全温超高速ECL双模预置分频器设计

本文叙述了全温(-55～+125℃)超高速ECL双模预置分频器的工作原理、电路设计、版图设计及研制结果,还简述了制作工艺。整个电路设计以提高电路工作速度和温度特性为中心,采用优化的开关电流分配、最佳的电路工作点设置、带温度补偿的电阻反馈网络结构和合理的版图设计,来提高工作速度和保证良好的温度性能。研制的÷8/9分频器,在全温范围内最高工作频率达600MHz以上。     

气压高度表模拟器的研究

文中介绍了一种气压高度表模拟器，它能够对高度表的气路特性同时进行静态，动脉模拟。检验气压高度表的静，动态特性，其方法简单经济，可靠性高，可重复性高。     

频谱分析仪在射电法测量天线增益和G／T值中的应用

本文给出了频谱分析仪在射电法测量天线增益和Ｇ／Ｔ值中的应用方法以及计算公式，并对测量误差进行了分析，讨论了ＬＮＡ的噪声温度与Ｙ因子大小的关系，给出了对测量精度的影响和常用不同频段可测天线口径的下限。     

Order statistic filter banks

Filter banks play a major role in multirate signal processing where these have been successfully used in a variety of applications. In the past, filter banks have been developed within the framework of linear filters. It is well known, however, that linear filters may have less than satisfactory performance whenever the underlying processes are non-Gaussian. We introduce the nonlinear class of order statistic (OS) filter banks that exploit the spectral characteristics of the input signal as well as its rank-ordering structure. The attained subband signals provide frequency and rank information in a localized time interval. OS filter banks can lead to significant gains over linear filter banks, particularly when the input signals contain abrupt changes and details, as is common with image and video signals. OS filter banks are formed using traditional linear filter banks as fundamental building blocks. It is shown that OS filter banks subsume linear filter banks and that the latter are obtained by simple linear transformations of the former. To illustrate the properties of OS filter banks, we develop simulations showing that the learning characteristics of the LMS algorithm, which are used to optimize the weight taps of OS filters, can be significantly improved by performing the adaptation in the OS subband domain.     

北京平原地热资源与地热供暖

本文对北京平原地区地热资源条件和供暖现状进行了概述,分析了地热供暖技术的特点、优势以及当前制约其推广发展的“瓶颈”,针对北京平原地热资源的可持续发展提出了两点具体建议。     

KM496GB型柴油机机油压力低的原因分析及对策

通过对KM496GB柴油机机油压力低的试验分析表明,引起故障主要原因有:机油泵故障,限压阀未备紧,机油泵油量偏低,并介绍了所采取的相应措施。     

世界与中国的石油储产量现状及趋势

总结了2004年世界和中国石油储量、产量和贸易量的特点,预测了未来世界和中国石油供需的发展趋势。     

客车发动机在中国的现状和发展趋势

结合我国现有国情,论述客车用发动机:燃油车、混合动力车、电动车、燃料电池和氢燃料车的现状和发展趋势,着重探讨了CNG/LNG车在我国的现状和发展趋势,并对各项动力进行综合比较分析。     

一种新型高效敞开式空调系统

报道了一种应用于敞开吸收式空调系统的新型空气循环方式，它可以显著地改善系统进行特性，提高效率，减小设备尺寸，降低造价，同时还可提高系统致冷贮存能力。     

显示领域GaN发光二极管概述与专利分析

介绍了氮化镓材料的发光二极管的工作原理,并以氮化镓发光二极管在国内外专利申请的数据为分析样本,从氮化镓发光二极管专利申请的时间、国家、技术概况等角度进行研究,分析了氮化镓发光二极管的技术发展现状,介绍了最早的相关专利,给出了申请量分布图、当前重要申请人介绍以及中国在该领域内的发展状况以及未来的发展趋势.