的空间电荷场，进而影响空间孤子的宽度.在一定的条件下甚至可以实现亮、暗孤子的转换. 关键词： 屏蔽-光伏 空间孤子 孤子宽度 亮暗孤子转换     

A high-capacity broadband packet switch architecture based on a multilink approach

Broadband packet networks based on asynchronous transfer mode (ATM) are expected to provide a wide range of services, including motion video, voice, data and image. When these networks become prevalent, some applications such as motion video and high-speed LAN interconnections will place a very large bit rate requirement on the channels. Currently, the physical layer supported by the synchronous optical network (SONET) allows the transmission of up to 2.4 Gbit/s with the OC-48 optical interface. However, it is not feasible for the electronic packet switch to route packets at this rate on a single link. In this paper we present a design of a broadband packet switch that uses multiple links in parallel to realize a high-speed channel. This implementation permits the switch to operate at the lower link rate, which can be at 150 Mbit/s, while having the ability to support a virtual circuit at a higher rate (up to 2.4 Gbit/s). The main contribution of the design is that packet sequence on a channel is still maintained even though packets are allowed to use any of the links belonging to the same channel. Besides allowing the switch to function at a slower rate than the transmission channel rate, the implementation of the multilinks benefits from statistical multiplexing gain. Analytical results show the performance advantages of multilink design with respect to delay, throughput and packet loss probability.     

X441对数放大器的原理及其应用

本文主要介绍X441单片对数放大器的基本原理和应用,并列举了一些具体应用电路。     

Parallel feedforward class-AB control circuits for low-voltage bipolar rail-to-rail output stages of operational amplifiers

A new family of class-AB control circuits for bipolar rail-to-rail output stages of operational amplifiers is presented. Step by step, we report the development of five simple class-AB control circuits showing the advantages of using parallel feedforward. The circuits have been designed in such a way that temperature, supply voltage and process parameters have little influence. To test the output stages, one of them has been implemented in a very simple two-stage operational amplifier on a semi-custom chip. Measurements show a bandwidth of 2.5 MHz, a gain of 40 dB, a quiescent current of 23µA and a maximum output current of 250µA. Simulation results of three other simple operational amplifiers with the new class-AB control circuits are shown, which have a higher gain and maximum output current.     

PZT铁电薄膜的制备及电学性能研究

使用硝酸锆作锆源的溶胶－凝胶方法制备ＰＺＴ铁电薄膜。他们的电学性能被测试包括电滞回线，电流Ｉ（ｔ）特性，漏电流，矫顽场疲劳和老化。测到的ＰＺＴ薄膜剩余极化８．２μＣ／ｃｍ~２，矫顽场６８ｋＶ／ｃｍ．簿膜的寿命可超过１０~（１１）周期。     

一种提高微电路外壳使用可靠性的方法

简要分析了白瓷双列直插外壳的失效模式和失效机理，并进行了模拟实验，通过对实验结果的分析，提出对成品微电路进行二次电镀能够提高其外壳的使用可靠性。     

混合集成电路激光功能调值技术

本文提出了激光功能微调技术在高精度混合集成电路上的应用，讨论了关键技术问题，并以实例具体说明。该技术的应用为研制高精度混合集成电路开辟了新途径。     

B—ISDN宽带UNI信令点到多点配置的实现

本文根据ＩＴＵ－Ｔ最新的Ｑ．２９７１协议，以及笔者所从事的实际课题，提出一整套Ｂ－ＩＳＤＮ第三层ＵＮＩ信令的软件实现策略，其特点是能同时满足用户对点到点以及点到多点广播这两种通信方式的要求，而且可以动态配置。     

STN—LCD的新进展

STN-LCD采用新的取向层,消除了残象;采用新的驱动波形,消除了串扰;采用二(口恶)烷、卤化物、链烯基、醚和二苯乙炔,改进了液晶料材的性能,使STN-LCD获得高的对比度、快的响应速度、低的驱动电压;采用有源矩阵驱动方法,消除了帧响应,使STN-LCD获得高的对比度、高的亮度及视频响应速度;使用温度跟踪电路,自动跟踪STN-LCD的阀值电压,使STN-LCD获得宽的工作温度。     

数字程控交换机与专网中的多媒体通信

本文以一个多媒体通信应用VISIT为实例,介绍了多媒体通信在数字程控交换机及专网中的应用情况。