Showing papers on "Voltage-controlled filter published in 2017"
TL;DR: In this paper, a series-parallel-resonant LCL (SPRLCL) filter for single-phase half-bridge active power filters is proposed, which consists of a series resonance introduced by adding a small inductor to the capacitor branch loop and a parallel resonance by paralleling a small capacitor with the gird-side inductor.
Abstract: This paper proposes a novel high-order passive filter, i.e., series-parallel-resonant LCL (SPRLCL) filter, for single-phase half-bridge active power filters. The proposed SPRLCL filter consists of a series resonance introduced by adding a small inductor to the capacitor branch loop and a parallel resonance by paralleling a small capacitor with the gird-side inductor. Three design methods are proposed to fine tune the parameters of the SPRLCL filter. Design method I and method II enable the SPRLCL filter to attenuate more switching-frequency and double switching-frequency current harmonics than LCL or LLCL filters, while with design method III, the SPRLCL filter can be more robust against filter parameter variations. In order to achieve a better damping performance and facilitate the design of active damping control, the dominant resonance frequency of the proposed filter is set at one-third of the system sampling frequency. Based on this, a comprehensive parameter design process of the SPRLCL filter is presented, where the variation of source inductance is also considered. A proportional plus repetitive current-loop controller is designed to ensure system control stability and satisfactory harmonic compensation. Simulation and experimental results are finally presented to validate the feasibility of the theoretical analysis.
96 citations
TL;DR: This paper explains how reconfigurable third-order FLF topology is used in order to approximate both FLPF and FHPF in concerned frequency band of interest.
Abstract: This paper presents design of electronically reconfigurable fractional-order filter that is able to be configured to operate as fractional-order low-pass filter (FLPF) or fractional-order high-pass filter (FHPF). Its slope of attenuation between pass band and stop band, i.e., order of the filter, is electronically adjustable in the range between 1 and 2. Also, pole frequency can be electronically controlled independently with respect to other tuned parameters. Moreover, particular type of approximation can be also controlled electronically. This feature set is available both for FLPF and FHPF-type of response. Presented structure of the filter is based on well-known follow-the-leader feedback (FLF) topology adjusted in our case for utilization with just simple active elements operational transconductance amplifiers (OTAs) and adjustable current amplifiers (ACAs), both providing possibility to control its key parameter electronically. This paper explains how reconfigurable third-order FLF topology is used in order to approximate both FLPF and FHPF in concerned frequency band of interest. Design is supported by PSpice simulations for three particular values of order of the filter (1.25, 1.5, 1.75), for several values of pole frequency and for two particular types of approximation forming the shape of both the magnitude and phase response. Moreover, theoretical presumptions are successfully confirmed by laboratory measurements with prepared prototype based on behavioral modeling.
48 citations
TL;DR: In this paper, a variation-aware and reliable design of a fully integrated radio frequency (RF) bandpass filter realized using a voltage differencing transconductance amplifier is presented, characterized by its high frequency operation, low power consumption, high quality factor, and it is insensitive to process, voltage, and temperature variations.
Abstract: In this paper, a variation-aware and reliable design of a fully integrated radio frequency (RF) bandpass filter realized using a voltage differencing transconductance amplifier is presented. The filter is characterized by its high frequency operation, low power consumption, high quality factor, and it is insensitive to process, voltage, and temperature variations. Sensitivity analysis has been performed to analyze the circuit performance in the presence of parasitics. The inductor-less approach finds its application in integrated building blocks of RF front ends, thus eliminating the requirement of off-chip filters in transceivers. Centered at 2.511 GHz and operating within the 36.21 MHz 3-dB bandwidth, the filter draws 0.168 mA from a ±1 V power supply, attains a voltage gain of 72.6 dB, a quality factor of 69.34 and noise figure of ~29.6 dB. In addition, it has a dynamic range of 125.84 dB-Hz and a 1-dB compression of −1.5 dBm which translates into a figure of merit as high as 94 dB.
31 citations
TL;DR: A five-inputs single −output voltage-mode universal biquadratic filter using active building block, namely voltage differencing differential difference amplifier (VDDDA) is presented and measured results agree well with theoretical expect.
30 citations
Journal Article•
TL;DR: The second order universal voltage-mode filter using voltage differencing differential difference amplifiers (VDDDAs) has been proposed in this article, which has high input impedance voltage mode biquad filter with orthogonal tune of natural frequency and quality factor.
Abstract: The second order universal voltage-mode filter using voltage differencing differential difference amplifiers (VDDDAs) has been proposed It has high input impedance voltage-mode biquad filter with orthogonal tune of natural frequency and quality factor The proposed filter simultaneously provides five filter responses: low-pass ( LP ), high-pass ( HP ), band-reject ( BR ), all-pass ( AP ) and band-pass ( BP ) in the same circuit topology The natural frequency and quality factor can be tuned electronically and orthogonally dc bias current The output impedance at output nodes HP , AP and BR has low impedance which can connect to other circuit without the use of voltage buffers The proposed filter consists of three VDDDAs, one grounded resistor and two grounded capacitors This makes the proposed filter suitable for integrated circuit development With slightly modifying the proposed filter, the voltage-mode qudrature sinusoidal oscillator with low output impedance and independent control of condition of oscillation (CO) and frequency of oscillation (FO) has been achieved The results shown in this paper are from PSPICE simulation and experiment to validate the proposed circuits
29 citations
TL;DR: This brief proposes a new low-phase-noise microwave voltage-controlled oscillator (VCO) with a harmonic-suppressed stepped-impedance-resonator (SIR) filter that can alleviate the noise contributed from the oscillation harmonics.
Abstract: This brief proposes a new low-phase-noise microwave voltage-controlled oscillator (VCO) with a harmonic-suppressed stepped-impedance-resonator (SIR) filter. Since the filter is synthesized by multiple resonators, it can provide a high-quality factor to improve the phase-noise performance. In addition, the harmonic-suppressed property of the filter adopted in this brief can alleviate the noise contributed from the oscillation harmonics. By applying the two techniques mentioned, the proposed VCO is designed at 2.4 GHz with a three-pole Butterworth filter, which is synthesized by the parallel transmission-line SIRs to reduce the circuit size. The proposed VCO using a three-pole filter has a measured phase noise of −147 dBc/Hz at 1-MHz offset frequency with a corresponding figure-of-merit of −203.18 dBc/Hz.
28 citations
TL;DR: In this article, a tri-function filter with three different responses (bandstop, bandpass, and all-pass) has been proposed, which is able to exhibit three responses over a 1.2:1 frequency tuning range.
Abstract: In this paper, we present a reconfigurable filter capable of having three different responses, such as bandstop, bandpass, and all-pass responses. For designing the tri-function filter, we have developed a new topology containing coupled resonators and a switch-embedded transmission line running from the input to output ports. A bandpass response can be obtained by opening the switches embedded in the transmission line. On the other hand, closing the switches produces bandstop and all-pass responses. The details of the coupling structure design satisfying three sets of the coupling coefficients for the three responses are presented. In addition, we also discuss in detail an approach for incorporating the measured parameters of the nonideal switch in our filter design. For demonstration, a frequency-tunable tri-function filter has been designed using substrate-integrated waveguide resonators. It is shown that the designed filter is able to exhibit three responses over a 1.2:1 frequency tuning range.
26 citations
TL;DR: The Schmidt-Kalman (or "consider" Kalman filter) has often been used to account for the uncertainty in so-called "nuisance" parameters when they are impactful to filter accuracy and consistency.
Abstract: The Schmidt–Kalman (or “consider” Kalman filter) has often been used to account for the uncertainty in so-called “nuisance” parameters when they are impactful to filter accuracy and consistency Us
26 citations
TL;DR: In this paper, a simple topology of a current mode MOSFET-only filter with single-input and multi-output (SISO) transistors is proposed.
Abstract: In this paper, a very simple topology of a current mode MOSFET-only filter with single-input and multi-output is proposed. It is very important to emphasize that it is possible to obtain five of the filter functions, namely low-pass (LP), band-pass (BP), high-pass (HP), band-stop (BS) and all-pass (AP) using the proposed topology without using external passive elements. The core circuit of the proposed filter employs only four MOS transistors; therefore, it occupies very small chip area. It is also possible to adjust the filter gain with the biasing voltage. In addition, the circuit exhibits a very low input impedance and also high output impedances which make it possible for cascading. The MOSFET capacitances which determine the transfer functions are all grounded, so physical capacitances can be used instead of MOSFET parasitic capacitances to operate the filter at very low frequencies. Moreover, proposed filter structure has low supply voltage as 1 V in order to be applicable to low voltage operations. Detailed simulation results, including noise and Monte Carlo analysis, are provided using 0.18 µm TSMC technology parameters to verify the feasibility of the filter circuit.
23 citations
TL;DR: In this paper, a balanced hybrid substrate-integrated waveguide (SIW) and coplanar waveguide bandpass filter was proposed, which combines a hybrid SIW-CPW filter and a balanced structure for the first time.
Abstract: This Letter proposes a balanced hybrid substrate-integrated waveguide (SIW)–coplanar waveguide (CPW) bandpass filter, which combines a hybrid SIW–CPW filter and a balanced structure for the first time. High performance common mode suppression can be achieved with high quality factor, compact size, and quasi-elliptic differential mode response.
20 citations
TL;DR: In this article, a frequency-tunable substrate-integrated waveguide bandpass filter is presented, in which the operating frequency band can be switched between $S$ -band and $X$-band.
Abstract: In this paper, we present a frequency-tunable substrate-integrated waveguide bandpass filter of which the operating frequency band can be switched between $S$ -band and $X$ -band. One of unique features of the presented filter is that a single-filter structure can replace a filter bank composed of an $S$ -band filter, an $X$ -band filter, and two switches at input and output ports for selecting one of two filters. In addition, the filter can tune the center frequency in each band. This paper provides the design method, fabrication, and measurement of the presented filter structure.
TL;DR: A new second-order current-mode universal filter using only two plus-type differential voltage current conveyors, three resistors and two grounded capacitors is proposed, which can realize high-pass and all-pass filter responses with interconnection of relevant output currents.
Abstract: In this paper, a new second-order current-mode universal filter using only two plus-type differential voltage current conveyors, three resistors and two grounded capacitors is proposed. The proposed circuit with two identical inputs and three outputs can simultaneously provide second-order high output impedance low-pass, band-pass and notch filter responses. Also, it can realize high-pass and all-pass filter responses with interconnection of relevant output currents. It can be easily tuned electronically. It can be operated properly at high frequencies. A number of simulations based on SPICE program and an experimental test are achieved in order to demonstrate the performance of the proposed filter.
TL;DR: In this article, a second-order voltage-mode filter with three inputs and single-output voltage using single commercially available IC, called LT1228, is manufactured by Linear Technology Corporation.
Abstract: This paper presents a second-order voltage-mode filter with three inputs and single-output voltage using single commercially available IC, one resistor, and two capacitors. The used commercially available IC, called LT1228, is manufactured by Linear Technology Corporation. The proposed filter is based on parallel RLC circuit. The filter provides five output filter responses, namely, band-pass (BP), band-reject (BR), low-pass (LP), high-pass (HP), and all-pass (AP) functions. The selection of each filter response can be done without the requirement of active and passive component matching condition. Furthermore, the natural frequency and quality factor are electronically controlled. Besides, the nonideal case is also investigated. The output voltage node exhibits low impedance. The experimental results can validate the theoretical analyses.
TL;DR: In this article, a straightforward discrete adaptive filter was proposed to observe fundamental and harmonic sequence components of the grid voltage, and the frequency error transmission was analyzed when the frequency of input voltage was unequal to the center frequency of the filter.
Abstract: To improve the control performance for grid-tied power converters, the fundamental frequency and harmonics of the grid voltage should be quickly and accurately estimated even under distorted voltage condition. This paper introduces a straightforward discrete adaptive filter to observe fundamental and harmonic sequence components of the grid voltage. The proposed filter possesses a simple and straightforward implementation. Based on the newly developed filter, frequency error transmission was analyzed when the frequency of the input voltage was unequal to the center frequency of the filter. Consequently, a frequency estimation loop was designed to adapt to the frequency variation for the filter. Compared to previous algorithms, the proposed algorithm has a better dynamic performance rating for frequency estimation, robust stability, and a simpler implementation. The effectiveness of the algorithm is verified by simulations and laboratory experiments.
TL;DR: The proposed NGDF does not require a lumped resistor to generate a negative group delay and has source-load and inter-resonator couplings, and the center frequency of the filter is tuned by varying the bias voltage of the varactor diodes.
Abstract: In this letter, a negative group delay filter (NGDF) with tunable center frequencies is presented. The proposed filter is designed using finite unloaded- $Q_{u}$ resonators based on the coupling matrix approach. The proposed NGDF does not require a lumped resistor to generate a negative group delay and has source-load and inter-resonator couplings. The center frequency of the filter is tuned by varying the bias voltage of the varactor diodes. The design theory for the proposed filter is validated experimentally through fabrication of a second-order NGDF at a center frequency of 2.14 GHz.
TL;DR: In this paper, the use of MOS-only active filters in the implementation of area-effective low-IF image reject filters is discussed and a new complex image-reject filter with reduced chip area, which can be used in dual-band GNSS receivers, is obtained.
Abstract: In this paper, the use of MOS-only active filters in the implementation of area-effective low-IF image reject filters is discussed. For this purpose, complex filter design procedure is considered regarding MOS-only filter realization techniques and a new second-order filter topology which favors filter’s area-effective implementation is proposed. Owing to the presented approach, a new complex image-reject filter with reduced chip area, which can be used in dual-band GNSS receivers, is obtained. Issues related to IQ imbalance are briefly discussed and a calibration imbalance circuit is proposed. By virtue of the current-mode design technique, the IQ imbalance circuit is embedded with the complex filter, simplifying the system topology. In order to illustrate the feasibility of the filter, post-layout simulation results of a fourth-order Butterworth-type image reject filter designed for dual-band GNSS receivers are provided using SPECTRE simulation tool in CADENCE design environment.
TL;DR: In this paper, a compact size and high selective bandpass filter is presented for 3.5 GHz with two transmission zeros at 3.35 GHz and 3.85 GHz.
Abstract: A compact size and high selective bandpass filter is presented in this paper. The filter is designed to serve at 3.5 GHz with two transmission zeros at 3.35 GHz and 3.85 GHz. The filter is designed as two gap capacitor coupled to two coupled composite right–left handed transmission lines. The coupled lines were designed to demonstrate a zeroth order phase at 3.5 GHz. Also, the transmission zeros were achieved as a consequence of the electrical/magnetic couplings between the two coupled transmission lines. The employed cell, filter design equations are emphasized. The filter S-parameters were extracted based on the circuit model, full wave simulation, and experimental measurements. A good agreement between modeled, simulated, and measured results is achieved. The measured center frequency of the bandpass filter is 3.55 GHz and 100 MHz bandwidth which is suitable for WiMAX applications. Also, the filter has low measured insertion loss which does not exceed 1 dB within passband. Finally, the filter has advantages of compactness (size is 20 3 18 mm2) which is only 50% compared to conventional non-selective one-stage coupled line filter.
TL;DR: An innovative application of a hyperbolic tangent sigmoid (HTS) function to vary the time-varying pole-radius of the pole-zero-constrained (PZC) IIR notch filter to optimally attain these two requirements together is presented.
TL;DR: In this article, a sensorless active damping technique that is able to restrain the resonant current component through the estimation of the filter capacitor current using the Kalman filter is proposed.
TL;DR: In this paper, a differential eight-path bandpass filter with tunable center frequency and bandwidth is presented, where a wideband low-noise amplifier (LNA) is designed to precede the 8-path filter and acts as an active single-to-differential converter.
Abstract: This paper presents a differential eight-path bandpass filter with tunable center frequency and bandwidth. Fully differential Miller compensated Butterworth Gm-C biquads are used to implement the active low-pass filters required in the structure of the eight-path filter. The −3-dB bandwidth of each Gm-C filter can be tuned from 2.5 to 51 MHz by means of six digital bits. The center frequency of the eight-path filter can be tuned from 100 MHz to 2 GHz by varying the frequency of the 12.5% duty cycle clocks applied to the gates of the switches in the filter. A wideband low-noise amplifier (LNA) is designed to precede the eight-path filter and acts as an active single-to-differential converter while providing a moderate voltage gain to compensate for the noise produced by the eight-path filter. The LNA has a noise canceling common-gate common-source with 20 dB of gain and a noise figure (NF) of 1.8 dB. The filter and LNA are designed and fabricated in 180-nm CMOS process. The circuit operates in 100 MHz to 2 GHz frequency range, achieving a voltage gain of 19 dB and a total NF of 3.3 dB. The achieved out-of-band input third-order intercept point of the circuit is +23 dBm, and the power consumption of the filter is approximately 32.3 mW, while the LNA consumes 16.5 mW.
TL;DR: In this paper, a control strategy for a hybrid filter has been proposed based on minimizing the effective value of the voltage at the point of common coupling to ensure the transfer of the power demanded by the load.
TL;DR: In this article, a dual-mode dual-band bandpass filter is proposed based on the inside-outside-reversed dual-ring topology, where the degenerate modes of the inner ring move down and form the first passband, whereas the second passband is constructed by the outer ring.
Abstract: A compact dual-mode dual-band bandpass filter is proposed based on the inside–outside–reversed dual-ring topology. Different from the traditional design, the total size of the filter is limited by the second passband with shorter wavelength at higher frequency, instead of the first passband with longer wavelength at lower frequency. By loading four square patches in the inner ring, the degenerate modes of the inner ring move down and form the first passband, whereas the second passband is constructed by the outer ring. By utilising the coplanar-waveguide feeding at ground plane, a prototype of the dual-band filter with two operating frequencies at 0.92 and 1.47 GHz is designed and verified experimentally.
TL;DR: In this article, a novel currentmode universal filter configuration composed of five plus-type second-generation current conveyors (CCII+s) as active components besides three resistors and three grounded capacitors as passive elements is proposed.
Abstract: A novel current-mode (CM) universal filter configuration composed of five plus-type second-generation current conveyors (CCII+s) as active components besides three resistors and three grounded capacitors as passive elements is proposed in this paper The proposed filter can simultaneously provide high-pass, band-pass and low-pass responses Also, it can realize all-pass and notch responses with interconnection of convenient output currents It can be cascaded with other CM ones easily because it has low input and high output impedances It offers orthogonal control of angular resonance frequency and quality factor An electronically tunable universal filter can be easily obtained if plus-type current controlled current conveyors are replaced instead of each of the five CCII+s and all the three resistors are removed Nevertheless, it needs a single passive element matching constraint for notch and all-pass filter responses Some simulation and experimental test results are included to confirm the theory
TL;DR: A comprehensive transmission line model is investigated within this paper which showed excellent agreements with full-wave simulations and measurements, and the implemented UWB filter is investigated with respect to its frequency-domain characteristics and group delay response.
Abstract: Modern wireless communication systems typically employ multiple frequency bands for several standards. A new class of miniaturized ring filters with tuning capability is introduced for this purpose. The proposed filter structure is based on a single multi-mode resonator with variable section impedances in microstrip technology. The bandwidth of the filter can be significantly extended to cover the whole ultra wideband (UWB) frequency range with high adjustability. Moreover, a tunable bandnotch is introduced within the filter response, which can be arbitrarily placed according to the required application. Varactor and PIN diodes are also utilized to facilitate a high tuning capability throughout the different filter characteristics with respect to bandwidth, center frequency, and bandnotch frequency. Based on the symmetry of the filter, even-odd mode analysis is applied to investigate the different filter design characteristics. In addition, a comprehensive transmission line model is investigated within this paper which showed excellent agreements with full-wave simulations and measurements. The implemented UWB filter is investigated with respect to its frequency-domain characteristics and group delay response. The realized filter has a fractional bandwidth of more than 119% with a low group delay. All measured results are in a very good agreement with analysis and simulations. The overall filter dimensions, including housing, do not exceed 25 mm $\times 25$ mm.
01 Apr 2017
TL;DR: In this paper, the authors proposed an analysis and comparative study of two different schemes of hybrid active power filter (HAPF) configurations with the arrangement of series, passive and shunt filter.
Abstract: Improvement of power quality (PQ) has became an essential aspect in current situation of power system. Conventionally power quality improvement was done through passive filters, shunt filter and series filter but they suffer from problems like resonance, fixed compensation and other PQ problems. Therefore in order to eradicate these issues some hybrid combination of filters including passive and active power filter (APF) are used. This paper proposes an analysis and comparative study of two different schemes of hybrid active power filter (HAPF). HAPF is configured with the arrangement of series, passive and shunt filter. One arrangement is modeled with shunt passive filter linked in series with shunt active filter and the other is designed with series active filter and shunt passive filter. For both the schemes of hybrid filter, different control strategy and power circuit design are considered. Finally for individual configuration the control and compensation design is proved by simulation.
TL;DR: The inductor-less filter is designed and implemented using voltage differencing transconductance amplifier (VDTA) as an active building block and a grounded capacitor, thereby validating its suitability for fully integrated circuit applications.
Abstract: Summary
This paper presents a novel design methodology for realizing a variation-aware widely tunable active inductor-based RF bandpass filter (BPF). The inductor-less filter is designed and implemented using voltage differencing transconductance amplifier (VDTA) as an active building block and a grounded capacitor, thereby validating its suitability for fully integrated circuit applications. Digital ‘coarse’ tuning and analog ‘fine’ tuning are employed to achieve better frequency coverage. The designed filter exhibits a tuning range of 1.65–3.015 GHz and a 3-dB bandwidth of 1400–122 MHz which translates into a quality factor of 1.17–24.71. It offers a voltage gain of 0–22.91 dB, noise figure of 28.16–28.95 dB, has a 1-dB compression point of 2.50–2.478 dBm and draws 0.065–0.232 mW power from 1-V power supply. Our proposed design shows a figure-of-merit of 82.08–91.27 dB, which is higher as compared to its counterparts available in the literature. The filter is implemented in 45-nm CMOS technology node using metal gate and strained silicon. Copyright © 2017 John Wiley & Sons, Ltd.
01 Jun 2017
TL;DR: A transfer-function-adaptive quasi-elliptic-type microwave bandpass filter is presented that features less in-band insertion-loss levels and improved linearity behavior — specially for narrow-band states — when compared to more-classic bandwidth-tunable filters that use inter-resonator coupling variation.
Abstract: A transfer-function-adaptive quasi-elliptic-type microwave bandpass filter is presented. The devised fully-reconfigurable filter is based on a resonator-cascade structure with static impedance inverters and only exploits the tuning of its resonating nodes to achieve all its reconfiguration properties. They include center-frequency, bandwidth, and transmission-zero (TZ) control for bandpass-type responses, as well as the intrinsic switching-off — i.e., without RF switches — of the filter. Moreover, it features less in-band insertion-loss levels and improved linearity behavior — specially for narrow-band states — when compared to more-classic bandwidth-tunable filters that use inter-resonator coupling variation. The operational foundations of the engineered fully-reconfigurable filter architecture are theoretically expounded in a coupling-matrix framework. Besides, a tunable three-pole microstrip filter prototype in the range 1.2–1.7 GHz is developed and tested for experimental-demonstration purposes.
TL;DR: A new technique for designing the all-pass-based notch filter that has the mirror-image symmetry relation between the numerator and denominator polynomials and a relationship between the pole angel and the zero angle is derived.
Abstract: In this brief, a new technique for designing the all-pass-based notch filter is proposed. An all-pass-based notch filter consists of an all-pass filter, which has the mirror-image symmetry relation between the numerator and denominator polynomials. With this property, a relationship between the pole angel and the zero angle of an all-pass-based notch filter is derived. Knowing this relationship, we can design an all-pass-based notch filter by assigning the pole position according to the zero position. The process of the new technique is illustrated in this brief. Moreover, experiments are presented to examine a track of the pole position at the specific frequency and to demonstrate a design example of an all-pass-based notch filter.
TL;DR: In this article, a 3D reconfigurable microwave multiband bandpass filters in substrate-integrated evanescent-mode-cavity-resonator technology is presented.
Abstract: The development of 3-D reconfigurable microwave multiband bandpass filters in substrate-integrated evanescent-mode-cavity-resonator technology is presented. The proposed filter approach exploits multiband quasi-bandpass sections whose tunable resonators do not directly interact with one another. In this manner, a multiband filtering transfer function with independently frequency-controllable passbands and interband transmission zeros is realized. Moreover, the number of active passbands can be dynamically selected in this filter architecture through their spectral merging as well as their intrinsic switching-OFF through resonators’ detuning. These operational capabilities are theoretically demonstrated by means of several coupling-matrix-level synthesis examples. Furthermore, for experimental-validation purposes, a triple-band second-order prototype with three electronically tunable transmission bands in the range 2.2–2.8 GHz is designed, manufactured, and tested.