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.

A hybrid filter for image enhancement

Abstract: We present a new hybrid filter design methodology. Our hybrid filter consists of a nonlinear impulsive noise filter and a fuzzy weighted linear filter. This hybrid filter can efficiently remove large amounts of mixed Gaussian and impulsive noise while preserving the image details. The performance and robust stability of the proposed filter are compared to linear filters and nonlinear filters theoretically and experimentally.

Analysis of Harmonic Damping Effect of the Distributed Active Filter System

Abstract: The harmonic resonance in the power distribution system or in the industrial facilities has been reported. The harmonic termination by installing a shunt active filter at the end of a radial line can suppress harmonic resonance; however, the harmonic voltage distortion along the line may still be significant due to harmonics standing waves. The distributed active filter system, which consists of multiple active filter units deployed along the power line, can effectively reduce voltage harmonics. Based on the pre-determined droop characteristics, the active filter units can share harmonic filtering workload without any communications. In this paper, the distributed active filter system is applied to a radial distribution line and a loop distribution line, which is often used in high-tech industrial parks for enhancing power reliability. This paper provides the theoretic analysis of harmonic resonance, simulation results and laboratory test results to verify the performance of the distributed active filter system. The deployment strategies of active filter units are also presented.

Voice activity detection with adaptive noise floor tracking

Abstract: The present invention relates to a method and apparatus for detecting voice activity in a communication signal, wherein filter means are provided for estimating or suppressing an offset component of the level of the communication signal. A filter parameter is controlled based on the output of the filter means. Furthermore, the estimation or suppression of the offset component is limited in response to the output of the filter means. The filter means may be based on a non-linear adaptive notch level filter or a noise floor tracking filter. Thereby, the tracking behavior of noise floor estimation to sudden rises in noise floor can be improved and the voice activity detection can work efficiently over a wide dynamic range.

Computer Generation of Digital Filter Banks

Abstract: In order to reduce the design time of digital filter bank circuits, a design system has been developed. The software consists of the filter compiler which converts high level filter descriptions to hardware descriptions and the layout generator which converts the hardware descriptions to a layout file. To verify the algorithms before fabrication, a test system is employed. The development time of this system was kept to a minimum by designing the hardware to be easily micro coded and assembled. Several circuits have been fabricated and tested that were generated with this system, including a single bandpass filter chip, a 112-pole 16-channel filter bank for a speech recognition system and a 16-channel spectrum analyzer for consumer stereo applications. The speech recognition chip achieved a SNR of 80 dB with an area of 25 mm /sup 2/ in a 4-micron NMOS technology.

Flexible interpolation filter structures for video coding

Abstract: Systems and methods of signaling different filter structures for each pixel or sub-pixel position in motion compensation prediction video coding are provided. An encoder signals to a decoder one filter structure among a plurality of pre-defined candidates that is used for a respective pixel or sub-pixel position. In accordance with one embodiment, filter structures signaled to the decoder from the encoder "switch" between directional filter and radial filter structures during interpolation at the sub-pixel level. In accordance with another embodiment, filter structures that are signaled may switch between a directional filter structure and a separable filter structure at the sub-pixel level. Thus, not only can an encoder switch between different filter structures during interpolation, but a filter structure pair is provided that the encoder can utilize to interpolate a wide range of signals without increasing tap-length.