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In this paper, we use a matrix adaptive filter as the synthesis stage of a Uniform Filter Bank (UFB) to reconstruct the input signal. We first develop the mathematical theory behind it by applying the model of optimal filtering at the synthesis stage of the UFB and obtaining an expression for the matrix Wiener filter. We have developed a theorem which we use to simplify the expression further. In the absence of required information about the analysis stage, we use adaptive filtering to arrive at the Wiener solution. We use the Least Mean Square (LMS) algorithm to update the filter coefficients. Through experimental results, we find that the adaptive filter is convergent for a stable Wiener filter.

This chapter presents passive and active filter topologies and design techniques, including practical design examples and system simulations. In DSP systems, there are analog filters required for signal conditioning and limiting the bandwidth before sampling. To design these filters, designers need to be knowledgeable of operational amplifiers, DC biasing circuits, AC coupling techniques and traditional passive components like inductors, capacitors and resistors.

This work studies torque oscillation control of a hybrid driveline, and proposes a new cross-domain collaborative (C2) control strategy that comprises a notch filter, a PI filter, and a backlash estimator. The C2 control strategy is centered on a notch filter, which is built on digitalization of the driveline system and analyses of oscillation elements in the frequency domain. To enhance the performance of the notch filter in the time domain, a PI filter is connected in series to the notch filter. Considering that the driveline is a nonlinear time system during backlash travel, a backlash estimator is developed to handle the torque control target. The notch frequency and backlash travel time are identified through simulations, and the control strategy and selected parameters are evaluated in road tests. The results indicate that this control strategy can reduce the peak torsion speed to 71%.

A filter circuit is required to suppress noise and have high gain attenuation characteristics in a wide band. Gain attenuation decreases because the relative permeability of an inductor core employed in a filter circuit drops sharply as drive frequency increases. Thus, by combining a core with a magnetic composite material with excellent frequency characteristics, we suppressed inductance reduction over a wide frequency range. As a result, the inductance of a hybrid inductor increased by 17.8% and 116% at 1 and 80 MHz, respectively, compared with that of a conventional inductor. When we applied a hybrid inductor to a Pi filter circuit, it was attenuated by 6.5 and 5.0 dB at 100 and 80 MHz, respectively, compared with a conventional inductor.

This study presents a control method for DC–DC switching power converters to avoid the instability caused by the interaction between a tightly controlled switching converter and an input low-pass filter. The proposed method is based on the Lyapunov stability criterion. A non-linearised model is established, and the instantaneous quantities of the state variables are considered. The switching command is formulated by calculating the stability of the system. The inductor current and voltage across the filter capacitor, along with the state variables in the switching converter, follow the corresponding references. A boost converter is considered to demonstrate the associated effectiveness. The results of several simulations and experiments pertaining to the start-up, tracking, and regulation stages validate the proposed control approach. Moreover, the robustness of the approach against variations in the parameters of the controlled system is examined experimentally. To demonstrate the superiority of the proposed method, the method is compared with the proportional–integral, fuzzy, and flatness-based controllers.

The paper proposed a novel broadband crossover based on microwave multilayer PCB technique with two-layer structure. Low-pass PI filter is introduced to lower coupling capacitance between crossed transmission lines of slight RF performance degradation. The proposed crossover is optimized and simulated by commercial EM software HFSS; among the working band 1–18 GHz, return loss is better than 13 dB, insertion loss is better than 0.5 dB, and isolation between two transmission lines is better than 18 dB. The dimension of the proposed crossover is less than 2 × 2 mm, which is much smaller than traditional crossover on single layer.

The Schmidt–Kalman (or “consider” Kalman filter) has often been used to account for the uncertainty in so-called “nuisance” parameters when they are impactful to filter accuracy and consistency. Us...

not present; this is a Technical Note, only requiring an Introduction section

This study deals with a control scheme for single-stage solar photovoltaic (SPV) grid-interfaced system. The voltage-source inverter (VSI) is a power electronic interface between SPV array and the grid. The VSI provides power quality features, i.e. harmonics mitigation, power factor correction and perturb and observe maximum power point tracking for single-stage SPV grid-interfaced system. The SPV array supplies active power to the non-linear load and grid through VSI, during daytime only or when SPV generation is more than the load power. To increase the utilisation of VSI, it is used as an active power filter at night, to mitigate harmonics and to provide active power to the load from the utility grid. The proposed adaptive linear combiner filter has the capability to extract harmonics and enhances the power quality in SPV grid-interfaced system. It has also satisfied an IEEE-519 standard of harmonics by improving the quality of power of SPV grid-integrated system. Simulation results of the SPV system are presented, which are simulated using MATLAB and response of system under non-linear load and varying environmental condition are also studied experimentally on a developed prototype in the laboratory.

This paper presents a second-order tunable single-ended (unbalanced) bandpass filter (BPF) with continuous 0.4–3-GHz coverage and a tunable balun BPF with continuous 1.1–1.7-GHz coverage for software-defined radio transceivers with the use of band-switchable and radio frequency (RF)-micro-electromechanical systems (MEMS)-tuned resonators. The BPFs are realized with two pairs of RF switches for coarse-tuning and RF-MEMS-tunable capacitors for fine-tuning. On the one hand, for the tunable single-ended BPF, a transition between three bands is enabled using two pairs of RF switches. On the other hand, for the tunable balun BPF, a transition between two bands is enabled using one pair of RF switches. Furthermore, the three-band switchable single-ended BPF is constructed in a nested two-filter bank structure for expanding the tuning range without increasing the footprint. In addition, to complement the discrete band gaps, RF-MEMS capacitor-tuned resonators are used, and a continuous tuning range of nearly the entire ultra-high-frequency band is achieved. The filter bank is fabricated on a Duroid substrate with εr = 3.5 and h = 0.787 mm. The filter bank has an insertion loss of 3.2–6.8 dB and a 1-dB bandwidth of 65–450 MHz with a continuous tuning range of 0.4–3 GHz.

In this study, a monolithic microwave integrated circuit channelized active bandpass filter using noise cancelling circuit is presented. We propose a new structure on the channelized bandpass filter. By adding output currents of three bandpass filters and using current to voltage converter, the proposed three-channel bandpass filter is achieved. In designing each bandpass filter, a recursive differential structure has been used. Also, to decrease the noise of this filter, a new noise cancelling circuit operated in a wide range from 1 to 7 GHz is investigated. By using this circuit, input impedance matching is obtained simultaneously. The chip has been implemented using GaAs 0.15 µm technology and occupies an area of 2.5 × 2.4 mm2. The post layout simulation results show a noise figure of 1.4–3.7 dB with a good input and output impedance matching less than −10 dB. The centre frequencies of channelized filter are 2, 4, and 6 GHz while the voltage gains are 18, 12, and 10 dB, respectively. The circui...

The Alpha-Beta-Gamma tracking filter is useful for tracking a constant acceleration target with zero lag error in the steady state. It, however, depicts a constant lag error for a maneuvering target. Various algorithms of the Alpha-Beta-Gamma tracking filter exist in literature and each one of them presents its own unique challenges and advantages depending on the design requirement. This study investigates the operation of three Alpha-Beta-Gamma tracking filter design methods which include Benedict-Bordner also known as the Simpson filter, Gray-Murray filter and the fading memory constant acceleration filter. These filters are then compared based on the ability to reduce noise and follow a maneuvering target with minimum lag error, against the jerky model Alpha-Beta-Gamma-Eta. Results obtained from simulations of the input model of the target dynamics under consideration indicate an improvement in performance of the jerky model in comparison with the constant acceleration models.

This paper proposes a novel high-order passive filter, i.e., series-parallel-resonant LCL (SPRLCL) filter, for single-phase half-bridge active power filters. The proposed SPRLCL filter consists of a series resonance introduced by adding a small inductor to the capacitor branch loop and a parallel resonance by paralleling a small capacitor with the gird-side inductor. Three design methods are proposed to fine tune the parameters of the SPRLCL filter. Design method I and method II enable the SPRLCL filter to attenuate more switching-frequency and double switching-frequency current harmonics than LCL or LLCL filters, while with design method III, the SPRLCL filter can be more robust against filter parameter variations. In order to achieve a better damping performance and facilitate the design of active damping control, the dominant resonance frequency of the proposed filter is set at one-third of the system sampling frequency. Based on this, a comprehensive parameter design process of the SPRLCL filter is presented, where the variation of source inductance is also considered. A proportional plus repetitive current-loop controller is designed to ensure system control stability and satisfactory harmonic compensation. Simulation and experimental results are finally presented to validate the feasibility of the theoretical analysis.

This article presents a new topology for implementing an electronically tunable bandpass filter using the current-feedback operational amplifier. The electronic tuning of the center frequency of the proposed circuit is achieved using an externally connected voltage amplifier in the feedback path without disturbing the constituents of the filter itself, that is a shadow filter. The proposed circuit can be used for developing an undergraduate experiment which illustrates the operation of bandpass filter and the electronic control of its center frequency using the concept of shadow filter. Experimental results obtained using the AD844 current-feedback operational amplifier are included.

In this paper, a method is proposed to reduce harmonic fold back HFB problem of N-path filters, without increasing the input reference clock fCLK frequency. The HFB at the N-path filter is analyzed, and simple expressions are extracted to model this problem. Using the results of the analysis, an M-of-N-path filter has been proposed that behaves like an M×N-path filter in terms of HFB problem; however, the fCLK frequency of this structure is the same as an N-path filter. To demonstrate the feasibility of the proposed idea, a 3-of-4-path filter is designed, and its characteristics are compared with 4-path and 12-path filters by simulation. Impacts of different non-idealities like clock-phase error, mismatch, and parasitic capacitance are investigated. The transistor-level implementation of this filter is performed in 0.18µm Complementary Metal Oxide Semiconductor CMOS technology. The simulation results show that the filter has the pass-band gain of 17dB, tuning range of 0.2-1.2GHz, -3dB bandwidth of 25MHz, quality factor of 8-48, 18dB out-of-band rejection, 16dB rejection of the third harmonic of switching frequency fs, and the noise figure of 4.35dB using ideal Gm cells and 6.95dB for practical Gm cells. The strongest harmonic folding to the filter pass-band occurs around 11fs with the attenuation of 23.8dB. Each Gm cell draws about 12.4mA from 1.8V supply, and the out-of-band IIP3 and P1dB,CP are 17 and 4dBm, respectively. Copyright © 2016 John Wiley & Sons, Ltd.

This article presents the design and realization of a new bandpass filter (BPF) fabricated on multilayered substrates. The proposed BPF schematic is based on the traditional elliptic-function filter schematic. The novel schematic features a specific parallel section, which grants the new schematic the ability in reducing the undesirable value of inductors in serial arms of the conventional elliptic BPF circuit schematic. As an illustrative example, a prototype BPF with 800 MHz center frequency is designed and fabricated. The measured stop-band rejection is better than 45 dB up to 2 GHz, and a relatively narrow bandwidth is obtained. The measured result agrees very well with the electromagnetic (EM) designed response. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1891–1894, 2016

In this paper we propose a new class of selective CIC filters in recursive and nonrecursive form. The filters use a modification of CIC concept, which is achieved by applying a set of non-identical comb sections in cascade. We illustrate examples of the proposed filter function and calculate integer coefficients of filter impulse response. Detailed comparison between the proposed selective filter class and classical CIC filters is given. The results show that the stopband selectivity can be improved significantly in comparison with classical CIC filters with the same filter complexity.

This paper presents an adaptive Volterra filter implementation based on an exponentially-weighted a posteriori H∞ filtering algorithm. Its fast array form is immediately obtained by following...

A general cascaded filter design technique is implemented to get a tunable narrow-band filter response based on the general Chebyshev bandpass filter. A cavity combline microwave filter is fabricated by cascading two asymmetrical filters without using an isolator between them. Tuning is provided by means of the screws on top of each resonator of the cavity combline filter. An optimization is applied to get the desired response. The designed example is presented together with the simulation and measurement results. The measured data are in good agreement with the simulation results.

In the present work the lock-in range of PLL-based circuits with proportionally-integrating filter and sinusoidal phase-detector characteristics are studied. Considered circuits have sinusoidal phase detector characteristics. Analytical approach based on the methods of phase plane analysis is applied to estimate the lock-in ranges of the circuits under consideration. Obtained analytical results are compared with simulation results.

This Letter proposes a balanced hybrid substrate-integrated waveguide (SIW)–coplanar waveguide (CPW) bandpass filter, which combines a hybrid SIW–CPW filter and a balanced structure for the first time. High performance common mode suppression can be achieved with high quality factor, compact size, and quasi-elliptic differential mode response.

A compact dual-mode dual-band bandpass filter is proposed based on the inside–outside–reversed dual-ring topology. Different from the traditional design, the total size of the filter is limited by the second passband with shorter wavelength at higher frequency, instead of the first passband with longer wavelength at lower frequency. By loading four square patches in the inner ring, the degenerate modes of the inner ring move down and form the first passband, whereas the second passband is constructed by the outer ring. By utilising the coplanar-waveguide feeding at ground plane, a prototype of the dual-band filter with two operating frequencies at 0.92 and 1.47 GHz is designed and verified experimentally.

In this paper, the optimal damping circuits of pi-filters for EMI filter designs are proposed. The optimal damping parameters of a pi-filter which is normally used when one designs an equivalent circuit in differential-mode of an EMI filter are presented. The performances in terms of impedance suppression and achievable total volume of each proposed damping circuits are compared and verified by simulations. Finally, a trade-off of each proposed damping circuits is discussed. Moreover, the most suitable damping circuits of pi-filters for EMI filter designs are recommended.

Filter design by transfer equation can be cumbersome and formidable to an engineer accustomed to the digital, firmware, and FPGA design world. The vast majority of filter applications do not have to be general in scope—a unity gain, Butterworth response is all that is needed. Very quick calculations can design a filter without the need to resort to the more general (and more complex) solutions.

Any electronic device is prone to degradation and damage due to operational as well as environmental causes. For capacitors, a prominent cause is switching action in filters. Under a stable switching supply, the stress observed is not due to peak voltage but peak inrush current (also known as ripple current). This paper explores the analysis of degradation in pi filter capacitors of an existing safety-critical module. The results of the test conducted shall better provide a method to predict the device useful life.

An ultra-low complexity three-dimensional (3-D) linear-phase infinite-extent impulse response (IIR) velocity filter is proposed for attenuating moving artifacts in videos while enhancing objects moving on smooth approximately-linear trajectories. The proposed 3-D linear-phase IIR velocity filter consists of an ultra-low complexity 3-D wide-angle linear-phase IIR cone filter bank between two two-dimensional (2-D) spatial variable-shift filters. The ultra-low complexity 3-D wide-angle linear-phase IIR cone filter bank consists of a one-dimensional (1-D) temporal modified discrete Fourier transform filter bank and 2-D spatial allpass, IIR highpass and allstop filters. A typical 3-D linear-phase IIR velocity filter of order $$4\times 4\times 510$$4×4×510, applied to enhance a heavily corrupted test video signal, requires only 26 real multiplications and 60 real additions to process a sample and provides a scene-complexity-independent signal-to-interference-and-noise ratio improvement of 13.86 dB. The proposed 3-D linear-phase IIR velocity filter is employed to attenuate sunlight flicker patterns in shallow underwater videos, and experimental results are presented to confirm the effectiveness of the proposed method and its robustness to motion estimation errors.

Complementary Filter is commonly used in signal processing method for real-time position measurement. Butterworth filter characteristic has a uniform gain in the pass band, the blocking band has a good blocking characteristics. Therefore, we propose a method of designing a complementary filter having a characteristic of Butterworth filter characteristic. By setting the appropriate filter coefficients in the simulation it appears to improve the performance of the filter. In the experiment it shows a real-time signal processing is possible by using the calculated filter coefficients in the simulation.

An ultra-wideband (UWB) bandpass filter with extended upper-stopband on multilayer liquid-crystal-polymer (LCP) substrate is presented in this paper. The proposed filter is designed to select the frequency band from 1.0 to 20 GHz. The filter consists of two parallel-coupled stub-loaded resonators separated by a composite lowpass filter. The composite lowpass filter is implemented to obtain a very wide rejection band. The proposed filter is fabricated using multilayer LCP technology. Excellent agreement between expected and measured results of the filter is obtained. The measurement results show that the fabricated filter has a fractional bandwidth of 180% and a very low insertion loss of less than 0.6 dB at center frequency of 10.5 GHz. The measured filter has a wide stopband and an excellent rejection level higher than 40 dB.

A switching median and morphological filter is presented for removing impulse noise. In the proposed filter, the noise detector is first adopted to identify noise pixels by combining the morphological gradient based on the erosion and dilation operators with the top-hat transform. Then the detected impulses are removed by the hybrid filter, which combines the improved median filter using only the noise-free pixels with the conditional morphological filter using the improved morphological operations. Extensive simulations demonstrate that the proposed filter can realize accurate noise detection and it has significantly better restoration performance than a number of decision-based filters at the various noise ratios.

This brief presents the degree equation of an equiripple narrow bandpass finite-impulse response filter, which follows from the filter approximation rather than from empirical data. The degree equation relates the filter specification and the corresponding filter degree. It completes the closed-form filter design, and it is useful in numerical design procedures as well. Two examples demonstrate its functionality and usefulness.