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LTE-A(Long Term Evolution-Advanced)以其优异的性能,成为未来4G的通信标准.然而LTE-A指标要求数字前端滤波器不仅要有很窄的过渡带,还要有很低的通带纹波,使数字前端滤波器的复杂度显著提升.采用基于频率屏蔽响应技术的FRM(frequency-response masking)滤波器,通过对其插值因子、滤波长度和纹波幅度的优化,实现了满足LTE-A性能的低复杂度前端数字滤波器.仿真结果表明,在LTE-A标准下,当带宽为1.4MHz、3MHz、5MHz、10MHz、15MHz和20MHz时,FRM滤波器的复杂度分别为68、79、87、87、87和87.与传统FIR滤波器相比,此FRM滤波器复杂度降低约50%,性能也优于FIR滤波器. 相似文献
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时间交叉模数转换结构是提高模数转换系统采样率的一种有效途径。由于制造工艺的局限和布线的差异,这种结构会引入通道失配而限制系统的性能。通道失配包括偏置失配、增益失配和时间失配。文中提出了一种基于快速傅里叶变换(Fast Fourier Transform,FFT)计算时间失配并采用有限冲激响应(Finite Impusle Response,FIR)滤波器对它进行补偿的方法,并通过Matlab仿真验证了算法的有效性和可行性。 相似文献
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高速FIR滤波器的8路多相直接分解实现结构的工作频率是单路串行实现结构的1/8,计算复杂度是单路串行实现结构的8倍。针对高速FIR滤波器的8路多相直接分解实现结构计算复杂度大这一问题,对FIR滤波器的多相并行实现结构进行了详细推导,提出了FIR滤波器的8路多相27子滤波器实现结构,提出的FIR滤波器的8路多相27子滤波器实现结构的计算复杂度是单路串行实现结构的3.375倍。FPGA实验验证了提出的FIR滤波器的8路多相27子滤波器实现结构的优越性。 相似文献
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为满足太赫兹无线通信系统对大容量基带信号处理算法的要求,基于直接从多项式分解导出的传统滤波器并行实现算法,通过矩阵变化推导出复杂度更小的快速有限冲激响应(FIR)滤波器并行实现。在此基础上通过张量积的表示给出了2并行、4并行和8并行的转换公式以及实现架构。既而推导出2N并行快速FIR滤波器的通用实现公式,并对比了优化前后的复杂度差异。最后给出了64并行的快速FIR滤波器的推导公式和具体实现架构,以及优化前后的硬件复杂度对比,64并行的快速FIR滤波器算法资源消耗更少。 相似文献
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在有限冲激响应(Finite Impulse Response,FIR)滤波器设计中,如果系统只要求通带或某个频域区间具有线性相位而其他频域区间相位非线性,则系数对称的FIR滤波器设计方法不再适用。为此,提出了一种基于二阶锥规划(Second-Order Cone Programming,SOCP)的通带线性相位FIR滤波器设计方法。该方法使用二阶锥规划实现滤波器设计,其中优化目标为通带最小群延迟,约束条件为全频域振幅误差。实验结果显示,所提方法设计的FIR滤波器有着很好的幅频特性和通带线性相位,通带群延迟误差很小。该方法实现简单,计算复杂度低,可以广泛应用于数字信号处理领域。 相似文献
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FIR滤波器具有绝对稳定性和线性相位的优势,然而当对滤波器的频域性能要求较高时,FIR滤波器通常需要很高的阶数,这使得FIR滤波器硬件执行的复杂度很高。为降低FIR滤波器的硬件执行复杂度,诸多研究者进行了探索。文章对低复杂度FIR滤波器设计方法进行研究,着重介绍比较典型的频率响应罩设计方法、外插脉冲响应设计方法和基于压缩感知的设计方法。 相似文献
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A method is presented to synthesize wideband linear-phase finite-impulse-response (FIR) filters with a piecewise-polynomial-sinusoidal
impulse response. The method is based on merging the earlier synthesis scheme proposed by the authors to design piecewise-polynomial
filters with the method proposed by Chu and Burrus. The method uses an arbitrary number of separately generated center coefficients
instead of only one or none as used in the method by Chu–Burrus. The desired impulse response is created by using a parallel
connection of several filter branches and by adding an arbitrary number of center coefficients to form it. This method is
especially effective for designing Hilbert transformers by using Type 4 linear-phase FIR filters, where only real-valued multipliers
are needed in the implementation. The arithmetic complexity is proportional to the number of branches, the common polynomial
order for each branch, and the number of separate center coefficients. For other linear-phase FIR filter types the arithmetic
complexity depends additionally on the number of complex multipliers. Examples are given to illustrate the benefits of this
method compared to the frequency-response masking (FRM) technique with regard to reducing the number of coefficients as well
as arithmetic complexity. 相似文献
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The frequency-response masking (FRM) approach has been introduced as a
means of generating narrow transition band linear-phase finite impulse response (FIR)
filters with a low arithmetic complexity. This paper proposes an approach for synthesizing
two-channel maximally decimated FIR filter banks utilizing the FRM technique. For this
purpose, a new class of FRM filters is introduced. Filters belonging to this class are used
for synthesizing nonlinear-phase analysis and synthesis filters for two types of two-channel
filter banks. For the first type, there exist no phase distortion and aliasing errors, but this
type suffers from a small amplitude distortion as for the well-known quadrature mirror
filter (QMF) banks. Compared to conventional QMF filter banks, the proposed banks lower
significantly the overall arithmetic complexity at the expense of a somewhat increased
overall filter bank delay in applications demanding narrow transition bands. For the second
type, there are also small aliasing errors, allowing one to reduce the arithmetic complexity
even further. Efficient structures are introduced for implementing the proposed filter banks,
and algorithms are described for maximizing the stopband attenuations of the analysis
and synthesis filters in the minimax sense subject to the given allowable amplitude and/or
aliasing errors. Examples are included illustrating the benefits provided by the proposed
filter banks. 相似文献
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Hakan Johansson 《Circuits, Systems, and Signal Processing》2006,25(2):175-200
This paper introduces two classes of frequency-response masking
(FRM) linear-phase finite (length) impulse response (FIR)
filters for interpolation and decimation by arbitrary integer
factors M. As they are based on the FRM approach, the proposed
filters are low-complexity (efficient) sharp-transition
linear-phase FIR interpolation and decimation filters. Compared
to previously existing FRM linear-phase FIR filter classes for
interpolation and decimation, the new ones offer lower
complexity and more freedom in selecting the locations of the
passband and stopband edges. Furthermore, the proposed classes
of FRM filters can, as special cases, realize efficient
Mth-band FRM linear-phase FIR interpolation and decimation
filters for all values of M. Previously, only half-band
(M = 2) FRM linear-phase FIR filters have appeared in the
literature. The paper includes design techniques suitable for
the new filters and design examples illustrating their
efficiency. 相似文献
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In this paper, computationally efficient filter structures based on the frequency-response masking (FRM) technique are proposed
for the synthesis of arbitrary bandwidth sharp finite impulse response (FIR) filters. A serial masking scheme is introduced
in the new structures to perform the masking task in two stages, which reduces the complexity of the masking filters. Compared
to the original FRM and interpolated FIR-FRM (IFIR-FRM) structures, the proposed structures achieve additional savings in
terms of numbers of arithmetic operations. 相似文献
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Design of Computationally Efficient Sharp FIR Filter Utilizing Modified Multistage FRM Technique for Wireless Communications Systems
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Modern wireless communications gadgets demand multi-standard communications facilities with least overlap between different input radio channels. A sharp digital filter of extremely narrow transition-width with lower stop band ripples offers alias-free switching among the preferred frequency bands. A computationally competent low pass filter (LPF) structure based on the multistage frequency response masking (FRM) approach is proposed for the design of sharp finite impulse response (FIR) filters which are suitable for wireless communications applications. In comparison of basic FRM with other existing multistage FRM structures, the proposed structure has a narrow transition bandwidth and higher stop band attenuation with significant reduction in terms of the number of computational steps. A design example is incorporated to demonstrate the efficiency of the proposed approach. Simulation results establish the improvement of the proposed scheme over other recently published design strategies. 相似文献
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This paper offers two main contributions to the theory of low-delay frequency-response masking (FRM) finite impulse response
(FIR) filters. First, a thorough investigation of the low-delay FRM FIR filters and their subfilters or three different structures,
referred to as narrow-, wide-, and middle-band filter structures, is given. The investigation includes discussions on delay
distribution over the subfilters as well as estimation of the optimal periodicity of the periodic model filter. Second, systematic
design procedures are given, with explicit formulas for distribution of the ripples and the delay to the subfilters. For each
of the three structures, two design procedures are given that include joint optimization of the subfilters. The first proposal
uses partly linear-phase FIR subfilters and partly low-delay FIR subfilters. Thus, it has a lower arithmetic complexity compared
to the second proposal, which has exclusively low-delay FIR subfilters. The second proposal is instead more flexible and can
handle a broader range of specifications. The design procedures result in low-delay FIR filters with a lower arithmetic complexity
compared to previous results, for specifications with low delay and narrow transition band. 相似文献
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Perfect linear-phase two-channel QMF banks require the use of finite impulse response (FIR) analysis and synthesis filters. Although they are less expensive and yield superior stopband characteristics, perfect linear phase cannot be achieved with stable infinite impulse response (IIR) filters. Thus, IIR designs usually incorporate a postprocessing equalizer that is optimized to reduce the phase distortion of the entire filter bank. However, the analysis and synthesis filters of such an IIR filter bank are not linear phase. In this paper, a computationally simple method to obtain IIR analysis and synthesis filters that possess negligible phase distortion is presented. The method is based on first applying the balanced reduction procedure to obtain nearly allpass IIR polyphase components and then approximating these with perfect allpass IIR polyphase components. The resulting IIR designs already have only negligible phase distortion. However, if required, further improvement may be achieved through optimization of the filter parameters. For this purpose, a suitable objective function is presented. Bounds for the magnitude and phase errors of the designs are also derived. Design examples indicate that the derived IIR filter banks are more efficient in terms of computational complexity than the FIR prototypes and perfect reconstruction FIR filter banks. Although the PR FIR filter banks when implemented with the one-multiplier lattice structure and IIR filter banks are comparable in terms of computational complexity, the former is very sensitive to coefficient quantization effects 相似文献
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Reconfigurable non-uniform channel filters are now being widely used in software define radio (SDR). The hardware implementation of these filters requires low complexity, low chip area and low power consumption. The frequency response masking (FRM) approach is proved to be a good candidate for the realization of a sharp digital finite impulse response (FIR) filter with low complexity. To reduce the complexity further, this paper gives an optimal design method which makes the channel filters totally multiplier-less. This is done in two steps. The channel filters are designed using the FRM approach with continuous filter coefficients. To obtain multiplier-less design, these filter coefficients are converted to finite-precision coefficients using signed power of two (SPT) space and the filter coefficients are synthesized in the canonic signed-digit (CSD) format. But this may lead to degradation of the filter performance. Hence the filter coefficients synthesis in the CSD format is formulated as an optimization problem. Several meta-heuristic algorithms like Differential Evolution (DE), Artificial Bee Colony (ABC), Harmony Search Algorithm (HSA) and Gravitational Search Algorithm (GSA) are modified and deployed and the best one is selected. 相似文献
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In this paper, we propose a method for designing a class of M‐channel, causal, stable, perfect reconstruction, infinite impulse response (IIR), and parallel uniform discrete Fourier transform (DFT) filter banks. It is based on a previously proposed structure by Martinez et al. [1] for IIR digital filter design for sampling rate reduction. The proposed filter bank has a modular structure and is therefore very well suited for VLSI implementation. Moreover, the current structure is more efficient in terms of computational complexity than the most general IIR DFT filter bank, and this results in a reduced computational complexity by more than 50% in both the critically sampled and oversampled cases. In the polyphase oversampled DFT filter bank case, we get flexible stop‐band attenuation, which is also taken care of in the proposed algorithm. 相似文献