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14
Efficient largescale filter/filterbank design via LMI characterization of trigonometric curves
 in Proc. of IEEE Inter. Conf. on Acoustics, Speech and Signal Processing (ICASSP 05
"... Abstract—Many filter and filterbank design problems can be posed as the optimization of linear or convex quadratic objectives over trigonometric semiinfinite constraints. Recent advances in design methodology are based on various linear matrix inequality (LMI) characterizations of the semiinfinite ..."
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Abstract—Many filter and filterbank design problems can be posed as the optimization of linear or convex quadratic objectives over trigonometric semiinfinite constraints. Recent advances in design methodology are based on various linear matrix inequality (LMI) characterizations of the semiinfinite constraints, and semidefinite programming (SDP) solutions. Despite these advances, the design of filters of several hundredth order, which typically arise in multicarrier communication and signal compression, cannot be accommodated. This hurdle is due mainly to the large number of additional variables incurred in the LMI characterizations. This paper proposes a novel LMI characterization of the semiinfinite constraints that involves additional variables of miminal dimensions. Consequently, the design of highorder filters required in practical applications can be achieved. Examples of designs of up to 1200tap filters are presented to verify the viability of the proposed approach. Index Terms—Filter and filter bank, semidefinite programming, trigonometric polynomial. a linear TSIC in the filter coefficients [19], [32] (more precisely, (2) leads to two linear TSICs [16]). More general constraints [1], [2], [37] involving bounds on the frequency response of the FIR filter are also expressible in terms of linear TSIC. Imposing a passband ripple of in the passband, and a stopband attenuation of in the stopband is equivalent to the following linear TSICs (2) I.
Niemistö: Lowdelay nonuniform oversampled filterbanks for acoustic echo control
 Proc. EUSIPCO ’06
, 2006
"... We propose an algorithm for designing nonuniform oversampled filterbanks with arbitray delay. The filterbank has uniform sections obtained by generalized DFT modulation; between the uniform sections, there are transition filters. There is no a priori constraint on the widths of transition filters ..."
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We propose an algorithm for designing nonuniform oversampled filterbanks with arbitray delay. The filterbank has uniform sections obtained by generalized DFT modulation; between the uniform sections, there are transition filters. There is no a priori constraint on the widths of transition filters channels, as in previous publications. The design algorithm is composed of three steps, in which a bank (analysis or synthesis) is optimized by solving convex optimization problems for finding the prototypes of uniform sections and the transition filters. In the first step, an orthogonal filterbank is designed, while in the other steps a bank is given and the other is optimized. We present an example of design suitable to subband processing of wideband speech signals. 1.
Evolutionary design of digital filters with application to subband coding and data transmission
 IEEE Transactions on Signal Processing
, 2007
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Performance Analysis of Filtered Multitone Modulation Systems for Underwater Communication
"... is split into a number of subbands in which singlecarrier signals are modulated onto separate carriers with very little spectral overlap, making the waveform resilient to intercarrier interference. Demodulation is followed by a bank of parallel equalizers, one for each subband. The length of each e ..."
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is split into a number of subbands in which singlecarrier signals are modulated onto separate carriers with very little spectral overlap, making the waveform resilient to intercarrier interference. Demodulation is followed by a bank of parallel equalizers, one for each subband. The length of each equalizer is less than what would be needed in a singlecarrier system operating over the same total bandwidth. A channelestimationbased decisionfeedback equalization method using a twostep procedure (estimation/fusion) is proposed for FMT. In this structure, channel estimates are used to cancel postcursor intersymbol interference from input signals prior to linear equalization. Parallel channel estimates of adjacent subbands are then fused, i.e. linked to a common underlying multipath model which exploits frequency correlation to improve upon the channel estimates. The sparse nature of underwater acoustic channels may be exploited by setting to zero all but the significant channel taps, thus further relieving equalization of the estimation noise. The performance of underwater FMT is assessed via simulation and using real data transmitted over 800 m in shallow water at rates of 2–6 kbit/s. The results are compared to OFDM and singlecarrier QPSK modulation operating at similar bandwidth efficiencies. I.
1Optimization of Synthesis Oversampled Complex Filter Banks
"... An important issue with oversampled FIR analysis filter banks (FBs) is to determine inverse synthesis FBs, when they exist. Given any complex oversampled FIR analysis FB, we first provide an algorithm to determine whether there exists an inverse FIR synthesis system. We also provide a method to ensu ..."
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An important issue with oversampled FIR analysis filter banks (FBs) is to determine inverse synthesis FBs, when they exist. Given any complex oversampled FIR analysis FB, we first provide an algorithm to determine whether there exists an inverse FIR synthesis system. We also provide a method to ensure the Hermitian symmetry property on the synthesis side, which is serviceable to processing realvalued signals. As an invertible analysis scheme corresponds to a redundant decomposition, there is no unique inverse FB. Given a particular solution, we parameterize the whole family of inverses through a null space projection. The resulting reduced parameter set simplifies design procedures, since the perfect reconstruction constrained optimization problem is recast as an unconstrained optimization problem. The design of optimized synthesis FBs based on time or frequency localization criteria is then investigated, using a simple yet efficient gradient algorithm. Index Terms Oversampled filter banks, inversion, filter design, optimization, time localization, frequency localiza
DESIGN OF OVERSAMPLED DFT MODULATED FILTER BANKS OPTIMIZED FOR ACOUSTIC ECHO CANCELLATION
"... This paper describes a method for designing oversampled DFT filter banks (FB) optimized for subband acoustic echo cancellation (AEC). For this application, the design requirements typically are good echo cancellation quality, low delay, small reconstruction error, and low computation complexity. Our ..."
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This paper describes a method for designing oversampled DFT filter banks (FB) optimized for subband acoustic echo cancellation (AEC). For this application, the design requirements typically are good echo cancellation quality, low delay, small reconstruction error, and low computation complexity. Our method explicitly includes a model for echo return loss enhancement (ERLE) as part of the optimization criteria. Convergence of the highdimensional, nonlinear optimization problem is facilitated by decorrelating the prototype filter impulse response via a discreet cosine transform (DCT), discarding many insignificant coefficients and thus reducing the dimensionality of the search. The experimental results demonstrate the effectiveness of our design and the effects on the performance of AEC, with ELRE improvements on the order of 3 dB or better. The method is flexible and could also be extended to other application domains. Index Terms – oversampled filter banks, modulated filter banks, acoustic echo cancellation, adaptive filters. 1.
unknown title
, 2010
"... F inite impulse response (FIR) filters have played a central role in digital signal processing since its inception. As befits that role, a myriad of design techniques is available, ranging from the quite straightforward windowing and frequencysampling techniques to some rather sophisticated optimi ..."
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F inite impulse response (FIR) filters have played a central role in digital signal processing since its inception. As befits that role, a myriad of design techniques is available, ranging from the quite straightforward windowing and frequencysampling techniques to some rather sophisticated optimizationbased techniques; e.g., [1]–[7]. Among the most prominent optimizationbased techniques is the ParksMcClellan algorithm [8] for the design of “equiripple ” linear phase FIR filters. One of the key features of that technique is the efficiency of the underlying Remez exchange algorithm. However, computing resources have grown more plentiful since the ParksMcClellan algorithm was developed [9], and this has spawned the development of more flexible design methodologies. Of particular note are METEOR [10] and the peakconstrained leastsquares (PCLS) approach [11], [12]. METEOR is a flexible platform for FIR filter design problems that can be formulated as the optimization of a linear objective subject to linear constraints; i.e., as a linear program. One such problem is the design of a linearphase lowpass filter with a “ripple ” constraint in the passband, a constraint on the stopband level, and the constraint that the passband response be a concave function of frequency. The PCLS approach provides efficient constraint exchange algorithms for finding filters that minimize a “least squares” approximation error subject to linear constraints; i.e., solve a quadratic program. One example is the design of a lowpass filter that minimizes the stopband energy subject to a bound on the stopband level. Linear and quadratic programs are two of the simpler forms of convex optimization problem, and effective algorithms for solving them have been available for some time. Around the time that METEOR
Article Time Reversal Acoustic Communication Using Filtered Multitone Modulation
, 2015
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"... Abstract—An efficient channelindependent design method for the prototype filter of a filtered multitone (FMT) transceiver is proposed, along with an iterative powerloading algorithm for FMT. The insight gained from this design is used to choose the number of subchannels in an FMT system. Index Ter ..."
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Abstract—An efficient channelindependent design method for the prototype filter of a filtered multitone (FMT) transceiver is proposed, along with an iterative powerloading algorithm for FMT. The insight gained from this design is used to choose the number of subchannels in an FMT system. Index Terms—Convex optimization, filtered multitone (FMT) modulation, multicarrier communications, power loading.