共查询到20条相似文献,搜索用时 31 毫秒
1.
Digital filters with adjustable frequency domain characteristics are referred to as variable digital filters. Variable filters are useful in the applications where the filter characteristics are required to be changeable during the course of signal processing. Especially in real time applications, variable filters are needed to change their coefficients instantaneously such that the real time signal processing can be performed. The present paper proposes a very efficient technique for variable 1D digital filter design. Generally speaking, the variable coefficients of variable digital filters are multidimensional functions of a set of spectral parameters which define the desired frequency domain characteristics. The authors first sample the given variable 1D magnitude specification and use the samples to construct a multidimensional array, then propose an outer product expansion method for expanding the multidimensional array as the sum of outer products of 1D arrays (vectors). Based on the outer product expansion, one can reduce the difficult problem of designing a variable 1D digital filter to the easy one that only needs constant 1D filter designs and 1D polynomial approximations. The technique can obtain variable 1D filters having arbitrary desired magnitude characteristics with a high design accuracy 相似文献
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Tian-Bo Deng 《IEEE transactions on circuits and systems. I, Regular papers》2005,52(1):148-167
This paper proposes a straightforward method for designing variable digital filters with arbitrary variable magnitude as well as arbitrary fixed-phase or variable fractional delay (VFD) responses. The basic idea is to avoid the complicated direct design of one-dimensional (1-D) variable digital filters by decomposing the original variable filter design problem into easier subproblems that only require constant 1-D filter designs and multidimensional polynomial approximations. Through constant 1-D filter designs and multidimensional polynomial fits, we can easily obtain a variable digital filter satisfying the given variable design specifications. To decompose the original variable filter design into constant 1-D filter designs and multidimensional polynomial fits, a new multidimensional complex array decomposition called vector array decomposition (VAD) is proposed, which is based on two new theorems using the singular value decomposition (SVD). Once the VAD is obtained, the subproblems can be easily solved. Furthermore, we show that the VAD can also be generalized to the weighted least squares (WLS) case (WLS-VAD) for the WLS variable filter design. Three design examples are given to illustrate that the WLS-VAD and VAD-based techniques are considerably efficient for designing variable digital filters with arbitrary variable magnitude and arbitrary fixed-phase or VFD responses. 相似文献
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二维零相位FIR数字滤波器设计的闭式最小二乘解 总被引:1,自引:0,他引:1
本文二维零相位FIR数字滤波器的解析最小二乘设计技术。通过建立频域误差差函数的矩阵形式,并运用与设计问题有关的矩阵的一些性质,得到了滤波器系数的闭式解,使得由给定的频响指标可直接计算滤波器系数,而不必对矩阵进行数值示逆,也不需要基于迭代运算的优化过程。文中给出了滤波器实例,其结果证实了该设计方法的简便性与有效性。 相似文献
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Tian-Bo Deng Takashi Soma Jun Murakami Yoshiaki Tadokoro 《Multidimensional Systems and Signal Processing》1994,5(1):97-119
In designing two-dimensional (2-D) digital filters in the frequency domain, an efficient technique is to first decompose the given 2-D frequency domain design specifications into one-dimensional (1-D) ones, and then approximate the resulting 1-D magnitude specifications using the well-developed 1-D filter design techniques. Finally, by interconnecting the designed 1-D filters one can obtain a 2-D digital filter. However, since the magnitude responses of digital filters must be nonnegative, it is required that the decomposition of 2-D magnitude specifications result in nonnegative 1-D magnitude specifications. We call such a decomposition the nonnegative decomposition. This paper proposes a nonnegative decomposition method for decomposing the given 2-D magnitude specifications into 1-D ones, and then transforms the problem of designing a 2-D digital filter into that of designing 1-D filters. Consequently, the original problem of designing a 2-D filter is significantly simplified. 相似文献
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具有任意幅度频响的二维线性相位FIR数字滤波器的设计 总被引:1,自引:0,他引:1
本文提出了设计任意幅度频响的二维线性相位FIR数字滤波器的解析最小二乘方法,通过最小化频域平方误差函数得到了滤波器系数的闭式解,运用导出的闭式式,可根据给定的任意幅度频响指标直接计算滤波器的系数,从而简化了滤波器设计程序,并大大降低了运算量。 相似文献
6.
Tian-Bo Deng 《Signal Processing, IEEE Transactions on》2004,52(6):1668-1681
This paper proposes a closed-form solution for designing variable one-dimensional (1-D) finite-impulse-response (FIR) digital filters with simultaneously tunable magnitude and tunable fractional phase-delay responses. First, each coefficient of a variable FIR filter is expressed as a two-dimensional (2-D) polynomial of a pair of parameters called spectral parameters; one is for independently tuning the cutoff frequency of the magnitude response, and the other is for independently tuning fractional phase-delay. Then, the closed-form error function between the desired and actual variable frequency responses is derived without discretizing any design parameters such as the frequency and the two spectral parameters. Finally, the optimal solution for the 2-D polynomial coefficients can be easily determined through minimizing the closed-form error function. We also show that the resulting variable FIR filter can be efficiently implemented by generalizing Farrow structure to our two-parameter case. The generalized Farrow structure requires only a small number of multiplications and additions for obtaining any new frequency characteristic, which is particularly suitable for high-speed tuning. 相似文献
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Two-Dimensional Farrow Structure and the Design of Variable Fractional-Delay 2-D FIR Digital Filters
《IEEE transactions on circuits and systems. I, Regular papers》2009,56(2):395-404
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Two- and three-dimensional (2-D and 3-D) depth migration can be performed using 1-D and 2-D extrapolation digital filters, respectively. The depth extrapolation is done, one frequency at a time, by convolving the seismic wavefield with a complex-valued, frequency- and velocity-dependent, digital filter. This process requires the design of a complete set of extrapolation filters: one filter for each possible frequency-velocity pair. Instead of independently designing the frequency- and velocity-dependent filters, an efficient procedure is introduced for designing a complete set of 1-D and 2-D extrapolation filters using transformations. The problem of designing a desired set of migration filters is thus reduced to the design of a single 1-D filter, which is then mapped to produce all the desired 1-D or 2-D migration filters. The new design procedure has the additional advantage that both the 1-D and 2-D migration filters can be realized efficiently and need not have their coefficients precomputed or tabulated 相似文献
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《IEEE transactions on circuits and systems. I, Regular papers》2009,56(3):574-582
12.
Zhu Weiping 《中国邮电高校学报(英文版)》1995,(1)
AVeryEfficientApproachfortheSynthesisof2-DRecursiveFanFiltersZhuWeiping(DepartmentofTelecommunicationEngineering,NanjingUnive... 相似文献
13.
Two-dimensional digital filters with sparse coefficients 总被引:1,自引:1,他引:0
Is sparsity an issue in 2-D digital filter design problems to explore and why is it important? How a 2-D filter can be designed to retain a desired coefficient sparsity for efficient implementation while achieving best possible performance subject to that sparsity constraint? These are the focus of this paper in which we present a two-phase design method for 2-D FIR digital filters in two most common design settings, namely, the least squares and minimax designs. Simulation studies are presented to illustrate each phase of the proposed design method and to evaluate the performance of the filters designed. 相似文献
14.
This paper shows that the problem of designing one-dimensional (1-D) variable fractional-delay (VFD) digital filter can be elegantly reduced to the easier subproblems that involve one-dimensional (1-D) constant filter (subfilter) designs and 1-D polynomial approximations. By utilizing the singular value decomposition (SVD) of the variable design specification, we prove that both 1-D constant filters and 1-D polynomials possess either symmetry or anti-symmetry simultaneously. Therefore, a VFD filter can be efficiently obtained by designing 1-D constant filters with symmetrical or antisymmetrical coefficients and performing 1-D symmetrical or antisymmetrical approximations. To perform the weighted-least-squares (WLS) VFD filter design, a new WLS-SVD method is also developed. Moreover, an objective criterion is proposed for selecting appropriate subfilter orders and polynomial degrees. Our computer simulations have shown that the SVD-based design and WLS-SVD design can achieve much higher design accuracy with significantly reduced filter, complexity than the existing WLS design method. Another important part of the paper proposes two new structures for efficiently implementing the resulting VFD filter, which require less computational complexity than the so-called Farrow structure. 相似文献
15.
Michael E. Zervakis Anastasios N. Venetsanopoulos 《Circuits, Systems, and Signal Processing》1990,9(4):383-408
Three-dimensional (3-D) signal processing offers many advantages over two-dimensional (2-D) processing, because it preserves 3-D correlations. In this paper the design and the stability of 3-D rotated filters are considered. These filters are designed by rotating a one-dimensional (1-D) digital filter in 3-D space. The rotated filters are valuable in the design of various 3-D filters which possess prescribed spectral specifications. An efficient algorithm for the design of 3-D lowpass (LP) digital filters, with approximately spherically symmetric magnitude responses, is introduced. To achieve the desirable spectral characteristics, a number of 3-D rotated filters is cascaded. The stability of the spherically symmetric filters designed is considered, and stable realizations are proposed. The relation between the cut-off isopotential sphere of the 3-D filter and the cut-off frequency of the 1-D filter employed in the design, is derived. Finally, configurations that result in highpass (HP) and bandpass (BP) filters are proposed. Examples of LP, HP, and BP filters, designed on the basis of the method proposed, are presented.This research was supported by the Public Benefit Foundation, Alexander S. Onassis. 相似文献
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本文提出了一种设计一维线性相位FIR数字滤波器的新方法。该方法采用频域的最小平方误差函数使所求的增益特性逼近所希望的增益特性 ,其计算公式非常简单 ,并可设计任意形状增益特性的FIR数字滤波器。设计实例表明提出的方法非常有效 相似文献
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It is well known that IIR digital filters require quite fewer computations,comparedwith FIR filters,in order to meet stringent magnitude specifications when the phase distortioncan be tolerated.An approximately linear phase,however,can be also obtained with the IIRfilter by making use of a technique without increasing the complexity.Based on a certain numberof attenuation zeros in the pass band,a new approach is developed for the design of polyphasewave digital filters with exact magnitude responses and Chebyshev approximation of the desiredphase responses.The minimum number of attenuation zeros is estimated,and some examples areincluded. 相似文献
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This paper proposes 2-D variable IIR digital filter structures with a small amount of calculations for coefficient update. The proposed realization method uses the 2-D parallel allpass structure derived from the separable denominator 2-D filter as the prototype structure for 2-D variable digital filters. In order to reduce the amount of calculations, all the redundant first-order complex allpass sections are combined by modularization of the variable structure. Furthermore, we can realize a very compact variable structure with a minimal number of first-order complex allpass sections by combining complex allpass sections with their complex conjugate allpass sections. Comparison of the calculation loads of the variable structures is presented to demonstrate that the amount of calculations for coefficient update of the proposed variable structure is far less than that of the original and the modular variable structure. 相似文献
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提出了一种程控数字滤波器的FPGA实现方法.以FIR数字滤波器为例,通过在单片FPGA芯片中构建嵌入式微处理器,加入系数可配置FIR滤波器等功能模块实现了频谱可控的程控数字滤波器.通过Modelsim后仿真和在Xilinx公司XUPV5-LX110T开发板上进行的实际测试,结果表明本文提出的方法是可行的. 相似文献