共查询到20条相似文献,搜索用时 62 毫秒
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We describe a noise-resistant pulse oximetry algorithm suited to both signal reconstruction and oxygen saturation estimation. The algorithm first detects relatively clean signal sections from which the heart rate is estimated. The heart rate is used to construct a synthetic reference signal that matches an idealized pulse signal. An adaptive filter continuously processes the sensor signals, reconstructing signals in a linear subspace defined by the reference signal. A projective subspace algorithm is then applied to find the oxygenation level of the blood. We show that under specific circumstances this algorithm solves the sufficiency condition for signal reconstruction in linear saturation estimators. The core principle of using a frequency modulated synthetic reference signal can be applied to adaptive filtering of other physiological signals controlled by the heartbeat, such as blood pressure and electrocardiogram. 相似文献
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中国移动多媒体广播外辐射源雷达参考信号获取方法研究 总被引:1,自引:0,他引:1
该文结合中国移动多媒体广播(CMMB)信号的特殊结构,提出了两种CMMB外辐射源雷达参考信号获取方法,即基于CMMB同步信号的自适应滤波提纯算法与利用CMMB调制解调理论的参考信号重构算法。首先给出了两种算法的具体处理流程;接着通过计算机仿真重点分析比较了两种算法的性能,利用实测处理验证了重构算法的有效性。研究表明基于参考信号重构的提纯方法能有效地消除参考信号中的噪声干扰和多径干扰,具有获取参考信号纯度高、算法稳健等优点。 相似文献
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This paper describes a digital receiver for radiomobile communications. The adaptive filter is a purely spatial filter. The used criterion is the minimisation of a mean square error between the array output signal and a reference signal. The reference signal is generated using the demodulator results. No learning sequence is required. The algorithm is digitally implemented and it uses a direct matrix inversion algorithm. The performance study, using simulation and experimental results, shows tracking properties, jammers cancelling and multivath correction. 相似文献
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Signal separation by symmetric adaptive decorrelation: stability,convergence, and uniqueness 总被引:4,自引:0,他引:4
The performance of signal enhancement systems based on adaptive filtering is highly dependent on the quality of the noise reference. In the LMS algorithm, signal leakage into the noise reference leads to signal distortion and poor noise cancellation. The origin of the problem lies in the fact that LMS decorrelates the signal estimate with the noise reference, which, in the case of signal leakage, makes little sense. An algorithm is proposed that decorrelates the signal estimate with a “signal-free” noise estimate, obtained by adding a symmetric filter to the classical structure. The symmetric adaptive decorrelation (SAD) algorithm no longer makes a distinction between signal and noise and is therefore a signal separator rather than a noise canceler. Stability and convergence are of the utmost importance in adaptive algorithms and hence are carefully studied. Apart from limitations on the adaptation constants, stability around the desired solution can only be guaranteed for a subclass of signal mixtures. Furthermore, the decorrelation criterion does not yield a unique solution, and expressions for the “phantom” solutions are derived. Simulations with short FIR filters confirm the predicted behavior 相似文献
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本文为了在语音信号处理中能消除含噪语音信号中的背景噪音,采用自适应信号处理的理论和技术来达到提高语音信号质量的目的。通过介绍自适应滤波器原理,在对自适应滤波器相关理论研究的基础上,研究了LMS自适应滤波算法,并对LMS自适应算法进行了分析。同时为了使输入的参考信号与噪声相关,加入分离周期信号与带有窄带干扰抑制的宽带信号。通过分析仿真结果表明基于LMS算法的自适应噪声抵消技术可以有效地抵消正弦干扰信号,同时加入宽带信号中的周期性噪声,在没有另外的与噪声相关的参考信号的情况下,可以使用自适应噪声抵消系统来消除这种同期性干扰噪声。 相似文献
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Wei Qing Yang Shaoquan Luo Ming Dong Chunxi 《电子科学学刊(英文版)》2006,23(2):216-219
This paper proposes a calibrated method for quasi-broadside side-looking mode SAR imaging with small squint angle and an improved method named as phase alignment algorithm of subaperture reference signal. The calibrated method adopts subaperture spotlighting algorithm of broadside mode to image the real data of quasi-broadside mode SAR, then based on the obtained image the small squint angle is estimated and the calibrated subaperture spotlighting algorithm of squint mode is employed to obtain the final image. The calibrated method can calibrate the abnormal region and obtain the correct image. The phase alignment algorithm of subaperture reference signal adjusts phases of respective subaperture reference signals in order to make them be in phase and constructs a new spotlighting window function for SAR imaging. Theoretical analysis shows that with the same sample data, the improved method can increase SAR imaging area in azimuth dimension. The methods are verified by the results of computer simulation. 相似文献
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The authors propose a new adaptive tracking algorithm which has been shown by computer simulations to outperform the conventional decision feedback equalisation algorithm. Basically, a cost function is formed by generating more than one reference signal based on the time recursive phase characteristic of an MSK signal 相似文献
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为实现强噪声背景下时延目标信号自提取,设计了相关检测模型,提出了基于目标数据段自截取和变分模态分解(Variational Mode Decomposition, VMD)算法的目标信号自适应定位和提取算法。首先,根据目标信号频域参数构建基准信号;然后,利用互相关检测技术并以峰值梯度为特征值确定目标信号时延参数;最后,利用预设参数自适应初始化的VMD算法对截取的数据段进行处理,并对分解的各分量进行自动筛选实现目标信号有效提取。不同算法的对比实验表明,自截取+VMD算法可有效实现强噪声下时延信号的定位提取,实时性基本满足实际应用需求。 相似文献
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D'Alessandro C.S. Delong Shang Bystrov A. Yakovlev A.V. Maevsky O. 《IEEE transactions on circuits and systems. I, Regular papers》2008,55(2):535-545
A novel self-timed communication protocol is based on the phase-modulation of a reference signal. The reference signal is sent on a number of transmission lines and the data can be recovered observing the sequence of events on the these lines. Employing several lines increases the number of states hence reducing the number of symbols required for a transmission. A new encoding algorithm is described which generates symbol-dependent matrices which are used to control the phase of transmission lines. The protocol concept, the algorithm and analysis of the system, together with simulation results, are presented. 相似文献
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Digital control of a voltage-mode synchronous buck converter 总被引:4,自引:0,他引:4
A digital control algorithm capable of separately specifying the desired output voltage and transient response for a synchronous buck converter operating in voltage mode was developed. This algorithm is based on superimposing a small control signal onto a voltage reference at each switching cycle to cancel out the perturbations. A zero steady-state error in the output voltage can be obtained with the aid of additional dynamics to allow the controller to track a load change and update the reference to a new load state. The specifications of the control algorithm are achieved by pole placement using complete state feedback. The control algorithm was implemented on a digital signal processor (DSP)-controlled synchronous buck converter. 相似文献
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基于天波雷达发射信号的外辐射源雷达需要在接收站提取发射信号用于匹配滤波处理, 而到达接收站的发射信号往往受到电离层反射与折射多径污染的问题, 提出了一种基于超指数与常数模盲均衡算法的发射信号混合盲反卷积方法.利用电离层折射与反射等多径杂波的稀疏性, 采用稀疏处理降低混合算法中超指数盲均衡算法的计算量, 从而实现发射信号的恢复.针对发射信号恢复质量对检测性能的影响进行了分析评估.计算机仿真表明, 所提出的盲均衡算法保持了超指数算法快速收敛的优点, 同时, 在性能损失很小的情况下计算量显著下降, 具有良好的工程应用前景. 相似文献
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本文关注的是多路信号之间时延差异的联合估计问题。不同于传统的自适应时延估计算法,本文以合成信号作为自适应时延估计的参考信号,给出了基于信号合成的联合自适应时延估计算法。同时本文推导和仿真了该算法时延估计的均值、学习曲线及方差特性。性能分析和仿真结果均显示,本文提出的基于合成的多路信号自适应时延估计为渐进无偏的时延估计。在不明显增加计算量的条件下,当算法收敛时,联合时延估计算法的方差显著低于传统的两路信号之间自适应时延估计算法方差。 相似文献
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ADS-B接收机S模式关键算法研究及实现 总被引:1,自引:0,他引:1
分析了广播式自动相关监视(ADS-B)模式S接收机的数字信号处理算法,着重阐述了基于参考功率进行位和置信度检测、判定算法的原理。根据接收机的性能参数,提出了一种基于时域处理的置信度算法。该算法主要是利用通过对数字信号的功率幅度值进行对比,然后用一定规则分析对比结果,最终得到数据位的比特位和置信度的高低。文中还给出了置信度算法的可编程门阵列(FPGA)实现方案,采用Verilog HDL语言完成了其功能模块的设计,并进行了电路仿真、实验。实验结果表明,该算法设计合理,能够快速准确地实现ADS-B系统报头的比特位和置信度的检测及提取。 相似文献
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针对雷达干扰信号模拟中算法设计快速验证的应用需求,为降低系统可重构开发中的复杂程度,研究了一种基于System Generator模型的FPGA设计开发方法,并以噪声调频和噪声卷积算法实现。对应用实例进行了设计演示验证,为雷达干扰信号算法验证实验提供技术参考。 相似文献