微波BJT超宽带低噪声放大器的设计

本文给出了一种频带覆盖达１０－１６００ＭＨｚ的微波ＢＪＴ超宽带低噪声放大器的设计方法，从微波ＢＪＴ的噪声模型出发，通过拟合５０Ω源阻抗下微波ＢＪＴ的噪声系数ＮＦ５０和Ｓ参数来提取其噪声参数，然后根据增益，噪声及驻波比要求优化设计放大器，使放大器在超宽带范围内获得平坦增益和低噪声，本文所给出的微波ＢＪＴ惨数提取及放大器优化设计方法已由实验结果所验证。     

一种新颖的半导体光放大器镀膜监控方法

本文介绍了一种在半导体光放大器镀膜过程中监测端面反射率的简单而有效的方法。理论模型的建立考虑了光放大器的漏电流和自发发射速率随载流于浓度的非线性变化，并且基于实验测量的ＰＩ（输出功率与注入电流）曲线，采用曲线拟合的方法来修正一些依赖于器件的参数，理论计算结果与有关文献的测量结果较好地吻合。     

A 24-GHz Patch Array with a Power Amplifier/Low-Noise Amplifier MMIC

This paper presents an active patch array designed at 24 GHz. It can be used as a front-end component for a phased array. A series resonant array structure is chosen which is compact and easy excite. With 5 elements, the array proved a 12-dB antenna gain. A power amplifier and a low noise amplifier are designed on a single GaAs chip (PALNA). Bias switch is used in the PALNA, which greatly reduces the switch loss in a transceiver and increases the efficiency. 20-dB small signal gain is achieved in both power amplifier and low noise amplifier. The active patch array is built by the combination of the patch array and PALNA. The measured active gain of this antenna is 35-dB for the PA mode and 31-dB for the LNA mode. This active patch array can obtain an EIRP of 34 dBm with a total radiated power of 22dBm and a maximum PAE of 32%. To check the noise performance, we applied sources at both normal temperature and 77K (liquid nitrogen) and extracted the noise figure (3.5 dB) of the active antenna by the Y factor method. The results proved that the active antenna is working efficiently as both a transmitting and receiving antenna.     

通信局(站)的接地与防雷

论述了分散接地与联合接地系统在防雷作用上的差异，归纳出通信局（站）在防雷与接地方面的若干原则。     

2.5Gb/s和3.125Gb/s速率级0.35μmCMOS限幅放大器

采用了TSMC0.35μm CMOS工艺实现了可用于SONET/SDH2.5Gb/s和3.125Gb/s速率级光纤通信系统的限幅放大器。通过在芯片测试其最小输入动态范围可达8mVp—p，单端输出摆幅为400mVp-p，功耗250mW，含信号丢失检测功能，可以满足商用化光纤通信系统的使用标准。     

宽带电流反馈运算放大器OPA623及其应用

以电流模技术和互补双极工艺制造的集成电路具有良好的高频性能，用其构成的电流反馈放大器频带宽，转换速率高，在视频和射频信号的放大和处理以及高速数字通信系统中都得到广泛的应用。通过OPA623集成“运放”，简要介绍电流反馈放大器的原理、性能及其在高清晰度电视及有线电视传输中的应用。     

Ubiquitous Information Services with JAIN Platform

To provide responsive information services in a ubiquitous computing environment, service software and system development are indispensable. A component-based ubiquitous information system with a JAIN (Java APIs for Integrated Networks) platform to achieve seamless transmissions and reach-everywhere communications was designed in our research. In this development, numerous ubiquitous service modules were identified: location management, roaming, mobile IP and WAP networking. These component-based network modules were constructed using a component composition language with component specification and interface definition, running on top of a distributed service architecture using a JAIN platform to distribute the ubiquitous information services to mobile users. Two applications, Wireless-Application-Protocol (WAP) Mail and Video-on-Demand (VoD) services, show that the JAIN-like platform with the developed networking components effectively fills the gap for application developers between mobile appliances and various kinds of ubiquitous information services.     

微波功率放大器预失真线性化技术分析

给出了两种基本形式的预失真线性化电路,对其工作原理和技术特点进行了分析。     

双程放大技术在光纤放大器中的应用

双程放大技术是一种高效率、低成本的实用化放大技术。本文介绍了双程放大技术的优点及在各种放大器中的应用。     

基于片上DC-DC的CMOS光接收机前置放大器

利用CSMC 0.6μm CMOS工艺,设计了基于片上DC-DC转换器的光接收机前置放大器。电路采用可调跨阻放大器与片上DC-DC结构,有效地克服了单端跨阻放大器易受电源波动的干扰,并解决了高灵敏度与低失真相互矛盾的问题。模拟结果表明,输入动态范围为83 dB(峰-峰值=0.2μA~3 mA),等效输入电流噪声为1.2 pA/Hz(155 MHz),可稳定工作在155 Mb/s速率上;在5 V电源电压下,功耗为95 mW。