Elliptic Filter Research Articles

Evaluation of Filtering Techniques applied to simulated Electroencephalogram signals for Visual Evoked Potential Detection

Introduction: In this paper, it is presented an assessment of different windowing techniques and denoising methods applied to detect the Visual Evoked Potential (VEP) contained into the electroencephalographic (EEG) signals. The objective is to analyze advantages and disadvantages of each technique performance to identify correctly the VEP waveform and to quantify the latency which is a parameter commonly used as an indicator of ocular diseases. Method: Assessment of techniques was performed considering rigorous controlled conditions on the signal set, to assure that obtained results were linked just to the technique performances and avoid any undesirable effect due to the natural interference of acquisition of signals. For this reason, a simulated signals set was created based on a typical VEP waveform commonly registered around 100ms after an external stimulus was applied in the routine clinical study. Additionally, two evaluation stages were considered: fixed latency parameters stage and random latency parameters stage.Results: The best results without filter was with rectangular window and the use of elliptic filter can help to extract the VEP with a rectangular window too. For wavelet denoising the best result is Biorthogonal 2.6 wavelet with a Hamming window. Discussion or Conclusion: Five parameters were proposed to assessment the VEP extraction performed: signal noise ratio (SNR) mean square error (MSE), average latency (AL), latency standard deviation (LSD) and latency correlation variance (LCV) as representative factors to be considered on evaluations of VEP extraction methods. SNR and MSE were focused to assess the level of noise that remain in signal after windowing & denoising method was applied. In the other hand AL, LSD and LCV were oriented to evaluate the impact of the method on the VEP latency estimation.

Simulating Elliptic Low-pass Filter based on MOCCCII

Multiple output current-control current conveyer (MOCCCII) based Elliptic low-pass filter by using a simulating of RLC ladder prototype is presented in this work. The good performances of RLC ladder as well as low-sensitivity are inherited. Signal flow graph (SFG) method is applied to convert the RLC Elliptic ladder low-pass filter prototype to be the different function blocks. These function blocks can be realized by integrator and differentiator. Lossy integrator, lossless integrator and lossless differentiator realized from MOCCCII are straightforward replaced in SFG. Due to the tuning ability of MOCCCII, the proposed Elliptic low-pass filter can be tuned by adjusting the bias current (IB ). In addition, the frequency responses can be varied from 50kHz to 1MHz by tuning IB from 1μA to 100 μA to prove the electronic tuning performance of the proposed filter. The simulation results are carried out by PSpice that the performances are totally agreed with the theory.

Design of wide stopband lowpass filter using transformed radial stub based on substrate integrated suspended line technology

AbstractA novel planar elliptic function lowpass filter (LPF) based on substrate integrated suspended line technology is developed and investigated. Transformed radial stub, stepped‐impedance resonators, and open stubs are cascaded to obtain sharp roll‐off and wide stopband. The proposed LPF produces six transmission zeros in the stopband, and the mechanism of the transmission zeros is studied. Both the simulation and measurement are conducted to verify the performance of the proposed filter, and good agreement between the simulated and measured results is observed. The filter shows attractive characteristics such as low insertion loss<0.6 dB, high return loss of 20 dB, wide stopband from 3.85 to 24 GHz with −20 dB attenuation level and a small area of 0.20 λg × 0.14 λg, where λg is the waveguide length at the cutoff frequency.

A Waveform Conversion Circuit Design Used for Square Wave to Sine Wave

As an efficient passive filter, elliptical filter can be used in the waveform conversion module of closed-loop self-excitation circuit based on infrared detectors with steep transition band. In this article, the elliptical filter is designed and used to transform rectangle wave to sine wave by the Advanced Design System (ADS) 2015. After setting the parameters and calculation, the elliptical low-pass filter of seventh-order whose pass band is 0-10.2kHz, ripple in the band is less than 0.3dB and signal suppression is 42.8dB with two notch points. Through the comparison with the fifth-order and seventh-order elliptical low-pass filters, the relationship between the orders is understood, and the requirement of waveform transformation is realized.

Design Procedure of Elongated Shape Filters for Cohesionless Soils

The present study is an attempt to develop design criterion of elongated shape filters for cohesionless bases on the basis of controlling constriction size of filters. The existing design criteria are based on certain particle size ratios of filter and base material and controlling constriction size. Recently, few studies have been carried out in which blade, rounded, irregular, sub-rounded and elliptical shape filter particles were considered for development of filter design criterion for these shapes. In the present study, the elongated shape filter particles and cohesionless bases were considered for the laboratory tests. It was observed on the basis of experimental results that the elongated shape filter particles are suitable for protecting the cohesionless bases. The experimental results indicate a relationship between d60, d10 of the base material and the design controlling constriction size d* of the elongated shape filter material. An empirical model has been developed for determining d* of the filter material based on d60 and d10 of the base material.

Study on the influence of venturi on the cleaning performance of elliptical filter cartridge

Pulse-jet cartridge filter is one of the high efficiency dust collectors for capturing ultra-fine powder. The incomplete cleaning becomes a difficult problem in the application of filter cartridge. However, most of the existing studies are focused on the cleaning performance of the circular cartridge in vertical filters, and there are few studies on the cleaning performance of elliptical horizontal cartridge filters. In this study, the effects of different venturis on the pressure drop of dust collector and the static pressure acting on the inner wall of the elliptical filter cartridge were investigated through numerical simulation and experiment. When the venturi throat diameter is 160 mm, the minimum pressure drop and the maximum peak pulse pressure of the inner wall can be obtained. The mechanism of venturi improving collection efficiency of elliptical filter cartridge is revealed by the flow field analysis method. The magnitude of peak pressure P1 to P3 are about 1.4–2.7, 1.1–1.7 and 1.1–1.4 times that of without venturi. The injection distance and pulse-jet tank pressure can be reduced by venturi. The results are helpful for the design and improvement of pulse-jet cleaning horizontal cartridge filters.

Special issue on SoC and AI processors

Special issue on SoC and AI processors

Reconfigurable Rectangular Filter With Continuously Tunable Bandwidth and Wavelength

We propose and demonstrate a rectangular optical lattice filter with reconfigurable bandwidth and wavelength. The proposed reconfigurable rectangular lattice filter consists of three-stage cascaded ring-assisted Mach-Zehnder interferometers (RAMZIs), and each RAMZI unit serves as an approximate optical elliptical filter with optimized shape factor. The scheme and design principle are presented with the method of zero-pole theory. As a proof of concept, the proposed structure is fabricated on the Si $_3$ N $_4$ waveguide platform. In the experiment, the 3-dB bandwidth of the proposed filter can be continuously tuned from 14.1 GHz to 4.1 GHz, maintaining a rectangular transmission response, and the wavelength can also be continuously tuned. This reconfigurable rectangular optical lattice filter shows the potential in many practical applications for reconfigurable optical signal processing due to flexibility and reconfigurability.

EEG Signal Analysis for Diagnosing Neurological Disorders Using Discrete Wavelet Transform and Intelligent Techniques.

Analysis of electroencephalogram (EEG) signals is essential because it is an efficient method to diagnose neurological brain disorders. In this work, a single system is developed to diagnose one or two neurological diseases at the same time (two-class mode and three-class mode). For this purpose, different EEG feature-extraction and classification techniques are investigated to aid in the accurate diagnosis of neurological brain disorders: epilepsy and autism spectrum disorder (ASD). Two different modes, single-channel and multi-channel, of EEG signals are analyzed for epilepsy and ASD. The independent components analysis (ICA) technique is used to remove the artifacts from EEG dataset. Then, the EEG dataset is segmented and filtered to remove noise and interference using an elliptic band-pass filter. Next, the EEG signal features are extracted from the filtered signal using a discrete wavelet transform (DWT) to decompose the filtered signal to its sub-bands delta, theta, alpha, beta and gamma. Subsequently, five statistical methods are used to extract features from the EEG sub-bands: the logarithmic band power (LBP), standard deviation, variance, kurtosis, and Shannon entropy (SE). Further, the features are fed into four different classifiers, linear discriminant analysis (LDA), support vector machine (SVM), k-nearest neighbor (KNN), and artificial neural networks (ANNs), to classify the features corresponding to their classes. The combination of DWT with SE and LBP produces the highest accuracy among all the classifiers. The overall classification accuracy approaches 99.9% using SVM and 97% using ANN for the three-class single-channel and multi-channel modes, respectively.

A Non-Adaptive Single-Phase PLL Based on Discrete Half-Band Filtering to Suppress Severe Frequency Disturbances

The interconnection of new generating and storing devices to the power grid imposes the necessity of synchronizing, so the power flow can be manipulated and distributed. In the presence of an increasingly perturbed electric grid, many proposals of novel and modified synchronization techniques attained enough robustness to deal with known perturbations. However, such proposals exhibit drawbacks on their own, leaving open enhancement opportunities, mostly over their discrete implementation—e.g., sampling issues and not-considered inter/harmonics—and their inherent complexity—e.g., the need for frequency adaptability. In this work, three traditional synchronous reference frame (SRF) phase-locked loops (PLL) are modified to implement discrete filtering, such as the well-known proposals based on moving average filters (MAFs), to avoid the problems mentioned above, known for affecting the MAF’s performance. This proposal makes use of discrete, efficient units modularly assembled to yield a signal’s average, based on elliptic half-band filters. The proposed PLLs were tested and exhibited clear advantages—robustness against frequency disturbances—over MAF-based equivalents at standardized tests over a typical simulation environment, setting through this work an initial milestone for its verification and further incorporation in more complex synchronization topologies.

Design Procedure of Continuous Profile Stopband Filters Implemented With Empty Substrate Integrated Coaxial Lines

This article presents a systematic procedure aimed to design continuous profile stopband filters assembled with empty substrate integrated coaxial lines. The coaxial filter is made of five low-cost substrate layers, where the central boards contain the filter profile. This structure exhibits unimodal TEM operation over a wide frequency band, it is not dispersive, it is shielded and cannot be interfered from external signals, and it can be easily integrated with other planar devices. Well-known scattering inverse methods based on the coupled-mode theory have been used for the dimensional synthesis of the proposed topology. Since these dimensions are obtained analytically, no further brute-force optimizations are needed. In particular, a nine-pole elliptic stopband filter operating in the $K_{u}$ band and covering the whole bandwidth of Hispasat 1E communication satellite is shown. The final manufactured filter prototype is large in the longitudinal dimension, but due to its continuous topology, it results to be rather insensitive to fabrication tolerances and errors. Measured results are in good agreement with full-wave simulations. The proposed empty substrate integrated coaxial technology is particularly suitable to realize stopband filters with moderate or wide bandwidths for next-generation satellite applications.

Some Remarks about Entropy of Digital Filtered Signals.

The finite numerical resolution of digital number representation has an impact on the properties of filters. Much effort has been done to develop efficient digital filters investigating the effects in the frequency response. However, it seems that there is less attention to the influence in the entropy by digital filtered signals due to the finite precision. To contribute in such a direction, this manuscript presents some remarks about the entropy of filtered signals. Three types of filters are investigated: Butterworth, Chebyshev, and elliptic. Using a boundary technique, the parameters of the filters are evaluated according to the word length of 16 or 32 bits. It has been shown that filtered signals have their entropy increased even if the filters are linear. A significant positive correlation (p < 0.05) was observed between order and Shannon entropy of the filtered signal using the elliptic filter. Comparing to signal-to-noise ratio, entropy seems more efficient at detecting the increasing of noise in a filtered signal. Such knowledge can be used as an additional condition for designing digital filters.

CMOS Analog Filter Design for Very High Frequency Applications

A design strategy for the synthesis of high-selectivity/low-order analog filters in Complementary Metal-Oxide-Semiconductor (CMOS) technology for very high frequency (VHF) applications is presented. The methodology for the reconstitution of a given transfer function by means of Signal Flow Graphs (SFG) manipulation in canonical form is proposed leading to a fully differential g m -C biquad filter. As a practical example, the design of a notch filter intended to suppress interferers in the lower sideband (400 MHz) of the Medical Implant Communication Service (MICS), in single-poly, 6-metal layers; Mixed-Signal/RF 0.18 µm CMOS technology is realized. To compare the performance of the proposal with some other solution, the design of a 7th order elliptic notch filter based on Frequency Dependent Negative Resistors (FDNRs) was also accomplished. The attained simulation results prove that the proposal is competitive compared to the FDNR solution and some other state-of-the-art filters reported in the literature. The most salient features of the proposed notch biquad include: the selectivity, whose value is comparable to that of a 7th order elliptic approach and some other 3rd order filters; a high-frequency operation without resonators; linearity, with a +15 dBm I I P 3 ; a reduced form factor with a total occupied area of 0.004282 mm2 and mostly a low design complexity.

EKG MORFOLOJİSİNE DAYALI ÖZELLİKLERİ KULLANAN ETKİLİ BİR ARİTMİK KALP ATIŞI SINI

Clinically, analyzing the ECG records is often quite time-consuming. Therefore, it is important to perform rapid analysis and detect abnormalities in ECG signals such as arrhythmias. For this reason, computer-aided diagnostic systems are being developed. With the developed systems, abnormalities in the ECG record can be easily detected. Thus, the developed systems are useful for clinicians in determining the diagnosis and treatment methods of heart diseases. In this study, an IIR based elliptic digital filter was used for removing the baseline wander in the ECG signal. Morphologically based features of the ECG signal are extracted. Then, the most meaningful of these features were selected by using the SelectKBest method and the f_ classif score function. Five basic arrhythmias labelled according to the AAMI standard have been classified using machine learning methods utilizing these feature data sets. Logistic Regression (LR), Linear Discriminant Analysis (LDA), Support Vector Machine (SVM) and Multi Layer Perceptron (MLP) machine learning methods were used as classifiers for arrhythmia diagnosis. The performance results obtained with these classifiers were examined and the LR method, which predicts the five basic arrhythmias as satisfactorily high was proposed as a classifier. The performance results of the LR method were obtained as Accuracy 99.766%, Sensitivity 99.416%, Specificity 99.854% and F1-Score 99.416%. In this study, the arrhythmia diagnosis method has been proposed which predicts five basic arrhythmias satisfactorily high. The proposed method can be used beneficially in computer-aided diagnostic systems. In this study, Google Colaboratory was used for the software and hardware needs of machine learning methods.

Modeling Seismic Vibrations under Massive Blasting in Underground Mines

The theoretical model is proposed, which allows tracing continuation of seismic vibrations after cessation of blast load by the analysis of velocigrams recording on ground surface during underground explosions. The comparison of the model and experimental velocigrams of massive blasts shows validity of elliptical filters for second-order low frequencies in modeling waveforms of the velocigrams. The model efficiency in the detection of time-delay errors is proved. The conditions of predicting peak particle velocities based on explosive weight per blast are determined. The pre-conditions for the resonance excitation in the rock mass-guarded object system are discussed, and the blast-induced load is predicted.

An Adaptive Filter Based on Local Slope by Adjusting Elliptic Filter Kernel for ICESat-2 Photon Counting Laser Altimetric Data

The Ice, Cloud and Land Elevation Satellite-2 (ICESat-2) was launched on September 15th, 2018, which continues to perform measurement tasks as the successor to ICESat. Unlike full waveform technology of ICESat, ICESat-2 employs micropulse photon counting technology, which provides higher accuracy, but produces plenty of noise. This paper proposes an adaptive filter based on local slope by adjusting elliptic filter kernel. The general approach is 1) data preprocessing, 2) Gaussian density calculation, 3) OTSU adaptive threshold calculation. This method is seen to be robust in identifying signal points from high background noise points and suitable for low density data caused by slope.

VR motion sickness recognition by using EEG rhythm energy ratio based on wavelet packet transform

Background and objectivesVirtual reality motion sickness (VRMS) is one of the main factors hindering the development of VR technology. At present, the VRMS recognition methods using electroencephalogram (EEG) signals have poor applicability to multiple subjects. MethodsAiming at this dilemma, the wavelet packet transform (WPT), was used to propose a feature extraction method for EEG rhythm energy ratios of delta (δ), theta (θ), alpha (α), and beta (β) in this research. Moreover, VRMS was recognized by combining k-Nearest Neighbor classifier (k-NN), support vector machine (SVM) with polynomial kernel (polynomial-SVM) and radial basis function kernel (RBF-SVM), respectively. The method is that the raw EEG signals were de-noised by an elliptical band-pass filter and segmented by a fixed window, 7-level db4 WPT was performed on each EEG segment, and the wavelet packet energy ratios of delta, theta, alpha and beta rhythms from FP1, FP2, C3, C4, P3, P4, O1 and O2 channels were calculated and combined to form feature vectors for recognizing VRMS. ResultsUnder the condition of 4-s window size, the average VRMS recognition accuracy of polynomial-SVM for the single subject was 92.85%, and the VRMS recognition accuracy of 18 subjects was about 79.25%. ConclusionsCompared with other VRMS recognition methods, this method does not only have a higher recognition accuracy to a single subject, but also have better applicability to multiple subjects. Meanwhile, when using the EEG four rhythm energy ratios of FP1, FP2, C3, C4, P3, P4, O1 and O2 channels as feature vectors, the polynomial-SVM achieved better VRMS recognition performance than the k-NN and RBF-SVM.

Reflectionless Filters for Generalized Elliptic Transmission Functions

Single-ended circuit topologies, and a theorem for the development thereof, are presented with which one may realize constant-resistance (or reflectionless) filters, having ideally zero reflection coefficient at all frequencies and from all ports, suitable for elliptic and pseudo-elliptic filter responses. The proposed theorem produces topologies of a type known as the coupled-ladder, which has been previously studied for only polynomial responses (e.g. Butterworth, Chebyshev, etc.). A comparison between these topologies and another classical approach known as the economy bridge reveals that those proposed here have a number of theoretical and practical advantages. The theory is tested by the construction of a sixth-order, low-pass reflectionless filter exhibiting a pseudo-elliptic frequency response. Measured results are in excellent agreement with theory, and show return loss better than 20 dB throughout the pass-band, the transition-band, and up to two octaves into the stop-band.

Quasi-Elliptic Waveguide Dual-Band Bandpass Filters

This article presents a novel folded configuration of dual-band filter employing TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11m</sub> dual-mode elliptical cavity resonators. The proposed side-coupled configuration leads to a significant reduction of filter footprint compared with previously reported in-line dual-band filter structures. Such configuration also facilitates cross couplings to realize advanced quasi-elliptic filter functions. The structure employs irises for both sequential and cross couplings. The limitations of bandwidth realization and spurious-free window are analyzed in detail, and new coupling structures are proposed to improve the overall in-band and out-of-band responses. All the proposed dual-band designs have low insertion loss and allow for independent control of each frequency and coupling parameter. To demonstrate the concept, two 8-pole C-band elliptical cavity dual-band filters are designed, manufactured, measured, and compared. To the best of the authors' knowledge, this is the first reported folded dual-band filter configuration based on metallic waveguide cavities.

0.3 V Differential Difference Current Conveyor Using Multiple-Input Bulk-Driven Technique

This paper presents a new ultra-low voltage and ultra-low power differential difference current conveyor (DDCC) which is suitable for portable electronic applications. The proposed DDCC uses the subthreshold technique to reduce the power consumption and the bulk-driven technique to obtain a rail-to-rail input common-mode swing. Unlike previous DDCCs, the multiple-input bulk-driven technique is used in the proposed DDCC to reduce the number of transistors and to achieve the compactness. The proposed DDCC was designed using 0.18 µm TSMC CMOS technology with 0.3 V power supply and 38 nW power consumption. To confirm the workability of the new active device, a third-order elliptic filter using the proposed DDCCs as active device has been introduced as an application example. The proposed DDCC and its application have been designed and simulated in Cadence/Specter environment, and the simulated results prove the functionality and the attractive results of the new circuits.