Chebyshev Filter Research Articles

Efficient calculation of X-ray absorption spectra using Chebyshev-Slepian filter diagonalisation.

The efficient, yet accurate, simulation of X-ray absorption spectra represents a significant challenge for ab initio electronic structure methods. Conventional approaches involve the explicit calculation of all core-excited states spanning the energy range of interest, even though only a small number of these states will contribute appreciably to the spectrum. We here report a different approach, based on a time-independent Chebyshev filter diagonalization scheme, which allows for the X-ray absorption spectrum to be computed without the explicit calculation of the core-excited eigenstates. Furthermore, in a subsequent postprocessing calculation, selected peaks may be analyzed via the calculation of natural transition orbitals, if desired. The scheme presented here is based on a refinement of the time-independent Chebyshev filter diagonalization approach. Previous formulations of this method have been characterized by a requirement for significant "user input" via the (sometimes unintuitive) tuning of various numerical parameters. To circumvent this, we introduce a new class of filters based on discrete prolate spheroidal sequences. We demonstrate that the resulting method, which we term Chebyshev-Slepian filter diagonalization, makes filter diagonalization essentially a black-box procedure. The Chebyshev-Slepian filter diagonalization method is implemented at the second-order algebraic diagrammatic construction level of theory and validated through the calculation of the X-ray absorption spectra of trifluoroacetonitrile and 1,4-benzoquinone.

Nonlinear active noise control system based on correlated EMD and Chebyshev filter

• A nonlinear ANC system using signal decomposition and Chebyshev filter is proposed. • The non-stationary primary noise is decomposed by the improved correlated EMD. • The Chebyshev nonlinear filter is investigated to expand the decomposed IMFs. • Simulation results indicate that proposed method outperforms conventional methods. Investigations into active noise control (ANC) have been widely conducted with the aim of effective control of low-frequency noise. This paper proposes a novel nonlinear ANC system to control non-stationary noise produced by rotating machinery under nonlinear primary path. A real-time correlated empirical mode decomposition (CEMD) is first presented to decompose non-stationary noise into intrinsic mode functions (IMFs), some of which are chosen by the correlation analysis between IMFs and primary noise. Subsequently, the second-order Chebyshev nonlinear filter is applied to expand selected IMFs that are controlled individually by the filtered-x LMS. The convergence of proposed nonlinear ANC system is also investigated. Simulation results demonstrate that proposed method outperforms the filtered-x LMS, filtered-s LMS and Volterra filtered-x LMS algorithms with respect to noise reduction and convergence rate.

Improving the navigation spacecraft radio visibility with signal processing algorithms usage

The article deals with topical issues of spacecraft external design for the global navigation satellite system (GLONASS). The development and analysis of data processing algorithms are considered a part of the external design phase. Data for processing algorithms was obtained from real orbital grouping spacecraft. Mathematical modelling was performed based on real data to analyse navigation signals propagation conditions from GLONASS satellites. Implementation of mathematical modelling approach included such aspects as finding the optimal antenna pattern and filtering radio frequency signals. Theoretically optimal antenna directivity patterns were implemented taking into account available data about satellite orbital parameters. Bessel, Butterworth, Chebyshev and elliptic filters were used as standard filtering methods. Modified low-pass filtering algorithm was considered as an improved filtering algorithm. Application of the modified filtering method allowed to reduce geometric dilution of precision value in the consumer positioning case. Obtained results are applicable to design possible options for improving the existing GLONASS orbital group.

Performance evaluation of different order fractional Chebyshev filter using optimisation techniques

ABSTRACT This paper presents the analysis of proposed different (α + β) fractional order low pass Chebyshev filters by comparing the results obtained using three different optimisation techniques. Simulated annealing (SA), nonlinear least square (NLS) and interior search algorithm (ISA) techniques are used to examine the proposed filters. Analysis of sensitivity and w-plane stability has been performed on the optimised results. Gain and cutoff frequency obtained from the optimisation techniques are compared with SPICE results. MATLAB and SPICE results have been compared to get the best optimisation techniques for designing the proposed different (α + β) fractional order low pass Chebyshev filters. Tow Thomas biquad circuit is used to validate optimised results of filters for different combinations of α and β using fractional order capacitors of α and β orders.

Design and Implementation of Chebyshev Band Pass Filter with M-Derived Section in Frequency Band 88 - 108 MHz

FM radio broadcasting is a wireless communication system. Transmission in the frequency 88-108 MHz requires a bandpass filter to avoid interference with frequencies adjacent to the radio transmitter. The type of filter that has a fairly good performance is the Chebyshev filter with a fairly high level of steepness. However, to get a high level of steepness, a fairly large element value is required. So, in this study adding the m-derived series to give a steeper filter response without adding more element values.The purpose of this thesis is to determine the effect of adding an m-derived section to the chebyshev bandpass filter. The parameters tested are passband bandwidth, stopband bandwidth, shape factor, insertion loss, roll off, and power attenuation when used on the transmitter.Based on the measurements that have been made, it can be seen that the bandpass filter without m-derived has a maximum insertion loss value of 7 dB and a minimum insertion loss of 9 dB, while the bandpass filter with m-derived is 11 dB and 13. In the bandpass filter without m-derived and m-derived have a passband bandwidth of 27 MHz and 29 MHz and a stopband bandwidth of 70 MHz and 50 MHz. So that the bandpass filter without derived and m-derived has a shape factor value of 2.59 and 1.72. In the implementation using the transmitter, the bandpass filter without m-derived has a power attenuation of 2.53 dB while the m-derived bandpass filter has an attenuation of 1.5 dB.

Design of Micro-strip Symmetrical Dual-band Filter Based on Wireless Sensor Network Nodes

The micro-strip antenna filter design of wireless sensor network nodes is usually used to improve the out-of-band suppression and frequency selectivity by increasing the order of the filters, but the filters are usually single band, not only the size is large, but also the in-band characteristics of the filters are not ideal. This paper proposes a method to design a micro-strip symmetric dual-band filter in wireless sensor network nodes. Firstly, the coupling matrix of single-passband filter is obtained by using the synthesis method of generalized Chebyshev filter function. Then, the coupling matrix of the dual-passband filter is generated according to the reflection zeros and the transmission zeros. Finally, the S parameters response curve is drawn by mapping the normalized frequency domain of the dual-passband to the actual frequency domain. According to the data analysis and experimental results, the method is feasible and effective to design a micro-strip symmetrical dual-band filter. It can not only provide a more guiding design method for the joint design of antenna and RF front-end circuit, but also realize the spread of single-passband filter to multi-frequency for a wireless sensor network node antenna.

ChebStaBlkCG: A block variant of ChebFilterCG

SummaryThe behavior of ChebFilterCG (an algorithm that combines the Chebyshev filter and Conjugate Gradient) applied to systems with unfavorable eigenvalue distribution is examined. To improve the convergence, a hybrid approach combining a stabilized version of the block conjugated gradient with Chebyshev polynomials as preconditioners (ChebStaBlkCG) is proposed. The performance of ChebStaBlkCG is illustrated and validated on a set of linear systems. It is shown how ChebStaBlkCG can be used to accelerate the block Cimmino method and to solve linear systems with multiple right‐hand sides.

Synthesis of Chebyshev/Elliptic Filters Using Minimum Acoustic Wave Resonators

Acoustic wave (AW) filters for next-generation wireless communication systems are designed to prevent signal interference and to be as small as possible. Using a pole-zero extraction method with a ladder-type AW filter, this paper proposes an algorithm to optimize the parameters for each AW resonator. The pole-zero positions of the equivalent circuit model are aligned with those of a Chebyshev or elliptic filter in the s-domain in order to give a frequency response that satisfies the system requirements in terms of insertion loss, out-band attenuation, and selectivity. The optimized parameters produce a system that has the minimum number of resonators to fulfill the filter performance specifications, with reduced manufacturing cost, which occupies a smaller area. Finally, the system is validated using a simulation with a LTE Band3 Rx elliptic filter and the parameters for an equivalent modified Butterworth-Van Dyke model (mBVD) for each resonator.

A Simple and Accurate Method for Extracting Super Wideband Electrical Properties of the Printed Circuit Board

In order to accurately design microwave, millimeter-wave components and circuits, a simple and accurate method for extracting extremely wideband characteristics of the printed circuit board (PCB), including relative dielectric constant, dielectric loss tangent, and equivalent copper conductivity, is proposed and validated in this paper. By properly selecting wideband distribution of multiple TMmn0 modes in the designed circular substrate integrated waveguide (CSIW) cavities, extremely broadband properties of PCB can theoretically be extracted with only one pair of CSIW cavities. The proposed method overcomes the limitations of conventional methods that only support narrowband applications, require a large number of cavities, and have relatively large errors. The experiments show that the proposed method is able to extract, accurately and efficiently, 8-110 GHz characteristics of a TLY-5Z substrate-based PCB and the extracted results are verified by designing and measuring the fourth-order Chebyshev filter at X-band.

Design of Microstrip Low Pass Filters

Microstrip filters have a significant role in Radio Frequency/Microwave applications. Microstrip filters are common on microwave circuits, satellite communications, radars, test equipments and so on. Because microstrip filters are compact, cheap and easy to produce, they are highly preferred for microwave applications. Microwave filter; microwave system is a two-ported element used to control the frequency response at a certain point by attenuating the frequencies in the stop band by transmitting in the frequency band. Typical frequency responses are low pass, high pass, band pass and band stop. Also approaches such as Butterworth, Chebyshev, and Elliptic are defining filter characteristics. In this paper, microstrip filters havign Chebyshev, Elliptic and Maximally Flat approaches were designed. For example Chebyshev filter of design filters having 6 GHz cut frequency and having 46,34 dB at 6,6 GHz. The insertion loss is -3,66 dB at 6 GHz. AWR Sonnet is used for the simulation and analysis of this filters.

Pseudo-elliptic slow wave line

Quasi elliptic filters are of great demand in the present day communication systems. Coupling matrix analysis of pseudo-elliptic low pass filter using conventional microstrip line is presented in this paper. The conventional microstrip line has no non-zero cut off frequency. The conventional microstrip line is transformed into a pseudo-elliptic low-pass filter using the concept of slow wave. The slow wave microstrip line exhibits pseudo-elliptic low-pass behavior with transmission zeros at finite frequencies unlike the conventional Butterworth and Chebyshev filters. The coupling matrix of the slow wave microstrip line is arrived at by using the generalized Chebyshev functions. The coupling matrix of the slow wave line is validated using the MATLAB tool box. Finally, the prototype is fabricated and the performance is measured.

Comparative performance of some polynomial-based lowpass filters for microwave/digital transmission applications

ABSTRACTThis paper reports on the comparative performances of some polynomial based lowpass filters in the lumped elements, microstrip and defected ground structure (DGS) environment. The microwave designers are normally familiar with Butterworth, Chebyshev and Bessel filters. However, many more polynomials based, ripple and non-ripple types LPF have been suggested for the low-frequency applications. Some of these LPF, such as L-opt, H-type, Transitional Butterworth-Legendre (TBL), Pascal, Legendre group of LPF, are compared for their applications in analog microwaves, digital transmission, efficiency enhancement of the linear power amplifiers and five level partial response modulations. A method is reported to compute the ripple frequency for the Legendre group of LPF and Pascal LPF. Further, a design is suggested to significantly improve group delay performance of high selectivity filters.

Performance Analysis of Different Electrical Filters in 10G Hybrid Passive Optical Network

With growing number of applications and network traffic, optic fibers are extensively used in the access part of the network. Passive Optical Networks (PON) in particular, Ethernet PON (EPON) networks based on Time Division Multiple Access (TDMA) are more prominently used in many parts of the world. Though Wavelength Division Multiplexing (WDM) PON has its own advantages, considering the cost and utilisation of such networks in the access part makes it less useful. On the other hand, Hybrid PON network combines the advantages of both EPON and WDM PON Networks. The objective of this paper is to identify suitable electrical filters for a 16-channel Hybrid Passive Optical Network with a transmission rate of 10Gbps per channel, by analysing their performance in terms of Q factor and Bit Error Rate. Different filters like the Bessel filter, Gaussian filter, Raised Cosine Filter, Rectangular filter, Butterworth filter, Chebyshev Filter are compared and their performances are evaluated. DB Modulation format that provides a longer reach is used at the transmitter to evaluate the different scenarios and the simulation is carried out using Optisystem.

A 0.18um CMOS Low Noise Amplifier for 3-5ghz UWB Receivers

This paper presents an Ultra-Wideband (UWB) 3-5 GHz Low Noise Amplifier (LNA) employing Chebyshev filter. The LNA has been designed using Cadence 0.18um CMOS technology. Proposed LNA achieves a minimum noise figure of 2.2dB, power gain of 9dB.The power consumption is 6.3mW from 1.8V power supply.

EMG extractor and blink detection for human health monitoring

In this paper we have proposed noise free EMG extractor for biomedical applications and also provide method for detecting blink signal. EMG signal is applied to preamplifier followed by Chebyshev filter and programmable gain amplifier further this processed EMG signal is applied to comparator to detect the blink. This topology is designed in UMC 180nm CMOS technology. Amplifier with gain of 81.155 dB and CMRR of 155.197 dB is designed. Preamplifier gain of 32.1244 dB with CMRR of 76.0743 dB which leads to common mode cancellation at priliminary stage. It also provide input referred noise ranges from 90 to 101.8636 µ V/sqrt(Hz) to reduce the noise for overall system. 4th order Chebyshev filter provides filtering with slope of -80 dB/decade with leads to reduce the unwanted signals. Filtered EMG signal is applied to programmable gain amplifier where gain ranges from 0 to 23 dB.It consumes power of 0.3µ W at 1V supply voltage.

Electronically Tunable Current-Mode Third-Order Square-Root-Domain Filter Design

In this study, electronically-tunable, current-mode, square-root-domain, third-order low-pass filter is proposed. The study is carried out with three circuit designs. First circuit is third-order low-pass Butterworth filter, second circuit is third-order low-pass Chebyshev filter and the last circuit is third-order low-pass elliptic filter. All the input and output values of the filter circuit are current. Only grounded capacitors and MOSFETs are required in order to realize the filter circuit. Additionally, natural frequency [Formula: see text] of the current-mode filter can be adjusted electronically using outer current sources. To validate the theory and to demonstrate the performance of third-order filter, frequency and time domain simulations of PSPICE program are used. To that end, TSMC 0.35[Formula: see text][Formula: see text]m Level 3 CMOS process parameters are utilized to realize the simulations of the filter.

A wideband UHF high-temperature superconducting filter system with a fractional bandwidth over 108%

A High-temperature superconducting (HTS) bandpass filter system containing a lowpass filter, a highpass filter and an LNA has been fabricated to meet the demands of wideband wireless signal receiving system. The filter system has an ultimate fractional bandwidth over 108% with the passband from 820 MHz to 2750 MHz. Besides, the filter system showed good frequency selectivity and out-of-band rejection. The 40 dB to 3 dB rectangle coefficient of our filter system is 1.4, which is better than that of an 8-pole Chebyshev filter, and the out-of-band rejection is better than 40 dB. Through systematical optimization, a return loss of better than 9.8 dB was received in the filter system. This system also showed advantages in design and fabrication precision.

Two-Level Chebyshev Filter Based Complementary Subspace Method: Pushing the Envelope of Large-Scale Electronic Structure Calculations.

We describe a novel iterative strategy for Kohn-Sham density functional theory calculations aimed at large systems (>1,000 electrons), applicable to metals and insulators alike. In lieu of explicit diagonalization of the Kohn-Sham Hamiltonian on every self-consistent field (SCF) iteration, we employ a two-level Chebyshev polynomial filter based complementary subspace strategy to (1) compute a set of vectors that span the occupied subspace of the Hamiltonian; (2) reduce subspace diagonalization to just partially occupied states; and (3) obtain those states in an efficient, scalable manner via an inner Chebyshev filter iteration. By reducing the necessary computation to just partially occupied states and obtaining these through an inner Chebyshev iteration, our approach reduces the cost of large metallic calculations significantly, while eliminating subspace diagonalization for insulating systems altogether. We describe the implementation of the method within the framework of the discontinuous Galerkin (DG) electronic structure method and show that this results in a computational scheme that can effectively tackle bulk and nano systems containing tens of thousands of electrons, with chemical accuracy, within a few minutes or less of wall clock time per SCF iteration on large-scale computing platforms. We anticipate that our method will be instrumental in pushing the envelope of large-scale ab initio molecular dynamics. As a demonstration of this, we simulate a bulk silicon system containing 8,000 atoms at finite temperature, and obtain an average SCF step wall time of 51 s on 34,560 processors; thus allowing us to carry out 1.0 ps of ab initio molecular dynamics in approximately 28 h (of wall time).

A Coupled-Line Coupling Structure for the Design of Quasi-Elliptic Bandpass Filters

A coupled-line coupling structure is proposed for the design of quasi-elliptic bandpass filters (BPFs). The coupled-line structure functions as the input coupling structure for a BPF and introduces one pair of symmetrical transmission zeros at around the cutoff frequencies. Equivalent circuit models play an important role in the design of microwave filters. Accordingly, this paper undertakes a major effort to develop the equivalent circuit of the coupling structure. The equivalent circuit is in a form that can be readily used in combination with a given direct-coupled filter. The coupling structure can serve as a basic building block for the design of quasi-elliptic BPFs. As demonstrated by the theoretical and experimental treatment, the coupling structure can be used to transform a Chebyshev filter into a quasi-elliptic filter.

Sparse Modeling of Nonlinear Secondary Path for Nonlinear Active Noise Control

In many practical active noise control systems, the nonlinear secondary path (NSP) model can offer broader applications than the linear secondary path (LSP) model for the widespread existence of nonlinearities in the secondary path. However, the computational burden often limits the application of the NSP algorithms. In this paper, we apply a sparse Volterra model for the LSP and NSP instead of the complete Volterra model, which may be over parameterized for the nonlinear active noise control (NANC) system. The developed new control algorithms greatly result in reduction of computational complexity. We also provide an analysis of the NANC system to show that the noise at the canceling point could be approximated by the function expansion filters when the secondary path is modeled as the second-order Volterra series. In addition, two new function expansion forms, the even mirror Fourier nonlinear filter with a linear finite-impulse response section and the Chebyshev filter, are explored to process the nonlinearities in the NANC system using the filtered-x least mean square and filtered-error least mean square algorithm structures. The computational complexity analysis and the computer simulations validate that the new control algorithms with a sparse Volterra model for the secondary path can significantly reduce computational load without sacrificing the control performance.