共查询到16条相似文献,搜索用时 109 毫秒
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介绍了一种新颖的频域陷波算法,以消除窄带干扰对通信的影响,并讨论了这种陷波算法在直接序列扩频通信中的应用。该算法将时域自适应滤波器中复杂的卷积运算转换为频域的相乘运算,从而减少了运算量,节省了资源,使得自适应陷波器更易于工程实现。仿真结果证实,该算法能有效地消除直接序列扩频方式中的窄带干扰。 相似文献
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在GNSS服务过程中,地面接收到的卫星导航信号的功率较小,且易受到周围复杂电磁干扰影响,这将会导致卫星无法正常定位。针对常见的窄带干扰,介绍一种新型自适应全通IIR陷波器,自适应算法采用高斯-牛顿迭代法,通过跟踪窄带干扰频点,对其频点进行陷波。文中在其基础上进行改进,在每次迭代过程中采用最佳收敛因子,最大程度地减少均方误差。这种算法可导致更快的收敛速度和更高的估计精度。仿真结果表明,IIR滤波器可有效去除高达70 dB的窄带干扰。 相似文献
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一种应用于限制零极点位置复数陷波器的迭代算法 总被引:1,自引:0,他引:1
基于最小均方误差准则(MMSE),本文推导出了一种修改限制零极点位置的一阶复数陷波器权值迭代算法,并进而提出了一种新的可应用于矩阵型高阶陷波器的自适应权值修改算法,该高阶陷波器由一阶陷波器作为陷波单元构成。该迭代算法直接修改陷波器权值的指数,因而在算法迭代过程中能够将高阶复数陷波器的极点始终限制在单位圆内,从而保证了陷波器的稳定工作。仿真结果表明,采用该算法的一阶和高阶复数陷波器工作稳定,对输入陷波器的宽带信号损伤小,且能快速跟踪和有效抑制其中的强单/多频信号。 相似文献
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Wei-Lung Mao Wann-Jiun Ma Ying-Ren Chien Chia-Hao Ku 《Circuits, Systems, and Signal Processing》2011,30(3):527-542
The global positioning system (GPS), which provides accurate positioning and timing information, has become a commonly used
navigation instrument for many applications. The application of a new adaptive all-pass based notch filter (ANFA) for narrowband/FM
interference suppression and frequency estimation in GPS receivers is proposed. An ANFA structure that achieves better unbiased
characteristics with its coefficients is employed to accurately estimate the narrowband interfering signals in online fashion.
A variable convergence factor that optimizes the maximal mean square error (MSE) reduction in each iteration is applied in
a modified adaptive Gaussian–Newton (MAGN) algorithm. The proposed MAGN algorithm can lead to both faster convergence speed
and higher estimation accuracy. Simulation results show that the ANFA offers a better performance than conventional linear
predictors in terms of the SNR improvement and the mean output power (MOP) under the interference environments of interest. 相似文献
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An intercept receiver which uses a transform-domain-processing filter is described. This receiver detects direct-sequence binary-phase-shift-keyed (DS-BPSK) spread-spectrum signals in the presence of narrowband interference by employing adaptive narrowband interference rejection techniques. The improvement in the system performance over that of conventional detection techniques is shown by presenting the results of experimental measurements of probability of detection versus false alarm for an enhanced total power detector. Also presented are certain results corresponding to detection of the spectral lines generated at twice the carrier frequency, wherein the goal is often not just signal detection, but also carrier frequency estimation. The receiver uses one of two transform-domain-processing techniques for adaptive narrowband interference rejection. In the first technique, the narrowband interference is detected and excised in the transform domain by using an adaptive notch filter. In the second technique, the interference is suppressed using soft-limiting in the transform domain 相似文献
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The stability issue in adaptive notch filters is investigated from a structural viewpoint. A new adaptive algorithm for direct frequency estimation is developed using a constrained pole-zero notch filter. The basic characteristic of this algorithm is that the notch filter is realised in a cascade form, with each stage implemented in a normal realisation. A simplified version of the gradient signals is derived, which makes the algorithm very efficient. It is shown that this proposed adaptive notch filter is bounded-input-bounded-output stable. Numerical examples with simulations, where the proposed algorithm performs well in terms of convergence and guaranteed stability, are given to support the theoretical results 相似文献
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A modified gradient algorithm is developed for improving the convergence speed of a first-order complex adaptive IIR notch filter, which is used for estimating an unknown frequency of a complex sinusoidal signal embedded in white Gaussian noise. The new cost function using new error criterion is presented and analyzed theoretically. The proposed technique can significantly improve the convergence speed as compared with a complex notch filter using plain gradient algorithm. The computer simulations are conducted to demonstrate the validity of the proposed complex adaptive notch filter. 相似文献