scispace - formally typeset
Search or ask a question

Showing papers on "Voltage-controlled filter published in 2013"


Journal ArticleDOI
TL;DR: In this paper, a commonmode (CM) filter based on the LCL filter topology is proposed, which provides a parallel path for ground currents and also restricts the magnitude of the EMI noise injected into the grid.
Abstract: A common-mode (CM) filter based on the LCL filter topology is proposed in this paper, which provides a parallel path for ground currents and which also restricts the magnitude of the EMI noise injected into the grid. The CM filter makes use of the components of a line to line LCL filter, which is modified to address the CM voltage with minimal additional components. This leads to a compact filtering solution. The CM voltage of an adjustable speed drive using a PWM rectifier is analyzed for this purpose. The filter design is based on the CM equivalent circuit of the drive system. The filter addresses the adverse effects of the PWM rectifier in an adjustable speed drive. Guidelines are provided on the selection of the filter components. Different variants of the filter topology are evaluated to establish the effectiveness of the proposed circuit. Experimental results based on EMI measurement on the grid side and the CM current measurement on the motor side are presented. These results validate the effectiveness of the filter.

112 citations


Journal ArticleDOI
TL;DR: In this article, a dual-band bandpass filter with controllable frequencies and bandwidths as well as a high out-of-band rejection level is presented, which utilizes a stub-loaded quad-mode resonator.
Abstract: This letter presents a novel dual-band bandpass filter with controllable frequencies and bandwidths as well as a high out-of-band rejection level. The proposed filter utilizes a novel stub-loaded quad-mode resonator. Every two modes, which can be flexibly controlled, are utilized to form a passband with controllable frequency and bandwidth. Source-load coupling and hook-shape feed lines are introduced and high selectivity is achieved. An experimental filter is implemented and the experimental results are presented for validation.

83 citations


Journal ArticleDOI
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


Patent
23 Jan 2013
TL;DR: In this article, the RF filter is coupled to receive a pulsed output voltage from the RF switching converter and a supply voltage from a low-drop out (LDO) regulation circuit.
Abstract: This disclosure relates to radio frequency (RF) power converters and methods of operating the same. In one embodiment, an RF power converter includes an RF switching converter, a low-drop out (LDO) regulation circuit, and an RF filter. The RF filter is coupled to receive a pulsed output voltage from the RF switching converter and a supply voltage from the LDO regulation circuit. The RF filter is operable to alternate between a first RF filter topology and a second RF filter topology. In the first RF filter topology, the RF filter is configured to convert the pulsed output voltage from a switching circuit into the supply voltage. The RF filter in the second RF filter topology is configured to filter the supply voltage from the LDO regulation circuit to reduce a ripple variation in a supply voltage level of the supply voltage. As such, the RF filter provides greater versatility.

68 citations


Patent
06 Jun 2013
TL;DR: In this article, a direct current (DC)-DC converter that includes a first switching converter and a multi-stage filter is disclosed, which includes at least a first inductance (L) capacitance (C) filter and a second LC filter coupled in series between the first switching converters and a DC-DC converter output.
Abstract: A direct current (DC)-DC converter that includes a first switching converter and a multi-stage filter is disclosed. The multi-stage filter includes at least a first inductance (L) capacitance (C) filter and a second LC filter coupled in series between the first switching converter and a DC-DC converter output. The first LC filter has a first LC time constant and the second LC filter has a second LC time constant, which is less than the first LC time constant. The first switching converter and the multi-stage filter form a feedback loop, which is used to regulate the first switching power supply output signal based on the setpoint. The first LC filter includes a first capacitive element having a first self-resonant frequency, which is about equal to a first notch frequency of the multi-stage filter.

68 citations


Journal ArticleDOI
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


Journal ArticleDOI
TL;DR: A new type of a passive filter, called hybrid LC filter, is proposed, based on design guidelines for the passive LC filters, and simulation and test results of the proposed filter in time and frequency domains are shown.
Abstract: This paper provides design guidelines for the passive LC filters Based on these guidelines, a method to design a new type of a passive filter, called hybrid LC filter, is proposed A filter design example accompanies the considerations; simulation and test results of the proposed filter in time and frequency domains are shown

67 citations


Journal ArticleDOI
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


Patent
Nadim Khlat1
26 Jul 2013
TL;DR: In this paper, a radio frequency (RF) notch filter is coupled between the parallel amplifier output and a ground, which is based on an RF duplex frequency and has a selectable notch frequency.
Abstract: A parallel amplifier (14), a switching supply (12), and a radio frequency (RF) notch filter (18) are disclosed. The parallel amplifier has a parallel amplifier output, such that the switching supply is coupled to the parallel amplifier output. Further, the RF notch filter is coupled between the parallel amplifier output and a ground. The RF notch filter has a selectable notch frequency, which is based on an RF duplex frequency.

60 citations


Journal ArticleDOI
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


Journal ArticleDOI
TL;DR: This paper presents a possible usage of the voltage differencing transconductance amplifier (VDTA) for the design of an electronically tunable single-input five-output voltage-mode universal filter.
Abstract: This paper presents a possible usage of the voltage differencing transconductance amplifier (VDTA) for the design of an electronically tunable single-input five-output voltage-mode universal filter. The presented filter is constructed using two VDTAs, two capacitors and two resistors that are all grounded. The circuit simultaneously realizes lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass (AP) filtering responses, without changing the circuit topology. The circuit is capable of providing an independent electronic control of the natural angular frequency (ω 0) and the quality factor (Q) through the transconductance gains of the VDTAs. By simply adjusting the transconductance ratio, a high-Q filter can also be obtained. Because of the high-input impedance of the circuit, it is advantageous for cascade connection. To support the theoretical analysis, the properties of the designed filter have been verified by PSPICE simulation results.

Journal ArticleDOI
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.

Patent
23 Jan 2013
TL;DR: In this paper, the RF filter is coupled to receive a pulsed output voltage from the RF switching converter and a supply voltage from a low-drop out (LDO) regulation circuit.
Abstract: This disclosure relates to radio frequency (RF) power converters and methods of operating the same. In one embodiment, an RF power converter includes an RF switching converter, a low-drop out (LDO) regulation circuit, and an RF filter. The RF filter is coupled to receive a pulsed output voltage from the RF switching converter and a supply voltage from the LDO regulation circuit. The RF filter is operable to alternate between a first RF filter topology and a second RF filter topology. In the first RF filter topology, the RF filter is configured to convert the pulsed output voltage from a switching circuit into the supply voltage. The RF filter in the second RF filter topology is configured to filter the supply voltage from the LDO regulation circuit to reduce a ripple variation in a supply voltage level of the supply voltage. As such, the RF filter provides greater versatility.

Journal ArticleDOI
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.

Journal ArticleDOI
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.

Journal ArticleDOI
TL;DR: In this paper, a dual output low-pass and band-pass filter using only six MOSFET transistors in its core is presented, which exhibits important features such as simplicity, lowvoltage/power operation, reduced chip area and wide frequency range compared to classical analog circuits that require active elements with large number of transistors.
Abstract: In this study, a current-mode dual output low-pass and band-pass filter is presented using only six MOSFET transistors in its core. Transconductances and gate-to-source capacitances of the MOS transistors are employed instead of passive resistors and capacitors. The proposed circuit exhibits important features such as simplicity, low-voltage/power operation, reduced chip area and wide frequency range compared to classical analog circuits that require active elements with large number of transistors. Simulations are performed to verify the theoretical results.

Journal ArticleDOI
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.

Journal ArticleDOI
TL;DR: In this paper, a recursive second-order Volterra (RSOV) filter is proposed to solve the problems of signal saturation and other nonlinear distortions that occur in nonlinear active noise control systems.

Journal ArticleDOI
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.

Journal ArticleDOI
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.

Journal ArticleDOI
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...

Book ChapterDOI
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.

Journal ArticleDOI
TL;DR: An electronically tunable universal voltage-mode biquadratic filter with single input and five outputs is introduced, which provides an orthogonal electronic control of its natural angular frequency and quality factor by adjusting only bias currents of the DDCCTAs for the fixed values of capacitors.

Proceedings ArticleDOI
27 Sep 2013
TL;DR: A digital infinite-impulse response (IIR) filter design is proposed and an implementation and evaluation of butter worth low pass infinite impulse response filter method to remove high frequency noise is applied to noisy ECG data sample.
Abstract: Electrocardiogram (ECG) signal has been widely used in cardiac pathology to detect heart disease. A digital infinite-impulse response (IIR) filter design is proposed in this paper. This includes an implementation and evaluation of butter worth low pass infinite impulse response filter method to remove high frequency noise and for this filter is applied to noisy ECG data sample and original sample are taken as reference signal. The suggested method considers the magnitude response for choosing the cutoff frequency and the FFT spectrum estimate response to find the lowest filter order. The structure and the coefficients of the digital IIR filter are designed using FDA tool in MATLAB. The filter output's average power before and after filtration are calculated using FFT and for simulation of this filter, the hardware is designed using micro controller At mega 16 A. For hardware designing the samples taken are record no. 108 and record no. 119 (taken from MIT-BIH database, ML II signal). Here samples are taken from MIT-BIH arrhythmia database (mitdb) ML II are used.

Journal ArticleDOI
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.

Journal ArticleDOI
TL;DR: An electronically tunable mixed mode universal filter based on multiple output current controlled current conveyor (MOCCCII) and this single topology without any alteration can be used in all four modes i.e., voltage, current, transimpedance and transadmittance.
Abstract: The configuration with electronic tunable characteristics that can work in mixed mode may be useful from IC realization viewpoint and application adaptability. This paper proposes an electronically tunable mixed mode universal filter based on multiple output current controlled current conveyor (MOCCCII) and this single topology without any alteration can be used in all four modes i.e., voltage (VM), current (CM), transimpedance (TIM) and transadmittance (TAM). The architecture uses four MOCCCIIs and two grounded capacitors; and can realize universal filter functions — low pass (LP), band pass (BP), high pass (HP), notch (NF) and all pass (AP) for all four modes. Moreover the input impedance is high and output impedance is low for voltage signal and vice-versa for current signal, hence the proposed topology is suitable for cascading for all four modes. The workability of the proposed circuit has been verified via SPICE simulations using AMS 0.35 μm CMOS technology.

Journal ArticleDOI
TL;DR: The proposed CDCTA simplifies the design of the current-mode filter circuit considerably, especially the designof high-order filter, and a current- mode nth-orderfilter based on the CDCTa is proposed in the paper.
Abstract: In this paper, a new active device, current differencing cascaded transconductance amplifier (CDCTA), has been presented. The proposed CDCTA simplifies the design of the current-mode filter circuit considerably, especially the design of high-order filter. Moreover, a current-mode nth-order filter based on the CDCTA is proposed in the paper. The proposed circuit, which adopts only an active component and n grounded capacitors, contains minimal active component and passive one. It enjoys the simple configuration and is suitable for integrated circuit (IC) fabrication. PSpice simulations for current-mode third-order filter based on this structure have also been conducted, and the results are in good agreement with the theoretical analysis. The influences of the CDCTA non-idealities are also discussed.

Journal ArticleDOI
TL;DR: In this paper, a microstrip low-pass filter was proposed that exhibits an quasi-elliptical function response with high out-of-band rejection for integration in ultra-wideband (UWB) chipless RFID receivers.
Abstract: A novel compact microstrip lowpass filter is described that exhibits an quasi-elliptical function response with high out-of-band rejection for integration in ultra-wideband (UWB) chipless radio frequency identification (RFID) receivers. The filter's characteristics include a wide-stopband and low passband insertion loss with a passband ripple of 0.03 dB. Out-of-band attenuation of 30 dB is achieved up to about four times the cutoff frequency (4f c), and 20 dB up to about seven times the cutoff frequency (7f c). In addition, the proposed filter structure offers a high figure-of-merit of 8657 that exceeds the lowpass planar filters with an equal cutoff frequency reported in the literature to date.

Journal ArticleDOI
TL;DR: A new adaptive filter algorithm is developed that uses a penalty function formulation to place multiple constraints on the filter directly in the frequency domain, and performs better than existing ones in terms of improved convergence rate and frequency-selective limiting.
Abstract: This article develops a new adaptive filter algorithm intended for use in active noise control systems where it is required to place gain or power constraints on the filter output to prevent overdriving the transducer, or to maintain a specified system power budget. When the frequency-domain version of the least-mean-square algorithm is used for the adaptive filter, this limiting can be done directly in the frequency domain, allowing the adaptive filter response to be reduced in frequency regions of constraint violation, with minimal effect at other frequencies. We present the development of a new adaptive filter algorithm that uses a penalty function formulation to place multiple constraints on the filter directly in the frequency domain. The new algorithm performs better than existing ones in terms of improved convergence rate and frequency-selective limiting.

Journal ArticleDOI
TL;DR: This paper proposes current controlled differential difference current conveyor transconductance amplifier (CCDDCCTA), a new active building block for analog signal processing and demonstrates the usefulness of the proposed element through an application, namely, wave filter.
Abstract: This paper proposes current controlled differential difference current conveyor transconductance amplifier (CCDDCCTA), a new active building block for analog signal processing. The functionality of the proposed block is verified via SPICE simulations using 0.25 μm TSMC CMOS technology parameters. The usefulness of the proposed element is demonstrated through an application, namely, wave filter. The CCDDCCTA-based wave equivalents are developed which use grounded capacitors and do not employ any resistors. The flexibility of terminal characteristics is utilized to suggest an alternate wave equivalents realization scheme which results in compact realization of wave filter. The feasibility of CCDDCCTA-based wave active filter is confirmed through simulation of a third-order Butterworth filter. The filter cutoff frequency can be tuned electronically via bias current.