Filter Design Method Research Articles

Event‐triggered filter design for Markovian jump delay systems with nonlinear perturbation using quantized measurement

SummaryThis paper deals with the problem of mixed passivity and H∞ filter design for a class of Markovian jump delay systems with nonlinear perturbation under event‐triggered scheme and quantization. Firstly, based on an integral inequality, a new sufficient condition for the stochastic stability and performance analysis of the filtering error system is proposed. Secondly, a mode‐dependent condition for the solvability of the filter design problem is given in terms of linear matrix inequalities (LMIs). The filter parameters can be derived using feasible solutions of the presented LMIs. Finally, three numerical examples are given to illustrate the effectiveness and advantages of the proposed filter design method.

Design method for dual-band filters with completely independent passbands

ABSTRACTA design method for transmission-line-based dual-band filters with completely independent passbands is demonstrated. The proposed method completely ignores the conventional restrictions imposed on the electrical lengths of the transmission lines. Consequently, each resonator is designed separately by the predetermined parameters. Unlike conventional dual-band filters, the susceptance slope parameters at two center frequencies do not need to be maintained in all sections. As a result, the proposed filter can be designed to not only have different bandwidths, but also different responses. In addition, tuning the J-inverter values increases the design’s flexibility and compensate the theoretical limitation. The experimental results for various filters verify the proposed method, including the outstanding passband insertion loss. For the first time, a filter with a Chebyshev response in one passband and a maximally flat time-delay response in the other is demonstrated in this work.

DESIGN OF BAND-PASS FILTERS WITH NON-EQUIRIPPLE FREQUENCY RESPONSES

Introduction. Band-pass filters circuit elements can be calculated by converting low-pass filter (LPF) parameters, which is the prototype of the designed band-pass filter. The conversion causes problems in case calculated values of circuit elements (resistors and capacitors) are out of standard values determined by the GOST standard. Obviously, frequency characteristics of band-pass filters are distorted when replacing the calculated values of circuit elements by the standard ones. The number of circuit elements with values different from standard can be reduced to zero by solving an additional system of equations that connects parameters of designed and reintroduced non-equiripple frequency responses. Objective. The objective of this work is to develop a calculation method of band-pass ladder filters with values of circuit elements corresponding to standard ones. Materials and methods. The filter design process includes two stages. The first stage is a parameters calculation of a polynomial LPF prototype. The calculated parameters are determined as a system of equations solution set. The equations are formed by equating coefficients of variables raised to the same powers in transfer function (TF) expressions of designed and realized filters. Initial characteristics are the filter order and frequency response unevenness. The transition to the standard values of circuit elements can be done when solving another system of equations that connects LPF converted parameters with unknown parameters of reintroduced non-equiripple frequency response. Results. TF of LPF prototypes up to the fifth order and frequency responses of band-pass filters (BPF) and bandrejection filters up to the tenth order are presented. Analytical expressions of non-equiripple and equiripple frequency responses are used to estimate distortions of the latter when a band-pass filter center frequency is tuned by using variable inductors or capacitors. The integral quadratic function of a variable is taken as a measure of real frequency response distortions. The tenth order BPF calculation example is given. Conclusion. The presented calculation methods of band-pass filters and given example demonstrate possibilities of the filter design method based on the systems of non-linear equations solution. In contrast to approximation methods of ideal filter frequency response by using special functions and tabular filters design, the presented method allows high-order filter calculation for any initial requirements without using reference data.

FPGA Implementation and Evaluation of an Approximate Hilbert Transform-Based Envelope Detector for Ultrasound Imaging Using the DSP Builder Development Tool.

In this paper, we present the FPGA implementation of an approximate Hilbert Transform-based envelope detector to compute the magnitude of the received ultrasound echo signals in real-time using a Model-based design flow. The proposed architecture exploits the negative odd-symmetry and interleaved zero-valued coefficients of a Hilbert Transform-based FIR filter to reduce hardware resource requirements and complexity. The hardware design is modeled using the DSP Builder development tool allowing the automatic generation of HDL algorithms directly from the Matlab/Simulink environment. The generated VHDL code was synthesized for an Intel Stratix IV FPGA and validated on a Terasic DE4-230 board. The accuracy and performance of the envelope detector are analyzed with real ultrasound phantom data for different filter orders, coefficient length and two filter design methods: Equiripple and Least-Squares. The normalized residual sum of squares (NRSS) and the normalized root mean square error (NRMSE) cost functions are used for comparison with the reference absolute value of the Matlab Hilbert function. The results demonstrate that the proposed method yields similar results to conventional envelope detection methods, while being simpler to implement and requiring lower computational cost.

Triple‐mode bandpass filter

triple‐mode bandpass filter

Parameter dependent filter design for linear continuous-time uncertain systems with arbitrarily time-varying parameters in polytopic domains

This paper is concerned with the problem of full-order H2 and H∞ linear parameter varying filter design for continuous-time systems with arbitrarily time-varying parameters. The time-varying parameters belong to a polytope with known vertices, affect all the system matrices and are assumed to be available online for implementation of the filters. The synthesis conditions are formulated in terms of parameter dependent Linear Matrix Inequalities (PDLMIs). A sequence of standard LMI conditions assuring the existence of homogeneous polynomially parameter-dependent (HPPD) solutions to the parameter-dependent LMIs for filter design is provided in terms of the vertices of the polytope yielding parameter dependent filters of arbitrary degree assuring quadratic stability of the error dynamics. By definition of slack variables, extra free dimensions are provided to the parameter dependent filter design optimization problem, so method presented in this paper expected to be less conservative than the existing methods for the polytopic uncertain systems and efficiency of the method for filter design is illustrated by means of numerical comparisons with some benchmark examples from the literature.

DC-side harmonic analysis and DC filter design in hybrid HVDC transmission systems

Hybrid high-voltage direct current (HVDC) transmission is a new transmission structure that uses line commutated converter (LCC) at the rectifier side and voltage source converter (VSC) at the inverter side. This study proposes a method to calculate DC side harmonic currents of hybrid HVDC transmission systems and design filters to mitigate DC-side low-frequency voltage pulsations. First, an equivalent harmonic analysis model of modular multilevel converter (MMC) is deduced according to the relationship among different harmonic components. The harmonic voltage expressions at DC side of 12-pulse LCC are deduced by combining the three-pulse harmonic voltage source model and FFT decomposition. On this basis, the expressions for harmonic currents are derived by multiplying the harmonic voltage transfer function and transfer admittance equation of DC network and are solved for the inverse Laplace transform. Two different types of DC filters are designed according to the requirements of DC filter on decaying specific order harmonic currents. The influence of partial element decay on the transfer characteristic of filter is analyzed, and appropriate partial component dissipation parameters are applied. The decay pole near the harmonic resonance frequency is configured to achieve reasonable DC-filtering results. Simulation results of a hybrid HVDC transmission system demonstrate the effectiveness of the proposed analysis model and filter design method.

Prototype Filter Design to Minimize Stopband Energy With Constraint on Channel Estimation Performance for OQAM/FBMC Systems

In this paper, we propose a prototype filter design method to minimize the stopband energy of the filter with guaranteed time-domain channel estimation performance for offset quadrature amplitude modulation based filter bank multicarrier (OQAM/FBMC) systems. First, we analytically derive the total mean squared error (MSE) of estimated channel impulse response with two channel estimation schemes, i.e., the linear minimum mean square error and weighted least square, where the impact of intrinsic interference from data symbols is taken into account. Then, we formulate an optimization problem of filter coefficients to minimize the stopband energy with constraint on the total MSE. By exploiting the Heisenberg–Gabor uncertainty principle, the original optimization problem is transformed into an equality-constrained one. Finally, we employ the Lagrange multiplier method to solve the transformed problem and obtain the filter coefficients with the Newton’s method. Simulation results demonstrate that the proposed filter outperforms the isotropic orthogonal transform algorithm and extended Gaussian function filters considering both the MSE and stopband energy performances.

Optimal Design of Microstrip Bandpass Filter in Ultra-wideband (UWB) Wireless Communication for Ship Based on Distributed Algorithm

ABSTRACT Zhan, A.; Hu, Y., and Yu, M., 2018. Optimal design of microstrip bandpass filter in ultra-wideband (UWB) wireless communication for ship based on distributed algorithm. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 585–589. Coconut Creek (Florida), ISSN 0749-0208. The traditional methods designed for microstrip bandpass filter in ultra-wideband (UWB) wireless communication for ship have some problems in performance. On the basis of the distributed algorithm, an optimal design method of microstrip bandpass filter in UWB wireless communication for ship is proposed in this paper. The low pass filter is in series with high pass filter used to complete the design of the microstrip bandpass filter in UWB wireless communication for ship. Alternately loaded form of grounding impedance of trapezoid and triangle is used to realize low pass filteris adopted, while the high pass filter is optimized by distortion and...

Optimization design of pushing distance estimation of hydraulic support using the Kalman filter with the covariance improvement

The accuracy of pushing displacement of hydraulic support determines the pushing ability, which is the key factor that affects the pushing straightness of the hydraulic support. In order to further improve the accuracy of pushing displacement, considering the inertial sensor as the tools for measuring the pushing distance, an improved filtering method is proposed based on the improved fruit fly optimization algorithm and Kalman filter. The parameters of the Kalman filter, processing noise covariance Q and observation noise covariance R, are optimally designed by the improved fruit fly optimization algorithm to accurately perceive the inertial data. Finally, the feasibility of the proposed method with tuning the Q and R has been verified by comparing with the tuning results of other algorithms. An integrated filtering design method of pushing distance and key parameter analysis of algorithm in the pushing distance perception of hydraulic support are formed, which have theoretical and practical values, and improve the automation level of hydraulic support and the straightness of the fully mechanized coal mining working face.

NO EROSION CRITERION FOR GRANULAR FILTERS BASED ON CONSTRICTION SIZE – AN EXPERIMENTAL STUDY

Filters are provided in embankments in order to arrest the eroded soil particles that are carried by the seepage water .Current design method of graded filters was developed by Terzaghi which is based on the particle size distribution of the filter material and the base material. This paper presents an attempt to develop filter design criteria in relation to constriction size in gravel filters. It is an alternative approach from the conventional filter design criteria of Terzaghi, which is based on the particle size distribution of the filter media and base material. In his study a criterion for filter to prevent erosion is proposed based on the constriction size distribution of the filter media. The proposed constriction size-based criterion, C10/d95 2 directly compares the controlling constriction size (C10) with the specific representative base size (d95) defines the effectiveness of filters, hence it is a more effective method compared to the Terzaghi criterion (D15 /d85<5) which is based purely on particle size. This ratio explains the behavior of filters more clearly and is proved by a number of tests on various base-filter combinations. When compared to Terzaghi criteria, constriction size distribution criterion proves to be more effective.

Networked $$H_\infty $$ H ∞ Filtering for Time-Varying Systems with Uncertain Multiple Packet Dropouts

This paper deals with the $$H_{\infty }$$ filtering problem for discrete time-varying systems with uncertain multiple packet dropouts. The network-induced packet dropouts are modeled as a Bernoulli-distributed stochastic sequence with uncertain but bounded probability distribution, which is closer to the actual network environment. The multiple channels model is utilized to describe the transmission process of measurement data from multiple sensors. The aim is to design a $$H_{\infty }$$ filter subject to uncertain multiple packet dropouts. By utilizing stochastic analysis technique, sufficient conditions guaranteeing the existence of desired filter are established, and then, the filter parameters are obtained by solving recursive linear matrix inequality. Finally, a simulation is given to demonstrate the filter design method.

Unscented Kalman filter for continuous‐time nonlinear fractional‐order systems with process and measurement noises

AbstractThis study proposes the design of unscented Kalman filter for a continuous‐time nonlinear fractional‐order system involving the process noise and the measurement noise. The nonlinear fractional‐order system is discretized to get the difference equation. According to the unscented transformation, the design method of unscented Kalman filter for a continuous‐time nonlinear fractional‐order system is provided. Compared with the extended Kalman filter, the proposed method can obtain a more accurate estimation effect. For fractional‐order systems containing non‐differentiable nonlinear functions, the method proposed in this paper is still effective. The unknown parameters are also discussed by the augmented vector method to achieve the state estimation and parameter identification. Finally, two examples are offered to verify the effectiveness of the proposed unscented Kalman filter for nonlinear fractional‐order systems.

Image super-resolution for heterogeneous embedded smart devices and displays in smart global village

The smart city has become the key factor of the progression of the future city, and the smart device sensors are widely used in real-time applications to achieve smart city. Especially, super-resolution techniques have resulted in embedded video surveillance turning into a principal method of protecting public security. In this paper, we present a super-resolution method for embedded system which interpolates unknown pixel components at the zero-padded signals. This work is for a smart global village by applying real-time embedded monitoring system (such as traffic purpose) using visual sensor networks. In general, images are obtained from a number of visual sensor nodes and cameras. The visual sensor node conveys them to the computer devices for processing. To this end, a process called image super-resolution is needed. In this work, a filter design method is researched by using a regression approach. There are two main stages of this work. First, we study filter designing method training dataset. Second, we implement super-resolution process by applying pre-designed filters. Experimental results are given to show the superiority of the proposed method compared to the conventional methods. This paper also demonstrates super-resolution results obtained by designed filter and its implementation.

Finite-time asynchronous H∞ resilient filtering for switched delayed neural networks with memory unideal measurements

This paper investigates the problem of asynchronous H∞ resilient filter design for delayed switched neural networks with memory unideal measurements over a finite-time interval. We design a comprehensive filter that considers the network-induced defects of asynchronous switching, randomly occurring uncertainty, the quantization effect, and data packet dropout in a unified framework. A new lemma is given to overcome the design difficulty relating to the product terms of two uncertainties. By applying the average dwell time technique and the piecewise Lyapunov–Krasovskii functional technique, sufficient conditions are obtained to ensure the mean-square finite-time boundedness of the filtering error system with a prescribed H∞ performance level and a filter design method is proposed. A numerical example is finally presented to demonstrate the effectiveness of the proposed method.

State Estimation Based on Multirate Kalman Filter for Power Systems Driven by Switching Inverter

This paper presents a design methodology of a Kalman filter for a multirate control system with a fast input system. There are many applications whose sensory system is slower than the input system in a power system. The sensory system is required to perform fast sensing while ensuring a low signal-to-noise ratio, although it requires additional time compared with that of a low-resolution converter. The Kalman filter is an effective tool in such a situation and it estimates parameters while eliminating noise. Because the optimality of this filter is ensured when the system model and noise variance on the system are well identified, rigorous discretization should be considered on the multirate control system. With this in mind, the paper presents the design method of a multirate Kalman filter as is the case for a single-rate controller. Further, the noise variance and oversampling ratio of the multirate controller is confirmed using the Monte Carlo method. Numerical simulation of a voltage inverter theoretically validates the design methodology.

선택적 외란 제거를 위한 외란 관측기의 Q 필터 설계

In a disturbance observer (DOB), introduced disturbances are monitored by a plant inverse model and a Q filter compensates the improper inverse model and is designed to stabilize closed loop systems. Therefore, the filter bandwidth is usually trimmed to control the attenuation rate of the disturbance. However, the conventional DOB cannot reduce selective disturbances but only lumped disturbances. To selectively reduce the disturbances, this note proposes a new Q filter design method. Through a mathematical derivation, it is verified that the Q filter design problem belongs to the category of the inverse function design of the introduced disturbance spectrum. Using numerical simulations, it is shown that the proposed method reduces selective disturbances and lumped disturbances.

The nonlinear-phase design of FBMC prototype filter based on filter coefficient symmetry characteristic

To promote filter bank multicarrier (FBMC) in future communication, a novel design method of nonlinear phase FIR filter (NLPFF) is proposed under the principle of constrained minimax (CMM), by which the designed filter will act as the FBMC prototype filter. In this method, the filter coefficient symmetry characteristic (FCSC) is exploited in replace of the conventional phase response error (PRE), which simplifies the establishment of phase constraint and benefits the construction of direct magnitude constraint. Consequently, the proposed constraints related to FCSC outperform the conventional constraints addressing complex frequency response errors, since the former yields a wider range of controllable PRE as well as the dramatically reduced constraint scale. Moreover, in order to restrict the sampling inter-symbol interference, the Nyquist condition (NYQ) is constrained in the frequency domain, which circumvents the initial nonconvex problem. Simulations confirm the effectiveness of the proposed method, where the FCSC can be sufficiently relaxed to improve the stopband attenuation, making this nonlinear-phase design more flexible than previous designs of FBMC prototype filter. Besides, the bit error rate test demonstrates that the designed NLPFFs are superior to the conventional PHYDYAS filter, therefore, the proposed design can certainly produce high quality prototype filter for FBMC system.

Reliable Filtering of Nonlinear Markovian Jump Systems: The Continuous-Time Case

This paper is concerned with the reliable $\boldsymbol {\mathscr {L}_{2}-\mathscr {L}_{\infty} }$ filter design problem for the nonlinear continuous-time Markov jump systems based on Takagi–Sugeno fuzzy model. A stochastic variable is introduced to describe the encountered sensor failures, the value of which is dependent on the considered plant mode based on a hidden Markov process. In practice, generally the information on plant modes is not fully accessible to the reliable filter, which results in the nonsynchronous phenomena between the modes of involved plant and filter, and has a negative effect on the system performance. A hidden Markov model is also adopted to depict such kinds of nonsynchronous phenomena. The filtering error systems are called fuzzy dual hidden Markov jump systems. A sufficient condition, associated to the modes of the plant, sensor failures, and the filter are proposed for the filtering error systems to ensure the stochastic stability and guaranteed $\boldsymbol {\mathscr {L}_{2}-\mathscr {L}_{\infty} }$ performance, based on which the existence condition and explicit design method of a nonsynchronous filter are both given. Finally, two simulation examples illustrate the effectiveness of the proposed approach.

Design of Bandpass and Bandstop Infinite Impulse Response Filters Using Fractional Derivative

In this paper, a new design method for digital bandpass and bandstop infinite impulse response filters with nearly linear-phase response is proposed. In this method, the phase response of an all-pass filter is optimized in the frequency domain to yield less passband error ${\text{Er}}_{p}$ and stopband error ${\text{Er}}_{s}$ with optimal stopband attenuation $A_{s}$ . To achieve high accuracy in passband and stopband regions, fractional derivative (FD) constraints are evaluated in the respective regions, and the filter coefficients are computed using the Lagrange multiplier method. The behavior of fidelity parameters measured in terms of ${\text{Er}}_{p}{,\text{Er}}_{s}$ , and phase error ${\text{Er}}_{{\text{ph}}}$ is multimodel w.r.t. FD values. Therefore, modern heuristic technique, known as cuckoo search optimization is used for determining the optimal value of FDs and reference frequency simultaneously to minimize the fitness function, which is constructed as a sum of the squared error in passband and stopband. The designed filter yields up to 60% reduction in ${\text{Er}}_{p}$ and ${\text{Er}}_{{\text{ph}}}$ in the case of bandpass filter. Meanwhile, the response of filter is not degraded due to the finite word length effect.