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991.
992.
HE Bo~ LI Jun~ LIN Jia-ru~ WU Wei-ling~ .School of Information Science Engineering Beijing University of Posts Telecommunications Beijing P.R. China .School of Information Science Engineering Shandong University 《中国邮电高校学报(英文版)》2005,12(2)
1IntroductionOFDM known as a multicarrier modulation schemehas recently received considerable attention for its ro-bustness to multipath selective fading,provided by onetap equalization in frequency domain. This technique isrecommendedin Europe bythe ITU-Ras atransmissionstandard for Digital Audio Broadcasting ( DAB) fromsatellite or terrestrial fixed stations to mobile users ;andit also being adopted by EBU for terrestrial DigitalVideo Broadcasting (DVB-T) .In wireless environments … 相似文献
993.
本文首先论述了短波实时选频和跳频通信的工作机理;然后讨论了控制器的两个主要功能模块,并对其跳频通信技术和控制器硬件结构,软件实现方法作了较详尽的介绍;最后给出了实时选频和跳频通信系统的实际线路实验情况。 相似文献
994.
Most writers on frequency assignment algorithms have described the details of a single algorithm, and evaluated the algorithm on selected data sets. There has been relatively little emphasis on describing the common features that are important if an algorithm is to have good performance. This paper describes the key features, with particular emphasis on algorithms for weighted fixed spectrum problems. The use of algorithms handling weighted constraints has become increasingly common in recent years. The advantages and disadvantages of weighting constraints are demonstrated. 相似文献
995.
996.
采用IPM (Intelligent Power Module智能功率模块)和MCU(Micro Control Unit 微控制器)作为主要部件研制的SPWM中频电源系统,具有系统结构简单,控制灵活的优点.由于中频电源通常应用于对电磁兼容性要求较高的场合,因此,对系统电磁兼容性的改进做了阐述. 相似文献
997.
998.
I. E. Zuikov A. A. Kutsak Yu. F. Tuzkov N. V. Zuikova 《Journal of Applied Spectroscopy》1999,66(4):636-639
On the basis of the general method of calculation of linear weakly coupled anisotropic resonators, we obtained specific analytical
expressions for the beat frequency between orthogonally polarized waves in resonators that contain a phase anisotropic plate
in the active part and a polarizer in the passive part. We carried out experimental investigations. Good qualitative and quantitative
agreement between theory and experiment is established.
To whom correspondence should be addressed.
Belarusian State Polytechnic Academy, 65, F. Skorina Ave., Minsk, 220027, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 66, No. 4, pp. 565–568, July–August, 1999. 相似文献
999.
Christine L. Valenzuela 《Journal of Heuristics》2001,7(1):5-21
The genetic algorithm (GA) described in this paper breeds permutations of transmitters for minimum span frequency assignment. The approach hybridizes a GA with a greedy algorithm, and employs a technique called Generalized Saturation Degree to seed the initial population. Several permutation operators from the GA literature are compared, and results indicate that position based operators are more appropriate for this kind of problem than are order based operators. My offspring versus mid-parent correlation studies on crossovers show Pearson's correlation coefficient to be a reliable predictor of performance in most cases. Results presented herein represent improvements over previously published results. 相似文献
1000.