About: Voltage-controlled filter is a(n) research topic. Over the lifetime, 5514 publication(s) have been published within this topic receiving 70872 citation(s). The topic is also known as: VCF.
Papers published on a yearly basis
••01 Dec 1993
TL;DR: A novel approach to filter design, based on Adams' ‘log-domain’ filters, is proposed that yields a truly current-mode circuit realisation and, by introducing an exponential map on the state-space description of the desired linear system, a log-domain filter can be fully realised.
Abstract: A novel approach to filter design, based on Adams'  ‘log-domain’ filters, is proposed that yields a truly current-mode circuit realisation. Adams' idea, which was introduced in a limited context, is generalised to permit a complete distortionless synthesis procedure, which results in circuit implementations readily realisable using complementary bipolar processes. It is shown that, by introducing an exponential map on the state-space description of the desired linear system, a log-domain filter can be fully realised with transistors configured in current mirror-type groupings, current sources and capacitors. Owing to the mapping, the state variables are intrinsically related to current, and not voltage, in the resulting circuits, a fact that emphasises the current-mode nature of the design. A general biquadratic filter section is designed, and, following discussion of cascading sections, a seventh-order Chebychev lowpass filter is designed. All designed circuits are shown to be tunable over a two-decade range in frequency while their characteristics are accurately preserved, even for biquad sections whose f0Q product is greater than fT/10. The Chebychev filter is shown in simulation to possess nearly 60 dB dynamic range relative to 0.9% THD, with a cutoff frequency of nearly 5 MHz, using transistor models from AT&T's CBIC-R 300 MHz complementary bipolar process.
TL;DR: This paper presents a 3rd order low-pass continuous-time filter with 4 MHz cut-off frequency, integrated in a 3 μm CMOS process, based on the direct simulation of a doubly-terminated LC ladder using capacitors and fully-balanced, current-controlled transconductance amplifiers with extended linear range.
Abstract: A third-order elliptic low-pass continuous-time filter with a 4-MHz cutoff frequency, integrated in a 3- mu m p-well CMOS process, is presented. The design procedure is based on the direct simulation of a doubly terminated LC ladder filter by capacitors and fully balanced, current-controlled transconductance amplifiers with extended linear range. The on-chip automatic tuning circuit uses a phase-locked loop implemented with an 8.5-MHz controlled oscillator that matches a specific two-integrator loop of the filter. The complete circuit features 70-dB dynamic range (THD >
TL;DR: In this article, a combined system of a shunt passive filter and a small rated series active filter was proposed to compensate for harmonics in power systems, and the results showed that the combined system was far superior in efficiency to conventional shunt active filters.
Abstract: A novel approach to compensating for harmonics in power systems is presented. It is a combined system of a shunt passive filter and a small rated series active filter. The compensation principle is described, and some filtering characteristics are discussed in detail. Excellent practicability and validity to compensate for harmonics in power systems are demonstrated experimentally. Although the source harmonic voltage was only 1%, the source harmonic current reached about 10% before the series active filter was started. After it was started, no harmonic current flowed into the shunt passive filter. In addition, no harmonic voltage appeared at the terminals of the shunt passive filter, because the source harmonic voltage was applied to the series active filter. The total loss of the series active filter was less than 40 W. It is concluded that the combined system is far superior in efficiency to conventional shunt active filters. >
07 Oct 1990
TL;DR: A combined system consisting of a passive filter and a small-rated active filter that are connected in series is discussed as a method of overcoming power system harmonic interferences caused by harmonic-producing loads such as diode or thyristor converters and cycloconverters.
Abstract: The authors present a combined system with a passive filter and a small-rated active filter, both connected in series with each other. The passive filter removes load produced harmonics just as a conventional filter does. The active filter plays a role in improving the filtering characteristics of the passive filter. This results in a great reduction of the required rating of the active filter and in eliminating all the limitations faced by using only the passive filter, leading to a practical and economical system. The active filter has a much smaller rating than a conventional active filter. Experimental results obtained from a prototype model are shown to verify the theory developed. >
TL;DR: In this paper, a three-phase four-wire shunt active power filter using a conventional three-leg converter without the need of power supply at DC bus has been described.
Abstract: This paper describes a three-phase four-wire shunt active power filter using a conventional three-leg converter, without the need of power supply at DC bus Two approaches have been developed to control the active filter Both control strategies consider harmonics and zero sequence components in the voltage and current simultaneously The first one provides constant power and the second one sinusoidal current to the source, even under unbalanced voltage conditions Simulation results from a complete model of shunt active filter are presented to validate and compare the control strategies
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