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SC混沌比例投影同步方法在保密通信中的应用 总被引:1,自引:0,他引:1
利用基于线性稳定性准则的SC混沌比例投影同步方法,提出一种应用于保密通信的混沌掩盖方案.适当分离出混沌系统的线性项与非线性项,构造一个非线性驱动向量函数,混沌状态变量包含用于投影同步的比例因子,把所需传递的有用信息掩盖入其中一个分量上,得到混沌载波信号,提高加密信息的复杂度和解码的困难度.以Lorenz吸引子和超混沌Rössler吸引子为例进行数值仿真,详细分析传输的正弦信息加密解密全过程,给出简单、最优的混沌掩盖方案,数值分析证明比例投影同步方法应用于保密通信领域的有效性. 相似文献
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时空混沌系统在保密通信中的应用 总被引:1,自引:1,他引:0
以环形腔中激光振荡输出空间扩展模型为例,研究了多组信息同时编码的时空混沌加密及解密,给出安全可靠的加解密结果,并对抗破译能力进行了检验,完成了互联网上保密通信实验,结果令人满意。 相似文献
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EMR对混沌同步保密通信系统干扰的初步研究 总被引:2,自引:2,他引:0
使用GTEM Cell实验系统,研究了连续波电磁辐射对基于混沌同步理论的保密通信系统的电磁干扰。混沌保密通信系统采用由典型的Chua氏混沌电路构造混沌同步系统,采用掩盖法对模拟信号进行加密传输。实验发现:在100MHz~150MHz的频率范围内,超过一定功率密度的电磁辐射会导致系统的混沌加密功能失效,此后即使停止电磁辐射,系统仍无法自行恢复到混沌加密状态。 相似文献
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光学双稳系统混沌驱动保密通讯原理研究 总被引:4,自引:0,他引:4
根据声光双稳系统混沌驱动下的动力学行为,提出利用系统的相位特性实现信息的混沌加密,并且由接收端混沌驱动产生的混沌信号完成信息提取的原理。发现在较大的噪声覆盖下仍然可以实现信息的安全传送,由于信息解密不需要与载波安全同步的混信号而只利用传输信号与接收端被驱动系统输出信号的相位关系,因此这种方法具有实际应用价值。 相似文献
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语音信号调制的微腔半导体激光器的抗噪音性能 总被引:4,自引:3,他引:1
假定微腔半导体激光器输入调制信号为实际语音信号,伴随语音信号的噪音为加性白噪音,在小信号近似下,得到了电流调制和自发发射寿命调制下激光器的传递函数;在大信噪比的前提下,对激光器进行了频域分析,得到了不同参量下的信噪比增益.数值模拟结果表明,在偏置电流的变化范围内,存在极低信噪比增益区,大自发发射因子、小自发发射寿命有利于使该区变窄;语音信号的通带范围和功率谱密度分布特征参量的适当选取,可以使激光器的抗噪音性能在偏置电流的某段范围内得以提高. 相似文献
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A new synchronization theorem for a class of chaotic systems is presented based on nonlinear observer theory. We take the first state variable of the drive system as the driving scalar signal. Its linear feedback gain is a function of a free parameter. It is proven that global synchronization can be attained through simple linear output error feedback. This approach is illustrated by the WGY hyperchaotic system and Chua's oscillator. 相似文献
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M F Dorman M T Hannley G A McCandless L M Smith 《The Journal of the Acoustical Society of America》1988,84(2):501-510
The phonetic identification ability of an individual (SS) who exhibits the best, or equal to the best, speech understanding of patients using the Symbion four-channel cochlear implant is described. It has been found that SS: (1) can use aspects of signal duration to form categories that are isomorphic with the phonetic categories established by listeners with normal auditory function; (2) can combine temporal and spectral cues in a normal fashion to form categories; (3) can use aspects of fricative noises to form categories that correspond to normal phonetic categories; (4) uses information from both F1 and higher formants in vowel identification; and (5) appears to identify stop consonant place of articulation on the basis of information provided by the center frequency of the burst and by the abruptness of frequency change following signal onset. SS has difficulty identifying stop consonants from the information provided by formant transitions and cannot differentially identify signals that have identical F1's and relatively low-frequency F2's. SS's performance suggests that simple speech processing strategies (filtering of the signal into four bands) and monopolar electrode design are viable options in the design of cochlear prostheses. 相似文献
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We study the synchronizing sensitive errors of chaotic systems for adding other signals to the synchronizing signal. Based on the model of the Henon map masking, we examine the cause of the sensitive errors of chaos synchronization. The modulation ratio and the mean square error are defined to measure the synchronizing sensitive errors by quality. Numerical simulation results of the synchronizing sensitive errors are given for masking direct current, sinusoidal and speech signals, separately. Finally, we give the mean square error curves of chaos synchronizing sensitivity and three-dimensional phase plots of the drive system and the response system for masking the three kinds of signals. 相似文献
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混沌信号与确定性小信号叠加生成的混合信号是一更高维的混沌信号,因而不能用一般的混沌信号噪声抑制的方法进行分离.提出了一种这类信号盲分离的方法.在重构未知的混沌信号的动力方程时,充分利用混沌吸引子的几何特性,并且限定动力映射为原混沌吸引子所在流形的内部映射,从而保证了重构的动力系统方程对应于原混沌信号,而不是同样具有混沌特性的混合信号.然后利用重构的动力方程,借用混沌信号中的噪声抑制思想,估计出原混沌信号对应的轨道,实现信号分离.通过对Lorenz系统中谐波信号、Henon映象中自回归过程,以及脑电信号中谐波信号进行提取的数值实验,验证了信号盲分离方法的有效性和可行性.
关键词:
混沌
非线性
信号处理
盲分离 相似文献
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This paper investigates a reconfigurable intelligent surface (RIS)-aided underlay cognitive radio (CR) multiple-input multiple-output (MIMO) wiretap channel where the secondary transmitter (ST) communicates with primary user (PU) and secondary user (SU) in the absence of the eavesdropper’s (Eve’s) channel state information (CSI). To enhance the secrecy performance in CR MIMO wiretap channel, the power of useful signal is minimized at ST, and then the residual power is further utilized to design artificial noise (AN) based on statistical CSI at ST. Specifically, we first optimize the transmit covariance matrix at ST and the diagonal phase-shifting matrix at RIS jointly leveraging large-system approximation results. Then the power allocation for SU is optimized to obtain the minimum transmit power of useful information at ST. Besides, we further design AN with the residual power by aligning it into the null space of the SU channel and thus avert the harmful effects of AN to improve the secure communication quality of SU. Finally, through numerical simulations, we illustrate the effectiveness of the proposed algorithm and validate the existence of a trade-off between the quality-of-service (QoS) at SU and secrecy rate. 相似文献
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F H Guenther C Y Espy-Wilson S E Boyce M L Matthies M Zandipour J S Perkell 《The Journal of the Acoustical Society of America》1999,105(5):2854-2865
The American English phoneme /r/ has long been associated with large amounts of articulatory variability during production. This paper investigates the hypothesis that the articulatory variations used by a speaker to produce /r/ in different contexts exhibit systematic tradeoffs, or articulatory trading relations, that act to maintain a relatively stable acoustic signal despite the large variations in vocal tract shape. Acoustic and articulatory recordings were collected from seven speakers producing /r/ in five phonetic contexts. For every speaker, the different articulator configurations used to produce /r/ in the different phonetic contexts showed systematic tradeoffs, as evidenced by significant correlations between the positions of transducers mounted on the tongue. Analysis of acoustic and articulatory variabilities revealed that these tradeoffs act to reduce acoustic variability, thus allowing relatively large contextual variations in vocal tract shape for /r/ without seriously degrading the primary acoustic cue. Furthermore, some subjects appeared to use completely different articulatory gestures to produce /r/ in different phonetic contexts. When viewed in light of current models of speech movement control, these results appear to favor models that utilize an acoustic or auditory target for each phoneme over models that utilize a vocal tract shape target for each phoneme. 相似文献
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构造了一个三维混沌系统, 简要分析了该混沌系统的平衡点性质、混沌吸引子相图和Lyapunov指数等特性. 在此基础上, 利用反馈同步思想设计了一种利用混沌信号部分信息实现混沌同步的方法, 完成了三维混沌系统的同步. 该方法仅利用混沌信号幅值信息即可实现两个混沌系统的同步, 其同步建立与混沌信号的极性无关, 此特性可有效提高混沌通信质量. 通过分析系统的条件Lyapunov指数证实该方法的有效性, 数值仿真表明该方法与利用混沌信号全部信息的线性反馈同步法相比, 同步建立时间基本相同. 相似文献