Results 11  20
of
61
Hierarchical Watermarking for Protection of DSP Filter Cores
 IN PROCEEDINGS OF THE CUSTOM INTEGRATED CIRCUITS CONFERENCE. PISCATAWAY, NJ: IEEE
, 1999
"... A hierarchical watermarking approach is developed that incorporates an ownership identification .directly into the design development process. This approach oftrs a high degree of tamper resistance and provides easy, noninvasive copy detection. We present two FIR digital filter cores, one watermarke ..."
Abstract

Cited by 5 (0 self)
 Add to MetaCart
A hierarchical watermarking approach is developed that incorporates an ownership identification .directly into the design development process. This approach oftrs a high degree of tamper resistance and provides easy, noninvasive copy detection. We present two FIR digital filter cores, one watermarked at the algorithm level and the second at the algorithm and architecture levels. A unique ownership signature (watermark) is placed at each level. At the algorithm level, the watermark is embedded in the filter coefficients during the development of the transfer function. At the architecture level, we use circuit transformations to watermark the design. Experimental results show approximately 7% area overhead of the algorithmlevel watermarked design over a nonwatermarked design. The cost of area for the design watermarked at both the algorithm and architecture levels is less than 40%.
Complex Chebyshev Approximation for FIR Filter Design
 IEEE Transactions on Circuits and Systems II
, 1995
"... The alternation theorem is at the core of efficient real Chebyshev approximation algorithms. In this paper, the alternation theorem is extended from the realonly to the complex case. The complex FIR filter design problem is reformulated so that it clearly satisfies the Haar condition of Chebyshev a ..."
Abstract

Cited by 4 (2 self)
 Add to MetaCart
The alternation theorem is at the core of efficient real Chebyshev approximation algorithms. In this paper, the alternation theorem is extended from the realonly to the complex case. The complex FIR filter design problem is reformulated so that it clearly satisfies the Haar condition of Chebyshev approximation. An efficient exchange algorithm is derived for designing complex FIR filters in the Chebyshev sense. By transforming the complex error function, the Remez exchange algorithm can be used to compute the optimal complex Chebyshev approximation. The algorithm converges to the optimal solution whenever the complex Chebyshev error alternates; in all other cases, the algorithm converges to the optimal Chebyshev approximation over a subset of the desired bands. The new algorithm is a generalization of the ParksMcClellan algorithm, so that arbitrary magnitude and phase responses can be approximated. Both causal and noncausal filters with complex or realvalued impulse responses can be ...
Optimal information storage: Nonsequential sources and neural channels
, 2006
"... Information storage and retrieval systems are communication systems from the present to the future and fall naturally into the framework of information theory. The goal of information storage is to preserve as much signal fidelity under resource constraints as possible. The information storage theor ..."
Abstract

Cited by 4 (4 self)
 Add to MetaCart
Information storage and retrieval systems are communication systems from the present to the future and fall naturally into the framework of information theory. The goal of information storage is to preserve as much signal fidelity under resource constraints as possible. The information storage theorem delineates average fidelity and average resource values that are achievable and those that are not. Moreover, observable properties of optimal information storage systems and the robustness of optimal systems
The Direct Solution Of Nonconvex Nonlinear FIR Filter Design Problems By A SIP Method
"... FIR filter design problems in the frequency domain are nonlinear (semiinfinite) optimization problems. In practice, however, these almost always have not been approached directly, but been solved in a simplified form and/or only under restricting assumptions. In this paper, quite general mathematic ..."
Abstract

Cited by 3 (3 self)
 Add to MetaCart
FIR filter design problems in the frequency domain are nonlinear (semiinfinite) optimization problems. In practice, however, these almost always have not been approached directly, but been solved in a simplified form and/or only under restricting assumptions. In this paper, quite general mathematical formulations of the four main design approximation problems in the frequency domain are presented, which enable the derivation of theoretical results (collected here from [31], [32]) and the application of generalpurpose optimization procedures to their direct solution. For the actual solution, a nonlinear semiinfinite programming method from the thesis [9] of the first author is discussed and applied to several specific design problems. In some cases, the computed solution of the nonlinear problem is compared with that of a convex approximation of the problem.
Design Approximation Problems for LinearPhase Nonrecursive Digital Filters
"... this paper is the study of four real, linear, possibly constrained minimum norm approximation problems, which arise in connection with the design of linearphase nonrecursive digital lters and are distinguished by the type of used trigonometric approximation functions. In case of unconstrained minim ..."
Abstract

Cited by 3 (3 self)
 Add to MetaCart
this paper is the study of four real, linear, possibly constrained minimum norm approximation problems, which arise in connection with the design of linearphase nonrecursive digital lters and are distinguished by the type of used trigonometric approximation functions. In case of unconstrained minimax designs these problems are normally solved by the ParksMcClellan algorithm, which is a straightforward adaptation of the second algorithm of Remez to these problems and which is one of the most popular tools in lter design. In this paper the four types of approximation problems are investigated for all L
The Asymptotics of Optimal (Equiripple) Filters
, 1999
"... fFor equiripple filters, the relation among the filter length N +1, the transition bandwidth 1!, and the optimal passband and stopband errors ffi p and ffi s has been a secret for more than 20 years. This paper is aimed at solving this mystery. We derive the exact asymptotic results in the weightfre ..."
Abstract

Cited by 3 (2 self)
 Add to MetaCart
fFor equiripple filters, the relation among the filter length N +1, the transition bandwidth 1!, and the optimal passband and stopband errors ffi p and ffi s has been a secret for more than 20 years. This paper is aimed at solving this mystery. We derive the exact asymptotic results in the weightfree case ffi p = ffi s = ffi, which enables us to interpret and improve the existing empirical formulas. Our main results are finally combined into formula (17). In the transition band, the filter response is discovered to be asymptotically close to a scaled error function. The main tools are potential theory in the complex plane and asymptotic analysis.
Second Order Volterra Inverses for Compensation of Loudspeaker Nonlinearity
, 1995
"... . High quality sound reproduction by loudspeakers is increasingly problematic if the dimensions of the loudspeaker decrease. To produce enough power, large diaphragm excursions are needed which give rise to significant distortions especially at very low frequencies. Instead of improving the mechanic ..."
Abstract

Cited by 3 (2 self)
 Add to MetaCart
. High quality sound reproduction by loudspeakers is increasingly problematic if the dimensions of the loudspeaker decrease. To produce enough power, large diaphragm excursions are needed which give rise to significant distortions especially at very low frequencies. Instead of improving the mechanical construction of the transducer we apply a feedforward nonlinear digital inverse circuit. Results of two 2 nd order Volterra compensators show a significant reduction of the second order harmonics, leaving higher order distortions unchanged. The structure of the realization influences the performance considerably. Two realization structures are considered, and the error caused by the differentiators in the output of the compensators are compared. Both algorithms are implemented in realtime on a Digital Signal Processor (DSP) for online testing with the transducer. 1. Introduction Because audio reproduction elements tend to decrease in size there is a search for smaller loudspeakers a...
Theory and Design of Multirate Sensor Arrays
"... Abstract—This paper studies the basic design challenges associated with multirate sensor arrays. A multirate sensor array is a sensor array in which each sensor node communicates a lowresolution measurement to a central processing unit. The objective is to design the individual sensor nodes and the ..."
Abstract

Cited by 3 (0 self)
 Add to MetaCart
Abstract—This paper studies the basic design challenges associated with multirate sensor arrays. A multirate sensor array is a sensor array in which each sensor node communicates a lowresolution measurement to a central processing unit. The objective is to design the individual sensor nodes and the central processing unit such that, at the end, a unified highresolution measurement is reconstructed. A multirate sensor array can be modeled as an analysis filterbank in discretetime. Using this model, the design problem is reduced to solving the following two problems: a) how to design the sensor nodes such that the timedelay of arrival (TDOA) between the sensors can be estimated and b) how to design a synthesis filterbank to fuse the lowrate data sent by the sensor nodes given the TDOA? In this paper, we consider a basic twochannel sensor array. We show that it is possible to estimate the TDOA between the sensors if the analysis filters incorporated in the array satisfy specific phaseresponse requirements. We then provide practical sample designs that satisfy these requirements. We prove, however, that a fixed synthesis filterbank cannot reconstruct the desired highresolution measurement for all TDOA values. As a result, we suggest a fusion system that uses different sets of synthesis filters for even and odd TDOAs. Finally, we use the optimality theory to design optimal synthesis filters. Index Terms—Delay estimation, filterbanks, FIR filters, optimization, multirate systems, multisensor systems, sensor fusion, sensor networks. I.
Approximate Fekete points for weighted polynomial interpolation
, 2009
"... We compute approximate Fekete points for weighted polynomial interpolation, by a recent algorithm based on QR factorizations of Vandermonde matrices. We consider in particular the case of univariate and bivariate functions with prescribed poles or other singularities, which are absorbed in the basis ..."
Abstract

Cited by 3 (3 self)
 Add to MetaCart
We compute approximate Fekete points for weighted polynomial interpolation, by a recent algorithm based on QR factorizations of Vandermonde matrices. We consider in particular the case of univariate and bivariate functions with prescribed poles or other singularities, which are absorbed in the basis by a weight function. Moreover, we apply the method to the construction of real and complex weighted polynomial filters, where the relevant concept is that of weighted norm.
Design Problems For Nonrecursive Digital Filters I
, 1997
"... The four main design problems for nonrecursive digital filters in the frequency domain are properly formulated as approximation problems and studied in regard to the existence of solutions and the convergence of the approximation errors. These are the problems of approximating a frequency response a ..."
Abstract

Cited by 2 (1 self)
 Add to MetaCart
The four main design problems for nonrecursive digital filters in the frequency domain are properly formulated as approximation problems and studied in regard to the existence of solutions and the convergence of the approximation errors. These are the problems of approximating a frequency response and a magnitude response and the problems of simultaneously approximating a magnitude and phase response and a magnitude and group response delay respectively. The errors are measured by an arbitrary L p  resp. l p norm, 1 p 1; and constraints on the filter coefficients are permitted. The topic of this first part of the paper is the approximation of a prescribed frequency response where linearphase filters are considered separately.