共查询到20条相似文献,搜索用时 15 毫秒
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小波分析在陀螺信号滤波中的研究 总被引:4,自引:0,他引:4
介绍了小波分析进行滤波法,建立了陀螺随机漂移的数学模型,使用了4种典型的小波基对陀螺的输出信号进行多尺度的小波分解,通过软阈值法消除了由噪声产生的小波系数,通过小波重构实现了滤波,试验数据验证了方法的有效性。 相似文献
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基于小波包的故障信号特征提取的研究 总被引:2,自引:0,他引:2
讨论了交--交变频调速系统故障诊断的重要性,在当前的检测方法与故障诊断手段研究的基础上,提出了一种改进的小波包算法,并运用该算法对变频调速系统输出电流进行分析.该算法的计算量和占用的存储空间较标准的小波包算法均减少80%.同时,运用基于改进的小波包的频带能量法提取变频调速系统的故障特征,分析了小波包分解层次对特征量提取的影响.经过仿真证明,该方法适用于变频调速系统故障信号的特征量提取. 相似文献
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Code Combining--A Maximum-Likelihood Decoding Approach for Combining an Arbitrary Number of Noisy Packets 总被引:2,自引:0,他引:2
It is well known that if the data rate is chosen below the available channel capacity, error-free communication is possible. Furthermore, numerous practical error-correction coding techniques exist which can be chosen to meet the user's reliability constraints. However, a basic problem in designing a reliable digital communication system is still the choice of the actual code rate. While the popular rate-1/2 code rate is a reasonable, but not optimum, choice for additive Gaussian noise channels, its selection is far from optimum for channels where a high percentage of the transmitted bits are destroyed by interference. Code combining represents a technique of matching the code rate to the prevailing channel conditions. Information is transmitted in packet formats which are encoded with a relatively high-rate code, e.g., rate 1/2, which can be repeated to Obtain reliable communications when the redundancy in a rate-1/2 code is not sufficient to overcome the channel interference. The receiver combines noisy packets (code combining) to obtain a packet with a code rate which is low enough such that reliable communication is possible even for channels with extremely high error rates. By combining the minimum number of packets needed to overcome the channel conditions, the receiver optimizes the code rate and minimizes the delay required to decode a given packet. Thus, the receiver adapts to the actual jammer-to-signal(J/S) ratio which is critical when the level of interferenceJ is not known a priori. 相似文献
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Loffeld O. Nies H. Knedlik S. Yu Wang 《Geoscience and Remote Sensing, IEEE Transactions on》2008,46(1):47-58
This paper considers the problem of unwrapping the phase image obtained from a noisy interferometric synthetic aperture radar (InSAR) image. The implicit nonlinearity of the problem is reflected, as well as the drawbacks of this nonlinearity on the performance of phase unwrapping approaches. Some general concepts concerning basic estimation techniques are shortly reviewed. On this background, a Kalman filter-based data fusion approach to unwrap and simultaneously filter the phases of InSAR images is developed. The data fusion concept exploits phase information extracted from the complex interferogram rather than from the phase image and fuses that information with phase slope information extracted from the power spectral density of the interferogram. 相似文献
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提出了基于AR(自回归)模型的小波变换与LMS(最小均方)自适应滤波相结合的脑电信号分析方法,并利用它来消除脑电信号中的噪声干扰。实验结果表明,利用小波变换与自适应滤波相结合能有效去除脑电信号中的噪声干扰。 相似文献
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Benkrid Abd.S. Benkrid K. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2009,17(5):709-722
This paper presents four novel area-efficient field-programmable gate-array (FPGA) bit-parallel architectures of finite impulse response (FIR) filters that smartly support the technique of symmetric signal extension while processing finite length signals at their boundaries. The key to this is a clever use of variable-depth shift registers which are efficiently implemented in Xilinx FPGAs in the form of shift register logic (SRL) components. Comparisons with the conventional architecture of FIR filter with symmetric boundary processing show considerable area saving especially with long-tap filters. For instance, our architecture implementation of the 8-tap low Daubechies-8 FIR filter achieves ~ 30% reduction in the area requirement (in terms of slices) compared to the conventional architecture while maintaining the same throughput. Two of the above-cited novel architectures are dedicated to the special case of symmetric FIR filters. The first architecture is highly area-efficient but requires a clock frequency doubler. While this reduces the overall processing speed (to a maximum of 2), it does maintain a high throughput. Moreover, this speed penalty is cancelled in bi-phase filters which are widely used in multirate architectures (e.g., wavelets). Our second symmetric FIR filter architecture saves less logic than the first architecture (e.g., 10% with the 9-tap low Biorthogonal 9&7 symmetric filter instead of 37% with the first architecture) but overcomes its speed penalty as it matches the throughput of the conventional architecture. 相似文献
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小波包分析在旋转机械故障诊断中的应用 总被引:10,自引:0,他引:10
简述了小波包分析的基本原理及其用于故障特征识别的机理,研究了小波包分析在旋转机械故障诊断中的应用。由于此技术能够从复杂的信号中有效地提取微弱的故障特征信号,因此与小波分析相比,分析更为精细简单。实例采用小波包原理对一类旋转信号进行分解重构后,成功地提取了故障特征,体现了小波包分析的优良特性,其结果证明了该方法是行之有效的。 相似文献
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The monogenic signal is the natural 2D counterpart of the 1D analytic signal. We propose to transpose the concept to the wavelet domain by considering a complexified version of the Riesz transform which has the remarkable property of mapping a real-valued (primary) wavelet basis of L2(R2) into a complex one. The Riesz operator is also steerable in the sense that it give access to the Hilbert transform of the signal along any orientation. Having set those foundations, we specify a primary polyharmonic spline wavelet basis of L2(R2) that involves a single Mexican-hat-like mother wavelet (Laplacian of a B-spline). The important point is that our primary wavelets are quasi-isotropic: they behave like multiscale versions of the fractional Laplace operator from which they are derived, which ensures steerability. We propose to pair these real-valued basis functions with their complex Riesz counterparts to specify a multiresolution monogenic signal analysis. This yields a representation where each wavelet index is associated with a local orientation, an amplitude and a phase. We give a corresponding wavelet-domain method for estimating the underlying instantaneous frequency. We also provide a mechanism for improving the shift and rotation-invariance of the wavelet decomposition and show how to implement the transform efficiently using perfect-reconstruction filterbanks. We illustrate the specific feature-extraction capabilities of the representation and present novel examples of wavelet-domain processing; in particular, a robust, tensor-based analysis of directional image patterns, the demodulation of interferograms, and the reconstruction of digital holograms. 相似文献
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一种信号分选和特征提取联合处理的雷达信号分析方法研究 总被引:3,自引:0,他引:3
研究广度优先搜索邻居的聚类算法和直方图法用于雷达信号分选和特征提取的原理和方法,并将两者相结合用于雷达信号分析使分选和特征提取更加准确.仿真实验证明联合处理法是高效和实用的. 相似文献
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基于FRFT的LFM信号自适应滤波算法及分析 总被引:1,自引:0,他引:1
针对线性调频(LFM)信号自适应滤波问题,利用分数阶傅里叶变换(FRFT)对LFM信号良好的能量聚集性的特点,提出了一种分数阶傅里叶域LFM信号自适应滤波算法.算法采用分级迭代运算的方法确定最佳变换角度,保证参数估计精度的同时,降低了运算量.结合泄漏LMS(LLMS)和归一化LMS(NLMS)算法,对传统LMS自适应算法的跟踪和滤波性能进行了改进,并给出了算法的收敛条件.在加权矢量的迭代公式中引入泄露因子,降低了记忆效应对滤波器的影响;并对自适应步长进行功率归一化,提高了收敛速率.仿真分析了参数对算法收敛性能的影响,结果表明,当输入LFM信号频率变化较快时,算法有较好的收敛性能和较小的均方误差,同时在低信噪比(SNR=10 dB)下也有良好的滤波效果. 相似文献
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《Signal Processing, IEEE Transactions on》2008,56(9):4255-4262
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复解析小波变换与语音信号包络提取和分析 总被引:21,自引:2,他引:19
利用传统的Hilbert变换方法提取语音信号包络存在一些固有缺陷,为此本文建议了一种复解析小波变换包络提取新方法。该方法将Hilbert分析与小波分析紧密地结合在一起。文中推导并论述了新包络滤波器的时域、频域构造条件和设计方法,选择Morlet复小波对语音信号进行了初步数字仿真实验,结果证实了理论分析的正确性,并显示出文中提出的新的分析方法对于信号处理上有许多独特优势和潜在性能。 相似文献
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地震信号分析在地质岩性、储层、流体、沉积相带的检测,以及地层界面识别与储层分析、地震资料处理和解释等方面具有重要研究意义。针对现有时频分析算法在处理地震信号时,存在时频分辨率低、能量聚集性差等问题,该文以Ricker子波为数学模型,提出了一种新的2阶挤压小波变换算法(SWT2)。考虑到传统时频同步压缩变换中的瞬时频率估计对地震信号失效,利用改进的母小波对地震信号进行匹配,进而通过谱峰对齐对参考频率进行修正,从而提升时频能量聚集性和时频分辨率。仿真实验结果表明,提出的2阶挤压小波变换算法可以极大地提升地震信号的时频聚集性,精确地反映信号的时延和主频,对地层结构的刻画更加精确。 相似文献