共查询到19条相似文献,搜索用时 265 毫秒
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针对传统频域插值傅里叶变换参数估计精度低的问题,在分析频谱泄漏产生原理基础上,提出适用于多频信号的高精度频域迭代插值方法。该方法先利用传统插值法估算信号各频率参数,然后利用信号的估计参数值计算泄漏补偿因子,并用补偿因子重新计算信号各频率参数,最后通过多次迭代实现所需的计算精度。通过对方法的估计结果进行噪声干扰敏感性分析、参数变化对估计精度影响及对方法敏感性分析结果表明,在噪声干扰与长程泄漏明显情况下,所提方法仍具最好估计精度及稳定性,且收敛速度快,可作为改进信号参数估值精度的可选方法。对IC芯片封装中引线键合过程数据处理与分析结果表明,所提方法能较好抑制长程泄漏影响,提高参数估计精度。 相似文献
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时延估计是双基阵被动定位中的重要问题。在非相关噪声干扰下,应用广义互相关法进行时延估计可以取得良好的估计效果,但在相关噪声干扰情况下其估计性能严重下降。使用高阶累积量进行时延估计,可以有效地去除相关高斯噪声的干扰。采用类似广义互相关加权的方法对高阶累积量进行PHAT加权,进一步抑制噪声的影响,提高了高阶累积量法的估计性能。结果表明,在相关噪声背景下加权高阶累积量时延估计效果优于广义互相关法和高阶累积量法。 相似文献
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针对含有人体动态的座椅悬架系统,通过合理选择状态变量及干扰变量,将地面激励建模成系统的一类可从控制通道输入的匹配干扰,同时考虑模型参数变化这一类不匹配干扰对系统的影响,基于滑模控制理论,设计了全程滑模切换函数;结合不匹配干扰估计器,构造了座椅悬架系统控制器;根据Lyapunov理论,证明了系统的鲁棒稳定性。利用座椅位移量和人体加速度量这两个可测输出量,设计了滑模观测器,实现了对状态变量的估计。仿真结果表明,相比于LQR和传统的滑模控制方法,带不匹配干扰估计的全程滑模控制方法可以使得座椅悬架系统在刚度系数和阻尼系数变化以及恶劣地况的情况下,获得更佳的动态性能及鲁棒性。 相似文献
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本文介绍了一种利用计数器校准时间继电器延时误差的方法。操作简便、准确度高,通过测量结果的不确定度评定,证明该方法完全满足时间继电器延时误差的校准要求,是目前国内用于校准时间继电器延时误差较先进、方便实用的方法。 相似文献
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本文论述了振动系统模态参数的一种统计识方法——模态参数的极大似然估计法。文中详细叙述了该方法的理论背景,参数识别的方法及程序,参数识别精度的比较,以及该方法在一个实际的轻型、高速、大阻尼转子上的应用。该方法的特点是它认识到实际观测数据的随机性,并充分运用观察数据的统计信息,从而能充分考虑各种外界的随机干扰及非线性误差的影响,使参数识别的精度提高。文中还对极大似然估计法与最小二乘估计法进行了比较。理论计算及实际结果表明,该方法比目前常用的最小二乘估计法更有普遍意义,具有更高的估计精度,特别是在信噪比较低,干扰较大的情况下,更为优越。 相似文献
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Wen-Ben Jone Wu-Sung Yeh Chingwei Yeh Das S.R. 《IEEE transactions on instrumentation and measurement》2001,50(5):1109-1118
For verifying the correctness of a circuit, not only its logic function, but also its timing behavior must be considered. Although the path delay fault model can handle part of the weakness of the gate delay fault model, it also has inherent deficiencies. Since the number of paths in a logic circuit is tremendous, exhaustively testing each signal propagation path is prohibitive. To deal with the weakness of traditional delay test techniques, based on the path delay fault model, a new delay test approach including a new delay test output observation method and an adaptive path selection method is proposed in this work. The basic idea of the approach is to measure the signal transition time for each delay test, and more paths are selected for a second-stage test (if necessary) to ensure the timing behavior of the circuit under test. Experimental results obtained by computer simulation demonstrate that a more thorough test is really a need if many significantly late signal transitions are observed 相似文献
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Microarray imaging is considered an important tool for large scale analysis of gene expression. The accuracy of the gene expression depends on the experiment itself and further image processing. It's well known that the noises introduced during the experiment will greatly affect the accuracy of the gene expression. How to eliminate the effect of the noise constitutes a challenging problem in microarray analysis. Traditionally, statistical methods are used to estimate the noises while the microarray images are being processed. In this paper, we present a new approach to deal with the noise inherent in the microarray image processing procedure. That is, to denoise the image noises before further image processing using stationary wavelet transform (SWT). The time invariant characteristic of SWT is particularly useful in image denoising. The testing result on sample microarray images has shown an enhanced image quality. The results also show that it has a superior performance than conventional discrete wavelet transform and widely used adaptive Wiener filter in this procedure. 相似文献
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《Radar, Sonar & Navigation, IET》2008,2(6):449-457
A new beamforming approach to combat the arbitrary unknown heavy-tailed impulsive noises including all a-stable noises with infinite variance or infinite mean is presented. The new approach, termed as linearly constrained minimum-`normalized variance? beamformer (LCMNV), is formulated as one to minimise the normalised variance of the beamformer?s output, subject to a pre-specified set of linear constraints. The normalised variance is defined as a pseudo-correlation function of the instantaneously adaptive, infinity-norm snapshot-normalised data, as an alternative to the customary `fractional lower-order moments? (FLOM) for heavy-tailed impulsive noise environments. The proposed beamformer is in essence second-order statistics based, and produces an instantaneously scaled beamformer output. The LCMNV beamformer outperforms the FLOM beamformer with the following advantages: (i) computationally simpler with a closed-form solution, (ii) requiring no prior information or estimation of the effective characteristic exponents of the impulsive noises, (iii) applicable to a wider class of heavy-tailed impulsive noises and (iv) offering better interferencerejection ability. 相似文献
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一种科里奥利质量流量计的信号处理方法 总被引:17,自引:4,他引:13
本提出了一种新的科里奥利质量流量计信号处理方法,从含有各种噪声干扰的信号中,准确测得质量流量.采用多抽--滤波器,对流量计中的两个传感器的输出信号进行滤波,以减少随机噪声的影响,并减少采样数据;采用自适应陷波滤波方法,以抑制确定性噪声的干扰,测得流量管振动基频的频率,并跟踪其变化。采用离散傅里叶变换方法,计算振动管基频处的相位差和时间延迟,从而测得质量流量。仿真结果证明了本所提方法的有效性和准确性。 相似文献
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针对直接互相关被动时延估计法定位管道异常振动事件存在噪声干扰影响定位精度的问题,提出了基于三阶累积量及自适应滤波时延估计的管道异常事件定位方法。该方法对顺、反两路异常振动信号进行三阶自累积量和互累积量估计,抑制高斯相关噪声和对称分布噪声。然后利用自适应滤波时延估计算法对三阶自累积量和互累积量信号的时延进行迭代计算,在不依赖先验知识的情况下抑制非高斯相关噪声。经现场实验证明,该方法可以准确地对管道异常事件进行定位,对噪声具有很好的抑制作用,改善了直接互相关时延估计的性能。相对于直接互相关时延估计方法,相对定位误差由2.7%降低到0.6%,定位一致性提高了三倍,平均定位精度可达14m。 相似文献
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In modern active and passive sonar systems, broadband beamforming for acoustic arrays is widely used to suppress unwanted interference and to detect target signals of interest. A broadband low sidelobe beamforming scheme in time domain is proposed in this paper. The first step of this scheme is to delay the outputs of each element in the acoustic array by a tapped-delay-line (TDL) to accomplish the integer part of the time delay need to form a beam. Then, finite impulse response (FIR) digital filters are used to implement the fractional part of the time delay. The weighting coefficients for all array elements at different frequencies to realize the low sidelobe beams are also implemented with the FIR digital filters. Finally, the outputs of the digital filters are summed up to yield the time domain beam output. The design of low sidelobe beam pattern and that of the FIR digital filters are two crucial technical issues in this beamforming procedure. The low sidelobe beams of each sub-band are designed using the optimized beam synthesis approach based on the principle of MVDR beamforming. An improved adaptive approach are used for the design of FIR digital filters, and the design requirements of these filters were specified by the weights of low sidelobe beams of each sub-band over the broad frequency band. Results of computer simulation for a twelve-element arc array show that the beamforming scheme is very effective in forming low sidelobe broadband beam. 相似文献