Showing papers on "Butterworth filter published in 2010"

Power line filter design for switched-mode power supplies

Abstract: Filtering. Graphical attentuation calculations. Conduction modes. Filter load impedance and measurement techniques. Filter source impedance. Power supply. Filter/supply interaction. Filter topologies and damping. Common mode component selection. Radiation coupling to on-board filters.

Guideline for a Simplified Differential-Mode EMI Filter Design

Abstract: The design of electromagnetic interference (EMI) input filters, needed for switched power converters to fulfill the regulatory standards, is typically associated with high development effort. This paper presents a guideline for a simplified differential-mode (DM) filter design. First, a procedure to estimate the required filter attenuation based on the total input rms current using only a few equations is given. Second, a volume optimization of the needed DM filter based on the previously calculated filter attenuation and volumetric component parameters is introduced. It is shown that a minimal volume can be found for a certain optimal number of filter stages. The considerations are exemplified for two single-phase power factor correction converters operated in continuous and discontinuous conduction modes, respectively. Finally, EMI measurements done with a 300-W power converter prototype prove the proposed filter design method.

Novel Voltage-Mode All-Pass Filter Based on Using DVCCs

Abstract: In this paper, a novel design for realizing a voltage-mode (VM) all-pass filter utilizing two differential voltage current conveyors (DVCCs) is proposed. Also, the suggested filter uses a canonical number of passive elements (one grounded capacitor and one resistor) without requiring any element matching condition. The proposed filter has high input and low output impedances, which make it suitable for cascading. The effects of the nonidealities of the DVCCs on the proposed design are investigated. As an application, a quadrature oscillator is designed using the proposed VM all-pass filter and an integrator. The proposed filter and oscillator circuits are simulated using the SPICE simulation program to confirm the theory.

High- $Q$ RF-MEMS 4–6-GHz Tunable Evanescent-Mode Cavity Filter

Abstract: This paper presents a miniature high-Q tunable evanescent-mode cavity filter using planar capacitive RF microelectromechanical system (MEMS) switch networks and with a frequency coverage of 4.07-5.58 GHz. The two-pole filter, with an internal volume of 1.5 cm3, results in an insertion loss of 4.91-3.18- and a 1-dB bandwidth of 17.8-41.1 MHz, respectively, and an ultimate rejection of > 80 dB. RF-MEMS switches with digital/analog tuning capabilities were used in the tunable networks so as to align the two poles together and result in a near-ideal frequency response. The measured Qu of the filter is 300-500 over the tuning range, which is the best reported Q using RF-MEMS technology. The filter can withstand an acceleration of 55-110 g without affecting its frequency response. The topology can be extended to a multiple-pole design with the use of several RF-MEMS tuning networks inside the evanescent-mode cavity. To our knowledge, these results represent the state-of-the-art in RF-MEMS tunable filters.

Planar Tri-Band Bandpass Filter With Compact Size

Abstract: This letter presents a compact planar tri-band bandpass filter with high selectivity. The proposed filter employs two sets of resonators, i.e., stub-loaded resonators and half-wavelength resonators. The former is designed to operate at the first and third passbands and the latter at the second passband. The passband frequencies can be conveniently tuned to desired values. One set of resonators is embedded in the other and thus the filter is compact in size. On each side of each passband, there is at least one transmission zero, resulting in high skirt selectivity. For validation, a demonstration filter is implemented. The design methodology and the experimental results are presented.

Compact Low-Loss Tunable $X$ -Band Bandstop Filter With Miniature RF-MEMS Switches

Abstract: This paper presents a compact low-loss tunable X-band bandstop filter implemented on a quartz substrate using both miniature RF microelectromechanical systems (RF-MEMS) capacitive switches and GaAs varactors. The two-pole filter is based on capacitively loaded folded-λ/2 resonators that are coupled to a microstrip line, and the filter analysis includes the effects of nonadjacent inter-resonator coupling. The RF-MEMS filter tunes from 11.34 to 8.92 GHz with a - 20-dB rejection bandwidth of 1.18%-3.51% and a filter quality factor of 60-135. The GaAs varactor loaded filter tunes from 9.56 to 8.66 GHz with a - 20-dB bandwidth of 1.65%-2% and a filter quality factor of 55-90. Nonlinear measurements at the filter null with Δf = 1 MHz show that the RF-MEMS loaded filter results in > 25-dBm higher third-order intermodulation intercept point and P-1 dB compared with the varactor loaded filter. Both filters show high rejection levels ( > 24 dB) and low passband insertion loss ( <; 0.8 dB) from dc to the first spurious response at 19.5 GHz. The filter topology can be extended to higher order designs with an even number of poles.

First-order voltage-mode all-pass filter employing one active element and one grounded capacitor

Abstract: A new circuit topology of first-order voltage-mode all-pass filter providing high-input and low-output impedances is described. The filter consists of only one grounded capacitor and one active element, namely VD-DIBA (Voltage Differencing-Differential Input Buffered Amplifier), with the possibility of electronically tuning the natural frequency. The filter is assembled from commercial integrated circuits, and the frequency responses measured are compared with the theoretical characteristics.

A New Implementation Method of Wavelet Packet Transform Differential Protection for Power Transformers

Abstract: This paper presents an innovative implementation of the wavelet packet transform using Butterworth passive filters for differential protection of power transformers. The proposed implementation is based on designing cascaded stages of high pass 3$^{rd}$ order Butterworth filters with cut-off frequencies identical to the cut-off frequencies of wavelet packet transform associated digital quadrature mirror filters. These high pass filters are designed to extract the second level high frequency components present in the three-phase differential currents. The extraction of these frequency components is required in order to detect and classify transients in three-phase power transformers. The output of the designed Butterworth high pass filters is utilized to initiate a trip signal in case of internal fault currents. The 3$^{rd}$ order Butterworth high pass filters are designed to simplify their practical implementation as well as their integration with the differential protective relay for the tested power transformer. Different magnetizing inrush, through-fault and internal fault currents are investigated for different loading conditions. Performances of the proposed Butterworth passive filter-based differential relay are compared with those of the digital wavelet packet transform-based relay. Comparison results show that the Butterworth filter wavelet packet transform-based differential relay is able to provide a low cost good diagnosis and fast responses to internal fault currents.

Digital Filters and Signal Processing: With MATLAB® Exercises

Abstract: Preface. 1: Introduction: Terminology and Motivation. 2: Discrete-Time Signals and Systems. 3: The z Transform. 4: Input/Output Relationships. 5: Discrete-Time Networks. 6: Sampling and Fourier Analysis. 7: Discrete Fourier Transform. 8: IIR Filter Design by Transformation. 9: FIR Filter Design Techniques. 10: Filter Design by Modeling. 11: Quantization Effects. 12: Digital Filter Implementation. 13: Filter and Systems Examples. Answers to Selected Problems. References. Index.

Kolmogorov–Zurbenko filters

Abstract: We reviewed the properties of the Kolmogorov–Zurbenko (KZ) filter and its extensions with applications in high resolution signal and image processing. The KZ filter is defined as an iteration of a moving average (MA) filter. The impulse response function of the KZ filter is a convolution of the rectangular window being used in a MA filter. Zero derivatives at the edges of the impulse response function make it a sharply declining function, providing high frequency resolution. The KZ Fourier transform (KZFT) is derived from the KZ filter by applying it to Fourier transform. Extensions of the KZ filter and the KZFT are demonstrated with examples. Copyright © 2010 John Wiley & Sons, Inc. For further resources related to this article, please visit the WIREs website.

A New Dual-Band Microstrip Bandpass Filter Using Net-Type Resonators

Abstract: In this letter, a new dual-band microstrip bandpass filter is developed using net-type resonators. The net-type resonator is designed to simultaneously operate at two closely specified resonant frequencies, f1 and f2, and then applied to construct a dual-band filter based on the filter design concept of adding extra coupled resonators. The dual-band filter with the elliptic function response is designed, implemented and experimentally verified in this letter. The measured results of the developed filter are in a good agreement with the simulated results by full-wave electromagnetic simulator. In addition, the developed filter not only has an excellent mid-band rejection, but also provides a wide stopband suppression.

Frequency Response Control in Frequency-Tunable Bandstop Filters

Abstract: This letter presents a tunable bandstop filter with the capability of controlling the shape of the frequency response. The proposed filter structure can be tuned to have either a Butterworth or a Chebyshev response. The filter can also be tuned to have different center frequencies. Both the frequency response and the center frequency of the filter can be tuned by only adjusting the resonant frequency of each resonator without controlling inter-resonator coupling. Since the proposed filter structure has non-zero inter-resonator coupling, it can find its future application in reconfigurable filters which can be tuned to exhibit either a bandstop or a bandpass response.

Impedance-Transforming Symmetric and Asymmetric DC Blocks

Abstract: Design formulas of symmetric and asymmetric dc blocks are presented for achieving Chebyshev and Butterworth frequency responses. They can also be used for impedance transformers. Design formulas of symmetric dc blocks are first derived and those of asymmetric dc blocks are also computed based on the symmetric ones. For easy derivation of design formulas of the symmetric dc blocks, coupling coefficient, being proportional to bandwidth, is defined. It is then clarified that symmetric Chebyshev dc blocks are not possible for the impedance transforming. For the symmetric Butterworth dc blocks, three design methods are exploited. To verify the symmetric Butterworth dc blocks, a microstrip dc block with 50- and 25-Ω termination impedances designed at a center frequency of 2 GHz was fabricated. The measured S12 = S21 and S11 = S22 are - 0.19 and - 57 dB around 2 GHz, showing quite good agreement with simulation results. Based on synthesized symmetric dc blocks, the coefficients of transfer function |S12|2 are calculated and design formulas of the asymmetric dc blocks are derived based on the symmetric ones. Asymmetric Chebyshev dc blocks are verified by the measurements provided in a previously published paper and asymmetric Butterworth dc blocks by the symmetric Butterworth dc block measured in this paper.

Switchable microwave photonic filter between high Q bandpass filter and notch filter with flat passband based on phase modulation.

Abstract: We propose and demonstrate a novel switchable microwave photonic filter based on phase modulation. Both a microwave high Q bandpass filter and a microwave notch filter with flat passband are achieved respectively. And the switchability between them by tuning the two tunable optical bandpass filters is demonstrated. We also present a theoretical model and analytical expression for the proposed scheme. A frequency response of a high Q bandpass filter with a Q factor of 327 and a rejection ratio of exceeding 42 dB, and a frequency response of a notch filter with flat passband with a rejection ratio exceeding 34 dB are experimentally obtained. The operation frequency of microwave photonic filter is around 20 GHz.

An Improved Method for Designing Quadrature Mirror Filter Banks via Unconstrained Optimization

Abstract: This paper proposes an algorithm to design a two-channel linear phase quadrature mirror filter (QMF) bank. The design problem is presented systematically as an unconstrained optimization that minimizes the weighted sum of error of transfer function of the filter bank at quadrature frequency, stopband energy and the passband error of a prototype filter (PF). A new method is developed for the design of a low pass prototype filter for QMF banks. For solving given optimization problem, Quasi-Newton optimization technique is used. Numerical examples and comparisons with several existing methods are included to show the performances and effectiveness of this method. An application of the proposed method is considered in the area of subband coding of the images.

Single CCII-based voltage-mode universal filter

Abstract: A new voltage-mode universal biquad filter is presented which can realize all the five standard filter functions namely lowpass, bandpass, highpass, notch, and allpass employing only one CCII as active element. The new circuit is composed of only one CCII, two capacitors, and three resistors, and realizes five generic filter signals without any inverting-type voltage input signals. This is unlike biquad reported by filter structures which employs more active components and needed an inverting-type voltage input signal to realize allpass signal.

A fifth-order 880MHz/1.76GHz active lowpass filter for 60GHz communications in 40nm digital CMOS

Abstract: For the analog baseband section of a 60GHz receiver for fast download applications, two 5th order Butterworth filters with cutoff frequency of 880MHz and 1.76GHz for 60GHz radios are implemented in 40nm low power digital CMOS, using Sallen and Key biquads. Drawing 25/21mA from a 1.1V supply, an IIP3 of −13/−12dBV to −16.7/−18.3dBV and an input-referred noise of 320/280µVrms are measured for the 880/1760MHz filter.

Miniaturised microstrip lowpass filter with broad stopband and sharp roll-off

Abstract: A novel miniaturised microstrip lowpass filter has been studied. With triangular and high-low impedance resonators symmetrically loaded, the proposed filter has successfully achieved size reduction and performance enhancement simultaneously. A demonstrator filter with 3 dB cutoff frequency at 1.5 GHz has been designed, fabricated and measured. Results show that a roll-off of 257 dB/GHz together with a relative stopband bandwidth of 157.4% can be obtained while achieving a high figure-of-merit of 38747.

A Compact Design of High-Power Spurious-Free Low-Pass Waveguide Filter

Abstract: In this letter, a new technique is proposed for the design of a compact high-power low-pass rectangular waveguide filter with a wide spurious-free frequency behavior. Specifically, the new filter is intended for the suppression of the fundamental mode over a wide band in much higher power applications than the classical corrugated filter with the same frequency specifications. Moreover, the filter length is dramatically reduced when compared to alternative techniques previously considered.

A Coplanar Stripline Ultra-Wideband Bandpass Filter With Notch Band

Abstract: In this letter, a design of a compact coplanar stripline ultra-wideband bandpass filter with a narrow rejection band is reported. The filter characteristic is obtained by using stepped impedance open-circuited series stubs. It is shown that the rejection band can be placed at a desired frequency by tuning the width of the high impedance section of the series stub. Full-wave simulated and experimental results of a filter prototype are presented.

Design of Miniaturized Microstrip Dual-Mode Filter With Source-Load Coupling

Abstract: A miniaturized microstrip dual-mode filter with different responses is developed in this letter. A coupling and routing scheme is presented to model the operations of this filter. The new filter reduces the occupied area up to 33% compared with the conventional one at 1.89 GHz. Meanwhile, the proposed circuit enables the second harmonic response to be effectively suppressed. A demonstrator filter is designed and validated with good agreement between the full-wave electromagnetic simulations and measurements.

Towards the realization of fractional step filters

Abstract: In this paper we propose a fractional lowpass transfer function of the order (n + α) where n is an integer and 0 < α < 1. We show how this filter can be designed using an integer-order transfer function approximation of the fractional-order Laplacian operator sα. A 1st order lowpass filter with fractional steps from 0.1 to 0.9, that is of order 1.1 to 1.9 is given as an example with its characteristics compared to 1st and 2nd order Butterworth filters. PSPICE simulations and experimental results of a prototype filter verify the operation of the fractional step filter.

Compact lowpass filter with wide stopband using modified semi-elliptic and semi-circular microstrip patch resonator

Abstract: A compact microstrip lowpass filter based on a novel patch resonator is reported. The novel semi-circle and semi-ellipse patch resonators are loaded by rhomboid and delta-stub structures, respectively. The filter consists of three cascaded microstrip patch resonators with different dimensions. The stopband with an attenuation level better than -20 dB is obtained from 3.68 up to 19 GHz. The proposed filter has low insertion loss in the passband, sharp, high and wide rejection in the stopband, and compact size. The filter is optimally designed, fabricated and measured. Simulation and measurement results are presented and compared and good agreement with the response of simulation and measurement is demonstrated.

14.4 nW fourth-order bandpass filter for biomedical applications

Abstract: A bandpass biquad with ultra low power consumption suitable for biomedical applications is proposed. In this biquad, one zero and two complex poles are synthesised in a single differential stage. An all-PMOS fourth-order Butterworth prototype comprising two such biquads has been fabricated in 0.18 μm CMOS process. The measured passband is from 523 to 1024 HZ, and it consumes only 14.4 nA under 1.0 V supply voltage. 1% THD is achieved with 80 mVpp input, along with 50 μVrms input-referred noise yielding a dynamic range of 55 dB.

Design of a K-Band Chip Filter With Three Tunable Transmission Zeros Using a Standard 0.13- $\mu\hbox{m}$ CMOS Technology

Abstract: A novel bandpass filter (BPF), which is fabricated with a commercial CMOS process, demonstrating a low insertion loss in the passband and multiple transmission zeros in stopbands, is presented for 24-GHz automotive ultrawideband (UWB) radar systems. The filter combines a second-order asymmetrically compact resonator filter with a source-load coupling mechanism to realize three transmission zeros; two zeros are arranged in the lower stopband, and one zero is located in the upper stopband. To achieve a compact layout size and a low insertion loss, a semilumped approach, which is accomplished with mixed utilization of high-impedance coplanar waveguide lines and lumped capacitors, is used to construct the chip filter. A K-band experimental prototype that has a very compact size of 0.35 × 0.8 mm2 was realized. The average insertion loss in the filter's passband is about 2.7 dB, the return loss is greater than 15 dB within the frequencies of 24-27.5 GHz, and the attenuation levels at the three transmission zeros all greater than 35 dB.

Coherence-Free Microwave Photonic Bandpass Filter Using a Frequency-Shifting Recirculating Delay Line

Abstract: A new microwave photonic filter that realizes a high-resolution bandpass filter response with coherence-free operation and without the limitations of phase-induced intensity noise is presented in this paper. It is based on a frequency-shifting recirculating delay line, which can simultaneously achieve a multitap, high-resolution filter and a very large suppression of noise, while also enabling the use of a conventional narrow-linewidth laser source without suffering from coherent interference effects. Experimental results demonstrate a filter Q value of 200 and an SNR improvement of 40.3 dB compared to conventional recirculating delay line structures.

Component value selection for analog active filter using particle swarm optimization

Abstract: In this work, a PSO based component value selection method is proposed for analog active filter. PSO is an efficient intelligent evolutionary algorithm for solving optimization problems. The aim of this work is to minimize the total design error of a 4th order Butterworth low pass active filter that would be realized with component values which are compatible with E12 series. PSO provides a maximally flat response in the pass band and achieves smaller design error compared with previous methods.

Design of a new bandpass filter with sharp transition band using multilayer-technique and U-defected ground structure

Abstract: A novel compact microstrip bandpass filter with sharp rejection bands is proposed. The proposed filter structure is composed of U-shape microstrip resonators, ‘U-strip’, backed by similarly shaped U-slots ‘U-defected ground structure’ (U-DGS). By controlling the electrical coupling between the U-strip and the U-DGS, the bandpass filter's stopband is optimised for better rejection. The proposed filter has low insertionloss and compact size because of the slow-wave effect. Meanwhile, sharp rejection bands induced by the presence of two transmission zeros on both sides of its passband are achieved. The measured centre frequency, bandwidth and passband insertion loss are 3.6 GHz, 40% and 0.5 dB, respectively. The simulated and measured results show good agreement and validate the proposed approach.