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7382887 |
Method and device for reducing high frequency error components of a multi-channel modulator
A method and device for reducing error components of a multi-channel modulator. The method comprises the steps of inverting substantially half of the channels of a modulator, and reducing error...
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7356186 |
Digital representation of audio waveforms using peak shifting to provide increased dynamic range
A system allows greater dynamic range in fixed-width sample representations of waveforms. Known properties of the waveform are used to determine an unlikely, or impossible, data condition to be...
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7319761 |
Method and apparatus for locating and correcting sound overload
The invention describes a graphical method for detecting and adjusting audio overload conditions. The graphical user interface provides a user complete playback control of several audio tracks,...
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7260209 |
Methods and apparatus for improving voice quality in an environment with noise
A method for improving a downlink signal received by a listener on a phone is disclosed. The method includes calculating an environment noise level of the listener and filtering and adjusting gain...
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7248690 |
Voice signal clipping circuit and telephone set therewith
A voice signal clipping circuit comprising, an amplifier which amplifies an input voice signal to a permissible level and a clipper which clips an amplitude component in excess of the permissible...
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7231037 |
Active audio compressing in telecommunication
An output reducing system for a telephone system, e.g., implemented in a headset, includes an input line and an output line, wherein the input line transmits an incoming signal to an output...
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7200238 |
Acoustic signal level limiter
An acoustic signal level limiter provides a telephone handset/headset user protection against loud audible signals generated within a communications system. The acoustic signal limiter comprises an...
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7130433 |
Noise reduction apparatus and noise reduction method
An apparatus for reducing noise component contained in an input signal has: a detecting device for detecting a level of the noise component; an adjusting device for adjusting a level of the input...
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7035417 |
System for reducing noise in the reproduction of recorded sound signals
A noise reduction system is connected to at least two input channels for receiving input signals that have substantially identical program content but differing instantaneous noise transients. The...
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6795740 |
Rectifying overflow and underflow in equalized audio waveforms
The invention is a method, apparatus and computer readable program for eliminating overflow and underflow by re-adjusting or rectifying the audio levels of an audio signal in those portions where...
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6795559 |
Impulse noise reducer detecting impulse noise from an audio signal
An impulse noise reducer detects impulse noise in an audio signal by detecting and smoothing the high-frequency amplitude of the audio signal, attenuating the non-smoothed amplitude according to...
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6654471 |
Method, equipment and recording device for suppressing pulsed interference in analogue audio and/or video signals
Clicks in voice and music signals are removed by detecting and interpolating the click. The use of a permanently set threshold value above the peak value of the audio signal is known for detecting...
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6556685 |
Companding noise reduction system with simultaneous encode and decode
A system and method for reducing noise in an audio signal. The system includes an encoder, a decoder and a single feedforward sidechain for generating a control signal that is used as input to a...
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6516067 |
Anti pop for power off
In order to quickly decrease voltage applied to a mute pin 18 of an audio amplifier circuit 19 of an electronic appliance, an end of a capacitor 20 connected to the mute pin is connected to a...
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6255904 |
Anti-pop circuit for AC amplifiers
The anti-pop circuit includes a unity gain buffer with an input coupled to the source of the reference voltage and an output coupled to the input of the amplifier to accelerate the charging of the...
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6205225 |
Lower sideband modulation distortion cancellation
An audio peak limiter in which the lower sideband of the modulation distortion spectrum is canceled. The peak limiter is realized by multiplying the input signal by a control signal. The Hilbert...
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6058194 |
Sound-capture and listening system for head equipment in noisy environment
The system of the invention includes a sound-capture and listening system for a helmet in a noisy environment, and is characterized in that it includes, on the sound-capture side, at least one...
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5894522 |
Distortion reduction system
A distortion reduction system for an audio device having first and second power supply voltages, a driver circuit for amplifying an audio signal, and, a speaker for outputting the amplified audio...
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5881157 |
Apparatus for compensating a frequency characteristic of a reproduction audio signal
An apparatus for compensating a frequency characteristic of a reproduction audio signal removes noise from the reproduction signal in the high-frequency region during reproduction of the audio...
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5828762 |
Apparatus for compensating audio signal recording
An audio signal recording compensation apparatus enhances a frequency characteristic and prevents saturation of a recording signal by controlling the level of the recording signal when an audio...
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5812598 |
Hearing assist system employing time variant modulation transmission to hearing aid
A short range magnetically coupled wireless communication system employs time variant modulation of a high repetition rate pulse stream and magnetic coupling between a transmission magnetic element...
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5796850 |
Noise reduction circuit, noise reduction apparatus, and noise reduction method
A mixed signal which contains a noise is inputted. Then, the signal is inverted and amplified by an inverting amplifier which has a high gain, and attenuated by a attenuator in order to generate an...
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5771301 |
Sound leveling system using output slope control
A sound leveling system for maintaining an output signal below a slope of predetermined maximum output levels includes a signal adjusting circuit, an integrator, and a peak rate limiter circuit....
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5586192 |
Method of and device for detecting pulsatory interference signals in a sound signal
For detecting pulsatory interference in a sampled audio signal, the value of a given signal sample is compared with the values of previous as well as subsequent signal samples within a selected...
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5535280 |
Circuit for removing ignition noise from a multiplex signal
In a digital circuit which removes ignition noise from a multiplex signal in a radio receiver, especially in a car radio, the multiplex signal is supplied via a high-pass filter (3) and a squaring...
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5278774 |
Alarm for transient underwater events
An alarm for detecting transient senic events determines an estimate of background environmental acoustic events or noise by computing a short time correlation function for individual segments of...
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5226088 |
Apparatus and methods for active noise suppression in stereo multiplex signals
Method and apparatus for active noise suppression in stereo multiplex signals particularly in an automotive radio receiver includes an insertion circuit where the disturbed signal section is...
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5201009 |
Signal processor
An operational amplifier (1) and resistors (11) and (12) damp an input signal (V 1 ) by -6dB. Since a positive input terminal of the operational amplifier (1) is fixed at -3V, DC component of the...
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5168526 |
Distortion-cancellation circuit for audio peak limiting
Apparatus for reducing distortion in a peak limited audio siganl. The amount of low-frequency spectral energy in the input audio signal is determined for a peak limited signal and used to control...
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4928307 |
Time dependent, variable amplitude threshold output circuit for frequency variant and frequency invariant signal discrimination
A voice signal compression system wherein the compression threshold may be adjusted to a calibrated level. The system includes a variable gain amplifier for amplifying a voice input signal based on...
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4899389 |
Pulsating noise removal device
A pulsating noise removal device includes first and second variable attenuators for varying signal levels of an audio signal component and a noise signal component both involved in an entered...
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4815141 |
Apparatus and methods for removing unwanted components from a communications signal
A tuner includes circuitry for conditioning an audio signal including (i) a pilot signal canceller, (ii) a noise limiter, (iii) a notch filter, and (iv) a de-emphasizer; as well as an attenuator...
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4742570 |
Multipath noise detecting circuit
A multipath noise detecting circuit, which is not affected by ignition noise nor by the level of the antenna input voltage, includes a band pass filter having a mean frequency of 114 KH supplied...
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4578818 |
System for processing audio frequency information for frequency modulation
In FM transmitters, particularly land mobile FM transmitters, wherein a speech signal is pre-emphasized between 300 Hz and 3 kHz, whereafter it is filtered to provide a sharp cut-off and wherein...
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4495643 |
Audio peak limiter using Hilbert transforms
A peak limiter is described which employs the Hilbert transform. Effectively distinct processing occurs for low frequency and high frequency signals and harmonic distortion results only when the...
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4479250 |
Dual audio capture limiter squelch circuit
A communications receiver squelch circuit for use in frequency modulation systems which has tight squelch sensitivity. The squelch circuit includes two audio limiters and provides improved squelch...
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4468537 |
Sound system having suppression of AM stereophonic receiving circuit-induced noise
A multi-function sound system including an AM stereophonic receiving function in which interference with operating circuits in modes other than the AM stereophonic mode is eliminated. A limiter...
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4398061 |
Audio processing apparatus and method
The disclosure is directed to an apparatus and method for processing an input electronic audio signal to relatively attenuate portions thereof to prevent those portions from exceeding a...
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4272846 |
Method for cancelling impulsive noise
A method for cancelling impulsive noise in a system of transmitting a band-limited baseband signal through a channel with a wider band than that of the baseband signal, in which an impulsive noise...
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4266099 |
Pulse rejection and duration correction circuit
A circuit which is particularly adapted for reconstructing fixed time duration dialing pulses in a telephone communications system while rejecting spurious pulses of less than a selected pulse...
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4259742 |
Electronic switching system for reducing noise transients
A system for reducing noise transients in electrical carrier signals, carried simultaneously over two separate channels, that are identical in their program component but differ in transient noise...
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4216430 |
Noise eliminating circuit with automatic gain control
A noise eliminating circuit for detecting and eliminating a noise pulse component included in an amplitude modulated wave, characterized by a circuit arrangement wherein an output of a detector...
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4208634 |
Circuit for suppressing noise caused by scratches on a phonograph record
A circuit for suppressing pulse-shaped interferences in an audio signal caused by scratches on a phonograph disc, comprising a signal processing section connected between an audio frequency input...
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4208548 |
Apparatus and method for peak-limiting audio frequency signals
A peak-limiting apparatus and method particularly useful in systems employing high frequency pre-emphasis to compensate for steep high frequency rolloff in a receiver, or the like. The apparatus...
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4198541 |
Signal holding circuit
A signal holding circuit is disclosed in which a parallel circuit of a constant current source circuit comprising a transistor having a constant voltage supplied to a base thereof and a hold...
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4187396 |
Voice detector circuit
A voice detector circuit including a slew-rate limited amplifier at the input thereof so as to reduce the interference with the voice detection process caused by impulse noise. The slew-rate...
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4155041 |
System for reducing noise transients
A system for reducing noise transients in identical electrical carrier signals carried simultaneously over separate channels, comprising means for comparing the noise transients in the respective...
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4063033 |
Signal quality evaluator
In an arrangement for evaluating an incoming speech signal to enable the selection of a receiver with the best quality speech signal over a substantial range of input signal levels, the logarithm...
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4006307 |
Impulse noise suppression circuit
A circuit for reducing transmitted and radiated impulse noise which is generated by opening and closing connections between a transmission path and a source of potential. In the case of closing...
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3989897 |
Method and apparatus for reducing noise content in audio signals
Unwanted background noise in audio signals, and particularly in musical material, is significantly reduced by a multiple band dynamic filtering system operated in response to the fundamental and...
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