Class / Patent application number | Description | Number of patent applications / Date published |
381093000 | FEEDBACK SUPPRESSION | 37 |
20080273716 | Feedback Sound Eliminating Apparatus - A control unit gives acoustic environment instruction data to a picked up sound directionality control unit and an adaptive filter. According to this, the picked up sound directionality control unit generates a picked up sound signal constituted by a predetermined picked up sound directionality. The adaptive filter detects the picked up sound directionality from the acoustic environment instruction data, and reads out the filter parameter corresponding to this picked up sound directionality, from a memory. The adaptive filter sets a delay coefficient and a filter coefficient of an FIR filter, and generates a pseudo echo signal by an impulse response with respect to the received sound signal. Based on an error signal obtained by subtracting the pseudo echo signal from the picked up sound signal by an adder, the adaptive filter sets a more optimum filter parameter, and generates the next pseudo echo signal. | 11-06-2008 |
20090116661 | MIXER WITH ADAPTIVE POST-FILTERING - A noise reduction system includes multiple transducers that generate time domain signals. A transforming device transforms the time domain signals into frequency domain signals. A signal mixing device mixes the frequency domain signals according to a mixing ratio. Frequency domain signals are rotated in phase to generate phase rotated signals. A post-processing device attenuates portions of the output based on coherence levels of the signals. | 05-07-2009 |
20090175465 | INTERFERENCE SIGNAL REMOVING APPARATUS AND RF RECEIVER USING THE SAME - An interference signal removing apparatus of a radio frequency (RF) receiver includes a low noise amplification unit which performs low noise amplification, a feedback processing unit which removes a necessary signal in a desired band from a signal output from the low noise amplification unit, and performs feedback of the signal from which the necessary signal is removed, and a signal processing unit which transmits a processed RF signal by synthesizing an input RF signal and the feedback signal to the noise amplification unit. | 07-09-2009 |
20100020984 | SIGNAL PROCESSING SYSTEM AND METHOD - A signal processing system comprises a microphone ( | 01-28-2010 |
20100054496 | SYSTEM FOR ELIMINATION OF ACOUSTIC FEEDBACK - A method and system is provided for eliminating acoustical feedback in a system. The method determines a parameter for at least one notch filter, adjusting the notch filter based on the parameter, processing the digital signals through the notch filter, testing at the effect of the notch filter in the system, and removing the notch filter if the notch filter is not effective. Also disclosed is a method and system of selecting candidate frequencies which might be feedback, as opposed to other wanted sound frequencies. The selection method sampling the digital signals, converting the time domain digital signal samples by a fast Fourier transform algorithm into the frequency domain, using a ballistics approach to find prominences in the frequency spectrum, and testing the sizes of the prominences. | 03-04-2010 |
20100142726 | Noise Cancellation Earphone - An active noise cancellation earphone ( | 06-10-2010 |
20100166213 | Anti-Feedback Device and Anti-Feedback Method - An anti-feedback device includes an anti-feedback filter provided in a closed loop, The anti-feedback device down-samples a signal of specific band selected from an output signal of an adaptive target signal transfer system and a signal of the same band selected from an input signal of the transfer system, and a filtering coefficient of the adaptive filter is updated by use of the down-sampled signals. The filter controller controls a filtering characteristic of the anti-feedback filter so that a peak gain of a frequency of an amplitude characteristic within a specific band of a closed loop determined from the filtering coefficient of the adaptive filter is suppressed. Moreover, the filter controller estimates a gain of the closed loop outside the specific band from the amplitude characteristic in the specific band and controls the amount of suppression of the anti-feedback filter, outside the band in accordance with a result of estimation. | 07-01-2010 |
20100172513 | Electronic Signal Processor - An electronic signal processor for processing signals includes a complex first filter, one or more gain stages and a second filter. The first filter is characterized by a frequency response curve that includes multiple corner frequencies, with some corner frequencies being user selectable. The first filter also has at least two user-preset gain levels which may be alternately selected by a switch. Lower frequency signals are processed by the first filter with at least 12 db/octave slope, and preferably with 18 db/octave slope to minimize intermodulation distortion products by subsequent amplification in the gain stages. A second filter provides further filtering and amplitude control. The signal processor is particularly suited for processing audio frequency signals. Related methods include filtering the input signal with an input filter of the second or third order high pass type, amplifying the filtered signal and further filtering the amplified signal with a low pass filter, which may be of the second order type. | 07-08-2010 |
20100246848 | MOTIONAL FEEDBACK SYSTEM - An audio amplifier is operated in an audio system with optimized source impedance to minimize distortion in a loudspeaker that is paired with the audio amplifier. The audio amplifier provides an amplified audio signal to drive the loudspeaker. A variable output impedance of the audio amplifier is controlled using a feedback control loop to allow negative output impedance at low frequencies that changes to positive output impedance at higher frequencies. The change from negative output impedance to positive output impedance occurs at a determined threshold frequency or determined transitional frequency band. | 09-30-2010 |
20100260351 | Speakerphone Feedback Attenuation - A method is disclosed for acoustic feedback attenuation at a telecommunications terminal. A speakerphone equipped with a loudspeaker and two microphones is featured. Signals from the two microphones are subjected to a calibration stage and then to a runtime stage. The purpose of the calibration stage is to match the microphones to each other by advantageously using both magnitude and phase equalization across the frequency spectrum of the microphones. During the runtime stage, the microphones monitor the ambient sounds received from sound sources, such as the speakerphone's users and the loudspeaker itself, during a conference call. The speakerphone applies the generated set of filter coefficients to the optimized microphone's signals. By combining the signal from the reference microphone with the filtered signal from the optimized microphone, the speakerphone is able to attenuate the sounds from the loudspeaker that would otherwise be transmitted back to other conference call participants. | 10-14-2010 |
20100290641 | ENTRAINMENT RESISTANT FEEDBACK CANCELLATION - This invention concerns a method, and a device, for feedback cancellation. This invention also concerns a computer program product comprising computer program code means to make a computer execute a procedure for feedback cancellation. The method comprises providing an adaptive feedback cancellation filter which adapts under the control of a control module, and filtering at least one input of the control module to suppress correlated signals from the input prior to the control module operating upon the input. The device comprises an adaptive feedback cancellation filter, a control module and at least one filter. The control module controls adaptation of the adaptive feedback cancellation filter. The filter suppresses correlated signals from an input to the control module prior to the control module operating upon the input. | 11-18-2010 |
20110051954 | SIGNAL CONDITIONER WITH SUPPRESSION OF INTERFERING SIGNALS - A semiconductor die with an integrated circuit providing a signal conditioner ( | 03-03-2011 |
20110091048 | Method for virtual bass synthesis - This invention relates to a method for virtual bass synthesis. The low frequency signal is attained by applying a low pass filter to the original. In order to reduce the operations, process of down sampling the low frequency signal, moving the low frequency signal to a series of harmonics whose frequencies are integral times as large as the frequency of low frequency signals, and then up sampling them are provided. By means of psycho-acoustic theory, the weights of harmonics are attained and applied to the harmonics. Finally the weighted harmonics are combined to produce the bass signal. As the result, the virtual bass effect which is almost the same as the low frequency of the original audio signal can be accomplished. Because the harmonic signals are high frequency ones, the virtual effect can be made in the panel speakers or ordinary low-end speakers. | 04-21-2011 |
20110091049 | OUTPUT PHASE MODULATION ENTRAINMENT CONTAINMENT FOR DIGITAL FILTERS - Method and apparatus for entrainment containment in digital filters using output phase modulation. Phase change is gradually introduced into the acoustic feedback canceller loop to avoid entrainment of the feedback canceller filter. Various embodiments employing different output phase modulation approaches are set forth and time and frequency domain examples are provided. Additional method and apparatus can be found in the specification and as provided by the attached claims and their equivalents. | 04-21-2011 |
20110103613 | AUDIO SYSTEM WITH FEEDBACK CANCELLATION - An audio system includes a signal processor for processing an audio signal, and a feedback suppressor circuit configured for modelling a feedback signal path of the audio system by provision of a feedback compensation signal based on sets of feedback model parameters for the feedback signal path that are stored in a repository. | 05-05-2011 |
20110110532 | HOWLING SUPPRESSION USING ECHO CANCELLATION - A method for reducing howling in a communication system containing collocated mobile devices is presented. In a transmitter, an audio signal is received at a microphone. Acoustic feedback is removed from the audio signal and the resulting signal is encoded and transmitted either using direct or trunked mode operation to a receiver. The encoded signal is decoded at the transmitter, in addition to at the receiver, and fed back to an echo canceller with sufficient delay to account for substantially the entirety of a loop delay from encoding of the audio signal to reception of the acoustic feedback at the microphone to enable removal of the acoustic feedback. An estimate of the acoustic feedback is used to initially remove the acoustic feedback, the error being fed back to the processor to adaptively change the signal being subtracted from the audio signal to better reduce the acoustic feedback. | 05-12-2011 |
20110164762 | AUDIO FEEDBACK SUPPRESSION DEVICE AND METHOD FOR SUPPRESSING AUDIO FEEDBACK - An audio feedback suppression device is provided that outputs a sound while changing a phase so as not to generate audio feedback without performing a relatively complicated process. A phase control section | 07-07-2011 |
20110170706 | Feedback-Killing Speaker System - A speaker system includes an interface, a powered mixer, a first amplifier, a switch, a feedback killer and a second amplifier. The interface can receives an audio signal from a sound source. The powered mixer adjusts the audio signal by amplifying some of the frequencies of the audio signal. The first amplifier preliminarily amplifies the adjusted audio signal. The switch connects the first amplifier to the feedback killer if the amplitudes of any frequencies of the preliminarily amplified audio signal are outside a predetermined range and otherwise connects the first amplifier to the second amplifier. If the first amplifier is connected to the second amplifier, the second amplifier amplifies the gain of the preliminarily amplified audio signal. If the first amplifier is connected to the feedback killer, the feedback killer executes feedback killing on the preliminarily amplified audio signal before sending it to the second amplifier. | 07-14-2011 |
20120140949 | CONFERENCE SYSTEM FOR INDEPENDENTLY ADJUSTING AUDIO PARAMETERS - A conference system for independently adjusting audio parameters is provided, including a microphone module, a storage module, a digital signal processing module and an amplifier. When any microphone of the microphone module generates an audio signal transmitted to the digital signal processing module, the priority controller determines the priority order of the audio signals entering the digital signal processing module, the digital signal processing module will read the corresponding adjustment parameters stored in the storage module, and the volume controller, equalizer, feedback suppressor perform adjustment on the audio signal. Finally, the mixer mixes the audio signals and outputs to the amplifier. The amplifier amplifies the mixed audio signal and outputs to speakers. In this manner, a single digital signal processing module can adjust different audio signals from different microphones based on different adjustment parameters, without affecting the audio signal from other microphones. | 06-07-2012 |
20120219162 | APPARATUS AND METHOD FOR REPRODUCING SOUND, AND METHOD FOR CANCELING A FEEDBACK SIGNAL - Provided are a method and apparatus for reproducing sound. A sound signal may be generated by receiving sound around the apparatus. An output signal may be generated by performing a process according to functions of the apparatus on a residual signal obtained by canceling a feedback signal from the sound signal. | 08-30-2012 |
20120275622 | Electronically compensated micro-speakers - Electronics for altering the audio frequency response of a micro-speaker without modifying the micro-speaker itself are used to provide a selected frequency response of the micro-speaker. The micro-speaker has a resonant peak region, from which the response declines for both higher and lower frequencies. In one embodiment the electronics includes a first circuit for modifying the frequency response curve up to the resonant peak region, and a second circuit for modifying the frequency response curve for audio frequencies higher than this region. Each filter yields an integer multiple of 6 dB per octave slope. In the described embodiment, for approximately correcting presbyacusis (age related hearing loss), a set of high pass filters, low pass filters, and/or high order filters are connected to the micro-speaker to progressively attenuate the frequency response curve as the frequency decreases from 10000 Hz to 100 Hz. | 11-01-2012 |
20120281855 | ACOUSTIC FEEDBACK SUPPRESSION APPARATUS, MICROPHONE APPARATUS, AMPLIFIER APPARATUS, SOUND AMPLIFICATION SYSTEM, AND ACOUSTIC FEEDBACK SUPPRESSION METHOD - An acoustic feedback suppression apparatus includes an amplitude measurement section for measuring the amplitude of a sound signal input from a microphone, an amplitude attenuation section for attenuating the amplitude of a sound signal output to a speaker, and an acoustic feedback determination section for determining whether or not acoustic feedback is occurring based on the sound signal input from the microphone. If it is determined that acoustic feedback is occurring, a sound-deadening control section enables sound-deadening control so that the amplitude of the sound signal output to the speaker is attenuated to a sound-deadening level. A sound-deadening release section releases the sound-deadening control if the amplitude of the sound signal input from the microphone is more than specified threshold amplitude and if it is determined that acoustic feedback is not occurring while the sound-deadening control is conducted. | 11-08-2012 |
20130156222 | Method and Apparatus for Blind Signal Extraction - An apparatus for extracting a signal from convolutive mixtures includes a receiving unit which includes two or more receivers and receives a signal; a transfer function calculation unit which calculates transfer functions for demixing; and a demixing unit which demixes the received signal using the calculated transfer functions. The transfer function is determined such that a signal is extracted from a source closest to the receivers, and is calculated on the basis of a transfer function for a path to each receiver being approximated to a delta function as closer to the source. | 06-20-2013 |
20130156223 | SYSTEM AND METHOD FOR INCREASING A FEEDBACK DETECTION RATE IN AN AUDIO SYSTEM - A system and method for removing feedback noise in an audio system includes an analyzing unit, which may utilize FFT processing and Feedback signal detection, and an adaptive feedback cancellation unit for removing the feedback noise, which may include, for example, 36 MR notch filters for one channel. A method to detect feedback noise in a substantially short amount of time combines increasing signal characteristics with full scale characteristics to find the feedback signal in a limited amount of time. | 06-20-2013 |
20130279717 | SENSOR CIRCUIT AND CALIBRATION METHOD - A read out circuit for a sensor uses a feedback loop to bias the sensor to a desired operating point, such as the maximal possible sensitivity, but without the problem of an instable sensor position as known for the conventional read-out with constant charge. The reference bias to which the circuit is controlled is also varied using feedback control, but with a slower response than the main bias control feedback loop. | 10-24-2013 |
20140153741 | AUDIO ADJUSTING METHOD AND ACOUSTIC PROCESSING APPARATUS - An acoustic processing apparatus and an audio adjusting method for the acoustic processing apparatus are provided. The acoustic processing apparatus is electrically connected with a microphone and a speaker. The acoustic processing apparatus includes an input unit, a storing unit, a computing unit, an adjusting unit, and an output unit. The audio adjusting method includes steps of: receiving a feedback audio from the microphone, calculating a current residue audio according to the feedback audio, a stored residue audio and an offset parameter, performing a correlation calculation to find out a relationship between the feedback audio and the stored residue audio, selectively modifying the offset parameter according to a result of the correlation calculation, and outputting the current residue audio to the speaker. | 06-05-2014 |
20140254825 | FEEDBACK CANCELING SYSTEM AND METHOD - Reducing feedback in an input signal that contains a signal component based on an output signal from a proximate output. The input signal is separated into a plurality of frequency bands by band pass filters. The power of signal in each band is determined, and the band signal with the greatest power is selected. That band's signal is sampled at a sampling rate, and at regular intervals one of the samples is selected. Blind signal separation is used to estimate signal sources from the selected samples. The estimated signals are compared to the output signal, and the estimated signal most similar to the output signal is subtracted from the input signal. | 09-11-2014 |
20140294198 | FEEDBACK CANCELLATION FOR VEHICLE COMMUNICATIONS SYSTEM - The present disclosure relates to a system and method of cancelling feedback in a vehicle communications system. The system and method may adjust a phase and a polarity of the microphone signal to produce an inverted microphone signal having a shifted phase. A speaker signal may be summed with the inverted microphone signal to cancel out at least a portion of a microphone signal component of the speaker signal. | 10-02-2014 |
20140314252 | METHOD AND DEVICE FOR REDUCING ACOUSTIC FEEDBACK - Acoustic feedback in an audio device is reduced or eliminated via a feedback compensator. The feedback compensator disposes of at least one adaptive filter whose adaptation is governed by a step-size parameter p. A step-size parameter p of the adaptive filter is set at a high level to eliminate acoustic feedback and the parameter p is decreased when a critical excitation signal is detected. This way to proceed allows for efficient elimination of feedback whistling while required environment signals are retained. | 10-23-2014 |
20150010165 | MICROPHONE MODULE WITH AND METHOD FOR FEEDBACK SUPPRESSION - A microphone module and method for suppressing feedback in a microphone. The module has a casing with a hollow bore therethrough and a microphone mounted in one end of the bore. The other end of the bore is completely covered by a film mounted onto the top of the casing. The film has at least one slit therethrough in the film portion that covers the other end of the bore. The method includes introducing a sound wave to a film having at least one slit therethrough that separates the film into at least two parts; generating a sound wave from each film part; and conveying the generated sound waves in a sound tube to a microphone as a rejoined sound wave. | 01-08-2015 |
20150104039 | APPARATUS AND METHOD OF SUPPRESSING HOWLING - Disclosed herein is an apparatus of suppressing howling, including: a microphone sensing a voice of a user to generate a voice signal; a memory storing a command for suppressing howling of the voice signal; and a processor suppressing the howling of the voice signal depending on the command, wherein the command includes a command allowing the following steps to be performed: calculating a first ratio, which is a ratio between a power of the current frame signal for the howling candidate frequency and the short-section average, and a second ratio, which is a ratio between the long-section average and the short-section average; determining the howling candidate frequency to be a howling frequency of the current frame signal; and suppressing the howling of the voice signal depending on the howling frequency. | 04-16-2015 |
20150124998 | MULTI-BAND HARMONIC DISCRIMINATION FOR FEEDBACK SUPRESSION - A method and audio signal processor for detecting feedback in an electrical amplification system divides a frequency spectrum into a plurality of frequency bands, classifies a tone present in an incoming audio signal into one of the plurality of frequency bands based on a frequency of the tone, selects a threshold value based on the frequency band into which the tone is classified, and disqualifies the tone from potentially being feedback if an amplitude of the tone is greater than an amplitude of a harmonic of the tone by less than the threshold value. The tone is deemed to be potentially feedback if the amplitude of the tone is greater than an amplitude of a plurality of harmonics of the tone by at least the threshold value. | 05-07-2015 |
20150381821 | METHOD AND APPARATUS FOR AUDIO PROCESSING - An audio apparatus comprises a circuit ( | 12-31-2015 |
20160029123 | FEEDBACK SUPPRESSION USING PHASE ENHANCED FREQUENCY ESTIMATION - A feedback suppression system for reducing acoustic feedback may include a controller configured to buffer a series of incoming digital sample signals to provide a plurality of buffered signals, the incoming digital sample signal being indicative of an audio input signal that includes audio data and acoustic feedback, determine a complex spectrum of the plurality of buffered signals, determine a magnitude squared spectrum from the complex spectrum, identify at least one peak in the magnitude squared spectrum, identify a frequency of the at least one identified peak using a phase enhanced frequency estimate, and set a notch filter at the identified frequency to eliminate the acoustic feedback of the audio input signal. | 01-28-2016 |
20160080863 | FEEDBACK SUPPRESSION TEST FILTER CORRELATION - A feedback suppression system for detecting a feedback peak may include a controller configured to identity at least one peak of an audio input signal that includes audio data and acoustic feedback, apply at least one signature to the at least one peak, determine a response of the at least one peak to the at least one signature, identify the at least one peak as a feedback peak in response to the determined response, and set a notch filter at the identified frequency to eliminate the acoustic feedback of the audio input signal. | 03-17-2016 |
20160112795 | VERY HIGH DYNAMIC-RANGE SWITCHED CAPACITOR ADC WITH LARGE INPUT IMPEDANCE FOR APPLICATIONS TOLERATING INCREASED DISTORTION AND NOISE AT LARGE INPUT SIGNAL LEVELS - A modulator is configured to respond to input swings by providing a feedback voltage via a feedback path to compromise an increase in noise and distortion power with increasing signal power at signal levels exceeding a predetermined threshold. A digital-to-analog converter (DAC) generates a feedback voltage with a resistor string biased with a given current and switches as a function of an input value to mitigate the voltage swing at a summing node. | 04-21-2016 |
20160163328 | TERMINAL, AUDIO DEVICE COMMUNICATING WITH TERMINAL, AND VEHICLE - A terminal includes: a communication unit configured to communicate with a hands-free device and an audio device provided in a place in which speech is produced; and a control unit configured to perform control such that: i) when a filter generation mode is selected, a test signal is generated, ii) when a microphone signal transmitted from the hands-free device is received, the received microphone signal and the generated test signal are mixed, and the mixed signal is transmitted to the audio device, and iii) when a feedback signal transmitted from the hands-free device is received, a sound feedback removing filter is generated based on the received feedback signal, and the generated sound feedback removing filter is transmitted to the audio device. | 06-09-2016 |