Goran Stancic - Academia.edu (original) (raw)

Papers by Goran Stancic

International Journal of Electronics, Feb 24, 2020

A new approach to the design of the nearly-linear phase infinite impulse response lowpass differe... more A new approach to the design of the nearly-linear phase infinite impulse response lowpass differentiators using a parallel all-pass structure is discussed in this paper. The magnitude and phase responses of the proposed low-pass differentiators are first formulated as functions of the phase responses of the corresponding all-pass filters, and a set of equations is derived such that the magnitude response approximates the ideal one in the weighted Chebyshev sense both in the passband and the stopband. The maximum passband phase response linearity error is shown to be related to the maximum passband magnitude error and the value of an additional design parameter. Comparison with the existing nearly-linear phase infinite impulse response low-pass differentiators shows that the low-pass differentiators designed using the proposed method usually require less multiplications, which comes at the cost of a somewhat higher filter order and consequently higher group delay. However, as the reduced number of multiplications lead to lower power consumption if hardware implementation is considered, the proposed low-pass differentiators are an attractive alternative in applications where low group delay is not of crucial importance.

ABSTRACT A new method for design of recursive digital notch filter with linear phase is described... more ABSTRACT A new method for design of recursive digital notch filter with linear phase is described in this paper. Obtained filter is realized using parallel connection of delay line and IIR all-pass filter. The resulted amplitude characteristic in all pass-bands is equiripple. Coefficients of the obtained filter are calculated by approximation of all-pass ideal linear phase characteristic. The efficiency of the proposed algorithm is demonstrated on a few examples. The algorithm exhibits a fast convergence and an easy determination of initial values.

Facta universitatis. Series electronics and energetics, 2011

The procedure for design of narrow stopband recursive digital filter realized through parallel co... more The procedure for design of narrow stopband recursive digital filter realized through parallel connections of two allpass sub-filters is described in this paper. This solution also allows realization of complementary filter, using only one additional adder, and exhibit low sensitivity on coefficients quantization. The method is based on phase approximation of allpass sub-filter. The procedure is very efficient and solution can be obtained within only a few iterations even for large filter order n. Every stopband provides two more equations, one at notch frequency and the other at passband boundary. It is not possible to control attenuation at both passband boundaries, but described procedure provides that achieved attenuations are less or equal to prescribed values. Using this algorithm full control of passband edges is obtained comparing with existing methods where it is not possible.

Facta Universitatis, Jan 27, 2020

This paper proposes a method for tackling the problem of scalable object instance detection in th... more This paper proposes a method for tackling the problem of scalable object instance detection in the presence of clutter and occlusions. It gathers together advantages in respect of the state-of-the-art object detection approaches, being at the same time able to scale favorably with the number of models, computationally efficient and suited to textureless objects as well. The proposed method has the following advantages: a) generality-it works for both texture-less and textured objects, b) scalability-it scales sub-linearly with the number of objects stored in the object database, and c) computational efficiency-it runs in near real-time. In contrast to the traditional affine-invariant detectors/descriptors which are local and not discriminative for texture-less objects, our method is based on line segments around which it computes semi-global descriptor by encoding gradient information in scale and rotation invariant manner. It relies on both texture and shape information and is, therefore, suited for both textured and texture-less objects. The descriptor is integrated into efficient object detection procedure which exploits the fact that the line segment determines scale, orientation and position of an object, by its two endpoints. This is used to construct several effective techniques for object hypotheses generation, scoring and multiple object reasoning; which are integrated in the proposed object detection procedure. Thanks to its ability to detect objects even if only one correct line match is found, our method allows detection of the objects under heavy clutter and occlusions. Extensive evaluation on several public benchmark datasets for texture-less and textured object detection, demonstrates its scalability and high effectiveness.

Facta Universitatis, Jan 8, 2019

In this paper the design of selective digital filters that consists of a parallel connection of t... more In this paper the design of selective digital filters that consists of a parallel connection of two all-pass sub-filters is presented. The phase of these filters has given an arbitrary shape ϕ(ω) in both pass-band and stop-band. The proposed method allows the calculation of selective filters with elliptic-like magnitude characteristic. Equations given in the paper are general and suitable for design of filters with arbitrary phase. The efficiency of the method is demonstrated on design of filters with piecewise linear and quadratic phases.

Radioengineering, Jun 14, 2019

In this paper, a comprehensive analysis of hardware complexity of different configurations for th... more In this paper, a comprehensive analysis of hardware complexity of different configurations for the realization of approximately linear phase filters is presented. Hardware complexity for the realization of the parallel all-pass structure (PA) is compared to the standard elliptic filters with the adequate group delay corrector (EC) in cascade. Both considered filters are designed to have the same cutoff frequency and magnitude approximation error, as well as the same maximal group delay error in all pass-bands. All analyzed infinite impulse response (IIR) filters will have an elliptic shape magnitude and approximately linear phase (i.e. constant group delay). In addition, the resulting group delay error of all the considered filters has an equiripple nature. The performed analysis revealed that consistently better results could be achieved with PA filters in terms of power consumption and hardware complexity. At the same time, the PA filters introduce significantly lower delay. The filter banks for efficient sub-band coding and signal transmission in communication systems could be successfully realized using the PA filters. The results presented here could be a valuable resource for designers of IIR filters to select the appropriate configuration for realization.

Facta Universitatis, Nov 26, 2018

A comprehensive analysis of realization of digital filters with complex coefficients obtained by ... more A comprehensive analysis of realization of digital filters with complex coefficients obtained by decomposition of real digital filters, using complex and real allpass networks, is given in the paper. Realization of complex coefficient filters obtained directly in the z domain is also discussed in the paper. An analysis of hardware costs for different structures used for realization of complex coefficient filters is presented.

This paper describes a new procedure for design of complementary IIR digital filters based on gro... more This paper describes a new procedure for design of complementary IIR digital filters based on group delay approximation. The filters are realized as parallel sum of two all-pass filters, a structure for which low complexity implementations exist. Problem with phase warping which is inevitable if filter design is made through phase approximation will be removed using proposed method. Adequate initial solution is also proposed. Realized amplitude characteristics of complementary filters will be approximately equriripple. The design examples illustrate that the proposed algorithm is very efficient in term of computation time and number of iterations.

Circuits, Systems, and Signal Processing, 2018

A novel all-pass-based infinite impulse response (IIR) digital multiplenotch filter design method... more A novel all-pass-based infinite impulse response (IIR) digital multiplenotch filter design method is presented in this paper. The proposed method ensures that, for an arbitrary pass-bands ripple value, specifications regarding positions of notch, left-and right-hand cutoff frequencies are exactly met, which leads to symmetric magnitude responses about notch frequencies. Although iterative in its nature, proposed method requires a small number of iterations to find coefficients of the multiple-notch filter, making it very useful for designers. Since the magnitude response of the allpass-based IIR multiple-notch filter is more sensitive in the stop-bands than in the pass-bands, sensitivity analysis along with simulation in limited word-length environment is performed.

International Journal of Circuit Theory and Applications, 2016

A method for design of a new class of digital infinite impulse response filters realized as paral... more A method for design of a new class of digital infinite impulse response filters realized as parallel connection of two all-pass filters is presented in this paper. A new approach to approximation of quadratic phase of allpass filter at all frequencies is given. Chosen parallel structure offers opportunity for realization of filters with arbitrary shape phase. The presented algorithm is based on all-pass filter phase approximation. Phases of both all-pass filters approximate ideal quadratic phase in minimax sense at all frequencies. Such filters can be applied for chirp signal compression or expansion. Magnitude characteristic of described filters is very selective and elliptic-like. Obtained filters are compared with elliptic filter and group delay corrector in cascade. For the same specifications, much better results are achieved by the proposed filters. Parallel connection of all-pass filters introduces lower signal delay, and for a given maximal phase, approximation error demands less complex network. Examples to illustrate the proposed method are given.

2021 56th International Scientific Conference on Information, Communication and Energy Systems and Technologies (ICEST), 2021

The different structures of digital notch filters realized as parallel connection of two allpass ... more The different structures of digital notch filters realized as parallel connection of two allpass subfilters are investigated in this paper. The research was done for notch filters with only one notch frequency. The influence of filter coefficients quantization on filter characteristics is analysed for three configurations and the results are displayed. Unlike Butterworth and elliptic filters it is shown that notch filters realised as parallel connection of two allpass filters remain selective even in case the coefficients are represented with only three fractional bits. All given results are obtained using Matlab® package.

Digital Signal Processing, 2019

Abstract A new approach for the design of recursive fullband digital differentiators using parall... more Abstract A new approach for the design of recursive fullband digital differentiators using parallel all-pass structure is discussed in this paper. While magnitude response of designed fullband differentiator approximates the ideal one in the weighted Chebyshev sense, its phase response is a nearly-linear function of frequency at low frequencies. The low-pass differentiators, presented in this paper, are obtained by cascading the proposed recursive fullband differentiators with the corresponding low-pass filters. The phase response linearity error of such low-pass differentiators is shown to be primarily affected by the phase response nonlinearity of the utilized low-pass filter. A comparison with some of the existing fullband and low-pass differentiators shows that proposed differentiators require less multiplications, while their phase and magnitude responses are either better or slightly worse than those of existing differentiators.

International Journal of Circuit Theory and Applications, 2018

IET Signal Processing, 2018

In this study, the authors present a new procedure for the synthesis of the nearly linear-phase i... more In this study, the authors present a new procedure for the synthesis of the nearly linear-phase infinite impulse response (IIR) filters with two close notch frequencies based on all-pass filter application. The filter is obtained using a parallel connection of the delay line and IIR all-pass filter with a piecewise approximately linear phase. The desired magnitude characteristic is achieved by equiripple approximation of the all-pass filter phase. The magnitude characteristic is equiripple in all passbands. The proposed method is also suitable for the synthesis of complementary filters for extraction of the signal components at prescribed frequencies. The initial solution for the arbitrary order of an all-pass filter is proposed, which attains a sufficient number of phase error extrema. All phase error minima and maxima corresponding to the initial solution have almost identical values, excluding the ones near notch frequencies. As a result, the method exhibits fast and strong convergence. The described method can also be applied for the design of multiple notch filters with two very close notch frequencies.

Journal of Sandwich Structures & Materials, 2009

The new 3D models of the prestressed symmetrical and unsymmetrical ultrasonic sandwich transducer... more The new 3D models of the prestressed symmetrical and unsymmetrical ultrasonic sandwich transducers are described in this article. The sandwich transducers are modeled through the application of a 3D matrix model of piezoceramic rings and discs, recently proposed by the authors. Theoretical analyses prove the proposed models as simple and easy to calculate, particularly suitable for the investigation of coupled vibrations cases. Experiments show that the measured resonance and antiresonance frequencies are in good agreement with the predicted results. Compared with traditional 1D models and methods, the results obtained by the proposed models matched better with the experimental results.

AEU - International Journal of Electronics and Communications, 2002

ABSTRACT A method for synthesis of digital bandpass and bandstop filters obtained by parallel con... more ABSTRACT A method for synthesis of digital bandpass and bandstop filters obtained by parallel connection of two allpass networks, is considered. A procedure is based on allpass network linear phase approximation at three levels in mini-max sense, which enables obtaining of selectivedigital filters in form of elliptic filters with linear phase in both passband and stopband.

Sadržaj-U radu je opisan postupak za dekompoziciju Chebyshev-ljeve IIR filtarske funkcije propusn... more Sadržaj-U radu je opisan postupak za dekompoziciju Chebyshev-ljeve IIR filtarske funkcije propusnika opsega frekvencija. U ovom radu je opisana kompletna dekompozicija za selektivne digitalne filtarske funkcije propusnike opsega. Dat je generalni pristup dekompozicije i sa realnim i sa kompleksnim koeficijentima za isti red filtra. Ova generalizacija dekompozicije biće ilustrovana na primeru Chebyshev-ljevog filtra propusnika opsega frekvencija dvanaestog reda. U radu je opisana realna dekompozicija za filtarsku funkciju parnog reda. Prototipska filtarska funkcijašestog reda (parnog) ima samo jedno rešenje i to kompleksnu dekompoziciju.

International Conference on Microelectronics, 1995

This paper presents a method for designing digital all-pass filters for pulse compressing, the ph... more This paper presents a method for designing digital all-pass filters for pulse compressing, the phase of which approximates to a squared phase in the Chebyshev (minimax) sense in the given frequency region. The method is based on the solution of a linear equation system which provided final solutions with a very small number of iterative cycles

Proceedings of International Conference on Microelectronics, 1995

This paper presents a new method for designing digital bandpass filters from analog lowpass filte... more This paper presents a new method for designing digital bandpass filters from analog lowpass filters. The method is based on evaluating a recurrence relation for calculating the coefficients of a digital bandpass transfer function from a known analog lowpass function