排序方式: 共有21条查询结果,搜索用时 15 毫秒
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Statistical distributing and magnitude of the first and second-order polarization mode dispersion (PMD) vectors are evaluated and the timing displacements of its effects on dispersion-managed soliton (DMS) are also given with help of coarse-step approach, such as Jones matrix (JME) and coupled nonlinear Schrodinger equations (CNLSE). The results showed that the coarse-step approach can not only simulate the statistical characteristics of PMD, but also compute the nonlinear pulse characteristic of timing and energy jitters evolution affected by PMD. The presented results are very useful to simplify the measurement of second-order PMD and instructively reveal the degree of PMD effects in DMS systems. 相似文献
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一种新的大容量的二维光正交码 总被引:3,自引:3,他引:0
构造了一种扩展的双曲线性同余码(EHLC)并分析了其码字性能.用该码作为时间扩频伪随机序列和以素数码(PC)作为波长跳频伪随机序列,再构成一种新的二维光正交码EHLC/PC.然后分析了EHLC/PC码字的性能,并与EQC/PC作了比较.相比之下,前者的互相关性能略有下降,但码字容量大大增加.因此,EHLC/PC适合于用户数较多的OCDMA系统. 相似文献
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采用最大似然准则,研究了多波长光码分多址接收机的最佳判决门限值.通过检测信道的光信号能量,接收端估计出信道的并发用户数,并通过最大似然准则得到了最佳判决门限值与并发用户数、码字参量的变化关系.当并发用户数超过一定值后,最佳判决门限值将随并发用户数量变化,相应地改变接收机的判决门限值.根据最佳判决门限值,得到了多波长光码分多址系统误码率与并发用户数的关系.理论分析和模拟结果表明,采用最大似然准则得到的最佳判决门限值,MW OCDMA系统的误码率将明显降低. 相似文献
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The performance of normalized throughput in wavelength division multiplexing (WDM) based coherent time-spreading optical code division multiple access (TS-OCDMA) system is studied. The upper bound and lower bound of normalized throughput are obtained with 8 wavelength channels and 127-length Gold code, and with 4 wavelength channels and 511-length Gold code respectively. It is shown that when all simultaneous users are equally allocated to different wavelength channels, WDM+TS-OCDMA has much better performance. However, if there is no central control to allocate wavelength channels equally, WDM+TS-OCDMA system has the in-between performance of normalized throughput. 相似文献
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Turbo码对快跳频光码分多址系统性能的改善 总被引:2,自引:2,他引:0
在考虑多用户干扰、色散效应和差拍噪声的情况下,分析了Turbo码对二进制脉冲位置调制(BPPM)的快跳频光码分多址(FFH OCDMA)系统性能的影响.在均匀交织器的情况下,用Turbo码的条件重量枚举函数得到了该系统的误码率的上界.数值模拟表明,Turbo码对FFH OCDMA系统的误码率性能有明显的改善,并且随着用户数的提高,Turbo码对误码率的改善程度也随之提高.也就是说,在一定的误码率性能要求下,Turbo编码的FFH OCDMA系统增加了同时使用的用户数. 相似文献