With Amplitude Control Patents (Class 381/102)
  • Publication number: 20080130915
    Abstract: An audio signal processing apparatus includes a high-pass filter for extracting from an audio signal a frequency component higher than f0, n band-pass filters for extracting, from the audio signal, frequency components falling within a frequency range from f0/N to f1/N, n harmonic overtone generators for frequency multiplying each of outputs of the n band-pass filters by N, a first combining unit for combining the generated harmonic overtone components, a level detector for detecting a level of a supplied harmonic overtone component, a gain controller for controlling dynamically the harmonic overtone component supplied from the first combining unit, and a second combining unit for combining the frequency component extracted by the high-pass filter and a harmonic overtone component output from the gain controller, where N is (n being a natural number), f0 is a first predetermined frequency, and f1 is a second predetermined frequency higher than f0.
    Type: Application
    Filed: October 16, 2007
    Publication date: June 5, 2008
    Applicant: Sony Corporation
    Inventors: Masaru Shimura, Taro Nakagami, Kazunobu Ohkuri
  • Publication number: 20080085013
    Abstract: This invention relates to a sound system and method for processing acoustical sound. The sound system comprises a microphone for converting an acoustical sound to an electrical sound signal, a processor for processing the sound signal and for generating a processed sound signal, and a speaker for converting the processed sound signal to a processed acoustical sound.
    Type: Application
    Filed: October 10, 2006
    Publication date: April 10, 2008
    Applicant: PHONIC EAR INC.
    Inventor: Deepak Somasundaram
  • Patent number: 7346173
    Abstract: A method for influencing, e.g., for decreasing, the treble reproduction of an audio signal for reproduction obtained from a received signal, the received field strength and reception quality of the received signal being evaluated and, as a function thereof, the transfer function of at least one filter unit that can be impinged upon by the audio signal being controlled, as well as a circuit assemblage or arrangement for performing such a method for the modification of treble reproduction, so that, among other things, reproduction of the interference may always be reliably concealed and so that no noticeable and/or irritating “flutter” effects may occur. The method may include processing of the output signals of at least two reception interference detectors, and processing of the received field strength may be accomplished respectively in at least one first processing branch operating at a first, e.g.
    Type: Grant
    Filed: June 3, 2003
    Date of Patent: March 18, 2008
    Assignee: Robert Bosch GmbH
    Inventor: Marcus Risse
  • Patent number: 7343019
    Abstract: A normalization for streaming digital audio signals applies a gain factor according to the maximum sample magnitude in a window of samples and compare the gain factor to prior gain factors to adjust the gain factor for the samples in the window of samples. Adaptation of the gain factor with rapid decreases but slow increases avoids saturation but allows quiet passages.
    Type: Grant
    Filed: July 25, 2002
    Date of Patent: March 11, 2008
    Assignee: Texas Instruments Incorporated
    Inventors: Timothy C. Hankins, Thomas Millikan, Christopher A. Scarr, Jason Kridner, Gabriel Dagani
  • Patent number: 7340069
    Abstract: A system and method for automatically controlling gain in a signal chain are presented. A first signal is processed to produce a processed signal. A gain is adjustably applied to the processed signal using an automatic gain control (AGC) mechanism. A resulting signal is produced. The gain is adjusted based on the first signal. As such, even when a desired signal is not substantially present in the first signal, gain is not excessively applied to the processed signal.
    Type: Grant
    Filed: September 14, 2001
    Date of Patent: March 4, 2008
    Assignee: Intel Corporation
    Inventor: Arthur E. Sheiman
  • Patent number: 7330554
    Abstract: A volume control apparatus and a method enable the volume of sound output from a sound output system to be adjusted in units of an increase/decrease interval set by a user, the volume control apparatus controlling the volume of sound output from the sound output system on a basis of volume level information set by the user.
    Type: Grant
    Filed: June 24, 2003
    Date of Patent: February 12, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Hyun-sig Lim, Eun-young Kim
  • Publication number: 20080013751
    Abstract: An electronic equipment is provided that includes an audio reproduction circuit for receiving an audio signal and reproducing the audio signal in accordance with a preselected audio frequency gain profile. In addition, the electronic equipment includes a volume gain control circuit for providing user adjustable volume gain to the audio signal reproduced by the audio reproduction circuit. The electronic equipment also includes an audio output for outputting the reproduced audio signal. The audio reproduction circuit alters the preselected audio frequency gain profile as a function of the user adjusted volume gain.
    Type: Application
    Filed: July 17, 2006
    Publication date: January 17, 2008
    Inventor: Per HISELIUS
  • Patent number: 7319764
    Abstract: Some embodiments of the invention provide a method for controlling the volume of an audio track. This method represents the volume of an audio track with a graph. This graph is defined along two axes, with one axis representing time and the other representing the volume level. A user can adjust the graph at different instances in time in order to change the volume level in the audio track at these instances. Different embodiments use different types of graphs to represent volume. For instance, some embodiments use a deformable line bar.
    Type: Grant
    Filed: January 6, 2003
    Date of Patent: January 15, 2008
    Assignee: Apple Inc.
    Inventors: Glenn Reid, James Brasure
  • Publication number: 20070269057
    Abstract: The present invention provides a sound reproduction device and method for automatic gain control. The method includes steps of: providing a gain index table for listing a plurality of time period each referencing a predetermined gain value; providing a plug for attaching to an audio signal source, receiving audio signals from the audio signal source, and generating a request signal; receiving the request signal generated by the plug; reading a current time and determining a time period corresponding to the current time; reading a predetermined gain value referenced by the time period in the gain index table; replacing the default gain value with the predetermined gain value referenced by the time period; and amplifying the audio signals received from the audio signal source by the predetermined gain value referenced by the time period, thereby audio energy of the amplified audio signals is proper to a user's hearing.
    Type: Application
    Filed: February 5, 2007
    Publication date: November 22, 2007
    Applicant: HON HAI PRECISION INDUSTRY CO., LTD.
    Inventors: Rong-Hwa Ding, Xiao-Guang Li, Bing Li, Kuan-Hong Hsieh
  • Patent number: 7286675
    Abstract: An audio signal processor includes a tone control (23). The tone control comprises two low-pass filters (221, 222) operating in current-mode and a subtractor (223) which subtracts the output currents of the filters to produce a band-pass characteristic. Each filter is a tuneable log-domain current-mode filter comprising MOS transistors operating in weak inversion. The tone control is useful in audio signal processors, hearing aids and single-channel and multi-channel Cochlear implants.
    Type: Grant
    Filed: January 8, 1999
    Date of Patent: October 23, 2007
    Assignee: Imperial College of Science, Technology & Medicine
    Inventors: Graham O'Neill, Walter Germanovix, Christopher Toumazou
  • Patent number: 7266205
    Abstract: A method for use with equipment having filters, the method characterized by multiplying a matrix having a specified cut-boost setting of a filter of a graphic equalizer by a correction matrix to create a matrix having a corrected cut-boost setting of the filter of the graphic equalizer; adjusting an actual cut-boost setting of the filter of the graphic equalizer to be substantially equal to the corrected cut-boost setting of the filter of the graphic equalizer; and configuring the filter to have a Q value substantially equal to a linearizing Q value. In addition to the foregoing, other method embodiments are described in the claims, drawings, and text forming a part of the present application.
    Type: Grant
    Filed: January 13, 2003
    Date of Patent: September 4, 2007
    Assignee: Rane Corporation
    Inventor: Raymond S. Miller
  • Patent number: 7248702
    Abstract: A system for enhancing sound quality comprising a filter that square roots the instantaneous amplitude of frequencies in an input signal for generating artificial harmonics corresponding to said frequencies. The system can comprise an automatic level control that momentarily boosts the amplitude of artificially generated harmonics to emphasize attack transients occuring within the input signal.
    Type: Grant
    Filed: January 6, 2003
    Date of Patent: July 24, 2007
    Inventor: Thomas Nelson Packard
  • Publication number: 20070160232
    Abstract: An audio input signal is processed to produce a processed audio output signal. An audio input signal is received as an original signal. The audio input signal is dynamically filtered to produce a first stage signal consisting of a selected frequency band of the input signal. Gain applied to the first stage signal is dynamically controlled in response to a control signal to produce a second stage signal. The control signal is derived from the first stage signal. Processing the original signal in combination with the second stage signal to produce a processed audio output signal. Processing the original signal in combination with the second stage signal and the first stage signal to produce a processed audio output signal.
    Type: Application
    Filed: December 13, 2006
    Publication date: July 12, 2007
    Applicant: RED LION 49 LIMITED
    Inventors: Christopher Sefton JENKINS, Mark Nicholas STOW
  • Patent number: 7171010
    Abstract: Audio processing methods and apparatus are provided for at least partially compensating for the Fletcher-Munson effect. An audio processor includes a variable filter receiving an input signal and providing a filtered output signal, the variable filter having a fixed cutoff frequency and a quality factor that is controllable in response to a control signal, and a control circuit configured to detect a signal level representative of input signal level in a selected band and to generate the control signal in response to the detected signal level. The control circuit may include a low-pass band select filter and a detector for detecting a signal level in the band selected by the low-pass filter and for generating the control signal.
    Type: Grant
    Filed: September 11, 2003
    Date of Patent: January 30, 2007
    Assignee: Boston Acoustics, Inc.
    Inventors: Stephen L. Martin, Gregory B. Burlingame, John R. David, Glenn G. Rogge
  • Patent number: 7123724
    Abstract: The invention is directed to a sound system with four loudspeakers and at least one signal processing device connected to the input of two loudspeakers and controlled by two input signals. The signal processing device produces control signals for the loudspeakers. The respective control signals are equal to the sum of the input signals which are weighted differently with respect to amplitude and phase, so that the radiation characteristic of the two loudspeakers depends on the weighting of the input signals.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: October 17, 2006
    Inventors: Gerhard Pfaffinger, Franz Lorenz, Markus Christoph
  • Patent number: 7116790
    Abstract: Conventional analog loudspeakers have a limited dynamic range as compared to the available dynamic range of digital recordings. Digital recordings use up to 24 bits and this implies a dynamic range of 141 dB. Digital loudspeakers, involving 2N single bit devices (with N=24, this number is 1.7×107) have been proposed. The present improvement is the provision of at least one loudspeaker, a plurality of analog drivers and the audio input supplied to a control processor which in turn drives one or more of the plurality of independent analog drivers. The number of drivers in operation at any one time is determined by the amplitude of the input audio signal to the control processor.
    Type: Grant
    Filed: February 4, 2002
    Date of Patent: October 3, 2006
    Assignee: QinetiQ Limited
    Inventors: Kenneth H Heron, Malcolm Nash, Andrew P Payne
  • Patent number: 7110555
    Abstract: A sound signal reproducing apparatus for supplying sound signals of a plurality of channels to speakers via sound amplifier circuits includes: a power supply voltage controller for controlling a power supply voltage to the sound amplifier circuits; a plurality of filter circuits for passing predetermined frequencies of the output signal of each of the sound amplifier circuits in the plurality of channels; a plurality of level detection circuits for detecting levels of output signals of the plurality of filter circuits; an adder circuit for adding output signals of the plurality of level detection circuits; and a comparator circuit for comparing an output signal of the adder circuit with a reference level, so that an output signal of the comparator circuit controls the power supply voltage controller.
    Type: Grant
    Filed: July 30, 2002
    Date of Patent: September 19, 2006
    Assignee: Sony Corporation
    Inventor: Hideaki Shiobara
  • Patent number: 7107109
    Abstract: The present invention relates to a process for adjusting the sound volume of a digital sound recording characterized in that it comprises: a step consisting of determining, in absolute values, for a recording, the maximum amplitude values for sound frequencies audible for the human ear, a step consisting of calculating the possible gain for a specified sound level setting, between the maximum amplitude value determined above and the maximum amplitude value for all frequencies combined, a step consisting of reproducing the recording with a sound card by automatically adjusting the amplification gain level making it possible to obtain a sound level for the recording of a specified value so that it corresponds to the gain calculated for this recording.
    Type: Grant
    Filed: June 1, 2000
    Date of Patent: September 12, 2006
    Assignee: Touchtunes Music Corporation
    Inventors: Guy Nathan, Dominique Dion
  • Patent number: 7095860
    Abstract: A method and apparatus for applying a gain characteristic to an audio signal are provided. Data storing a plurality of gain characteristics at a plurality of different levels is stored in a storage means. The amplitude of an input signal is repeatedly assessed and from this a gain characteristic to be applied to the input is determined.
    Type: Grant
    Filed: November 11, 1999
    Date of Patent: August 22, 2006
    Inventor: Michael Joseph Kemp
  • Patent number: 7068799
    Abstract: In correcting the sound field, the loudspeakers 6FL to 6WF are sounded by the noise. The attenuation factors of the inter-band attenuators ATF11 to ATFki for adjusting gains of the band-pass filters BPF11 to BPFki to the frequency in respective channels are corrected based on detection results of the reproduced sounds of the loudspeakers 6FL to 6WF. Then, the attenuation factors of the channel-to-channel attenuators ATG1 to ATG5 are corrected based on the detection results of the reproduced sounds of the loudspeakers 6FL to 6WF. Then, the delay times of the delay circuits DLY1 to DLY5 are corrected based on the detection results of the reproduced sounds of the loudspeakers 6FL to 6WF. Then, the attenuation factor of the channel-to-channel attenuator ATGk is corrected based on the detection result of the reproduced sound of the loudspeaker 6WF as the subwoofer, whereby the levels of the reproduced sounds reproduced by the loudspeakers 6FL to 6WF are adjusted to be made flat over the audio frequency band.
    Type: Grant
    Filed: February 13, 2001
    Date of Patent: June 27, 2006
    Assignee: Pioneer Corporation
    Inventor: Yoshiki Ohta
  • Patent number: 7058187
    Abstract: A filter coefficient of a graphic equalizer GEQ is corrected based on detection results of reproduced sounds generated by supplying a noise to all frequency band loudspeakers 6FL to 6RR and a low frequency band exclusively reproducing loudspeaker 6WF via the graphic equalizer GEQ. Then, attenuation factors of channel-to-channel attenuators ATG1 to ATG5 are corrected based on the detection results of the reproduced sounds generated by supplying the noise to the loudspeakers 6FL to 6RR via the graphic equalizer. Then, delay times of delay circuits DLY1 to DLYk are corrected based on the detection results of the reproduced sounds generated by supplying the noise to the loudspeakers 6FL to 6WF via the graphic equalizer.
    Type: Grant
    Filed: February 13, 2001
    Date of Patent: June 6, 2006
    Assignee: Pioneer Corporation
    Inventor: Yoshiki Ohta
  • Patent number: 7024260
    Abstract: Maximal and minimal values represented by samples of a digital audio signal are detected. A number of samples from a sample representing a minimal value to a maximal-value-corresponding sample is detected. A number of samples from a sample representing a maximal value to a minimal-value-corresponding sample is detected. Calculation is given of a first difference between the maximal-value-corresponding sample and the immediately-preceding sample. Calculation is given of a second difference between the minimal-value-corresponding sample and the immediately-preceding sample. First and second coefficients are calculated from the detected sample numbers. The first coefficient and the first difference are multiplied to generate a first multiplication result. The second coefficient and the second difference are multiplied to generate a second multiplication result. The maximal value represented by the maximal-value-corresponding sample is incremented by the first multiplication result.
    Type: Grant
    Filed: November 8, 2001
    Date of Patent: April 4, 2006
    Assignee: Victor Company of Japan, Ltd.
    Inventor: Toshiharu Kuwaoka
  • Patent number: 7024008
    Abstract: A method of enhancing the audio quality in a reproduction medium having unknown characteristics. With this method a predetermined finite set of single frequency tones are generated and these tones are then passed through the reproduction medium to generate an output signal, which in turn is passed through a set of sub-band filters. Each of the sub-band filters pass at least a frequency corresponding to one of the tones in the set of tones. The characteristics of the reproduction medium is then estimated as a result of passing the output signal through the set of sub-band filters. Based on the estimated characteristics of the reproduction medium, a set of sub-band inverse filters are constructed. Finally before passing the audio signal through the reproduction medium the signal is passed through the set of inverse filters to improve the quality of the audio signal after it passes through the reproduction medium.
    Type: Grant
    Filed: May 17, 2001
    Date of Patent: April 4, 2006
    Assignee: International Business Machines Corporation
    Inventors: Anand Narasimhan, Ganesh Nachiappa Ramaswamy
  • Patent number: 6970571
    Abstract: An earmuff comprising a headpiece and a circuit. The headpiece supports the earmuff on the head of an individual. The circuit has an input device for receiving external sound energy and converting the external sound energy to electrical sound signals.
    Type: Grant
    Filed: February 3, 2003
    Date of Patent: November 29, 2005
    Assignee: Jackson Products, Inc.
    Inventors: Jon P. Knorr, Benjamin P. Knapp
  • Patent number: 6928172
    Abstract: In correcting the sound field, loudspeakers 6FL to 6WF are sounded by the noise. The attenuation factors of the inter-band attenuators ATF11 to ATFki for adjusting gains of the band-pass filters BPF11 to BPFki to the frequency in respective channels are corrected based on detection results of the reproduced sounds of the loudspeakers 6FL to 6WF. The attenuation factors of channel-to-channel attenuators ATG1 to ATG5 are corrected based on the detection results of the reproduced sounds of the loudspeakers 6FL to 6WF. The delay times of delay circuits DLY1 to DLY5 are corrected based on the detection results of the reproduced sounds of the loudspeakers 6FL to 6WF. The attenuation factor of a channel-to-channel attenuator ATGk is corrected based on the detection result of the reproduced sound of the loudspeaker 6WF as the subwoofer. Therefore, the levels of the reproduced sounds reproduced by the loudspeakers 6FL to 6WF are adjusted to be made flat over the audio frequency band.
    Type: Grant
    Filed: February 13, 2001
    Date of Patent: August 9, 2005
    Assignee: Pioneer Corporation
    Inventor: Yoshiki Ohta
  • Patent number: 6895290
    Abstract: Minimizing the damaging effects of loud music but with minimal reduction in aesthetic quality of the music. When music presented through an audio is sampled in order to determine average frequency, music having very low average frequencies is predictably likely to be played louder than sampled music having higher average frequencies. This unexpected observation is based upon a human factor, i.e. rock and related music that is ordinarily composed and presented at relatively low frequencies, e.g. 500 to 1000 Hz is likely to be played on the audio system at very high volume because of the tastes of its listeners. An audio system for a data processor controlled presentation of music with a set up for minimizing the damaging effects of loud music comprising an implementation for predetermining a minimum average frequency of music being presented in combination with measuring whether the music being presented falls below said minimum average frequency for a sampling period.
    Type: Grant
    Filed: July 11, 2002
    Date of Patent: May 17, 2005
    Assignee: International Business Machines Corporation
    Inventors: Faisal M. Awada, Joe Nathan Brown, Philip Bernard Burkes
  • Patent number: 6795740
    Abstract: 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 overflow/underflow occurs. In a first preferred embodiment a single stage scale down solution is provided in starting and end points of the overflow/underflow areas in the audio signal are detected, and a number of discrete sampling points along the audio signal curve between these two points are adjusted by a predetermined multiplier in order to reduce the positive level (in the case of overflow) or negative level (in the case of underflow) of each discrete sampling point. Using the single stage scale down solution of the present invention, a new audio signal is created having no overflow/underflow, yet maintaining the former generally smooth shape of the audio signal waveform and signal characteristics, without completely clipping the audio levels.
    Type: Grant
    Filed: March 1, 2000
    Date of Patent: September 21, 2004
    Assignee: Apple Computer, Inc.
    Inventors: Ke Chiang Chu, Hong Kaura, James Peter Hoddie
  • Publication number: 20040136547
    Abstract: A system and method providing content for access by a portable device at an event is provided. The method includes receiving a plurality of signals from a plurality of sources and combining at least some of the plurality of signals for transmission to a plurality of broadcast systems, with the plurality of broadcast systems corresponding to a plurality of events. The method further includes determining the broadcast systems to which each of the combined signals is to be transmitted, transmitting the combined signals to at least one of the determined broadcast systems, and broadcasting the combined signals received by at least one of the broadcast systems corresponding to at least one event. The combined signals are configured to allow selection of content with a portable device, with the content defined by at least one of audio and video signals of the combined signals.
    Type: Application
    Filed: October 7, 2003
    Publication date: July 15, 2004
    Inventors: Tazwell L. Anderson, Robert J. Kniskern, Todd H. Steele
  • Publication number: 20040091120
    Abstract: Acoustical characteristics of rooms or other environments in which audio systems operate may be improved by equalization derived from measures of relative acoustic energy storage of the audio system such as a Relative Acoustic-energy Decay Spectrum (RADS). A RADS may be calculated from a measure of absolute energy storage such as RT60 values obtained from models or measurements of the audio system, and normalized with respect to a measure of acoustic energy storage of a reference system.
    Type: Application
    Filed: November 12, 2002
    Publication date: May 13, 2004
    Inventors: Kenneth L. Kantor, Andrew David Unruh
  • Patent number: 6731768
    Abstract: An improved hearing aid is disclosed having a switched release automatic gain control. In one embodiment, an input signal is presented to a comparator with a reference typically around, for example, 65 dB SPL instantaneous. The output of the comparator controls a switch in a release circuit of an automatic gain control. While the instantaneous input level exceeds the threshold, the release circuit is enabled and the automatic gain control behaves normally. While the instantaneous input level does not exceed the threshold, the release circuit is disabled and the automatic gain control maintains its current gain setting, essentially indefinitely. Because speech, even soft speech, has a very high positive peak content, this circuit will recover any needed gain in the presence of speech (assuming an appropriate threshold) but not recover gain to background noise whose positive peak content is below the threshold.
    Type: Grant
    Filed: July 26, 2000
    Date of Patent: May 4, 2004
    Assignee: Etymotic Research, Inc.
    Inventor: David J. Delage
  • Patent number: 6665408
    Abstract: A circuit for providing a variable amount of bass control on an input signal dependent on a signal level of the input signal includes a high-pass filter, a variable impedance shunt connected to the output of the high-pass filter, and a signal level detector for controlling the variable impedance shunt. Depending on the signal level, the variable impedance shunt varies the Q value of the high-pass filter so that at low signal levels, the Q value is at its maximum while at high signal values, the Q value is lowered.
    Type: Grant
    Filed: November 13, 1998
    Date of Patent: December 16, 2003
    Assignee: Koninklijke Philips Electronics N.V.
    Inventor: Wayne Milton Schott
  • Publication number: 20020164039
    Abstract: A method for controlling audio gain balance in a multi-mode communications device (200) includes providing (201) microphone audio input to the multimode communications device. The audio is supplied to an amplifier gain stage while a dynamic instantaneous energy value of the audio input is computed (203) when in a first operational mode such as an analog mode. A predetermined gain algorithm is processed (207) representing an audio input when in a second mode such as a digital mode using the energy value. The audio gain stage in the multi-mode communications device is then adjusted (209) so that audio gain when in the first mode substantially approximates an audio gain when in an second mode. This provides a consistent audio amplitude output when receiving the first and second modes in a radio receiver.
    Type: Application
    Filed: May 4, 2001
    Publication date: November 7, 2002
    Inventors: Charles H. Carter, Karthik Narasimhan
  • Patent number: 6442281
    Abstract: Difference compensation circuits are connected to a volume controller having a tap in series. Each of the difference compensation circuit comprises a voltage control amplifier and an external CR network. The difference compensation circuits are arranged so as to independently attenuate a bass range and increase a mid-range in accordance with an amount of volume control by the volume controller.
    Type: Grant
    Filed: May 21, 1997
    Date of Patent: August 27, 2002
    Assignee: Pioneer Electronic Corporation
    Inventors: Shinichi Sato, Akira Shimizu
  • Publication number: 20020067838
    Abstract: Systems, devices, and methods are provided to inhibit apparent amplitude modulation in non-linear processing that causes distortion in a processed signal. One aspect of the invention includes a hearing aid. The hearing aid includes a microphone to receive an input signal, a speaker to reproduce the input signal, and a processor. The processor processes the input signal using a gain. The processor includes an inhibitor, which inhibits distortions, and an adjuster, which adjusts the gain. The inhibitor acts to smooth an envelope of the input signal to inhibit undesired modulation. The adjuster adjusts the gain if the envelope is either above or below a threshold.
    Type: Application
    Filed: December 5, 2000
    Publication date: June 6, 2002
    Applicant: Starkey Laboratories, Inc.
    Inventors: Jon Schmidt Kindred, Bryant Sorensen, Jerry Wahl
  • Publication number: 20010033667
    Abstract: A circuit for processing an audio signal includes an input stage to which the audio signal is applied and an output at which the processed audio signal is presented. The circuit comprises first and second input stages (11, 12) having nonlinear performance curves, the first stage receiving the audio signal at a specified phase, and the second stage receiving from an inverter (13) an inverse phase of the audio signal. A positive half wave of the input signal is processed nonlinearly and the negative half wave is processed linearly. A difference amplifier (14) receives the signals produced by the first and second input stages and generates an audio signal representing a difference between the signals present at its inputs.
    Type: Application
    Filed: March 29, 2001
    Publication date: October 25, 2001
    Inventors: Uli Behringer, Jan Duwe
  • Publication number: 20010033665
    Abstract: A method of enhancing the audio quality in a reproduction medium having unknown characteristics. With this method a predetermiined finite set of single frequency tones are generated and these tones are then passed through the reproduction medium to generate an output signal which in turn is passed through a set of sub-band filters. Each of the sub-band filters pass at least a frequency corresponding to one of the tones in the set of tones. The characteristics of the reproduction medium is then estimated as a result of passing the output signal through the set of sub-band filters. Based on the estimated characteristics of the reproduction medium, a set of sub-band inverse filters are constructed. Finally before passing the audio signal through the reproduction medium the signal is passed through the set of inverse filters to improve the quality of the audio signal after it passes through the reproduction medium.
    Type: Application
    Filed: May 17, 2001
    Publication date: October 25, 2001
    Inventors: Anand Narasimhan, Ganesh Nachiappa Ramaswamy
  • Patent number: 6298139
    Abstract: An apparatus and method for maintaining a constant speech envelope using automatic gain control, wherein the level of the audio signal is monitored. If increasing, a first level of gain increase is applied to the gain signal. If decreasing, a second level of gain decrease is applied to the gain signal, the second level being less than the first level. By applying a lower level of change to the gain signal when it is seen as decreasing, a more constant speech envelope is obtained during gaps and interstices in the analog signal that are common in speech.
    Type: Grant
    Filed: December 31, 1997
    Date of Patent: October 2, 2001
    Assignee: Transcrypt International, Inc.
    Inventors: Steven P. Poulsen, James P. Preston, II
  • Patent number: 6252968
    Abstract: A method of enhancing the audio quality in a reproduction medium having unknown characteristics. With this method a predetermined finite set of single frequency tones are generated and these tones are then passed through the reproduction medium to generate an output signal, which in turn is passed through a set of sub-band filters. Each of the sub-band filters pass at least a frequency corresponding to one of the tones in the set of tones. The characteristics of the reproduction medium is then estimated as a result of passing the output signal through the set of sub-band filters. Based on the estimated characteristics of the reproduction medium, a set of sub-band inverse filters are constructed. Finally before passing the audio signal through the reproduction medium the signal is passed through the set of inverse filters to improve the quality of the audio signal after it passes through the reproduction medium.
    Type: Grant
    Filed: September 23, 1997
    Date of Patent: June 26, 2001
    Assignee: International Business Machines Corp.
    Inventors: Anand Narasimhan, Ganesh Nachiappa Ramaswamy
  • Patent number: 6195438
    Abstract: A microcomputer for automatically controlling the sound in an audio or audio-visual system. Incoming audio signals from multiple channels are combined and fed to a pair of detector-rectifier circuits. One detector-rectifier circuit is a smoothing circuit with a time constant longer than that of the other detector-rectifier circuit. The signals with a longer time constant are fed to the microprocessor to control the volume function of an audio or audio-visual system. The signals with a shorter time constant are fed to the microprocessor to equalize the source frequency spectrum of an audio or audio-visual system.
    Type: Grant
    Filed: September 8, 1997
    Date of Patent: February 27, 2001
    Assignee: Matsushita Electric Corporation of America
    Inventors: Hideki Yumoto, Theodore S. Rzeszewski
  • Patent number: 6167139
    Abstract: A sound control apparatus and method for an audio/video appliance are disclosed.
    Type: Grant
    Filed: December 9, 1997
    Date of Patent: December 26, 2000
    Assignee: LG Electronics Inc.
    Inventor: Mun Seob Kim
  • Patent number: 6148189
    Abstract: A tuner is presented wherein each o a plurality of RF AGC gain controllable amplifiers are individually controlled by individual AGC control signals generated by an AGC controller so that the level of the output signal from each of the RF AGC gain controllable amplifiers is individually optimized for tuner performance.
    Type: Grant
    Filed: October 10, 1997
    Date of Patent: November 14, 2000
    Inventor: Felix Aschwanden
  • Patent number: 6147558
    Abstract: Two banks of differently-connected resistors are connected as an input to an op-amp feedback circuit.
    Type: Grant
    Filed: April 14, 1999
    Date of Patent: November 14, 2000
    Assignee: ESS Technology, Inc.
    Inventor: Terry L. Sculley
  • Patent number: 6108428
    Abstract: A volume/tone control circuit comprises first and second latch circuits (8) and (9) for latching the volume control data BD and the tone control data TD stored in the shift register (7); a volume regulating circuit (2) and a tone regulating circuit (3) for regulating the volume and the tone of the input audio signal according to the respective output data of the first and second latch circuits (8) and (9); and a zero-crossing detection circuit (12) for detecting zero-crossings of the input signal. The input audio signal is fed to the zero-crossing detection circuit (12) when a data detection circuit (20) detects that the input data and the output data of the first latch circuit (8) differ.
    Type: Grant
    Filed: April 23, 1997
    Date of Patent: August 22, 2000
    Assignee: Sanyo Electric Co., Ltd
    Inventors: Masaaki Suzuki, Masahiro Umewaka
  • Patent number: 6078670
    Abstract: An arrangement for reproducing audio signals includes a pitch control device for increasing or decreasing the amplification of audio signals in one or more defined frequency ranges and a volume control device for increasing and decreasing the amplification of the audio signals in a full effective frequency range of the audio signals wherein the pitch control device reduces the amplification in the defined frequency ranges if the amplification of the audio signals in the full effective frequency range is increased by the volume control device and wherein the pitch control device increases the amplification of the audio signals in the defined frequency ranges if the volume control device decreases the amplification of the audio signals in the full effective frequency range.
    Type: Grant
    Filed: September 24, 1997
    Date of Patent: June 20, 2000
    Assignee: Volkswagen AG
    Inventor: Detlev Beyer
  • Patent number: 6023513
    Abstract: A system and method for improving clarity of an audio signal to be transmitted over a limited bandwidth communication channel selects predetermined frequencies of the audio signal for processing and adds even harmonic distortion to the selected frequencies such that the distortion is added within the limited bandwidth of the transmission channel. The system and method are particularly suited for telephony applications and may be utilized in hearing aids due to the effectiveness of clarifying voice signals. In addition, the system and method may be applied to other very low bandwidth signals, such as data compressed audio signals, computer voice files, computer audio files, and numerous other technologies which have an audio response less than normal human perception. The technique also applies to the use of perceptually coded audio.
    Type: Grant
    Filed: January 11, 1996
    Date of Patent: February 8, 2000
    Assignees: U S West, Inc., MediaOne Group, Inc.
    Inventor: Eliot M. Case
  • Patent number: 5982907
    Abstract: An audio signal waveform emphasis processing device performs even-order integration on an input audio signal using one or a plurality of double integrators and even-order differentiation on the input audio signal using one or a plurality of double differentiators so as to obtain even-order integrated signal and even-order differentiated signal, and adds the even-order integrated signal and the even-order differentiated signal to the input audio signal in the same phase or reverse-phase with the input audio signal, whereby sound quality of audio signal in audio equipment is greatly improved by obtaining a desired frequency-gain characteristic without destroying the mutual phase relationship between, in particular, the middle frequency range vs. high frequency range and the middle frequency range vs. low frequency range frequency components close to the middle frequency range of an input audio signal.
    Type: Grant
    Filed: October 22, 1997
    Date of Patent: November 9, 1999
    Assignee: Jun-Ichi Kakumoto
    Inventors: Norio Akamatsu, Jun-ichi Kakumoto
  • Patent number: 5953430
    Abstract: A filter circuit adjustably decreases or increases the amplitude of audio signals in a predetermined frequency range. The filter circuit includes a filter module having an RC network with at least one frequency-response-determining RC member whose resistor component R is realized in SC technology. A setting device is connected to the filter module such that its setting determines the frequency response of the SC filter. The setting device renders possible a neutral setting in which the effective audio signal path of the filter circuit circumvents the filter module so that no decrease or increase of the amplitude of individual frequency portions takes place. Furthermore, an audio signal processor comprises at least one audio signal input, at least one audio signal output, and at least one control input.
    Type: Grant
    Filed: July 25, 1997
    Date of Patent: September 14, 1999
    Assignee: STMicroelectronics GmbH
    Inventors: Peter Kirchlechner, Jorg Schambacher, Jurgen Lubbe
  • Patent number: 5923767
    Abstract: Digital audio processing apparatus comprises: device for detecting the magnitude of an input digital audio signal; and a variable gain element for applying a gain to the input digital audio signal dependent on the detected magnitude of the input digital audio signal, in which:(i) the applied gain is linearly related to the envelope signal with a first predetermined slope, for detected magnitudes below a first threshold magnitude;(ii) the applied gain is linearly related to the envelope signal with a second predetermined slope, for detected magnitudes above a second threshold magnitude higher than the first threshold magnitude; and(iii) for detected magnitudes from the first threshold magnitude to the second threshold magnitude, the slope of the applied gain with respect to detected magnitude varies monotonically from the first predetermined slope to the second predetermined slope.
    Type: Grant
    Filed: February 19, 1997
    Date of Patent: July 13, 1999
    Assignees: Sony Corporation, Sony United Kingdom Limited
    Inventors: Paul Anthony Frindle, Peter Charles Eastty
  • Patent number: 5883963
    Abstract: The method of adjusting the volume and the loudness in an audio device uses a volume-control unit for attenuating an audio signal by a predetermined value and a loudness-control unit for attenuating, by a further predetermined value, every component of the audio signal when in an inactive state and only the high-frequency components when in an active state. The method includes the steps of setting a volume level, associating a first and a second attenuation value with the volume level set, attenuating the audio signal by the first value and by the second value by means of the volume-control unit and the loudness-control unit, respectively, and switching the loudness-control unit selectively between the active state and the inactive state.
    Type: Grant
    Filed: November 19, 1997
    Date of Patent: March 16, 1999
    Assignee: SGS-Thomson Microelectronics S.r.l.
    Inventor: Maurizio Tonella
  • Patent number: RE37223
    Abstract: An automatic dynamic equalization circuit has a potentiometer having a tap shunted by an active resonator circuit including a capacitor shunted by an active circuit presenting a high Q inductive reactance that is resonant at substantially 50 Hz and provides essentially no boost in the middle range of frequencies above 150 Hz with roll-off below about 45 Hz.
    Type: Grant
    Filed: May 10, 1999
    Date of Patent: June 12, 2001
    Assignee: Bose Corporation
    Inventors: Amar G. Bose, Richard G. Plourde