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Search results for: bandpass filter
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On Sample Rate Conversion Based on Variable Fractional Delay Filters
PublicationThe sample rate conversion algorithm based on variable fractional delay filters is often used if the resampling ratio cannot be expressed as the ratio of small integer numbers or if it is not constant. The main advantage of such solution is that it allows for arbitrary resampling ratios which can even be changed during the resampling process. In this paper a discussion on influence of different approaches to fractional filter...
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Compensation of Dead Time Effects for Shunt Active Power Filters
PublicationThe paper presents a comprehensive approach to the compensation of the grid current distortion for shunt active power filter systems. Four different sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, time delays in the estimation of compensating currents and grid voltages, fluctuations of the dc bus voltage, and the distortion of inverter output voltages due...
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Hand gesture recognition supported by fuzzy rules and Kalman filters
PublicationThe paper presents a system based on camera and multimediaprojector enabling a user to control computer applications by dynamic hand gestures. Gesture recognition methodology based on representing hand movement trajectory by motion vectors analysed using fuzzy rule-based inference is first given. For effective hand position tracking Kalman filters are employed. The system engineered is developed using J2SE and C++/OpenCV technology....
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Power flow in typical series-parallel hybrid filters topologies
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On tracking properties of real-valued generalized adaptive notch filters
PublicationGeneralized adaptive notch filters (GANFs) are used for identification/tracking of quasi-periodically varying dynamic systems and can be considered an extension, to the system case, of classical adaptive notch filters. The paper presents results of local performance analysis of a real-valued GANF algorithm, i.e., algorithm designed to track parameters of a real-valued system. This is an extension of the previous work which focused...
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Development of HFB with the Use of 2nd Order Pass-Band Filters
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Gradient-based optimization of filters using FD-TD software
PublicationW artykule opisane jest nowe podejście do zagadnienia optymalizacji filtrów mikrofalowych pasmowo-przepustowych. Optymalizacja prowadzona jest z wykorzystaniem metody gradientowej poszukiwania minimum wartości funkcji celu oraz przy założeniu pełnofalowej symulacji obwodów metodą różnic skończonych w dziedzinie czasu. W artykule pokazane jest, że stosując zaawansowane techniki cyfrowego przetwarzania sygnałów możliwa jest optymalizacja...
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Efficient tolerance analysis of continuous-time Gm-C filters
PublicationW pracy przedstawiono efektywną metodą analizy tolerancji dowolnych filtrów Gm-C. Przedstawiono ogólny model filtrów Gm-C oraz jego opis algebraiczny. Używając tego podejścia, wyprowadzono formuły pozwalające na wyznaczenie odchyłek funkcji przenoszenia filtru spowodowanych odchyłkami wartości elementów filtru od wartości nominalnych. Proponowana metoda charakteryzuje się niewielką złożonością obliczeniową, co pozwala na jej wykorzystanie...
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New approach to computer aided design of coupled resonator filters
PublicationW niniejszej pracy zastosowane zostały gradientowa metoda optymalizacji oraz nowa definicja funkcji celu do projektowania filtrów mikrofalowych. Definicja funkcji celu została oparta na badaniu położenia zer i biegunów funkcji przenoszenia optymazlizownanych układów.
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Canonic structures of old order elliptic Gm-C filters.
PublicationW pracy zaproponowano nowe struktury kanoniczne eliptycznych filtrów Gm-Crzędów nieparzystych. Opracowane układy filtrów wymagają małej liczby elementów zarówno aktywnych jak i pasywnych niezbędnych do realizacji żądanych charakterystyk częstotliwościowych.W pracy są również zaprezentowane rezultaty porównań właściwości przedstawionych struktur z przykładami realizacji układowych innych filtrów Gm-C.
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Algebraic model of continuous time Gm-LC filters and applications.
PublicationW pracy zaprezentowano model algebraiczny filtrów Gm-LC czasu ciągłego i jego wybrane zastosowania. Zaproponowany model obejmuje struktury pracujące zarówno w trybie napięciowym jak i prądowym. Użyteczność opracowanego modelu potwierdzono na przykładzie syntezy eliptycznego filtru Gm-LC rzędu nieparzystego.
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Structure generation and performance comparison of elliptic Gm-C filters.
PublicationW oparciu o zestaw macierzy opisujący ogólną topologię filtrów typu Gm-C opracowano procedurę efektywnej generacji struktur filtrów dolnoprzepustowych. Dla filtrów tego typu podano wyrażenia pozwalające analizować właściwości wrażliwościowe oraz określono zestaw odpowiednich kryteriów porównawczych. Szczegółowe badania porównawcze przeprowadzono dla wybranych filtrów 3-go rzędu w tym realizowanych w strukturach LF(leapfrog) i...
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Nonlinear distortion analysis and optimisation of general OTA-C filters.
PublicationW pracy przedstawiono opis analityczny ogólnej struktury filtrów OTA-C zawierających nieliniowe elementy aktywne. Wprowadzono nieliniowy układ równań różniczkowych zwyczajnych opisujący dynamikę tej klasy układów aktywnych. Opis ten pozwala, przy użyciu standardowych metod numerycznych, na przeprowadzenie efektywnej analizy czasowej filtrów OTA-C. Proponowane podejście może być stosowane do badania dowolnych efektów nieliniowych...
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Design of waveguide filters using multiple irises and folded elements.
PublicationW pracy został zaprezentowany przegląd metod projektowania filtrów falowodowych w kontekście zarówno klasycznych metod syntezy jak i współczesnych algorytmów. W szczególności rozważonoanalizę filtrów z wieloaperturowymi przegrodami oraz filtrówzbudowanych w wygiętych odcinkach falowodów. Zaprezentowano przykłady w pełni wykorzystujące zalety wygiętych falowodów a także pokazano wydajne metody optymalizacji oparte na badaniu położeń...
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Canonic structures of odd-order elliptic Gm-C filters.
PublicationW pracy zaproponowano nowe rozwiązania układowe struktur kanonicznych eliptycznych filtrów Gm-C czasu ciągłego, rzedu nieparzystego. Opracowane struktury charakteryzują się małą liczbą elementów pasywnych oraz aktywnych i są przewidziane do zastosowań w filtrach niskomocowych o małej wrażliwości. W przeprowadzonych badaniach porównywano wybrane struktury 3-go rzędu pod względem właściwości i wymagań układów scalonych, w których...
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Noise Analysis and Optimization of Continuous-Time OTA-C Filters
PublicationW pracy przedstawiono efektywną procedurę wyznaczania szumów w filtrach OTA C czasu ciagłego. Procedura wyprowadzona jest w oparciu o ogólny model filtru OTA C oraz jego opis macierzowy. Podano jawne formuły pozwalające okreslić odniesione do wejścia widmo szumów dowolnego filtru rozważanej klasy. Otrzymane wyniki teoretyczne zostały zweryfikowane poprzez porównanie z wynikami otrzymywanymi za pomocą symulatora SPICE dla wybranych...
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Analysis and Optimization of Noise in Continuous-Time OTA-C Filters
PublicationW pracy przedstawiono ogólną procedurę analizy szumów w filtrach klasy OTA-C czasu ciągłego. Procedura umożliwia analizę filtrów o dowolnej topologii i dowolnego rzędu w ramach rozważanej klasy. W oparciu o opis macierzowy ogólnej struktury filtru OTA-C wyprowadzono ogólne formuły pozwalające na wyznaczanie i optymalizację szumów dowolnego filtru OTA-C. Przedstawione wyniki są użyteczne nie tylko dla klasycznych (dyskretnych lub...
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Eigenvalue approach to synthesis of prototype filters with source/load coupling
PublicationArtykuł przedstawia nową, szybko zbieżną, technikę syntezy macierzy sprzężeń filtrów o charaktrystyce Czebyszewa. Synteza opiera się na zastosowaniu metody najmniejszych kwadratów w odniesieniu do wartości własnych macierzy sprzężeń oraz jej podmacierzy.
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Surgical tool tracking by on-line selection of structural correlation filters
PublicationIn visual tracking of surgical instruments, correlation filtering finds the best candidate with maximal correlation peak. However, most trackers only consider capturing target appearance but not target structure. In this paper we propose surgical instrument tracking approach that integrates prior knowledge related to rotation of both shaft and tool tips. To this end, we employ rigid parts mixtures model of an instrument. The rigidly...
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A Trisection Filter Design With Negative Slope of Frequency-Dependent Crosscoupling Implemented in Substrate Integrated Waveguide (SIW)
PublicationThis letter reports on a novel realization of a microwave bandpass filter in a triplet configuration with a frequency-dependent crosscoupling implemented in substrate integrated waveguide (SIW). The design involves implementing dispersive coupling with a negative slope, a feature that allows the capabilities of the classic triplet topology to be extended. In this particular case, the implementation of two transmission zeros on...
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Stability of softly switched multiregional dynamic output controllers with a static antiwindup filter: A discrete-time case
PublicationThis paper addresses the problem of model-based global stability analysis of discrete-time Takagi–Sugeno multiregional dynamic output controllers with static antiwindup filters. The presented analyses are reduced to the problem of a feasibility study of the Linear Matrix Inequalities (LMIs), derived based on Lyapunov stability theory. Two sets of LMIs are considered candidate derived from the classical common quadratic Lyapunov...
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Filter-Hilbert Method for Automatic Correction of Non-Anechoic Antenna Measurements with Embedded Self-Calibration Mechanism
PublicationOne of the most important steps in the process of antenna development involves measurements of its prototype. Far-field performance of radiators is normally characterized in strictly controlled environments such as anechoic chambers which can ensure certification-grade accuracy. Unfortunately, they are also characterized by high construction costs which might not be justified for low-budget research and/or teaching-related activities....
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A 0.5 V Nanowatt Biquadratic Low-Pass Filter with Tunable Quality Factor for Electronic Cochlea Applications
PublicationA novel implementation of an analogue low-power, second-order, low-pass filter with tunable quality factor (Q) is presented and discussed. The filter feature is a relatively simple, buffer-based, circuit network consisting of eleven transistors operating in a subthreshold region. Q tuning is accomplished by injecting direct current into a network node, which changes the output resistance of the transistors and, as a result, modifies...
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Lattice filter based multivariate autoregressive spectral estimation with joint model order and estimation bandwidth adaptation
PublicationThe problem of parametric, autoregressive model based estimation of a time-varying spectral density function of a multivariate nonstationary process is considered. It is shown that estimation results can be considerably improved if identification of the autoregressive model is carried out using the two-sided doubly exponentially weighted lattice algorithm which combines results yielded by two one-sided lattice algorithms running...
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Microstrip line with short-circuited edge as a high-pass filter operating up to millimeter-wave frequencies
PublicationPrzedstawiono prosty planarny filtr górnoprzepustowy wykorzystujący linię mikropaskową ze zwartym brzegiem. Układy zaprojektowano w taki sposób, aby pasmo przepustowe rozpoczynało się w zakresie K lub Ka. Wykonano dwa prototypy: na podłożu w postaci warstwy dielektrycznej wykonanej z ceramiki alundowej oraz na podłożu organicznym o niskiej przenikalności elektrycznej. Wykazano dużą zgodność teoretycznych i pomierzonych charakterystyk...
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Toward Wide-Band High-Resolution Analog-to-Digital Converters Using Hybrid Filter Bank Architecture
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Speed sensorless ac drive with inverter output filter and fault detection using load torque signal
PublicationIn this paper, a sensorless induction motor (IM) drive using speed observer system is presented. The system includes load torque computation for gear fault detection. Nonlinear control method is adopted for controlling the motor over a wide speed range. An LC filter for smoothing current and voltage waveforms is used at the output of the voltage inverter. The use of filter imposes more building of the used observer to avoid using...
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Estimation of time-frequency complex phase-based speech attributes using narrow band filter banks
PublicationIn this paper, we present nonlinear estimators of nonstationary and multicomponent signal attributes (parameters, properties) which are instantaneous frequency, spectral (or group) delay, and chirp-rate (also known as instantaneous frequency slope). We estimate all of these distributions in the time-frequency domain using both finite and infinite impulse response (FIR and IIR) narrow band filers for speech analysis. Then, we present...
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Speed Sensorless AC Drive with Inverter LC Filter and Fault Detection Using Load Torque Signal
PublicationThe industrial development in recent years has seen a major increase in the use of induction motors, whereby the cost has to be as low as possible and the lifetime as long as possible. To follow up this desire, investigations in this area have become very intense. For that reason, this paper presents a solution for driving an induction motor and simultaneous fault detection with no need for additional sensors. In order to achieve...
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MATCHED FILTER APPROACH FOR MICROSEISMIC SIGNAL PROCESSING OF REAL DATA FROM EAST POMERANIA SHALE GAS
PublicationThe microseismic monitoring is a method of monitoring of fracture propagation during hydraulic fracturing (HF)process. An array of several hundred geophones is placed on the surface to record little ground tremors induced by fracturing process. Filtration and summation of signals from geophones is essential to identify and locate fracturing events from underground. Authors propose a method of matched filtering, that is usually...
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Fifth-order low-pass CMOS OTA-C continuous-time filter with on-chip automatic tuning
PublicationW pracy przedstawiono budowę operacyjnego wzmacniacza transkonduktancyjnego (OTA) zasilanego napięciem stałym 2.8-4.5V wykonanego w technologii CMOS0.8um n-well. Wzmacniacz ten wykorzystano do budowy dolnoprzepustowego filtru czasu ciągłego typu OTA-C piątego rzędu. W układzie scalonym umieszczono także blok automatycznego dostrajania częstotliwości odcięcia filtru. Przedstawiono wyniki symulacji komputerowych (modele MOS BSIM3v3)...
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Variable-structure algorithm for identification of quasi-periodically varying systems
PublicationThe paper presents a variable-structure version of a generalized notchfiltering (GANF) algorithm. Generalized notch filters are used for identification of quasi-periodically varying dynamic systems and can be considered an extension, to the system case, of classical adaptive notch filters. The proposed algorithm is a cascade of two GANF filters: a multiple-frequency "precise" filter bank, used for precise system tracking, and a...
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Thermoplastic Elastomers Filled With GTR
PublicationIn recent years, searching for new and cost-effective methods of recycling waste tires has been a subject of research in many laboratories worldwide. This is due to regulations in the law and environmental factors, which have both stimulated industry to re-use high quality rubber found in ground tire rubber (GTR). One of the most promising solutions in this area seems to be thermoplastic elastomers (TPEs) filled with GTR, which...
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Silver intercalated carbon nanotubes
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The effect of using jug-type water filters on selected metals concentration in tap water – a case study
PublicationIn this study, the effect of the filtration process on Na, K, Mg, Ca, Fe and Zn concentration in water, using filters from one of the leading European manufacturers, was investigated. The increase in Na (up to 300%) and K concentration (up to 320%) at the beginning of jug filter usage was reported. A decrease in Ca, Fe and Zn concentration was observed. Standard filters remove 80–90% of Mg from tap water at the beginning of the...
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Processing and structure–property relationships of natural rubber/wheat bran biocomposites
PublicationIn this work, wheat bran was used as cellulosic filler in biocomposites based on natural rubber. The impact of wheat bran content [ranging from 10 to 50 parts per hundred rubber (phr)] on processing, structure, dynamic mechanical properties, thermal properties, physico-mechanical properties and morphology of resulting biocomposites was investigated. For better characterization of interfacial interactions between natural rubber...
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Rectangular Waveguide Filters Based on Deformed Dual-Mode Cavity Resonators
PublicationIn this paper, a novel design for rectangular waveguide filters with deformed dual-mode (DM) cavity resonators is demonstrated. The new resonant cavity shape is a result of applying shape deformation to the basic rectangular cavity to enable its dual-mode operation. Internal coupling between the two orthogonal cavity modes is realized by geometry deformation, eliminating the need for additional coupling elements. The designs are...
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A simple way of increasing estimation accuracy of generalized adaptive notch filters
PublicationGeneralized adaptive notch filters are used for identification/tracking of quasi-periodically varying dynamic systems and can be considered an extension, to the system case, of classical adaptive notch filters. It is shown that frequency biases, which arisein generalized adaptive notch filtering algorithms, can be significantly reduced by incorporating in the adaptive loop an appropriately chosen decision delay. The resulting performance...
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Pollutants removal effectiveness in hydrophyte filters with sequential vertical and horizontal flow
PublicationThe object of investigations was the constructed wetland in Wiedersberg in Saxonia in Germany supplied with domestic sewage from 145 inhabitants. The biological part was composed of sequential reed beds with vertical and horizontal flow of sewage. It in one of new solutions, because up till now configuration with vertical bed situated at front of biological part of treatment was applied.The evaluation of object performance was...
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Multisensor Tracking of Marine Targets - Decentralized Fusion of Kalman and Neural Filters
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Design of Analog Filters with Single Transmission Zeros, Dedicated for HFB Systems
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Coupled-resonator filters with frequency-dependent couplings: coupling matrix synthesis
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Fast multiplexer cad using surrogate models for channel filters synthesis
Publicationartykuł przedstawia metodę szybkiego projektowania multiplekserów mikrofalowych wykorzystującą dokładne modele zastępcze na etapie projektowania kanałów. przedstawiony został przykład trój-kanałowego multipleksera z filtrami dwurodzajowymi.
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Novel microstrip low-pass filters with fractal defected ground structures
PublicationIn this study, three microstrip low-pass filters (LPFs) containing fractal-shaped defected ground structures have been designed and manufactured. To improve the performance of microstrip LPF, cascades of inductively coupled fractal resonators have been applied. Simultaneously, to achieve relatively constant microstrip impedance resulting in essentially low reflection losses, a modification of the strip geometry has been introduced....
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Comprehensive compensation of grid current distortion by shunt active power filters
PublicationThe paper presents a comprehensive approach to the compensation of grid current distortion in shunt active power filter systems. Four sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, time delays in the evaluation of grid voltages and computation of compensating currents, fluctuations of the dc bus voltage, and the distortion of inverter output voltages due...
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Fast Full-Wave Multilevel Zero-Pole Optimization of Microwave Filters
PublicationA new concept is proposed for the full-wave computer-aided design of microwave filters. The method consists of two stages and operates on the zeros and poles of the transfer function and their derivatives. These quantities are evaluated from the response computed by a full-wave electromagnetic solver with two levels of accuracy. The two stages make use of different models that are optimized using a low-accuracy electromagnetic...
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Technique to improve CMRR at high frequencies in CMOS OTA-C filters
PublicationIn this paper a technique to improve the common-mode rejection ratio (CMRR) at high frequencies in the OTA-C filters is proposed. The technique is applicable to most OTA-C filters using CMOS operational transconductance amplifiers (OTA) based on differential pairs. The presented analysis shows that a significant broadening of CMRR bandwidth can be achieved by using a differential pair with the bodies of transistors connected to...
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Testing Stability of Digital Filters Using Optimization Methods with Phase Analysis
PublicationIn this paper, novel methods for the evaluation of digital-filter stability are investigated. The methods are based on phase analysis of a complex function in the characteristic equation of a digital filter. It allows for evaluating stability when a characteristic equation is not based on a polynomial. The operation of these methods relies on sampling the unit circle on the complex plane and extracting the phase quadrant of a function...
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Copper Slag as a Potential Waste Filler for Polyethylene-Based Composites Manufacturing
PublicationThe present study aimed to analyze the application of waste material from copper production– copper slag (ŻŻL) as filler for composites based on the high-density polyethylene (HDPE). Copper slag filler was introduced in the amounts of 1–20 wt%, and its influence on the appearance (color analysis), chemical structure (Fourier-transform infrared (FTIR) spectroscopy), microstructure (optical microscopy), as well as static (tensile...
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Application of regularized Savitzky–Golay filters to identification of time-varying systems
PublicationSavitzky–Golay (SG) filtering is a classical signal smoothing technique based on the local least squares approximation of the analyzed signal by a linear combination of known functions of time (originally — powers of time, which corresponds to polynomial approximation). It is shown that the regularized version of the SG algorithm can be successfully applied to identification of time-varying finite impulse response (FIR) systems....