Topic
Active filter
About: Active filter is a research topic. Over the lifetime, 16768 publications have been published within this topic receiving 244164 citations.
Papers published on a yearly basis
Papers
More filters
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01 Dec 1993TL;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' [1] ‘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.
722 citations
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01 Jan 1988TL;DR: In this article, the authors present a design-oriented course for operational amplifiers and analog ICs, which includes additional problems, more in-depth coverage of negative feedback, more effective layout, updated technology (current feedback and folded-cascode amplifiers, and low-voltage amplifiers), and increased topical coverage (current-feedback amplifier, switching regulators and phase-locked loops).
Abstract: Franco's "Design with Operational Amplifiers and Analog Integrated Circuits, 3e" is intended for a design-oriented course in applications with operational amplifiers and analog ICs. It also serves as a comprehensive reference for practicing engineers.
This new edition includes enhanced pedagogy (additional problems, more in-depth coverage of negative feedback, more effective layout), updated technology (current-feedback and folded-cascode amplifiers, and low-voltage amplifiers), and increased topical coverage (current-feedback amplifiers, switching regulators and phase-locked loops).
Table of contents
1 Operational Amplifier Fundamentals
2 Circuits with Resistive Feedback
3 Active Filters: Part I
4 Active Filters: Part II
5 Static Op Amp Limitations
6 Dynamic Op Amp Limitations
7 Noise
8 Stability
9 Nonlinear Circuits
10 Signal Generators
11 Voltage References and Regulators
12 D-A and A-D Converters
13 Nonlinear Amplifiers and Phase-Locked Loops
696 citations
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TL;DR: In this article, a linear, tunable integrator for very high-frequency integrated filters can be made, which has good linearity properties and non-dominant poles in the gigahertz range owing to the absence of internal nodes.
Abstract: CMOS circuits for integrated analog filters at very high frequencies, based on transconductance-C integrators, are presented. First a differential transconductance element based on CMOS inverters is described. With this circuit a linear, tunable integrator for very-high-frequency integrated filters can be made. This integrator has good linearity properties and nondominant poles in the gigahertz range owing to the absence of internal nodes. The integrator has a tunable DC gain, resulting in a controllable integrator quality factor. Experimental results of a VHF CMOS transconductance-C low-pass filter realized in a 3- mu m CMOS process are given. Both the cutoff frequency and the quality factors can be tuned. The cutoff frequency was tuned from 22 to 98 MHz and the measured filter response is very close to the ideal response of the passive prototype filter. Furthermore, a novel circuit for automatically tuning the quality factors of integrated filters built with these transconductors is described. >
674 citations
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TL;DR: This paper presents the comparative evaluation of the performance of three state-of-the-art current control techniques for active filters, the linear rotating frame current controller, the fixed-frequency hysteresis controller, and the digital deadbeat controller.
Abstract: This paper presents the comparative evaluation of the performance of three state-of-the-art current control techniques for active filters. The linear rotating frame current controller, the fixed-frequency hysteresis controller, and the digital deadbeat controller are considered. The main control innovations, determined by industrial applications, are presented, suitable criteria for the comparison are identified, and the differences in the performance of the three controllers in a typical parallel active filter setup are investigated by simulations.
659 citations
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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. >
656 citations