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Electronic filter

About: Electronic filter is a research topic. Over the lifetime, 13207 publications have been published within this topic receiving 93063 citations. The topic is also known as: filter.


Papers
More filters
Patent
15 Nov 1973
TL;DR: In this paper, a 2-stage Biquad notch filter was modified by adding an inverter at the input to each stage and by replacing certain of the Biquads resistors with a set of resistors in the filter circuit.
Abstract: The present invention modifies a 2-stage Biquad notch filter by adding an inverter at the input to each stage and by replacing certain of the Biquad resistors with a set of resistors in the filter circuit. The notch width, notch depth, and notch center frequency of this modified Biquad filter may now be varied independently among a set of discrete values.

30 citations

Patent
Luan Vu1
16 Dec 1999
TL;DR: In this paper, a band-gap filter circuit is proposed for use in a voltage regulator, where a capacitor charger (or "cap charger") circuit quickly charges a filter capacitor when power is applied to the voltage regulator circuit.
Abstract: A band-gap filter circuit is disclosed for use in a voltage regulator. A capacitor charger (or “cap charger”) circuit quickly charges a filter capacitor when power is applied to the voltage regulator circuit. At start-up, the cap charger begins charging the filter capacitor. Once an output node equals or nearly equals the voltage at the input node, the cap charger shuts off. The circuit provides a very fast turn-on time, reaching 95% of its steady state value within 200 microseconds, thus overcoming the long turn-on times associated with other designs. The present invention may be utilized in power sensitive applications, such as cellular telephones, that wish to shut off the voltage regulator in order to conserve power.

29 citations

Patent
13 Mar 2000
TL;DR: In this article, a digital comb filter for decoding composite video signals into a luminance and a chrominance component is used to determine important characteristics of an input video signal without demodulating the video signal.
Abstract: A digital comb filter for decoding composite video signals into a luminance and a chrominance component A Fast Fourier Transform (FFT) circuit or a band split filter circuit is used to determine important characteristics of an input video signal without demodulating the video signal The circuits produce a signature signal by which each of the video lines can be correlated Signature signals on various surrounding video lines that are of opposite subcarrier phase with the current line are compared to determine similarity and appropriate weighting coefficients for the surrounding lines If none of the surrounding lines are similar, the comb reverts to a band split filter to form chrominance A noise measure circuit determines an error signal input used to adjust the weighting coefficients as the noise level increases or decreases Multiplexer combines high pass and low pass taps of a band split filter into a single data stream Line delays, together with field delay memories, provide the interlaced line above and below the current line for the comb filter Interframe motion detector gives priority to the frame comb signal when no motion is detected between the current line and the frame delayed signal in the same vertical position as the current line Dynamic threshold modification is used to suppress unwarranted comb filter failures in the presence of luma edges

29 citations

Patent
09 Oct 2001
TL;DR: In this article, a circuit and method for the protection of transducers from over excursion, particularly for audio loudspeakers, was proposed for protecting transducers for audio audio speakers.
Abstract: A circuit and method provides for the protection of transducers from over excursion, particularly for the protection of transducers for audio loudspeakers. A frequency dependent excursion limiter circuit has an initial summing stage followed by a shaping filter stage. A clamping function is provided at the summing stage, or at a separate stage between the summing stage and the shaping filter stage, for clamping the driving signal at a predetermined maximum voltage if the driving signal exceeds the predetermined maximum voltage level. The shaping filter stage provides a frequency response shaping function based on a predetermined frequency response shaping criteria which is related to the frequency dependent excursion limits of the transducers being protected from mechanical overload. An inverse shaping filter function is provided at the initial summing stage by providing feedback from the shaping filter stage, thus eliminating the need for a separate inverse shaping filter circuit before clamping. The inverse shaping filter function allows low level signals below clamping to pass through the circuit unaffected. A frequency dependent excursion limiter circuit is also provided in the closed loop circuit of servo feedback system for protecting transducers in a servo feedback system from over excursion.

29 citations

Patent
06 Jul 2001
TL;DR: In this article, a terminal for a mobile communication system is provided so that transmission spurious property can be improved by removing 8192MHz clock noise of a baseband, by adding IQ low band filters to a preceding terminal of an QPSK modulator.
Abstract: PURPOSE: A terminal for a mobile communication system is provided so that transmission spurious property can be improved by removing 8192MHz clock noise of a baseband, by adding IQ low band filters to a preceding terminal of an QPSK modulator CONSTITUTION: A low band filter(101) removes 8192MHz frequency from a baseband signal processor by filtering an IF baseband signal A QPSK modulator(102) modulates the baseband signal from the low band filter(101) An LC band filter(103) passes a necessary frequency band by filtering the intermediate frequency from the QPSK modulator(102) An auto gain controller(104) controls a gain of the transmission signal A frequency up converter(105) converts the transmission signal from the auto gain controller(104) to a radio frequency A radio frequency band filter(106) filters the radio frequency from the frequency up converter(105) to a predetermined band A pre-amplifier(107) amplifies the output signal from the radio frequency band filter(106) A drive amplifier(108) amplifies the output signal from the pre-amplifier(107) to a predetermined level A final amplifier(109) amplifies the output signal from the drive amplifier(108) As the result, transmission spurious property is improved without requiring a saw filter In addition, current consumption of the amplifiers can be remarkably reduced by removing the loss of the transmission signal

29 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20237
202237
2021138
2020362
2019517
2018554