共查询到18条相似文献，搜索用时 78 毫秒
1.
跳频(时)序列分析与设计是跳频(时)扩频通信系统的核心技术.无碰撞区跳频序列是近年新出现的一个研究方向,现已成为通信领域的研究热点.对无碰撞区跳频序列的理论界及其设计进行深入研究,导出无碰撞区跳频序列的一些本质属性;讨论无碰撞区跳频序列集周期汉明相关函数的理论界,揭示几个理论界之间的关系,给出这些理论界等价的条件.提出最优无碰撞区跳频序列的一般构造方法.利用该构造方法,可以产生任意长度的最优无碰撞区跳频序列集.并且,任意一个最优无碰撞区跳频序列集,都可以由一般构造方法产生. 相似文献
2.
魏艳华 《成都信息工程学院学报》2007,22(1):84-87
跳频通信是一种有效的抗干扰通信技术，跳频序列的性能对跳频通信系统的性能有着决定性的影响。重点阐述了RS码作为跳频序列的编码方法及其性能，介绍了RS码序列的具体编写方法，并进行了计算机仿真，计算了所生成RS跳频序列的汉明相关性能。 相似文献
3.
针对BDS全星座播发三频信号的特点,利用1个三频载波伪距组合(1,4,-5)和2个三频无几何相位组合(1,1,-2)、(1,-2,1)联合的方法进行周跳探测,并结合最小2-范数确定整数周跳的搜索策略。实测数据表明,该方法对一般周跳、不敏感周跳及连续随机周跳均有较好的探测与修复效果。 相似文献
4.
轨道站点是城市轨道交通基本线网系统中的关键节点,科学的轨道站点分类,对了解城市功能分区及评价轨道交通基础设施建设情况具有重要意义。轨道交通站点时间序列客观记录了所观测的站点在各个时刻点的重要信息,研究其时间序列聚类,是认识和理解轨道交通站点时间序列形成本质的重要手段,也是挖掘轨道交通站点时间序列中隐含的有较高价值规律知识的重要方法。本文以北京IC卡轨道站点刷卡数据为研究对象,提出了描述轨道站点的4个数据集,即工作日进站数据集(WB)、工作日出站数据集(WA)、休息日进站数据集(RB)和休息日出站数据集(RA);并首次引入时间序列分析方法（符号集合近似(SAX)方法）对4个数据集进行聚类分析,实现了高维数据的有效降维和轨道站点之间的相似性度量。采用层次聚类方法并根据聚类有效性DB指数确定将195个站点分为8类更为合理。通过分析每类站点的日客流特征和空间位置分布情况,为轨道交通站点规划设计和管理服务提供一定的客观参考依据。 相似文献
5.
利用Hector软件解算山西地区10个陆态网络连续站2010-11～2021-01的观测数据,得到连续站坐标残差时间序列,并确定最优噪声模型及修正后的速度场.结果表明,山西地区坐标时间序列数据中主要存在白噪声(WN)、闪烁噪声(FN)和幂律噪声(PL);N方向的最优噪声模型为WN+PL;E和U方向的最优噪声模型均为WN... 相似文献
6.
王章雄 《成都信息工程学院学报》2006,21(3):454-456
bent函数是一类具有良好密码特性的编码组合函数,而S-box既可以对块密码的明文也可以在流密码中作为对密钥流的加密装置.将bent的优良性质带入S-box是一个很有意义的研究课题.以前用函数序列半群和置换群来构造bent型S-box.现通过陪集方法得到bent函数组,又利用适当的指标函数来构造S-box,使得其中任意一个部分组的非零线性组合仍然是bent函数,从而保证S-box的输出端具有很高的密码强度. 相似文献
7.
本文利用霍尔序列设计一种半导体激光天气雷达的发射波形,解决了用m序列时无法解决的信号压缩比要求和系统运算速度限制之间的矛盾。文中给出了波形的设计和产生方法及其性能模拟结果。 相似文献
8.
针对现有的周跳探测方法中载噪比(carrier-to-noise ratio, CNR)数据未被有效利用这一问题,在分析BDS卫星种类对MW(Melborne-Wubbena)组合观测值影响的基础上,基于传统TurboEdit算法,根据BDS不同种类卫星提出一种基于载噪比加权的MW组合周跳探测模型。测试结果表明,相比于传统TurboEdit算法,该方法可以有效减少BDS-2的IGSO卫星和MEO卫星因系统偏差引起的周跳漏检和误检,具有一定的优越性。 相似文献
9.
正交频分复用(OFDM)作为一种可以有效对抗符号间干扰(ISI)的高速传输技术,得到了广泛的应用,而信道估计技术作为其重要技术之一得到了很大的发展.信道估计分为盲信道估计、半盲信道估计和基于导频的信道估计.主要研究基于导频的最小平方(LS)信道估计和线性最小均方误差(LMMSE,Linear Minimum Mean Square Error)信道估计,在不同的信道环境和不同的循环前缀(CP)和导频子载波数下的性能比较并得出结论. 相似文献
10.
GPS周跳是影响监测成果精度的重要因素之一,其多值性及如何判断各自频率上的周跳尤为重要。本文针对双频周跳探测,以ΔΦ=ΔN1－(λ2/λ1)ΔN2为主方程,提出一种通过Grubbs准则探测ΔN1、ΔN2异常值的方法来约束双频周跳ΔN1、ΔN2的搜索范围,通过计算满足主方程整数解的方式探测周跳。通过采样率为1 s、5 s和15 s的GPS数据进行验证,结果表明,采用本文方法不仅可以解决普通周跳和特殊周跳的多值问题,而且能准确探测各频率上的周跳,计算准确率达100%。 相似文献
11.
跳频与同频复用是移动通信系统中重要的两种应用技术。简介跳频技术与同频复用的基本原理，并着重分析了在实际应用中跳频与同频复用相结合的几种方式。 相似文献
12.
Songliao Basin is filled predominantly with continental facies sediments including alluvial fan, fluvial plain, fan delta , lacustrine delta, shore ?shallow lacustrine, beach salty flat, semi - deep to deep lacustrine, subaqueous gravity flow, lacustrine swamp and pyroclastic sediments. However, some event units were formed during lake - marine linking periods of the Mid - Cretaceous in the basin, which include black shales with high values for salinity ( Sr/Ba) , alkalinity (Ca Mg)/ (Si Al) , reducibility ( Ni Zn)/Ga and sulfide sulfur as well as heavy isotopes. The Breitenholz ?section to be represen-ted for facies comparison with the Cretaceous evaporitic series in Northeast China is localized in Southwest Germany. Stratig-raphically it belongs to the Crabfeld Formation of Keuper of the Germanic Triassic corresponding to Ladinian - Camian of the international reference scale, and is generally called Lower Gipskeuper. The Germanic Triassic was deposited in the epiconti-nental(cratonic) central Euro 相似文献
13.
1 ＩｎｔｒｏｄｕｃｔｉｏｎＳｏｎｇｌｉａｏＢａｓｉｎｈａｓｂｅｅｎｂｅｉｎｇｔｈｅｌａｒｇｅｓｔｏｉｌａｎｄｇａｓｐｒｏｄｕｃｉｎｇｂａｓｉｎｏｆＣｈｉｎａｕｐｔｏｎｏｗ .Ｔｈｅｐｒｅｓｅｎｔｒｅｍｎａｎｔａｒｅａｏｆｔｈｅｂａｓｉｎｉｓａｂｏｕｔ 2 6 0 相似文献
14.
Songliao Basin is filled predominantly with continental facies sediments including alluvial fan, fluvial plain, fan delta, lacustrine delta, shore - shallow lacustrine, beach salty flat, semi - deep to deep lacustrine, subaqueous gravity flow,lacustrine swamp and pyroclastic sediments. However, some event units were formed during lake - marine linking periods of the Mid - Cretaceous in the basin, which include black shales with high values for salinity (Sr/Ba) , alkalinity ( Ca + Mg)/(Si + Al) , reducibility (Ni + Zn)/Ga and sulfide sulfur as well as heavy isotopes. The Breitenholz -section to be represented for facies comparison with the Cretaceous evaporitic series in Northeast China is localized in Southwest Germany. Stratigraphically it belongs to the Crabfeld Formation of Keuper of the Germanic Triassic corresponding to Ladinian - Carnian of the international reference scale, and is generally called Lower Gipskeuper. The Germanic Triassic was deposited in the epicontinental (cratonic) central Europe Basin. It covered the area in between Great Britain, North Sea, Poland and Southern Germany. It is composed of cyclic deposits of multicolored mudstones, gypsum/anhydrite, and dolomite beds. The two cases of marine ingression - influenced sequences share some common features. 相似文献
15.
WANGKuiyang LIANGRuicai R.Girault 《中国海洋大学学报(英文版)》2004,3(1):85-92
1 Introduction TheYellowSeahasaveragewaterdepthsbetween30and 90m (Liuetal.,1 987) .Liuindicatesthattworegressiveevents ,namedChengshantou (4 0 -75ka)andYellowSea (1 5 - 2 3ka) ,haveoccurredsincetheLatePleistocenebasedonthepeatbedsfoundincores (Liuetal.,… 相似文献
16.
A 605 bp section of mitochondrial 16S rRNA gene from Paralichthys olivaceus, Pseudorhombus cinnamomeus, Psetta maxima and Kareius bicoloratus, which represent 3 families of Order Pleuronectiformes was amplified by PCR and sequenced to show the molecular systematics of Pleuronectiformes for comparison with related gene sequences of other 6 flatfish downloaded from GenBank. Phylogenetic analysis based on genetic distance from related gene sequences of 10 flatfish showed that this method was ideal to explore the relationship between species, genera and families. Phylogenetic trees set-up is based on neighbor-joining, maximum parsimony and maximum likelihood methods that accords to the general rule of Pleuronectiformes evolution. But they also resulted in some confusion. Unlike data from morphological characters, P olivaceus clustered with K.bicoloratus, but P cinnamomeus did not cluster with t3. olivaceus, which is worth further studying. 相似文献
17.
Little is known about the genome of Pacific white shrimp (Litopenaeus vannamei). To address this, we conducted BAC (bacterial artificial chromosome) end sequencing of L. vannamei. We selected and sequenced 7 812 BAC clones from the BAC library LvHE from the two ends of the inserts by Sanger sequencing. After trimming and quality filtering, 11 279 BAC end sequences (BESs) including 4 609 paired- ends BESs were obtained. The total length of the BESs was 4 340 753 bp, representing 0.18% of the L. vannamei haploid genome. The lengths of the BESs ranged from 100 bp to 660 bp with an average length of 385 bp. Analysis of the BESs indicated that the L. vannamei genome is AT-rich and that the primary repeats patterns were simple sequence repeats (SSRs) and low complexity sequences. Dinucleotide and hexanucleotide repeats were the most common SSR types in the BESs. The most abundant transposable element was gypsy, which may contribute to the generation of the large genome size of L. vannamei. We successfully annotated 4 519 BESs by BLAST searching, including genes involved in immunity and sex determination. Our results provide an important resource for functional gene studies, map construction and integration, and complete genome assembly for this species. 相似文献