交流电动机矢量控制变压变频调速系统（八） 第八讲 双馈异步电动机矢量控制系统

本文首先介绍了双馈异步电动机调速系统的基本结构，在此基础上，介绍了异步电动机双馈矢量控制系统的基本原理，并且对气隙磁链的观测方法进行了介绍，最后，介绍了一种新型的双馈电饥矢量控制实现方法。     

录象机慢放功能在训练模拟器中的应用

近年来，训练模拟器得以广泛应用。其中，视觉效果模拟是一个重要方面。本文介绍的正是用录象机来实现视觉效果模拟。首先，介绍录象机重放的基本原理。为了获得干净而稳定的图象所应考虑的主要问题和方案介绍。进而，详细介绍了硬件设计要点。     

低成本板级电源的几种方案及合理设计

本文简要介绍几种低成本板级电源的解决方案，然后重点介绍如何合理设计，以减小电源纹波和噪音，有更好的电磁兼容性，最后介绍了测试的注意事项。     

液晶显示器光源技术的发展现状

简单介绍液晶显示器光源技术的发展现状，阐述背光源的主要形式，重点介绍冷阴极荧光灯背光源，由于反射型液晶显示器的发展，对前光源技术提出了进一步的要求，因此，本文对它也做一些简单介绍。     

ARM小记

本文摘自《爱上单片机》一书，此书从介绍单片机的简单入门到工程开发及行业介绍，其中ARM小记是行业介绍的其中一节。作者用通俗易懂的写作风格，生动地介绍了ARM技术及以学习方法。在此特别摘录，如需进一步了解。欢迎阅读《爱上单片机》一书。     

用户接入技术

本文介绍用户接入网技术，文章主要介绍了ADSL，HDSL，DLC，FTTC，FTTH，HFC和WLL。     

广东省智能网工程

对广东省智能网工程的建设背景，网络结构，网路组织，业务等作了较详细的介绍，其中包括对七号信令系统的应用，国际，国同，省内智能网关系等相关内容的介绍。最后，对广东省智能网的远期发展趋势作了介绍，并提出了近期发展的一些建议。     

干扰的测试与定位

本主要介绍无线通信中各种干扰的可能成因，干扰的测试、定位、处理方法，第一节着重介绍CDMA网络中干扰的主要来源、第二节介绍有关干扰的测试和定位，最后就干扰的处理做了一定的介绍。     

有线电视的射频加解扰

介绍有线电视射频加解扰技术的发展，重点介绍射频幅度调制型加解扰系统，简单介绍射频幅度调制的工作原理，分析高频电子开关和数字处理部分的电路，最后为用户提供一些应用建议。     

多媒体邮件服务综述

首先介绍了多媒体邮件服务的概貌，接着介绍了Ｘ．４００和ＭＩＭＥ，最后介绍了ＢＥＲＫＯＭ，ＣＩＯ，ＭＣＲ实验室开发的多媒体邮件服务。     

数据库存储过程设计及应用

以ORACLE数据库为例，介绍了数据库存储过程及外部存储过程的设计方法，并结合ORACLE数据库应用开发、管理与维护的需要，说明存储过程及外部存储过程的具体应用。最后，对数据库应用开发中设计并使用存储过程和外部存储过程的主要优点进行了总结。     

The structured design of cryptographically good s-boxes

We describe a design procedure for the s-boxes of private key cryptosystems constructed as substitution-permutation networks (DES-like cryptosystems). Our procedure is proven to construct s-boxes which are bijective, are highly nonlinear, possess the strict avalanche criterion, and have output bits which act (vitually) independently when any single input bit is complemented. Furthermore, our procedure is very efficient: we have generated approximately 60 such 4 × 4 s-boxes in a few seconds of CPU time on a SUN workstation.This work was partially supported by a grant from the Natural Sciences and Engineering Research Council of Canada.     

The design of two-dimensional gradient estimators based onone-dimensional operators

Two-dimensional (2-D) gradient estimators are some of the most useful tools in image processing. A computational procedure for the extension of one-dimensional (1-D) gradient estimators to two dimensions (2-D) is presented. The procedure is equivalent to the surface fitting method. It is, however, simpler in design, as the design is 1-D rather than 2-D. Higher order derivative estimators can also be constructed by the same procedure.     

The design of FM pulse compression signals

This paper gives a procedure for designing an FM signal of arbitrary envelope shape so that it will have a specified spectral modulus and hence, a specified autocorrelation function. The design procedure, which is based upon an approximate analysis, gives best results when the duration-bandwidth product of the signal is large, and it is therefore useful in the design of pulse compression signals. Examples are given to illustrate the design procedure and to show in a general way how the quality of the approximate solution depends upon the duration-bandwidth product of the signal and upon the shape of the signal envelope and the modulus of the signal spectrum.     

浅析FFU、高效过滤器安装中注意的要点

分析施工中容易出现过滤器泄露争议的情况，找到出现争议的原因，并在实际施工中去避免这些争议。     

微波件腔体加工工序能力评价

文章在介绍工序能力指数概念和基本原理的基础上,对微波件腔体加工工序进行了符合实际情况的评价,解决了微波件腔体加工过程评价问题。     

The estimation of the optimum linear decision function with a sequential random method

This paper is concerned with the categorizing of patterns by means of linear decision functions,^{1}as developed by Highleyman [1], [2]. A new procedure for the estimation of the optimum linear decision function is developed. This procedure determines the minimum estimation of the loss function with a sequential random method. An application of the procedure to the same problem as discussed in [1] and [2] yields better results than the procedure developed by Highleyman.     

The frequency-dependent impedance of p-i-n diodes

It is demonstrated that the impedance of a forward-biased p-i-n diode is definable as a function of frequency and depends on the diode's geometry and electronic properties. A procedure for calculating the equivalent series p-i-n diode impedance is presented and compared with experimental resistance versus frequency data for silicon p-i-n diodes. A procedure is also outlined for determining diode parameters for a desired resistance-frequency response     

The Stepped Digital Elliptic Filter

The design and synthesis of various types of microwave elliptic function filters has been accomplished by a number of authors. However, one problem in this field which remains is the realization of compact narrow-band bandpass elliptic function filters. In this paper, a procedure is presented which enables this class of filters to be constricted in a compact digital form. Since the physical realization is in the form of an n-wire line, one-quarter of a wavelength Iong at the center frequency of the passband, where the impedance levels are stepped along the center of the coupled lines, the filter has been termed the stepped digital elliptic filter. The absence of awkward interconnections in the filter due to the stepped digital structure inherently implies that reasonable insertion loss characteristics may be achieved in the X-band region and above, and also simplifies the mechanical construction. It is shown that the resonant elements in the filter, due to the design procedure adopted, are relatively insensitive to the absolute bandwidth of the filter, and consequently fractional bandwidths of approximately 30 percent and below may be readily achieved while the normalized impedance values of the elements in the network remain of the order of unity. This latter result is similar to that obtainable from conventional interdigital filters but in the case of narrow bandwidths the stepped digital filter is considerably smaller in physical size. A systematic procedure is also formulated for the inclusion of the parasitic lumped end effect capacitances into the overall design procedure in order to maintain the equiripple passband and stopband responses. Experimental results are presented for a five-element, 11 percent bandwidth filter and are shown to be in good agreement with theoretical predictions.     

The Reliability of Redundant Multiple-Line Networks

This paper develops a procedure for determining a lower bound to the reliability of multiple-line redundant networks. The procedure is general in that there are no restrictions on the interconnection pattern between the functions of the network, and it allows, within limitations, different parts of the network to take on different orders of redundancy. The approximation to reliability is very good if the reliabilities of the circuits in the network are close to unity.