Filtering (fir, Hpf, Widrow-hoff, Lms) Patents (Class 379/390.02)
  • Patent number: 11539833
    Abstract: A multi-channel acoustic echo cancellation (AEC) system that includes a step-size controller that dynamically determines a step-size value for each channel and each tone index on a frame-by-frame basis. The system determines that near-end signals are present by calculating a scaled error and determining that the scaled error exceeds a threshold value. When the scaled error exceeds the threshold value, the system may switch from a first cost function to a second cost function and determine a step-size value using a robust algorithm. The robust algorithm may prevent the system from diverging due to the presence of the near-end signal. For example, the robust algorithm may select a different cost function to determine the step-size value and/or combine different step-size computations, resulting in the step-size value being temporarily reduced. Thus, the robust algorithm may enable the AEC to better model the near-end disturbance statistics while the near-end signal is present.
    Type: Grant
    Filed: January 10, 2020
    Date of Patent: December 27, 2022
    Assignee: Amazon Technologies, Inc.
    Inventor: Carlos Renato Nakagawa
  • Patent number: 11146225
    Abstract: A method and system for a headset with programmable modes, where the headset comprises a beamforming microphone: sensing an ambient sound level near the headset, and configuring the headset in one of a plurality of modes by configuring a beam pattern of the beamforming microphone based on at least the sensed ambient noise level. A user of the headset may configure the headset in the one of the plurality of modes or it may be automatically configured. The beamforming microphone may comprise an array of sound sensing elements. The headset may be configured in a quiet mode when the sensed ambient sound level is below that of a desired sound source and may be configured with a wide beam pattern. The headset may be configured in a loud mode when the sensed ambient sound level is above that of a desired sound source.
    Type: Grant
    Filed: August 23, 2019
    Date of Patent: October 12, 2021
    Assignee: Voyetra Turtle Beach, Inc.
    Inventors: Shobha Devi Kuruba Buchannagari, Richard Kulavik
  • Patent number: 10938992
    Abstract: Traditional audio feedback elimination systems may attempt to reduce the effect of the audio feedback by simply scaling down the audio volume of the signal frequencies that are prone to howling. Other traditional feedback elimination systems may also employ adaptive notch filtering to detect and “notch” the so-called “singing” or “howling” frequencies as they occur in real-time. Such devices may typically have several knobs and buttons needing tuning, for example: the number of adaptive parametric equalizers (PEQs) versus fixed PEQs; attack and decay timers; and/or PEQ bandwidth. Rather than removing the singing frequencies with PEQs, the devices described herein attempt to holistically model the feedback audio and then remove the entire feedback signal. Two advantages of the devices described herein are: 1.) the system can operate at a much larger loop-gain (and hence with a much higher loudspeaker volume); and 2) setup is greatly simplified (i.e., no tuning knobs or buttons).
    Type: Grant
    Filed: May 6, 2019
    Date of Patent: March 2, 2021
    Assignee: Polycom, Inc.
    Inventors: Kwan Truong, Peter L. Chu
  • Patent number: 10547407
    Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for reducing jitter and latency in a PON. In one aspect, an optical network unit includes a downstream optical receiver configured to receive downstream traffic over a first wavelength; a first upstream optical transmitter having a first data rate; a second upstream optical transmitter having a second data rate that is higher than the first data rate; and a controller configured to direct upstream traffic to one of the first upstream optical transmitter or the second upstream optical transmitter depending on a traffic type of the traffic. Traffic having a control plane traffic type is directed to the first upstream optical transmitter and traffic having a data plane traffic type is directed to the second upstream optical transmitter.
    Type: Grant
    Filed: October 12, 2018
    Date of Patent: January 28, 2020
    Assignee: ADTRAN, Inc.
    Inventor: Jared Cress
  • Patent number: 10132889
    Abstract: A system and method for reducing MRI-generated acoustic noise is disclosed. A system control of an MRI apparatus causes a plurality of gradient coils and an RF coil assembly in the MRI apparatus to generate pulse sequences that each cause an echo train to form and acquire blades of k-space data of the subject of interest from the pulse sequences, with the blades being rotated about a section of k-space compared to every other blade. The system control also causes the plurality of gradient coils to generate gradient pulses in each pulse sequence having an optimized gradient waveform that reduces an acoustic noise level generated thereby and causes the RF coil assembly to generate a 180 degree prep pulse subsequent to generation of an RF excitation pulse and prior to generation of a first RF refocusing pulse, the 180 degree prep pulse minimizing echo spacing in the echo train.
    Type: Grant
    Filed: May 22, 2013
    Date of Patent: November 20, 2018
    Assignee: GENERAL ELECTRIC COMPANY
    Inventors: Dawei Gui, Anton M. Linz, Ajeetkumar Gaddipati, Xiaoli Zhao, Shaorong Chang, Donglai Huo
  • Patent number: 10122340
    Abstract: An LC filter includes a laminate including insulating layers laminated in a lamination direction, an inductor having a spiral or helical shape around an axis parallel or substantially parallel to the lamination direction, and a capacitor in which capacitor conductors face each other. The inductor and the capacitor do not overlap as viewed from the lamination direction and all directions orthogonal or substantially orthogonal to the lamination direction.
    Type: Grant
    Filed: December 21, 2017
    Date of Patent: November 6, 2018
    Assignee: MURATA MANUFACTURING CO., LTD.
    Inventor: Hiroshi Masuda
  • Patent number: 9867012
    Abstract: A method for detecting whispered speech of a user of a mobile computerized device, the method comprises: detecting, by the mobile computerized device, whispered speech context; and attempting to detect, by the mobile computerized device and by using whispered speech detection parameters, the whispered speech; and wherein at least one whispered speech detection parameter of the whispered speech detection parameters differs from at least one corresponding non-whispered speech parameter that is used for detecting non-whispered speech.
    Type: Grant
    Filed: June 2, 2016
    Date of Patent: January 9, 2018
    Assignee: DSP GROUP LTD.
    Inventors: Yaakov Chen, Doron Koren
  • Patent number: 9800734
    Abstract: An audio echo suppressor includes a first receiver for receiving a first audio signal for rendering by a loud-speaker and a second receiver for receiving a microphone signal. A linear echo-cancellation filter generates a first compensation signal from the first audio signal and a compensator generates a residual signal by compensating the microphone signal for the first compensation signal. A first adapter determines filter parameters for the linear echo-cancellation filter. An estimator generates distortion measures where each distortion measure is indicative of the contribution to the residual signal in a frequency interval outside a first frequency interval. The residual signal results from rendering of signal components of the first audio signal that are within the first frequency interval. An echo reducer performs echo suppression based on the distortion measures.
    Type: Grant
    Filed: November 5, 2014
    Date of Patent: October 24, 2017
    Assignee: KONINKLIJKE PHILIPS N.V.
    Inventors: Patrick Kechichian, Cornelis Pieter Janse
  • Patent number: 9496920
    Abstract: A fueling environment communication system for providing high bandwidth information via existing field wiring to a plurality of forecourt devices. The communication system according to this aspect comprises a back room communication module having a first plurality of Ethernet ports for connection to external devices using Ethernet communication and a second plurality of Ethernet ports. The back room communication module further comprises a plurality of modulation interface devices each connected on a first side to a respective one of the second plurality of Ethernet ports. A summing and isolation module having a high pass filter is connected to each of the modulation interface devices on a second side thereof to pass a modulated high frequency signal. The summing and isolation module further has a low pass filter through which low frequency legacy data can be passed and combined with said modulated high frequency signal.
    Type: Grant
    Filed: November 16, 2012
    Date of Patent: November 15, 2016
    Assignee: Gilbarco Inc.
    Inventors: Giovanni Carapelli, Joseph D. Long, Wayne McNinch, Howard Myers
  • Patent number: 9064496
    Abstract: A system and method for processing a plurality of channels, for example audio channels, in parallel is provided. For example, a plurality of telephony channels are processed in order to detect and respond to call progress tones. The channels may be processed according to a common transform algorithm. Advantageously, a massively parallel architecture is employed, in which operations on many channels are synchronized, to achieve a high efficiency parallel processing environment. The parallel processor may be situated on a data bus, separate from a main general purpose processor, or integrated with the processor in a common board or integrated device. All, or a portion of a speech processing algorithm may also be performed in a massively parallel manner.
    Type: Grant
    Filed: August 16, 2013
    Date of Patent: June 23, 2015
    Inventor: Wai Wu
  • Patent number: 8918197
    Abstract: As the possible variations of “Hearing Thresholds”, “Hearing Loudness bandwidths” and “Voice Intonation” characteristics of people are finite, it is proposed to set a Database of these characteristics, where the data elements fully describe the Hearing and Talking characteristics of anyone, while many have the same characteristics. Thus any voice communication between two parties may be optimized by correcting the intensities of the call in the spectral domain, differently for each party and each ear. The optimizations are automatic given the “codes” of the parties and have a minimal latency. The system may be implemented either centrally in the world-wide-web or at the edges, in cellular phones, landline phones, VoIP, VoIM and in the audio parts of entertainment devices.
    Type: Grant
    Filed: June 13, 2012
    Date of Patent: December 23, 2014
    Inventor: Avraham Suhami
  • Patent number: 8892232
    Abstract: The invention describes the proprietary activities, services and devices provided to a networked community of Hearing impaired people, that help improve wired, wireless and direct voice communications.
    Type: Grant
    Filed: November 20, 2012
    Date of Patent: November 18, 2014
    Inventor: Avraham Suhami
  • Patent number: 8694326
    Abstract: A communication terminal includes a decoder which decodes an input bitstream received from another communication terminal, to generate an output audio signal and outputs the generated output audio signal to a speaker; and an echo canceller which obtains an input audio signal representing sound captured by a microphone placed in a space to which the speaker outputs the sound, and removes, for respective subbands, an echo component included in the obtained input audio signal and corresponding to the output audio signal, to generate an audio signal for transmission. An encoder codes the audio signal for transmission to generate an output bitstream and transmits the generated output bitstream to another communication terminal; and a control unit controls, for the respective subbands, echo cancellation processing according to a reproduction band of at least one of the output audio signal and the audio signal for transmission.
    Type: Grant
    Filed: August 21, 2012
    Date of Patent: April 8, 2014
    Assignee: Panasonic Corporation
    Inventors: Shuji Miyasaka, Kosuke Nishio, Ichiro Kawashima
  • Patent number: 8693677
    Abstract: A technique for updating filter coefficients of an adaptive filter includes filtering a signal with an adaptive filter, whose filter coefficients are grouped into filter blocks. In this case a number of the filter blocks is less than or equal to a number of the filter coefficients. During each update period, the filter coefficients for less than all of the filter blocks are updated based on a network echo path impulse response.
    Type: Grant
    Filed: April 27, 2010
    Date of Patent: April 8, 2014
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Hongyang Deng, Roman A. Dyba, Wen Wu Su
  • Patent number: 8619897
    Abstract: A frequency-domain based echo and NEXT canceller is provided. The canceller uses log2 encoding to precondition the error signal representing the echo. An improved gradient constraint is applied on at least a portion of a full weight vector in a least-mean-square algorithm. The least-mean-square algorithm is used to compute filter coefficients. The filter coefficients are multiplied by a frequency-domain data vector using a frequency-domain multiplier to generate frequency-domain output vector.
    Type: Grant
    Filed: December 9, 2008
    Date of Patent: December 31, 2013
    Assignee: Netlogic Microsystems, Inc.
    Inventor: Yehuda Azenkot
  • Patent number: 8509125
    Abstract: Systems, methods, and other embodiments associated with echo cancellation are described. According to one embodiment, a method uses two signals from a transmitter as input to a look-up table to generate a non-linear echo cancellation signal. The non-linear echo cancellation signal is applied to a receiving path to reduce non-linear echo distortion on the receiving path based at least in part on the current signal and the previous signal.
    Type: Grant
    Filed: October 13, 2010
    Date of Patent: August 13, 2013
    Assignee: Marvell International Ltd.
    Inventor: Jagadish Venkataraman
  • Patent number: 8363820
    Abstract: Systems and methods for operating a telecommunications device in whisper mode are presented. The method generally includes adjusting a transmit audio signal gain responsive to a transmit audio signal voice activity status, transmit audio signal speech level, transmit audio signal signal-to-noise ratio, and receive audio signal voice activity status. A sidetone feedback signal gain is adjusted in conjunction with adjusting the transmit audio signal gain.
    Type: Grant
    Filed: May 17, 2007
    Date of Patent: January 29, 2013
    Assignee: Plantronics, Inc.
    Inventor: John S Graham
  • Patent number: 8280462
    Abstract: Sound quality is enhanced in a sound system including handsets and headsets. Handset sound enhancing algorithms are implemented in a handset. The handset automatically determines which, if any, of a plurality of headset sound enhancing algorithms are active in a headset in communication with the handset. The handset determines how to use the handset sound enhancing algorithms in a sound processing channel based on which of the headset sound enhancing algorithms are active in the headset.
    Type: Grant
    Filed: November 17, 2010
    Date of Patent: October 2, 2012
    Assignee: Clarity Technologies, Inc.
    Inventors: Raymond W. Gunn, Michael A. Hayes
  • Patent number: 8190114
    Abstract: A method of transmitting information in a wireless communications system can be provided by selectively applying filtering to transmission of a carrier signal of a first band of frequencies of a wireless communications system based on a frequency separation distance between a frequency content of the carrier signal and a second band of frequencies allocated to a communications system other than the wireless communications system.
    Type: Grant
    Filed: July 17, 2006
    Date of Patent: May 29, 2012
    Assignee: ATC Technologies, LLC
    Inventors: Peter D. Karabinis, Santanu Dutta
  • Patent number: 8144852
    Abstract: A service to a user is prevented by providing, to the user, at least one communication link used to provide multiple services to the user. The plurality of services are activated over the at least one communication link. Transmission for the prevented service is prevented based on at least one characteristic of the at least one communication link over which the prevented service would be provided.
    Type: Grant
    Filed: December 14, 2007
    Date of Patent: March 27, 2012
    Assignee: AT&T Labs, Inc.
    Inventors: Mark A. Russell, Stephen Weinert
  • Patent number: 8098812
    Abstract: The invention concerns a method of controlling an adaptation of a filter, and a controller and a computer program product to execute this method. The filter is an adaptive finite impulse response (=FIR) filter for modelling an echo path impulse response for echo cancellation in a telecommunications connection between a first terminal providing a near-end signal at a first end of the telecommunications connection and a second terminal providing a far-end signal at another end of the telecommunications connection. In a multi-windowing scheme, a plurality of filter segments and segments of the far-end signal is determined in the time domain. An energy level associated to an individual segment of the far-end signal is compared with an energy level associated to a sample of the near-end signal. In dependence on the result of the comparison of the energy levels, the adaptation of an individual filter segment associated to the individual segment of the far-end signal is enabled or inhibited.
    Type: Grant
    Filed: December 12, 2006
    Date of Patent: January 17, 2012
    Assignee: Alcatel Lucent
    Inventors: Moulay Fadili, Sutharshini Illango, Abdelkrim Moulehiawy
  • Patent number: 8050397
    Abstract: In one embodiment, a method for discriminating between a machine generated multi-tone signal and a simulated voice multi-tone signal is provided. The method may comprise comparing output profiles generated from sampled outputs of a plurality of filters. The plurality of filters may have a single input sample stream applied to them and each filter may be preset at a measured multi-tone frequency associated with an identified prospective multi-tone signal. Based on the comparison of the output profiles, an inequality degree between the output profiles is generated and compared to an inequality threshold, thereby to determine whether the input sample stream comprises a machine generated multi-tone signal.
    Type: Grant
    Filed: December 22, 2006
    Date of Patent: November 1, 2011
    Assignee: Cisco Technology, Inc.
    Inventor: Brooks Stevens Read
  • Patent number: 8027461
    Abstract: A telecommunication system has a telecommunication line for communicating a combined signal and a splitter that is coupled to the telecommunication line. The splitter has a high-pass filter, a low-pass filter, and a current limiter. The high-pass filter is configured to transmit a first component signal of the combined signal, and the low-pass filter is configured to transmit a second component signal of the combined signal. The current limiter is configured to limit a current of the second component signal thereby preventing at least one inductor in the low-pass filter from saturating.
    Type: Grant
    Filed: October 11, 2007
    Date of Patent: September 27, 2011
    Assignee: ADTRAN, Inc.
    Inventors: Jared D. Cress, Daniel M. Joffe
  • Patent number: 8009823
    Abstract: A method to design low complexity and low power echo and NEXT cancellers based on wordlength reduction technique is presented. A circuit architecture to implement echo and cancellers is also presented. The low complexity and low power design relies on the fact that a TH precoder can be viewed as an IIR filter with an input equal to the sum of the original input to the TH precoder and a compensation signal. The proposed design also relies on the fact that sum of the original input to the TH precoder and the compensation signal has finite levels, which can be represented in less bits than the original input of the echo and NEXT cancellers. An improved design by exploiting the statistics of the compensation signal is also proposed to further bring down the complexity and power consumption of these cancellers.
    Type: Grant
    Filed: July 13, 2006
    Date of Patent: August 30, 2011
    Assignee: Leanics Corporation
    Inventors: Keshab K. Parhi, Yongru Gu
  • Patent number: 7903727
    Abstract: A channel memory length selection method for wireless communication systems is provided. The method comprises estimating an initial channel impulse response (CIR) for the wireless communication system; determining a first refined CIR with a first group of taps and a second refined CIR with a second group of taps based upon the initial CIR, number of the second group of taps being less than number of the first group of taps; and selecting either the number of the first group of taps or the number of the second group of taps as the channel memory length according to an energy concentration criterion in regard to the first refined CIR and the second refined CIR.
    Type: Grant
    Filed: November 24, 2006
    Date of Patent: March 8, 2011
    Assignee: VIA Technologies, Inc.
    Inventors: Yuan Xia, Min Lei, Lijun Zhang
  • Patent number: 7835773
    Abstract: A method for adjusting the volume and frequency response for the audio output in a mobile communication device comprises estimating the noise level of the environment surrounding the mobile communication device and then adjusting the volume and frequency response based on the estimated noise level.
    Type: Grant
    Filed: March 23, 2005
    Date of Patent: November 16, 2010
    Assignee: Kyocera Corporation
    Inventor: Athanasios Angelopoulos
  • Patent number: 7729491
    Abstract: A method and a device for amplifying a reception signal are provided, involving the adjustment of a gain by which the reception signal is amplified, in particular as a function of a signal level of the reception signal. For example, lowpass filtering with a variable cutoff frequency is used to filter out a gain-dependent frequency range of the reception signal, which may especially contain an undesirable echo signal. Such a method and such a device are suitable in particular for the reception of ADSL signals in a central office.
    Type: Grant
    Filed: February 11, 2005
    Date of Patent: June 1, 2010
    Assignee: Infineon Technologies AG
    Inventors: Alexander Kahl, Peter Pessl, Sergio Walter
  • Patent number: 7664165
    Abstract: Provided is a correlation apparatus based on symmetry of a correlation coefficient that can reduce complexity of hardware by reducing the number of adders and multipliers. Accordingly, when values of a real number part and an imaginary number part are exchanged with respect to a middle point of a correlation coefficient sequence and divided into two parts of left and right by the middle point of the correlation coefficient sequence, the values of the real number part and the imaginary number part are even-symmetrical with respect to the middle point of the divided two parts. Therefore, the number of the adders required for forming the correlation apparatus is reduced by at least 20% and the number of the multipliers is reduced by at least 70% in comparison with the 62 adders and the 64 multipliers required for a conventional correlation apparatus.
    Type: Grant
    Filed: November 21, 2005
    Date of Patent: February 16, 2010
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Hun-Sik Kang, Jung-Sik Kim, Do-Young Kim
  • Patent number: 7590419
    Abstract: A FCCH Burst detector includes a tone detection filter centered at 67.7 KHz, a tone rejection filter centered at ?67.7 KHz, moving average power calculation for the two filter outputs, and a detection logic. A FCCH burst is detected when the ratio of the moving average power of the tone detection filter output to that of the tone rejection filter output is larger than a threshold for a period longer than a threshold. The FB tone end time is detected when the ratio falls back to a threshold or the moving average power of the tone detection filter output falls below a threshold of the average power of the tone detection filter output over a predetermined period. The tone detection filter and the tone rejection filter is implemented by first frequency-shifting the received signal by ?67.7 KHz and +67.7 KHz in parallel, then passing the two frequency-shifted signals through two separate low-pass filters.
    Type: Grant
    Filed: May 12, 2006
    Date of Patent: September 15, 2009
    Assignee: Freescale Semiconductor, Inc.
    Inventor: Weizhong Chen
  • Patent number: 7457405
    Abstract: An ADSL POTS splitter includes low pass filter. The low pass filter includes a first inductor portion in communication with the line interface and a second inductor portion isolated from the line interface via an isolation capacitor. In one embodiment, the first inductor portion is characterized for non-saturation in conventional operating ranges. The first non-isolated inductor portion has a respective DC saturation current and the isolated inductor portion has a respective DC saturation current. The DC saturation current of the first non-isolated inductor portion is substantially greater than the DC saturation current of the isolated inductor portion for achieving higher inductance in the isolated inductor portion.
    Type: Grant
    Filed: January 28, 2005
    Date of Patent: November 25, 2008
    Assignee: Alcatel Lucent
    Inventor: Richard H. Bailey
  • Patent number: 7352857
    Abstract: A method for providing spectral containment over telecommunications service lines is provided. The method includes selecting a filter having spectral characteristics corresponding to a predetermined passband. The method also includes connecting the filter in series to at least one loop used to provide at least one telecommunications service to a customer. The method further includes activating service over the at least one loop. The filter attenuates signals transmitted on frequencies outside of the predetermined passband over the at least one loop.
    Type: Grant
    Filed: November 1, 2005
    Date of Patent: April 1, 2008
    Assignee: AT&T Labs, Inc.
    Inventors: Mark A. Russell, Stephen Weinert
  • Patent number: 7227944
    Abstract: The present invention provides an echo reduction apparatus, system, and method that advantageously reduces echo when communicating over packet-switched networks. An echo reduction apparatus, including echo reduction circuit, operably couples a headset or handset device to an audio source that is capable of transmitting a sound signal. The echo reduction circuit receives the sound signal from the audio source and a transmit signal from the headset or handset device and provides an adjusted sound signal to the audio source. Advantageously, a variety of headsets and handsets may be used in accordance with the present invention with reduced caller echo and without the need to purchase new headsets or handsets.
    Type: Grant
    Filed: March 22, 2006
    Date of Patent: June 5, 2007
    Assignee: Plantronics, Inc.
    Inventors: John F. Gerhardt, J. Stephen Graham, Robert M. Khamashta, Iain McNeill
  • Patent number: 7187765
    Abstract: A method of determining when to save default coefficients in an echo canceller so as to ensure that the capture of coefficients that correspond to the best possible echo cancellation in a current condition. Coefficients are saved at varying times depending on the amount of echo removed by the echo canceller. More particularly, the present method involves constantly monitoring the error signal to the echo canceller and comparing it with the error signal that would be obtained if default coefficients were to be used instead of the current coefficients. This ensures that the default coefficients are upgraded each time the current set of coefficients is better than the saved default coefficients.
    Type: Grant
    Filed: November 28, 2003
    Date of Patent: March 6, 2007
    Assignee: Mitel Knowledge Corporation
    Inventors: Mirjana Popovic, Xin Xu
  • Patent number: 7095846
    Abstract: A half duplex device and signal processing method thereof. First, a signal detection unit of a signal detector of a half duplex device obtains a short-term power and long-term power. Next, a data update unit of the signal detector sets a short-term power threshold as a default threshold, determines whether the long-term power is greater than the default threshold, sets the short-term power threshold value equal to the long-term power value if the long-term power value is greater than the default threshold value, and provides smooth performance in a noisy environment.
    Type: Grant
    Filed: July 22, 2004
    Date of Patent: August 22, 2006
    Assignee: Winbond Electronics Corp.
    Inventor: Yueh-Chang Chen
  • Patent number: 7079646
    Abstract: An ADSL receiver HPF architecture 300 that reduces the number of Op Amps below that required for known ADSL receiver HPFs. The ADSL receiver HPF 300 is implemented as an active RC filter to provide a single fifth-order Elliptic filter instead of the more conventional pair of third-order Elliptic filters. Since the HPF Elliptic filter stage having the lowest Q factor is reduced as the order of an Elliptic filter transfer function is increased, a single fifth-order Elliptic filter suitable for use as an ADSL receiver HPF can be implemented using only one Op Amp in the second 2nd-order HPF stage 308. A notch (imaginary zero) is provided by summing of output signals associated with active RC structure state variables. This structure minimizes the number of capacitors while preserving the capability to provide a high Q factor for the first 2nd-order HPF stage 304.
    Type: Grant
    Filed: September 17, 2002
    Date of Patent: July 18, 2006
    Assignee: Texas Instruments Incorporated
    Inventor: Naom Chaplik
  • Patent number: 7043013
    Abstract: A method for adaptive control of a multi-channel echo cancellation system including N loudspeakers, where N is an integer greater than or equal to 2, and M microphones, where M is an integer greater than or equal to 1. The system includes N×M identification filters with variable coefficients, the identification filters being used to estimate acoustic coupling between the loudspeakers and the microphones as a function of a variable coefficients adaptive step. The variable coefficients adaptive step depends on whether or not there is a signal present on the loudspeakers. The method is applicable to hands-off operation of communication tools.
    Type: Grant
    Filed: May 14, 2002
    Date of Patent: May 9, 2006
    Assignee: France Telecom
    Inventors: Gregoire Le Tourneur, Delphine Feurte
  • Patent number: 7039179
    Abstract: The present invention provides an echo reduction apparatus, system, and method that advantageously reduces echo when communicating over packet-switched networks. An echo reduction apparatus, including echo reduction circuit, operably couples a headset or handset device to an audio source that is capable of transmitting a sound signal. The echo reduction circuit receives the sound signal from the audio source and a transmit signal from the headset or handset device and provides an adjusted sound signal to the audio source. Advantageously, a variety of headsets and handsets may be used in accordance with the present invention with reduced caller echo and without the need to purchase new headsets or handsets.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: May 2, 2006
    Assignee: Plantronics, Inc.
    Inventors: John F. Gerhardt, J. Stephen Graham, Robert M. Khamashta, Iain McNeill
  • Patent number: 7020275
    Abstract: A filter passing only desired frequencies is selected according to a desired level of service for copper lines. At a point of access between a loop plant and Central Office, the filter is interposed in series over a telephone service line to provide spectral containment by restricting the frequencies of transmission passing along the line. The filter is preferably mounted within a 5-pin module used in a protector block at the Central Office or remote terminal facility, interfaces with a 5-pin module, or is placed upstream or downstream of a protector block such that it does not interfere with the operation thereof. Service is activated, and the spectral containment apparatus prevents the transmission of unexpected or unintended services over the line.
    Type: Grant
    Filed: December 11, 2003
    Date of Patent: March 28, 2006
    Assignee: SBC Technology Resources, Inc.
    Inventors: Mark A. Russell, Stephen Weinert
  • Patent number: 7003093
    Abstract: Disclosed is an integrated tone detection processor for discriminating between tone and voice signals and determining the tones. The tone detection processor performs Automatic Gain Control (AGC) to normalize the power of the tone or voice signal. Further, the energy of the tone or voice signals are determined at specific frequencies utilizing a Goertzel Filter process. The tone detection processor determines whether or not a tone is present, and if a tone exists, determines the type of tone. Based upon determining the two maximum energy levels of the Goertzel filtered tone, whether the tone is a single tone, dual tone, silence, or other (e.g. speech) can be discriminated. The tone can then be identified by a user-defined dictionary of tones. Based upon various ON and OFF cadence checks in combination with the use of TONE ON and TONE OFF counters, tones can be declared.
    Type: Grant
    Filed: August 23, 2001
    Date of Patent: February 21, 2006
    Assignee: Intel Corporation
    Inventors: Raghavendra S. Prabhu, Adam Strauss, Stan Hsieh, Zhen Zhu, Anurag Bist
  • Patent number: 6978011
    Abstract: An ADSL POTS splitter includes an enhanced low pass filter. The enhanced low pass filter includes a first filter capacitor, a first non-isolated inductor, a second non-isolated inductor, a first isolated inductor and a common mode choke. The second non-isolated inductor is connected to the first non-isolated inductor. A first winding of the second non-isolated inductor is connected in series with a first winding of the first non-isolated inductor. A second winding of the second non-isolated inductor connected in series with a second winding of the first non-isolated inductor. The first isolated inductor is connected to the first non-isolated inductor with a first winding of the first isolated inductor connected in series with the first winding of the first non-isolated inductor and to a first lead of the first filter capacitor. A second winding of the first isolated inductor connected in series with the second winding of the first non-isolated inductor and to a second lead of the first filter capacitor.
    Type: Grant
    Filed: March 26, 2001
    Date of Patent: December 20, 2005
    Assignee: Alcatel
    Inventor: Richard H. Bailey
  • Patent number: 6975140
    Abstract: A data transmitter and transmitting method are provided in which an adaptive finite impulse response (FIR) driver has a plurality of taps to which coefficients having updateable values are applied. The FIR driver has a transfer function between an input stream of data bits and an output stream of data bits such that each data bit output from the FIR driver has an amplitude adjusted as a function of the values of a plurality of data bits of the input stream, and the values of the coefficients. The data transmitter includes a rewriteable non-volatile storage, operable to be rewritten with control information representing the values of the coefficients updated during operation of the FIR driver.
    Type: Grant
    Filed: November 26, 2003
    Date of Patent: December 13, 2005
    Assignee: International Business Machines Corporation
    Inventors: Louis L. Hsu, Brian L. Ji, William F. Washburn
  • Patent number: 6928161
    Abstract: An echo cancellation unit includes a model store to store a current echo model from an adaptive filter when a real-time error occurs. The real-time error is detected by monitoring a convergence metric. In some embodiments, the convergence metric is echo return loss enhancement (ERLE). When a real-time error occurs, the current echo model is saved, and the adaptive filter is reset such that it will begin converging from the origin. As a new model emerges in the adaptive filter, it is compared to the saved model in the model store at several time lags. If a match is found, the emerging model is replaced with the saved model at the appropriate time lag. The result is faster convergence of the adaptive filter than if the adaptive filter were left to converge on its own.
    Type: Grant
    Filed: May 31, 2000
    Date of Patent: August 9, 2005
    Assignee: Intel Corporation
    Inventor: David L. Graumann
  • Patent number: 6925177
    Abstract: An echo canceler having a predictive filter that generates an echo replica signal and an adder that subtracts the echo replica signal from a send input signal also has a receive input amplifier and a clipping circuit. The clipping circuit clips the input to the predictive filter at a threshold level determined by increasing the receive input amplifier gain until distortion of the echo component causes echo cancellation performance to degrade. Alternatively, the echo canceler may have a send input amplifier, a send output amplifier, and an echo replica amplifier that amplifies the predicted echo replica signal. The gain of the send input amplifier is increased to determine the gain at which echo cancellation performance begins to deteriorate due to echo amplification, and the gain of the echo replica amplifier is set to compensate for the echo amplification.
    Type: Grant
    Filed: October 17, 2002
    Date of Patent: August 2, 2005
    Assignee: Oki Electric Industry Co., Ltd.
    Inventor: Eiichi Nishimura
  • Patent number: 6904146
    Abstract: Sub-band filtering, adaptive echo cancellation, and residual echo suppression are selectively and separately applied in hierarchical order under the control of a circuit that monitors four separate signals to determine n machine states. The number of machine states is further divided among m levels of noise in determining which, and how much of, sub-band filtering, adaptive echo cancellation, and residual echo suppression to use at any given time. A voice activity detector (VAD) is used to monitor each signal and provides statistical information in addition to whether or not a voice signal is detected. Sub-band filter, echo cancelling, and non-linear processing are not permitted to provide maximum reduction simultaneously. Even so, the invention provides at least 15 dB more echo suppression than systems without a sub-band filter bank series coupled with a non-linear processor in each channel.
    Type: Grant
    Filed: May 3, 2002
    Date of Patent: June 7, 2005
    Assignee: Acoustic Technology, Inc.
    Inventors: Steven M. Domer, Samuel L. Thomasson
  • Patent number: 6898280
    Abstract: A line card and method is provided which supports symmetric and asymmetric telecommunication services, such as symmetric and asymmetric DSL services. The line card may support concomitantly POTS and asymmetric DSL services or support DSL services. A xDSL interface provides processing for DSL signals and a POTS interface provides processing for POTS signals. The line card is capable of switching operating modes or which services it is supporting. Preferably, the line card is capable of switching operating modes during a communication session. The line card may switch modes based on instructions received from external devices, such as CPE or far end equipment, based on preprogrammed software or based on operation of the line card.
    Type: Grant
    Filed: November 15, 2000
    Date of Patent: May 24, 2005
    Assignee: Lucent Technologies Inc.
    Inventors: Kevin Eugene Dombkowski, Carl Robert Posthuma
  • Patent number: 6888938
    Abstract: A dynamically adjustable digital gyrator device for a telephone line interface (e.g., a DAA) utilizing extended feedback and a dynamically adjustable filter to achieve stable convergence in the control of DC line current on a telephone line a short period of time. The low pass filter of the digital gyrator includes at least two (2) different fast filter settings and at least two (2) different slow filter settings based on possible load terminations (e.g., PBX, TAS, etc.), which can be determined based on the dynamic detection of an oscillation on the line. For instance, in a disclosed example, a voice band modem system is allowed to go off-hook with a 1 Hz cutoff low pass filter, and then the output of the low pass filter is checked for an oscillation. If an oscillation is detected, then the poles and/or zeroes of the low pass filter cutoff are changed to a slower convergence rate cutoff frequency (e.g., to 0.1 Hz). As a result, the exemplary voice band modem will converge stably and quickly (e.g.
    Type: Grant
    Filed: June 20, 2001
    Date of Patent: May 3, 2005
    Assignee: Agere Systems Inc.
    Inventors: Hong Cui, Lane A. Smith
  • Patent number: 6845252
    Abstract: Programmable echo cancellation filter for echo signal cancellation for a transceiver having a signal input (13) for receiving the transmission signal emitted by the transceiver (1), an input resistor (36) connected to the signal input (13), an operational amplifier (39), whose signal input (38) is connected to the input resistor (36) and whose signal output (41) is connected to an output resistor (43), a first programmable resistor circuit (48), which is provided between the signal output (41) of the operational amplifier (39) and the signal input (38) of the operational amplifier, a second programmable resistor circuit (51), which is provided between the output resistor (43) and a signal output (15) of the echo cancellation filter (14), a third programmable resistor circuit (55) which is provided between the first programmable resistor circuit (48) and the signal output (15) of the echo cancellation filter (14), the programmable resistor circuits (48, 51, 55) each having a plurality of resistors (65) which a
    Type: Grant
    Filed: October 11, 2001
    Date of Patent: January 18, 2005
    Assignee: Infineon Technologies AG
    Inventors: Antonio Digiandomenico, Peter Pessl, Christian Fleischhacker
  • Patent number: 6842516
    Abstract: To achieve an improved convergence behaviour for, e.g., echo cancellation there is provided a digital adaptive filter which includes a filter coefficient update means to successively update filter coefficients in accordance with an input signal, an estimated power of the input signal, and an error signal between the input signal filtered in the digital adaptive filter and the input signal propagated along an external path being modelled by the digital adaptive filter. Here, an input signal power estimation means is adapted to perform recursive smoothing for an increasing input power and a decreasing input power in an asymmetric fashion with different smoothing factors. In case the estimation is carried out in the frequency domain the step size for the update of filter coefficients may be calculated for each frequency band individually.
    Type: Grant
    Filed: July 13, 1999
    Date of Patent: January 11, 2005
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventor: Werner Armbrüster
  • Patent number: 6842517
    Abstract: A filtering circuit is described for filtering out meter pulses of analog telephone communication, for example in analog modems. The circuit is mainly composed of resistors and capacitors and is configured as a double T element or a Wien bridge circuit. The filtering circuit is needed for attenuating interferences to such an extent that integrated circuits operating with low voltages are not overloaded.
    Type: Grant
    Filed: February 26, 2001
    Date of Patent: January 11, 2005
    Assignee: Infineon Technologies AG
    Inventor: Rainer Storn
  • Patent number: 6836546
    Abstract: An arrangement for implementing a network in an ISDN-based customer premises having a four-wire ISDN S0 bus. The ISDN-based customer premises includes a Network Termination Basic Access (NTBA) that interfaces between the residential customer premises and the public switched telephone network by mapping the two-wire ISDN signal onto the four-wire bus. A low pass filter is added to the two-wire send path to eliminate high frequency noise caused by harmonic reflections of the ISDN-based signals on the four-wire bus. Filters are also coupled between each ISDN device and the four-wire S0 bus, ensuring that the four-wire S0 bus is isolated from capacitive influences of the ISDN devices to optimize transmission of the higher frequency home network signals.
    Type: Grant
    Filed: February 1, 2000
    Date of Patent: December 28, 2004
    Assignee: Advanced Micro Devices, Inc.
    Inventor: Bernd Willer