scispace - formally typeset
Search or ask a question
Topic

Voltage-controlled filter

About: Voltage-controlled filter is a research topic. Over the lifetime, 5514 publications have been published within this topic receiving 70872 citations. The topic is also known as: VCF.


Papers
More filters
Journal ArticleDOI
TL;DR: An analytical treatment of the two-beam coupling devices is given in a Laplace transform framework in the undepleted pump approximation assuming plane wave inputs to allow a unified treatment ofThe current status of optical novelty filters and related devices is reviewed.
Abstract: A novelty filter detects what is new in a scene and may be likened to a temporal high-pass filter. The current status of optical novelty filters and related devices, based upon four-wave mixing and two-beam coupling in photorefractive media, is reviewed. A detector that shows only what is not new, a monotony filter, may be likened to a temporal low-pass filter. Demonstrations of high- and low-pass and bandpass temporal image filters are then discussed. An analytical treatment of the two-beam coupling devices is given in a Laplace transform framework in the undepleted pump approximation assuming plane wave inputs. This allows a unified treatment of the various filter characteristics. >

138 citations

Journal ArticleDOI
Joseph P. Kirk1, Alan L. Jones1
TL;DR: In this paper, a phase-only spatial filter was proposed for wave-front construction, in which both the amplitude and phase information necessary to construct an arbitrary image over a limited field are encoded.
Abstract: A new type of phase-only filter is described for wave-front construction, in which both the amplitude and phase information necessary to construct an arbitrary image over a limited field are encoded. It is shown that this phase-only filter can duplicate the performance of an ideal complex-valued spatial filter (a filter that controls both amplitude and phase transmittance). This phase-only filter controls the amplitude transmittance by the use of a modulated high-frequency phase carrier that diffracts a controlled amount of light into the image. This type of filter is particularly useful in the implementation of computational wave-front construction, because the maximum spatial frequency that must be plotted is associated with the image and not the carrier. The performance of the filter is examined both numerically and experimentally.

137 citations

Journal ArticleDOI
TL;DR: In this paper, a balanced bandpass filter with acceptable common-mode rejection is implemented with its differential-mode and commonmode stopbands extended up to 5.5 fo d, where fo d is the center frequency of differential mode passband.
Abstract: A novel fourth-order balanced bandpass filter is proposed based on the half-wavelength (lambda/2) stepped-impedance resonators (SIRs). By properly adjusting the parameters of each SIR, the proposed filter may be made compact and its stopband may also be extended simultaneously. Specifically, a balanced filter with acceptable common-mode rejection is implemented with its differential-mode and common-mode stopbands extended up to 5.5 fo d, where fo d is the center frequency of differential-mode passband.

137 citations

Journal ArticleDOI
TL;DR: In this article, the authors proposed automatic gain adjustment in a fully-digital-controlled shunt active filter to damp out harmonic propagation without considering the circuit parameters, which can reduce the compensating currents and losses in the active filter and avoid over-damping performance.
Abstract: This paper discusses automatic gain adjustment in a fully-digital-controlled shunt active filter. This is the first step in cooperative control of the multiple active filters based on voltage detection for harmonic damping throughout power distribution systems. In general, the active filter should be equipped with an optimal control gain corresponding to the characteristic impedance of a distribution line. However, it is difficult to know circuit parameters of a real distribution line having various shunt capacitors and loads. Therefore, a main purpose of the gain adjustment is to make the active filter damp out harmonic propagation without considering the circuit parameters. In addition, the gain adjustment can reduce the compensating currents and losses in the active filter, and moreover it can avoid over-damping performance. Experiment results obtained from a 200-V, 20-kW laboratory system verify the effectiveness of the active filter equipped with automatic gain adjustment.

132 citations

Patent
07 Nov 1998
TL;DR: In this paper, a cascade of two filters (114, 118) along with a short bulk delay (110) is used to model the feedback path of a hearing aid, and the second filter does not use a separate probe signal.
Abstract: Feedback cancellation apparatus uses a cascade of two filters (114, 118) along with a short bulk delay (110). The first filter (114) is adapted when the hearing aid is turned on in the ear. This filter adapts quickly using a white noise probe signal (216), and then the filter coefficients are frozen. The first filter models parts of the hearing-aid feedback path that are essentially constant over the course of the day. The second filter (118) adapts while the hearing aid is in use and does not use a separate probe signal. This filter provides a rapid correction to the feedback path model when the hearing aid goes unstable, and more slowly tracks perturbations in the feedback path that occur in daily use. The delay (110) shifts the filter response to make the most effective use of the limited number of filter coefficients.

131 citations


Network Information
Related Topics (5)
Capacitor
166.6K papers, 1.4M citations
86% related
Amplifier
163.9K papers, 1.3M citations
85% related
Voltage
296.3K papers, 1.7M citations
84% related
CMOS
81.3K papers, 1.1M citations
83% related
Integrated circuit
82.7K papers, 1M citations
82% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20239
202229
20201
20188
2017150
2016199