The whole architecture of software radio system is divided into five modules including wide band antenna and radiant frequency front - end module , wide band a / d and d / a one , converter one , digital signal processing one with high speed and instruction processing one . accordingly some technical nodi are analyzed and key techniques to solve these questions are stated in the every module at length . during the software design , the modularization design of the software radio is accomplished with borland c + + builder and the main module program is written so that the system can work in three different ways such as receiver , transmitter and gateway 本文跟踪国内外软件无线电最新研究现状，详细推导了软件无线电的基本理论；在方案论证的基础上，把pc机、 windows操作系统分别作为通用硬、软件平台，将软件无线电系统在结构上分为五个模块，分别为宽带天线及射频前端模块、宽带模数和数模转换模块、变频器模块、高速数字信号处理模块和信令处理模块，并对每个模块中的技术难点和实现此模块功能的关键技术进行详细论述；在系统软件化设计过程中，利用borlandc + + builder完成软件无线电系统总体模块化设计，编写了主模块程序，使整个系统能工作于三种状态：接收机、发射机和网关。
The research in software radio is not more than ten years , but has made a great many fruits , but it is too little to set up an integrated theory system , and software radio includes many areas such as modern communication system ( which includes modem source / channel encoding and decoding , equalization , encrypt and decrypt and so on ) , wideband antenna theory , digital signal process , microelectronics , computer and so on . this thesis mainly does research for modem in modem communication 软件无线电经过不到10年的研究，尽管取得了很多成果，但是对于建立一套完整的理论体系来说，还远远不够，况且软件无线电涉及的领域多、面广、发展快，如现代通信理论(含调制解调、信源信道编解码、均衡、加密解密等) 、宽带天线理论、数字信号处理、微电子、计算机等。
Considering the one - sidedness and inaccuracy of knowledge discovery only from single - color database , an approach is proposed to discover knowledge from 1331 groups of mix - color database with partial least - square regression , based on measuring and learning 400 groups of single - color database . by this method , the mean error decreases when converting from rgb to cmyk , the precision of color matching is improved , and the automatic and general problem in color matching is further solved 本文基于统计学习理论构造了一种快速自适应随机搜索算法,证明了算法的收敛性.给出了一种简易实用的宽带天线匹配设计新方法.应用该自适应算法进行天线匹配设计,不仅算法简单,易于编程实现;而且能够快速设计出具有较好性能的匹配网络,非常适用于各种短波、超短波天线的匹配设计问题
Firstly , the differences between the ultra - wideband antenna and conventional wideband antenna are introduced in this thesis , and the definitions of several performance parameters of the ultra - wideband antenna are presented , among which the phase center and the group delay time are primarily discussed in that they describe the time domain properties of the antenna 首先,简要介绍了超宽带天线与传统超宽带天线的区别,给出了超宽带天线的性能参数在时域的描述方法。着重介绍了描述超宽带天线时域特性的两个参数,即相位中心和群延时。
This dissertation is mainly concerned about the radiation of the tem - horn arrays which radiate uwb ( ultra wideband ) pulse , it mainly involves three parts : theory , numerical stimulation and experiment . the uwb antenna is a new research field in the world which has many differences from nb ( narrow band ) antenna . the most difference is that the uwb antenna such as tem - horn radiates nanosecond pulse which has wide frequency spectrum , but the nb antenna radiates single frequency signal 超宽带天线是一项新兴的研究领域，它与窄带天线有很多不同之处，最根本的不同在于：超宽带天线例如tem喇叭天线是辐射纳秒级短脉冲信号，这种脉冲信号有很宽的频谱；而窄带天线大都是辐射单一频率时谐信号的。
Many technologies of electrically small antennas and wide band antennas are discussed in theory , simulation and experiment . and some novel electrically small or wide band antennas are proposed . the loaded monopole is analyzed in depth integrating the genetic algorithm ( ga ) with the method of moments ( mom ) in order to increase the gain and decrease the vswr of antennas used at hf / vhf band 在本论文的研究过程中,通过合理利用各种现有的天线宽带化和小型化的理论成果、有效的综合各种技术措施,运用矩量法和遗传优化算法等数值方法,深入研究了加载单极子天线问题,旨在全面提高高频/甚高频频段内的天线增益和降低电压驻波比,以获得较高增益的、基本满足驻波要求的小型超宽带天线。
The circular monopole ultra - wideband antenna has not only the extremely wide band in frequency domain , but also stable phase center , which makes the antenna radiate and receive the short pulse signals without any distortion , and suitable for various ultra - wideband communication systems or the single antenna of other multi - frequency operating communication systems 这种天线不仅具有极宽的阻抗带宽,还拥有稳定的相位中心。这使得圆盘单极超宽带天线可以不失真地收发时域短脉冲信号。所以该天线不仅适用于超宽带通信中,还能够作为复杂多频工作系统的单一收发天线。
