Showing papers on "Butterworth filter published in 2013"
TL;DR: This paper presents a general procedure to obtain Butterworth filter specifications in the fractional-order domain where an infinite number of relationships could be obtained due to the extra independent fractional -order parameters which increase the filter degrees-of-freedom.
Abstract: This paper presents a general procedure to obtain Butterworth filter specifications in the fractional-order domain where an infinite number of relationships could be obtained due to the extra independent fractional-order parameters which increase the filter degrees-of-freedom. The necessary and sufficient condition for achieving fractional-order Butterworth filter with a specific cutoff frequency is derived as a function of the orders in addition to the transfer function parameters. The effect of equal-orders on the filter bandwidth is discussed showing how the integer-order case is considered as a special case from the proposed procedure. Several passive and active filters are studied to validate the concept such as Kerwin-Huelsman-Newcomb and Sallen-Key filters through numerical and Advanced Design System (ADS) simulations. Moreover, these circuits are tested experimentally using discrete components to model the fractional order capacitor showing great matching with the numerical and circuit simulations.
172 citations
TL;DR: A design methodology for synthesis of active N-path bandpass filters is introduced and a 0.1-to-1.2 GHz tunable 6th-order N- path channel-select filter in 65 nm LP CMOS is introduced, achieving a “flat” passband shape and high out-of-band linearity.
Abstract: A design methodology for synthesis of active N-path bandpass filters is introduced. Based on this methodology, a 0.1-to-1.2 GHz tunable 6th-order N-path channel-select filter in 65 nm LP CMOS is introduced. It is based on coupling N-path filters with gyrators, achieving a “flat” passband shape and high out-of-band linearity. A Miller compensation method is utilized to considerably improve the passband shape of the filter. The filter has 2.8 dB NF, +25 dB gain, +26 dBm wideband IIP3 ( MHz), an out-of-band 1 dB blocker compression point B1dB,CP of +7 dBm (Δf = +50 MHz) and 59 dB stopband rejection. The analog and digital part of the filter draw 11.7 mA and 3-36 mA from 1.2 V, respectively. The LO leakage to the input port of the filter is ≤-64 dBm at a clock frequency of 1 GHz. The proposed filter only consists of inverters, switches and capacitors and therefore it is friendly with process scaling.
156 citations
01 Jan 2013
TL;DR: In this paper, the authors introduce principles of the finite impulse response (FIR) filter design and investigate the design methods such as the Fourier transform method, window method, frequency sampling method, and optimal design method.
Abstract: This chapter introduces principles of the finite impulse response (FIR) filter design and investigates the design methods such as the Fourier transform method, window method, frequency sampling method, and optimal design method. Then the chapter illustrates how to apply the designed FIR filters to solve real-world problems such as noise reduction and digital crossover for audio applications.
95 citations
TL;DR: In this paper, a co-design configuration of a power amplifier in cascade with a high-Q bandpass filter is reported, which leads to smaller size/volume, minimized loss, and enhanced overall performance.
Abstract: This paper reports the first co-design configuration of a power amplifier (PA) in cascade with a high- Q bandpass filter. By matching the filter's input port directly to the transistor's drain node, the conventional output matching network (OMN) of a PA is entirely eliminated. This leads to smaller size/volume, minimized loss, and enhanced overall performance. To enable this co-design method, the matching-filter synthesis theory is proposed and investigated in detail in this paper. Based on this theory, a 3% bandwidth (centered at 3.03 GHz) two-pole filter, implemented using high- Q evanescent-mode cavity resonators, is designed as the PA OMN to provide optimized fundamental and harmonic impedances for a commercial 10-W GaN transistor. Simulation and measured results show that the co-designed PA-filter module yields a desired Chybeshev filter behavior while maintaining excellent PA performance in the passband with 72% efficiency, 10-W output power, >10-dB gain, and 60-dBm output third-order intercept point. This co-designed module experimentally presents a 8% higher overall efficiency compared to a control group developed using a conventional independent PA and filter, which further validates the effectiveness of this method.
71 citations
TL;DR: In this paper, a general coupled-inductive filter block is described and a brief history of its application starting with the earliest known version of the circuit, which dates back to a 1923 patent application.
Abstract: Coupled-magnetics and coupled-inductor filters provide smoothing in a power converter by steering ripple current away from the “quite port.” While this concept is not new, topologies claiming to be “new” or “novel” continue to be reported in the literature, suggesting that the ripple-steering phenomenon may not be well understood to be a property of the filter block itself. This paper describes a general coupled-inductor filter block and presents a brief history of its application starting with the earliest known version of the circuit, which dates back to a 1923 patent application. The coupled-inductor circuit model is reviewed, starting with the basic topology and ideal circuit elements. Real circuit elements are then considered along with the effects of equivalent series resistance and other parasitic elements. A circuit-based filtering approach is used to emphasize the filtering aspect of the coupled inductor. It will be seen that the coupled-inductor filter can exhibit a low pass with notch frequency response. This provides the ability to achieve extra attenuation at a particular frequency, such as the converter switching frequency, which can reduce the overall filtering burden without adding extra inductive components. When the filter components are treated as a functional circuit group, instead of an interconnection of inductors and capacitors, the coupled-inductor filter can be analyzed as a drop-in replacement wherever a smoothing choke would normally be used and does not depend on converter voltage waveforms. A topology transformation of the Cuk converter shows that “zero ripple” in not a special property of the topology, but can be achieved using the coupled-inductor filter block.
67 citations
TL;DR: Numerical simulations show that the proposed WFR filter can achieve the same performance as that obtained using the conventional least squares method, but has many advantages in filter design, filter size, computational cost, and filter stability over the transform filter designed by the LS method.
Abstract: For transmission of a physical sound field in a large area, it is necessary to transform received signals of a microphone array into driving signals of a loudspeaker array to reproduce the sound field. We propose a method for transforming these signals by using planar or linear arrays of microphones and loudspeakers. A continuous transform equation is analytically derived based on the physical equation of wave propagation in the spatio-temporal frequency domain. By introducing spatial sampling, the uniquely determined transform filter, called a wave field reconstruction filter (WFR filter), is derived. Numerical simulations show that the WFR filter can achieve the same performance as that obtained using the conventional least squares (LS) method. However, since the proposed WFR filter is represented as a spatial convolution, it has many advantages in filter design, filter size, computational cost, and filter stability over the transform filter designed by the LS method.
66 citations
TL;DR: This study investigated the effect of various standard filters on the morphology and measurement of extracellular gastric slow waves.
Abstract: Background Extracellular recordings are used to define gastric slow wave propagation. Signal filtering is a key step in the analysis and interpretation of extracellular slow wave data; however, there is controversy and uncertainty regarding the appropriate filtering settings. This study investigated the effect of various standard filters on the morphology and measurement of extracellular gastric slow waves.
Methods Experimental extracellular gastric slow waves were recorded from the serosal surface of the stomach from pigs and humans. Four digital filters: finite impulse response filter (0.05–1 Hz); Savitzky-Golay filter (0–1.98 Hz); Bessel filter (2–100 Hz); and Butterworth filter (5–100 Hz); were applied on extracellular gastric slow wave signals to compare the changes temporally (morphology of the signal) and spectrally (signals in the frequency domain).
Key Results The extracellular slow wave activity is represented in the frequency domain by a dominant frequency and its associated harmonics in diminishing power. Optimal filters apply cutoff frequencies consistent with the dominant slow wave frequency (3–5 cpm) and main harmonics (up to ∼2 Hz). Applying filters with cutoff frequencies above or below the dominant and harmonic frequencies was found to distort or eliminate slow wave signal content.
Conclusions & Inferences Investigators must be cognizant of these optimal filtering practices when detecting, analyzing, and interpreting extracellular slow wave recordings. The use of frequency domain analysis is important for identifying the dominant and harmonics of the signal of interest. Capturing the dominant frequency and major harmonics of slow wave is crucial for accurate representation of slow wave activity in the time domain. Standardized filter settings should be determined.
64 citations
TL;DR: The design results included in the paper clearly show the improvement of the proposed PSO technique over earlier reported results.
Abstract: In this paper, a new particle swarm optimization (PSO) based method is proposed for the design of a two-channel linear phase quadrature mirror filter (QMF) bank in frequency domain. The origional particle swarm optimization technique is modified by introducing the concept of Scout Bee from Artificial Bee Colony (ABC) technique for designing a low pass prototype filter having ideal filter characteristics in the passband and stopband regions, and its magnitude response at quadrature frequency is 0.707. The design problem is formulated as a linear combination of passband error and residual stop band energy of the low pass filter, and the square error of the overall transfer function of the QMF bank at the quadrature frequency π/2, in the transition band. The design results included in the paper clearly show the improvement of the proposed PSO technique over earlier reported results.
61 citations
TL;DR: In this article, a fluidic-based approach for designing tunable coupled resonator bandpass filters is presented, which employs broadside coupled split ring resonators (SRR) with one of their open loop resonators constructed from liquid metal.
Abstract: A fluidic-based approach for designing tunable coupled resonator bandpass filters is presented. These filters employ broadside coupled split ring resonators (BC-SRR) with one of their open loop resonators constructed from liquid metal. The tuning mechanism is based on dynamically moving the liquid metal to reshape the resonator. To demonstrate the concept, a second order Butterworth filter with continuous tuning range from 650 to 870 MHz is designed and experimentally verified by utilizing PTFE tubing filled with liquid metal and Teflon solution. Due to an inductive external coupling mechanism and 180° rotated resonators, the filter exhibits a near constant 5% fractional bandwidth throughout its tuning range with > 10 dB return and <; 3 dB insertion loss. The filter is realized over a 1.27 mm thick Rogers 6010.2LM substrate and has an approximate footprint of 20 × 40 mm2.
58 citations
TL;DR: This paper demonstrates a design of a frequency-agile bandstop-to-bandpass switchable filter that is composed of tunable substrate-integrated cavity resonators and can be switched to have either a bandstop or bandpass response.
Abstract: In this paper, we show a new bandstop filter circuit topology. Unlike conventional bandstop filter circuit topologies, the new circuit topology has inter-resonator coupling structures. The presence of these inter-resonator coupling structures enables convenient switching from a bandstop to a bandpass filter. Using the new bandstop filter topology, this paper demonstrates a design of a frequency-agile bandstop-to-bandpass switchable filter. The filter is composed of tunable substrate-integrated cavity resonators and can be switched to have either a bandstop or bandpass response. Switching is achieved by turning on and off switches placed within the filter structure. A prototype of the proposed design is fabricated and the concept is verified experimentally.
57 citations
TL;DR: In this article, a waveguide 3rd order bandpass filter was designed and fabricated using SU8 photoresist technology, and tested and presented, with a 53.7 GHz 3-dB bandwidth at a central frequency of 671 GHz.
Abstract: A WR-1.5 band (500-750 GHz) waveguide 3rd order bandpass filter has been designed, fabricated, using SU8 photoresist technology, tested and presented. The filter is composed of three silver-coated SU8 layers, each of the same nominal thickness of 191 μm. This filter structure is based on three offset resonators. This novel structure is ideally suitable for the layered SU8 micromachining process. The filter exhibits a 53.7 GHz 3-dB bandwidth at a central frequency of 671 GHz. The median passband insertion loss is measured to be 0.65 dB and the return loss is better than 11 dB over the whole passband.
TL;DR: The design of an operational transconductance amplifier-C (OTA-C) low-pass filter for a portable Electrocardiogram (ECG) detection system is presented, based on a novel class AB digitally programmable fully differential OTA circuit.
Abstract: This paper presents the design of an operational transconductance amplifier-C (OTA-C) low-pass filter for a portable Electrocardiogram (ECG) detection system. A fifth-order Butterworth filter using ladder topology is utilized to reduce the effect of component tolerance and to provide a maximally flat response. The proposed filter is based on a novel class AB digitally programmable fully differential OTA circuit. Based on this, PSPICE simulation results for the filter using 0.25-μm technology and operating under ±0.8 V voltage supply are also given. The filter provides a third harmonic distortion (HD3) of 53.5 dB for 100 mV p-p @50 Hz sinusoidal input, input referred noise spectral density of , total power consumption of 30 μW, and a bandwidth of 243 Hz. These results demonstrate the ability of the filter to be used for ECG signal filtering that is located within 150 Hz.
TL;DR: An optoelectronic oscillator (OEO) with wideband frequency tunability and stable output based on a bandpass microwave photonic filter (MPF) has been proposed and experimentally demonstrated.
Abstract: An optoelectronic oscillator (OEO) with wideband frequency tunability and stable output based on a bandpass microwave photonic filter (MPF) has been proposed and experimentally demonstrated. Realized by cascading a finite impulse response (FIR) filter and an infinite impulse response (IIR) filter together, the tunable bandpass MPF successfully replaces the narrowband electrical bandpass filter in a conventional single-loop OEO and serves as the oscillating frequency selector. The FIR filter is based on a tunable multi-wavelength laser and dispersion compensation fiber (DCF) while the IIR filter is simply based on an optical loop. Utilizing a long length of DCF as the dispersion medium for the FIR filter also provides a long delay line for the OEO feedback cavity and as a result, optical tuning over a wide frequency range can be achieved without sacrificing the quality of the generated signal. By tuning the wavelength spacing of the multi-wavelength laser, the oscillation frequency can be tuned from 6.88 GHz to 12.79 GHz with an average step-size of 0.128 GHz. The maximum frequency drift of the generated 10 GHz signal is observed to be 1.923 kHz over 1 hour and its phase noise reaches the -112 dBc/Hz limit of our measuring equipment at 10 kHz offset frequency.
TL;DR: In this paper, a voltage-mode (VM) multi-input-single-output (MISO) universal filter was proposed, which contains only single VDIBA, two capacitors, and one nMOS transistor, operated in triode region.
Abstract: To increase the universality of the recently introduced voltage differencing inverting buffered amplifier (VDIBA), this letter presents a new voltage-mode (VM) multi-input–single-output (MISO) universal filter. The proposed filter contains only single VDIBA, two capacitors, and one nMOS transistor, operated in triode region, and is used for resonance angular frequency tuning. Since in the structure no resistors are needed the filter can be classified as resistorless. The VM MISO filter compared with other active building block-based counterparts is very simple, it contains only few transistors, and has the smallest size area. Moreover, no component matching is required and it shows low sensitivity performance. The theoretical results are verified by SPICE simulations using TSMC 0.18 μm level-7 SCN018 CMOS process parameters with ±0.9 V supply voltages. In addition, the behavior of the proposed VM filter was also experimentally verified using commercially available integrated circuits OPA660 and AD830.
TL;DR: A new method is developed for the design of a low-pass prototype filter which minimizes the objective function by optimizing the filter taps weights using the Levenberg–Marquardt method and significantly reduces peak reconstruction error (PRE), error in passband, stopband and transition band.
Abstract: This paper presents an improved and efficient method for the design of a two-channel quadrature mirror filter (QMF) bank. In the proposed method, the filter bank design problem is formulated as a low-pass prototype filter design problem, whose responses in the passband and stopband are ideal and their filter coefficients value at quadrature frequency is 0.707. A new method is developed for the design of a low-pass prototype filter which minimizes the objective function by optimizing the filter taps weights using the Levenberg–Marquardt method. When compared with other existing algorithms, it significantly reduces peak reconstruction error (PRE), error in passband, stopband and transition band. Several design examples are included to show the increased efficiency and the flexibility of the proposed method over existing methods. An application of this method is considered in the area of subband coding of the ultrasound images.
TL;DR: In this article, a continuously varactor-tuned low-pass filter using microstrip stepped-impedance hairpin resonators is proposed, which not only provides a wide frequency tuning range of 46% from 1.60 to 2.94 GHz, but also offers an ability of selectivity controlling by using different applied voltages.
Abstract: A compact continuously varactor-tuned low-pass filter using microstrip stepped-impedance hairpin resonators is proposed in this paper. A detailed theoretical analysis for the performance tuning mechanism is illustrated by using equivalent circuit models. The experiment results are provided to validate the proposed filter. From the measured results, it is found that five varactor diodes with two applied bias voltages used in the proposed design work well as a flexible tuning network, which not only provide a wide frequency tuning range of 46% from 1.60 to 2.94 GHz, but also offer an ability of selectivity controlling by using different applied voltages. Furthermore, the proposed filter using multiple cascaded hairpin resonators provides a very sharp cutoff frequency response with low insertion loss in each state, together with a wide and deep stopband with a rejection level greater than 20 dB. Good agreement between the measured and simulated results can be observed finally.
TL;DR: In this article, the authors developed two techniques to reduce the parasitic parameters and improve the high-frequency performance of the planar integrated electromagnetic interference (EMI) filter, which can not only decrease the EPC, but also reduce the negative effect of ESL.
Abstract: This paper has developed two techniques to reduce the parasitic parameters and improve the high-frequency performance of the planar integrated electromagnetic interference (EMI) filter. First, each developed technique has been analyzed, respectively, then the performance of an EMI filter with both the developed techniques has been researched. The research contents are as follows. 1) Analyzing the improvement of the equivalent parallel capacitance (EPC) for a common mode (CM) EMI filter by two CM windings overlapped and interleaved layout. The EPC of the integrated EMI filter is about 14% of the reference EMI filter. 2) Analyzing the improvement of the equivalent series inductance (ESL) in the parallel branch for a CM EMI filter by each CM winding coupled with two ground winding layers. The resonance frequency brought by ESL is shifted to a higher frequency. At 30 MHz, the insertion loss is increased by 45 dB compared with the reference. In the mean time, the structure is equivalent to a two-stage L-type low-pass filter, which can largely increase the high-frequency attenuation compared with the one-stage L-type low-pass filter for the reference one. (3) Researching the performance of an EMI filter with both the proposed techniques. The developed EMI filter can not only decrease the EPC, but also reduce the negative effect of ESL. The developed EMI filter improves the high-frequency performance dramatically compared with the EMI filter with only one of the developed techniques. In the mean time, the differential mode (DM) capacitor is formed by the two overlapped and interleaved windings, and does not need an extra lumped DM capacitor. Therefore, CM inductors, CM capacitors, and DM capacitors can be integrated in the overlapped and interleaved L-C winding structure, so miniaturized EMI filter can be realized. The experiment results indicate effectiveness of the developed integrated EMI filters, and the cost and complexity is the same as the reference EMI filter.
28 Oct 2013
TL;DR: In this paper, a link passive filter of the power converters installed in a multi-megawatt wave power plant is designed based on the superposition of both LCL and trap filter configurations with the purpose of achieving enhanced grid interaction of a two-level voltage source converter.
Abstract: This paper presents a methodology for designing the link passive filter of the power converters installed in a multi-megawatt wave power plant. Such filter is based on the superposition of both LCL and trap filter configurations with the purpose of achieving enhanced grid interaction of a two-level voltage source converter. The LCL+Trap filter design is highly dependent on the electrical network characteristics; hence the distribution system of the plant is introduced in the paper to take into account its effects on the tuning parameters. The proposed LCL+trap filter topology arises as a successful alternative solution for the conventional LCL filter topology, thanks to its improved filtering capability while ensuring a reduced filter size. The validation of the proposed filter performance is evaluated in simulation by performing a comparative analysis between the LCL+trap and the LCL filters when operate in a wave farm application.
TL;DR: Christoffel-Darboux formula for Chebyshev continual orthogonal polynomials of the first kind is proposed to find a mathematical solution of approximation problem of a one-dimensional (1D) filter function in the z domain this article.
Abstract: Christoffel–Darboux formula for Chebyshev continual orthogonal polynomials of the first kind is proposed to find a mathematical solution of approximation problem of a one-dimensional (1D) filter function in the z domain. Such an approach allows for the generation of a linear phase selective 1D low-pass digital finite impulse response (FIR) filter function in compact explicit form by using an analytical method. A new difference equation and structure of corresponding linear phase 1D low-pass digital FIR filter are given here. As an example, one extremely economic 1D FIR filter (with four adders and without multipliers) is designed by the proposed technique and its characteristics are presented. Global Christoffel–Darboux formula for orthonormal Chebyshev polynomials of the first kind and for two independent variables for generating linear phase symmetric two-dimensional (2D) FIR digital filter functions in a compact explicit representative form, by using an analytical method, is proposed in this paper. The...
01 Nov 2013
TL;DR: A novel approach for addressing both the aforementioned issues in ECG signals employing sub-band decomposition using wavelets analysis and powerline suppression using one-dimensional structuring element is proposed.
Abstract: One of the major problems encountered in recording ECG is the appearance of unwanted distortions induced by power line interference in the electrocardiogram. In addition, infections due to impulse noise leads to variations in the amplitudes which represent the abnormalities associated with the heart. This paper proposes a novel approach for addressing both the aforementioned issues in ECG signals employing sub-band decomposition using wavelets analysis. Morphological filtering is applied to the detail sub-bands for removal of impulse noise using one-dimensional structuring element. Further, the powerline interference is removed using IIR Butterworth filter providing significant reduction in power spectral density levels between 50 to 60 Hz. The finally reconstructed ECG signal yields reasonably good impulse noise as well as powerline suppression using the proposed approach.
TL;DR: In this paper, a single-input multiple-outputs current-mode analog biquadratic filter based on current controlled current differencing transconductance amplifier (CCCDTA) is presented.
Abstract: In this study, a single-input multiple-outputs current-mode analog biquadratic filter, based on current controlled current differencing transconductance amplifier (CCCDTA) is presented. The proposed filter uses two CCCDTAs and two grounded capacitors without any external resistors, which is well suited for integrated circuit implementation. The filter simultaneously gives 3 standard transfer functions, namely, lowpass, highpass and bandpass filters with independent control of quality factor and pole frequency by electronic method. By summing of IHP and LLP, the notch filter can be also achieved. Moreover, the circuit has low input and high output impedance which would be an ideal choice for cascading in current-mode circuit. The PSPICE simulation results are included verifying the workability of the proposed filter. The given results agree well with the theoretical anticipation.
TL;DR: In this article, a waveguide bandpass filter with Chebyshev response was proposed, which has a center frequency of 300 GHz, a fractional bandwidth of 3.3% and a passband return loss of 20 dB.
Abstract: Presented is a WR-3 band (220–325 GHz) waveguide bandpass filter, which is constructed from three offset waveguide resonators operating at TE101 mode. This directly coupled resonator filter with Chebyshev response is designed to have a centre frequency of 300 GHz, a fractional bandwidth of 3.3% and a passband return loss of 20 dB. This filter is fabricated using thick SU-8 photoresist micromachining technique and has been tested. The measured average passband insertion loss is as low as around 0.4 dB. The measured return loss is better than 15 dB across the whole passband.
TL;DR: In this paper, a dual-band filter based on split-ring resonators (SRRs) and double-slit complementary SRRs is presented, where the basic cell of the filter is analyzed, and then the multistage dual-passband filter is achieved by cascading basic cells.
Abstract: A novel dual-band filter based on split-ring resonators (SRRs) and double-slit complementary SRRs is presented. The size of the filter is small and the two passbands can be individually designed. The basic cell of the filter is presented and analyzed, and then the multistage dual-passband filter is achieved by cascading basic cells. The design graphs for external quality factors of the resonators at input and output stages and the coupling coefficient between the adjacent resonators are constructed. The design graphs are utilized to determine the proper geometric parameters of each filter stage for a given filter specification. As an example, a prototype three-stage Chebyshev filter with a fractional bandwidth (FBW) of 2% at 0.9 GHz and a FBW of 3% at 1.3 GHz is demonstrated. The prototyped filter has an equal ripple of 0.4 dB at both passbands. The measurements of the prototyped filter agree well with the simulation results. The center frequencies and the FBWs of the two passbands of the prototyped filter can be individually designed with more flexibility compared to dual-band filters that utilize resonances of higher order modes. The overall size reduction of the proposed filter can be as high as by a factor of 3 compared to that of edge-coupled microstrip filters.
TL;DR: A novel first-order current-mode (CM) electronically tunable all-pass filter including one grounded capacitor and two dual-output current followers (DO-CFs) is presented, which satisfies all technology requirements such as small sizing, simple realization, low voltage and low power operation.
Abstract: In this paper, a novel first-order current-mode (CM) electronically tunable all-pass filter including one grounded capacitor and two dual-output current followers (DO-CFs) is presented. The used DO-CFs are implemented using only 10 MOS transistors granting the proposed CM all-pass filter extremely simple structure. The proposed filter is suitable for integrated circuit (IC) fabrication because it employs only a grounded capacitor and is free from passive component matching conditions. Interestingly the introduced configuration uses minimum number of components compared to other works. It also offers other interesting advantages such as, alleviating all disadvantages associated with the use of resistors, easy cascadability and satisfies all technology requirements such as small sizing, simple realization, low voltage and low power operation. Additionally, the circuit parameters can be easily set by adjusting control voltages. Most favorably, the proposed CM all-pass filter can be simply used as a voltage-m...
TL;DR: A novel miniaturization method for filter implementation is presented and validated that has the wideband bandpass response in the required frequency band which is lower than the operation frequency.
Abstract: In this paper, a novel miniaturization method for filter implementation is presented and validated. According to frequency response transformation, the filter structure has the wideband bandpass response in the required frequency band which is lower than the operation frequency. The in-band and out-of-band characteristics are also improved to realize wide passband and stopband responses. For demonstration, three filters are designed based on the proposed ideas. The efficient circuit area is reduced by 56.8%-64.7% compared with the conventional wideband filter, indicating significant miniaturization using the proposed method. Another advantage of our work is that the stopband is extended to more than 9f0 than other wideband filter structures. Good agreement between simulation and experiment is obtained.
01 Jan 2013
TL;DR: A concise, to-the-point, quick design technique is proposed to cover the vast majority of filter needs with as few op amps as possible.
Abstract: Active filters are one of the most common and useful applications for op amps. Traditional methods of filter design presented in previous texts focused on detailed mathematical analysis based on transfer equations. A concise, to-the-point, quick design technique is proposed to cover the vast majority of filter needs with as few op amps as possible. Although a truly universal filter design board is elusive, a small set of boards are introduced that will implement all filter responses. Filter design utilities are introduced to calculate those responses.
01 Jan 2013
TL;DR: It was found that the proposed methodology performs better as compared to earlier reported results in terms of reconstruction error, number of iteration (NOI) and computation time (CPU time).
Abstract: In this paper, an efficient iterative algorithm is proposed for the design of multi-channel nearly perfect reconstructed non-uniform filter bank. The method employs the constrained equiripple FIR technique to design the prototype filter for filter banks with novelty of exploiting a new perfect reconstruction condition of the non-uniform filter banks instead of using complex objective functions. In the proposed algorithm, passband edge frequency (@w"p) is optimized using linear optimization technique such that the filter coefficients values at quadrature frequency are approximately equal to 0.707. Several design examples are included to illustrate the efficacy of this methodology for designing non-uniform filter bank (NUFB). It was found that the proposed methodology performs better as compared to earlier reported results in terms of reconstruction error (RE), number of iteration (NOI) and computation time (CPU time). The proposed algorithm is very simple, linear in nature, and easy to implement.
TL;DR: In this paper, the authors describe the basics of frequency filter design method using synthetic immittance elements with current conveyors and present a design process of simple second-order low-pass and high-pass filter.
Abstract: The paper briefly describes the basics of frequency filter design method using synthetic immittance elements with current conveyors. An introduction of the paper explains the advantages and also disadvantages of using this method. Other chapters briefly introduce a design process of simple second order low-pass and high-pass filter. A theory of current conveyors is discussed too, because they are the basic building blocs of proposed synthetic element and also active frequency filters. Finally, the particular solutions of low-pass and high-pass filters are given and verified by OrCAD PSpice simulations.
TL;DR: In this paper, a single-pole group delay equalizer was also given to flatten a nonlinear phase quasi-elliptic filter's phase, which solved the tuning difficulty of the HTSC linear phase filter.
Abstract: A variety of miniature half-wave multizigzag resonators was given, and an eight-pole high-temperature superconductor (HTSC) quasi-elliptic filter with no cross-line was developed with these resonators. In this paper, a novel single-pole group delay equalizer was also given to flatten a nonlinear phase quasi-elliptic filter's phase, which solves the tuning difficulty of the HTSC linear phase filter. Moreover, it cannot only ensure that the finished HTSC filter has a good linear phase characteristic but also solve the integration of the linear phase filter with external equalization. Finally, on YBCO/LaAlO3/YBCO substrate with the dimension of 31.6 mm × 29.2 mm, a miniature eight-pole HTSC quasi-elliptic linear phase filter using external equalization is developed, where the center frequency is 2250.84 MHz, the bandwidth is 14 MHz, the best insertion loss in passband is 2.09 dB, and the return loss is better than 18.97 dB, as per measurements. In passband, the measured group delay response has a good agreement with the simulated response, and its variation is less than 50 ns over 78.5% of the filter bandwidth.
22 Feb 2013
TL;DR: The IIR digital notch filter method is used for industrial frequency interference filter and the algorithm deduced on the fixed-point DSP programming method and overflow handling problems made elaborate incisively in digital audio signal processing system has been applied.
Abstract: In this paper the AC power 50Hz power interference, we use IIR digital notch filter method for industrial frequency interference filter. From the design of IIR digital filter method proceed with, on the IIR digital notch filter simulation, the algorithm deduced, on the fixed-point DSP programming method and overflow handling problems made elaborate incisively, and in digital audio signal processing system has been applied.