共查询到20条相似文献,搜索用时 883 毫秒
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基于非线性盲源分离的维纳系统算法中,采用固定步长导致算法的收敛速度和稳态误差之间存在矛盾,直接影响分离算法的性能。为了解决该问题,提出了基于非线性函数的变步长维纳系统盲源分离方法。该方法将更新的步长以非线性函数的形式引入到分离算法中,使得稳态时参数更新的步长尽可能小,以避免发生振荡。变步长算法在分离过程中的每次更新都会使步长自动进行合理的调整,使得收敛速度提高了53%,误差减小了45%。实验仿真表明,相对原算法,提出的维纳系统盲源分离方法可以更好地分离出信源信号,而且具有较小的误差和较快的收敛速度。 相似文献
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Volterra均衡器能够有效地克服卫星信道的非线性失真,但由于非线性均衡器的输入矩阵特征值扩展严重,使得自适应过程收敛缓慢。为克服这个缺点,提出应用变步长的频域LMS算法对Volterra均衡器的权值系数进行自适应更新。算法利用正交变换降低输入序列的相关性,同时动态地调整迭代步长提高均衡器的收敛速度。仿真结果表明与时域算法相比,均衡器的收敛速度提高了25倍左右;均衡器收敛后纠了信号的幅度和相位失真。 相似文献
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针对分布式飞行仿真的时钟同步问题,在Luca Schenato等人的ATS(Average Time Synchronization)算法的基础上,提出了基于归并策略的一致性时钟同步算法。该算法会在获得系统时钟后,通过邻近原则或者极大极小原则对时钟进行排序组合,以此加快算法的收敛速度;同时通过重定义ATS算法的调节因子σij,使时钟收敛具有自适应性,进一步加快时钟收敛速度,使得该算法更佳适用于飞行仿真控制试验的数据同步过程。实验表明该算法相比于原算法在同步精度、收敛速度、稳定性都得到提升。 相似文献
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自适应有源消声控制器常用的算法是滤波-XLMS(FLMS)算法。该算法收敛速度慢,对噪声自相关矩阵特征值散布敏感,应用于宽带有源消声并不十分理想.本文基于最小二乘原理,提出间歇自适应IRLS算法作宽带噪声有源抵消.该算法利用声波从次级源传播到误差传声器的间隔内递推更新自适应滤波器权系数.IRLS算法的特点是收敛速度快,对噪声特征值散布不敏感.仿真结果表明:与采用FLMS算法的消声系统相比,采用IRLS算法的系统在收敛性,稳定性及降噪量等方面均有显著改进。文章最后分析了IRLS算法硬件实现的可行性。 相似文献
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非理想信道下Colpitts混沌电路的自适应同步研究 总被引:1,自引:0,他引:1
本文研究了Colpitts混沌电路在非理想信道条件下的自适应同步问题。引入自适应控制器对输入到响应部分(response system)的衰变混沌信号进行预处理,来补偿衰落信道对于同步性能的影响。给出了系统的数学模型,对恒定信道衰变和时变信道衰变两种非理想信道条件下的混沌ColpiRs电路的自适应同步进行了数值仿真研究。仿真结果表明,对于恒定或慢变化的时变信道衰变,自适应控制器可以有效的提高Colpitts电路响应部分和驱动部分(Drive system)的同步性能。 相似文献
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《IEEE transactions on circuits and systems. I, Regular papers》2008,55(4):1064-1073
Common approaches to simulate the steady-state behavior of nonlinear periodic circuits forced by a periodic signal of small amplitude assume that the forcing signal effects are additive to the steady-state solution of the unperturbed circuit. This assumption leads to the adoption of the variational model of the nonlinear unperturbed circuit. The variational model does not pose any particular problem when dealing with nonautonomous circuits, but must be suitably formulated when autonomous circuits are considered and the frequency of the forcing signal is close to the working frequency of the unperturbed nonlinear circuit. We show that, in this case, synchronization effects must be accounted for, and, as synchronization phenomena are intrinsically nonlinear, it is impossible to take them into account using a variational model. In fact, conventional variational models are derived from the unperturbed nonlinear circuit working at steady state and with a fixed relative phase between perturbation and system, i.e., without any possibility of phase shifts (that is, of any dynamics leading to possible synchronization). In general, this yields inaccurate or even wrong results. In this paper, we investigate this limitation of the approaches based on the variational model. Some simulation results are reported that show the transition between the nonsynchronization region to the synchronization one of well-known simple oscillators, such as the Van der Pol one when the parameters of the small-signal perturbation are varied. 相似文献
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A. Y. Unger G. V. Kulikov 《Journal of Communications Technology and Electronics》2014,59(11):1162-1168
Algorithms of simultaneous superbaud, clock, and phase synchronization for the detectors of continuous-phase modulated signals with cyclically varying modulation index are considered. The algorithms are based on the theory of nonlinear filtering and optimized with respect to the minimum mean-square error. A closed-loop model of the synchronization system is constructed and comprehensively studied with the aid of computer simulation. 相似文献
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Experimental synchronization of mutually coupled semiconductor lasers with optoelectronic feedback 总被引:1,自引:0,他引:1
Anticipated or retarded synchronization of a mutually coupled nonlinear system is experimentally studied through a mutually coupled semiconductor laser system subject to optoelectronic feedback. These two types of synchronization are found to arise from a predictable relation between feedback/coupling delay times under particular feedback/coupling strength combinations. A comparison between the experimental results and the theoretical predictions is completed. The experimental results mostly agree with theoretical predictions. System limitations are also discussed. 相似文献
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该文针对含未知参数的异结构超混沌复系统,基于自适应控制及Lyapunov稳定性理论,提出一种新的自适应广义组合复同步方法 (GCCS)。首先给出广义组合复同步的定义,将驱动-响应系统的同步问题转化为误差系统零解的稳定性问题;然后从理论上设计了非线性反馈同步控制器及参数辨识更新律,并引入误差反馈增益,以控制同步的收敛速度;最后以超混沌复Lorenz系统、超混沌复Chen系统、超混沌复L系统的广义组合复同步与参数估计为例,从数值仿真角度验证了所提方法的正确性和有效性。 相似文献
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利用非线性函数控制的混沌异结构同步 总被引:1,自引:1,他引:0
万志超 《微电子学与计算机》2008,25(4):52-55
研究了利用非线性函数控制的混沌异结构同步问题.基于Lyapunov稳定性理论,设计了非线性控制函数,使得同步误差系统的Lyapunov函数的形式为V(e)=eTPe(P为正定矩阵),根据数学公式推导,理论证明了该方法可以实现不同混沌系统之间的异结构同步.数值模拟进一步验证了所提出方案的有效性. 相似文献
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