共查询到20条相似文献,搜索用时 125 毫秒
1.
Barker码的一些结论和二元码的优选问题 总被引:5,自引:2,他引:3
本文最终证明了不存在n>13位的Barker码,并探索了二相码的解析优选法。文中定义了一个Yn矩阵,并由Yn导出了二相码的重量w,Hamming距离d,游程数l和码长n之间的关系式,所得关系不仅揭示出二相码各参数之间,而且可用它来解决Barker码的存在性问题,从而将二相码的优选问题建立在解立在解析的基础上,文中还举出了应用实例。 相似文献
2.
3.
指出杨光正(1995)关于证明n13的Barker不存在的证明过程有误,因此,n13的Barker码是否存在仍然是一个猜想。 相似文献
4.
二相码信号由于实现简单,已经广泛地应用于各种脉冲压缩雷达,然而到目前,高压缩比、低旁瓣二相码信号的优选由于数学处理的困难和计算代价的昂贵一直没有很好解决。本文引入神经元计算的思想,提出了基于模拟退火的二相码选码方法。实验结果表明,这种方法不仅能搜索到最优码,搜索次数大大减少,而且易于做到优选二相码的优化程度与计算代价之间的折衷。 相似文献
5.
6.
首先给出了希尔波特解调过程,研究了相位编码信号的识别算法,接着对识别过程中存在的相位模糊问题提出了针对性的解决方法。基于上述算法,文中对二相编码信号、四相编码信号及多相码调制信号进行了仿真试验,得到了较好的效果,验证了文中算法的正确性和有效性,最后将算法应用于某雷达接收机的测试系统中,验证了其经济性和实用性。 相似文献
7.
分维几何学自七十年代中期出现以来,一直是十分热门的学科,最近愈来愈受到人们的重视。本文将分维的思想引入到信号设计领域中来,提出二相码选码的新方法——分维树生成法。与前人的结果比较,新方法的搜索次数大大减少,从而为搜索高压缩比低副瓣的二相码提供了一个有效途径。 相似文献
8.
9.
10.
相对于LDPC码、Turbo码等经典编码,极化码由于具有较低的编译码复杂度和容量可达的特性,成为近年来信道编码的研究热点之一。文中对极化码的研究意义进行了分析,总结了极化码的研究现状,对存在的问题进行了探讨并给出了未来研究方向的展望。 相似文献
11.
12.
In this paper, a new channelization code tree structure, namely an ROVSF (rotated-orthogonal variable spreading factor) code tree, is defined and investigated. Most existing code assignment schemes are investigated on the OVSF (orthogonal variable spreading factor) code tree in WCDMA systems. The main work of this investigation is to exploit and justify the new properties of the ROVSF code tree. We show that the ROVSF code tree offers the same code capability to that of the conventional OVSF code tree, but our ROVSF code tree additionally has the code-locality capability. With the code-locality capability, a fast code-assignment strategy is developed on the ROVSF code tree. Compared to existing code assignment schemes on OVSF code trees, a fast code assignment scheme is developed with lower search costs and a low blocking rate, due to its code-locality capability. Finally, the simulation results illustrate that our proposed scheme on the ROVSF code tree actually has lower search costs and a better blocking rate.This work was supported by the National Science Council of the R.O.C. under grant nos. NSC91-2213-E-194-041 and NSC91-2213-E-194-042. 相似文献
13.
The problem of Gray image of constacyclic code over finite chain ring is studied. A Gray map between codes over a finite chain ring and a finite field is defined. The Gray image of a linear constacyclic code over the finite chain ring is proved to be a distance invariant quasi-cyclic code over the finite field. It is shown that every code over the finite field, which is the Gray image of a cyclic code over the finite chain ring, is equivalent to a quasi-cyclic code. 相似文献
14.
The problem of Gray image of constacyclic code over finite chain ring is studied. A Gray map between codes over a finite chain ring and a finite field is defined. The Gray image of a linear constacyclic code over the finite chain ring is proved to be a distance invariant quasi-cyclic code over the finite field. It is shown that every code over the finite field, which is the Gray image of a cyclic code over the finite chain ring, is equivalent to a quasi-cyclic code. 相似文献
15.
16.
17.
18.
NRZ伪随机码序列同步时钟提取 总被引:2,自引:0,他引:2
在光纤数字通信系统中,NRZ非归零码是一种最常见的基带信号。它本身不含有位同步时钟分量。只有对其进行非线性处理,转换成RZ归零码后,方可提取出同步时钟,本文通过对NRZ,RZ伪随机码序列进行频谱分析,得知当NRZ码变换成码元占空比为1/2的RZ码时,所提取的同步时钟功率最强。 相似文献
19.
20.