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Using digital signal processing

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379 - Telephonic communications


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Class / Patent application numberDescriptionNumber of patent applications / Date published
379406080 Adaptive filtering 68
379406120 Frequency domain analysis 3
20130044873Clock Skew Compensation for Acoustic Echo Cancellers Using Inaudible Tones - Methods and apparatus are provided for acoustic echo cancellation in a speech signal. Acoustic echo is cancelled by inserting at least one tone in the speech signal, wherein the at least one tone is substantially inaudible to a listener; determining a clock skew between two sampling clocks based on a frequency shift of the at least one tone; re-sampling the speech signal based on the determined clock skew; and performing the acoustic echo cancellation using the re-sampled speech signal. The provided acoustic echo cancellers can be implemented, for example, as terminal-based and/or network-based acoustic echo cancellers. The tone optionally comprises an inaudible tone or multiple tones. The tone generation can be limited to only when a speech power in the vicinity of the tone frequency is larger than a pre-determined threshold, or to the beginning of a call. A level of the tone can optionally be controlled so that the tone is masked by the speech signal.02-21-2013
20090103712CONTROLLING ECHO IN A WIDEBAND VOICE CONFERENCE - In one embodiment, an echo canceller configured to cancel echo in a wideband voice conference is provided. A double-talk condition may be when a plurality of users are speaking substantially simultaneously. When a double-talk condition is detected in the wideband conference, a high-frequency process is enabled and used to process signals in the high band to reduce echo. Accordingly, echo in the high band may not be produced by end devices being used by the users' speaking. Also, the users speaking have the echo cancelled in the low band and substantial echo does not result. This results in the users speaking experiencing the conference in the narrowband. The other users that are not speaking, however, continue to receive wideband signals. The users not speaking also continue to have echo cancellation performed for the high band and low band because these users are not speaking and thus attenuation of their voices is not a consideration.04-23-2009
20080304654METHOD AND SYSTEM FOR CLEAR SIGNAL CAPTURE - A method and system for clear signal capture comprehend several individual aspects that address specific problems in improved ways. In addition, the method and system also comprehend a hands-free implementation that is a practical solution to a very complex problem. Individual aspects comprehended related to echo and noise reduction, and divergence control.12-11-2008
379406070 Using attenuator 3
20100119055SYSTEMS AND METHODS FOR HALF-DUPLEX SPEAKERPHONES AND OTHER TWO-WAY COMMUNICATION DEVICES - An apparatus to enable half-duplexing capabilities in a two-way communication device is disclosed. The apparatus estimates the signal power and background noise of a first input signal and a second input signal during approximately the same period. The apparatus further provides at least one control signal based on the result of one or more determinations. These determinations may include whether the estimated signal power of at least one of the first and second input signals exceeds a threshold value; whether the estimated signal power of the first input signal exceeds the sum of a first threshold value and the estimated background noise of the first input signal; and whether the estimated signal power of the second input signal exceeds the sum of a second threshold value and the estimated background noise of the second input signal. Other embodiments for use with two-way communication devices and related methods are also disclosed.05-13-2010
20120224684SOFT ATTENUATION OF HIGH-POWER SIGNALS - In one embodiment, a high-level compensation (HLC) module receives samples of an input signal and determines whether a magnitude of each sample, represented in a linear domain, is relatively low or relatively high by comparing the magnitude to a threshold. If a sample is less than or equal to the threshold, then it is considered to have a relatively low magnitude and the sample is not attenuated. If a sample is greater than the threshold, then it is considered to have a relatively high magnitude and the HLC module attenuates the sample according to a “soft” non-linear function. The “soft” non-linear function is characterized by at least two of the following characteristics: the non-linear function (i) increases monotonically, (ii) forms a convex upwards curve, (iii) has a first derivative at the threshold equal to one, and (iv) has a first derivative at a maximum possible magnitude value equal to zero.09-06-2012
20090296920ECHO CANCELLATION BALANCE USING NOISE GENERATOR AND AVERAGE POWER DETECTION - A communication system includes transmit and receive paths, a balancing filter, a noise generator, a detector, and an interface. The transmit path is operable to generate data for communication on a communication network. The receive path is operable to receive data from the communication network. The balancing filter is coupled between the transmit path and the receive path. The noise generator is operable to inject a noise signal on the receive path. The detector is operable to measure reflected power in the transmit path associated with the noise signal. The interface is operable to receive a plurality of sets of coefficients for configuring the balancing filter, wherein the detector is operable to measure the reflected power for each of the sets of coefficients.12-03-2009
379406110 Convolution processing 1
20080317241CODE-BASED ECHO CANCELLATION - An apparatus for canceling a signal is disclosed. The apparatus may include an identification code (ID code) generator configured to generate an ID code. The apparatus may also include an ID code injector configured to inject the ID code into at least one of the signal and a processed signal to produce a convolved signal. The processed signal is resulted from a processing of the signal. The apparatus may further include an ID code detector configured to detect at least one of the convolved signal, a transformed signal, and a transformation of the convolved signal. The transformed signal is resulted from the transformation of the convolved signal. The apparatus may further include an arithmetic function configured to remove at least one of the convolved signal and the transformed signal.12-25-2008
20090154692Voice processing apparatus, voice processing system, and voice processing program - A voice processing apparatus includes a band dividing portion dividing a first voice signal generated by a first microphone and a second voice signal generated by a second microphone into predetermined frequency bands, a sound source segregating portion segregating an echo component of a voice emitted by a first sound source included in a voice emitted by a second sound source in each of the predetermined frequency bands based on the power of the first and second microphones, and a band synthesis portion synthesizing the first and second voice signals from which the echo component of the first sound source has been segregated by the sound source segregating portion into a voice signal including the voice emitted by the first sound source and a voice signal including the echo component of the first sound source.06-18-2009
20100128868Acoustic echo canceler using an accelerometer - A system includes a loudspeaker, a microphone, an echo canceling circuit, and an accelerometer coupled to the loudspeaker for providing a reference signal, a(n), to the echo canceling circuit. Preferably, the accelerometer is attached to the loudspeaker. A speaker signal, x(n), is used to drive the loudspeaker and the system also includes a switch for coupling either a(n) or x(n) to the echo canceling circuit, depending upon the volume or loudness of the sounds involved.05-27-2010
20120224683SYSTEMS AND METHODS SELECTIVELY EXCLUDING TONES FROM VECTORING - A discrete multi-tone (DMT) transceiver communicates tones across a subscriber line. Vectoring is employed in an effort to reduce the effects of crosstalk. However, for some tones, such as tones significantly affected by radio frequency interference (RFI) or other forms of alien noise, vectoring may actually introduce distortions such that the vectoring degrades rather than improves overall signal quality. Control logic of the DMT transceiver is configured to sense when tones are affected by significant levels of alien noise and to exclude such tones from vectoring, thereby improving signal quality for such tones. The control logic also may lower the constellation densities of such tones in order to accommodate the vectoring exclusions applied to such tones.09-06-2012
20090129584Echo Canceller - An echo canceller which can respond to a sudden change in echo characteristics in real time and does not require an alteration outside the echo canceller, includes a smoothed sending-speech signal calculation means for calculating a smoothed sending-speech signal from the sending-speech signal, the smoothed sending-speech signal being obtained by smoothing the sending-speech signal; a smoothed receiving-speech signal calculation means for calculating a smoothed receiving-speech signal from the receiving-speech signal, the smoothed receiving-speech signal being obtained by smoothing the receiving-speech signal; a delay time information generation means for obtaining delay time information reflecting delay characteristics of an echo path in accordance with a correlation between the smoothed sending-speech signal and the smoothed receiving-speech signal; and an update information generation means for obtaining update information indicating execution or suspension of updating of the tap coefficients of the adaptive filter, in accordance with the sending-speech signal, the receiving-speech signal, and the delay time information.05-21-2009
20080285740Method and apparatus for crosstalk estimation - A line card including: a co-channel estimator and a code selector. The line card is configured to couple to digital subscriber lines to support multi-tone modulation of communications channels thereon. The co-channel estimator is configured to estimate co-channel crosstalk coupling coefficients among selected pairs of the subscriber lines at levels for which the total crosstalk into a selected victim line among the plurality of digital subscriber lines substantially corresponds to the sum of the products of the corresponding crosstalk coupling coefficient for each remaining disturber one of the plurality of subscriber lines and a corresponding substantially unique vector transmitted thereon. The code selector couples to the co-channel estimator. The code selector is configured to select a cross-talk estimation code type and to generate substantially unique code vectors derived there from for injection into selected ones of the of subscriber lines.11-20-2008
20080267391METHOD AND APPARATUS FOR REDUCING CROSSTALK BETWEEN DIGITAL SUBSCRIBER LINES - A method and apparatus for reducing crosstalk between digital subscriber lines includes: firstly, determining a parameter of VDSL (Very-high-bit-rate Digital Subscriber Line); secondly, determining frequency range of signal to be transmitted in the line and transmitting signal in the corresponding line according to the determined frequency range. This mainly means reducing or turning off the transmitting of the signal at a high frequency band and only using low frequency band for data transmitting in the case that the line parameter exceeds the predetermined threshold, so that crosstalk to neighboring lines is reduced. The present invention can effectively overcome the crosstalk against neighboring lines during the channel discovery phase of digital subscriber line and the transfer performance of the digital subscriber line in operation can be guaranteed. The present invention is realized based on the established standard, so the present invention is simple and easy to implement.10-30-2008
20100135481ECHO MITIGATION IN A CONFERENCE CALL - In an example embodiment, an example method is provided for echo mitigation in a conference call. In this method, a test audio signal is transmitted to a conference endpoint and as a result, an echo associated with the transmittal of the test audio signal is received. One or more parameters of the echo are then identified and an echo mitigation process is selected from multiple echo mitigation processes based on the identified parameters. The selected echo mitigation process is then applied.06-03-2010
20090080644SIGNAL PROCESSING - The present invention relates to detection of echo in telecommunications networks. The invention provides a method of echo detection comprising the steps of: generating a series of inbound vectors for an inbound signal; generating a series of outbound vectors for an outbound signal; repeating a predetermined number of comparison steps comprising the sub-steps of selecting an outbound vector from the outbound vectors; selecting an inbound vector from the inbound vectors; comparing said outbound vector with said inbound vector and with successive inbound vectors to generate a plurality of similarity metrics; and determining a relative position of the compared outbound vector having maximum correlation with said inbound vector; and counting the number of times each relative position is determined to be the position of maximum correlation.03-26-2009
20100002866VOICE COMMUNICATION APPARATUS - A voice communicating apparatus in which a far-end voice of high sound quality can be outputted from a loudspeaker and an echo which is caused by the outputted far-end voice can be accurately removed with high precision. An analog far-end voice signal supplied from a telephone unit is directly outputted from the loudspeaker and a digital detection sound signal of the far-end voice and a near-end voice detected by a microphone is delayed by a predetermined time and supplied to an arithmetic operating part.01-07-2010
20110103574System and Method to Reduce Crosstalk of Digital Subscriber Lines - A computer implemented method includes determining crosstalk characteristics of a plurality of digital subscriber lines. The computer implemented method includes identifying pairs of digital subscriber lines, each of the pairs including a first digital subscriber line and a second digital subscriber line, where the first digital subscriber line has a crosstalk characteristic that is correlated to the second digital subscriber line. The computer implemented method also includes rearranging terminations at an access node to assign at least one of the identified pairs of digital subscriber lines to a common vectoring group.05-05-2011
20090067616CAN echo cancellation level shifter - An echo cancellation system for use with a controller area network having at least two physical layers is disclosed. The system includes a flip flop circuit and a first resistor capacitor tank circuit and a second resistor capacitor tank circuit. The echo cancellation system uses a transition dependent delay in the circuit that will be tuned to be longer than the propagation delay of the CAN transceivers but less than the bit sample point for the CAN network thus eliminating any possibility of oscillation occurring within the CAN network during transfer of information between physical layers.03-12-2009
20120243676Method and System for Echo Cancellation in Presence of Streamed Audio - During playing of a streamed audio while engaging in a voice communication session, a communication device may be operable to generate a background audio during an echo cancellation operation for the voice communication session, using known information associated with the streamed audio. The streamed audio may comprise audio content that is received from one or more external sources and/or locally generated within the communication device. The known information associated with the streamed audio may comprise an echo replica corresponding to an echo associated with the streamed audio and/or a modified version of the streamed audio. In instances when a residual echo suppression is operational during the echo cancellation operation, the communication device may be operable to suppress a residual echo based on a signal level of the echo replica corresponding to the echo associated with the streamed audio and/or a signal level of the modified version of the streamed audio.09-27-2012
20090323926METHODS AND SYSTEMS FOR VOICE COMMUNICATION - An intermediary communication system, the intermediary communication including: (a) a first network interface, configured for transmitting over a first network connection to a first remote end unit a first sound sequence; and for receiving from the first remote end unit a returning sound sequence that is responsive to the first sound sequence; (b) a processor, configured to determine an echo reduction parameter in response to a relationship between a first sound sequence parameter and a returning sound sequence parameter; and (c) a second network interface, for transmitting to a second remote end unit, over a second network connection, a processed sound sequence that was generated in response to the echo reduction parameter from a preprocessed sound sequence which was generated by the first remote end unit.12-31-2009
20100135482INTERFERENCE CANCELLATION SYSTEM - An adaptive interference cancellation system is described. In one example the system operates by receiving a data signal using a DSL (Digital Subscriber Line) and receiving a reference signal, the reference signal corresponding, in part, to noise on the data signal. The reference signal is classified and a noise cancellation signal is applied to the data signal based on the classification.06-03-2010
20120063591METHOD AND APPARATUS FOR CONTROLLING ECHO IN THE CODED DOMAIN - A method and corresponding apparatus for coded-domain acoustic echo control is presented. An echo control problem is considered as that of perceptually matching an echo signal to a reference signal. A perceptual similarity function that is based on the coded spectral parameters produced by the speech codec is defined. Since codecs introduce a significant degree of non-linearity into the echo signal, the similarity function is designed to be robust against such effects. The similarity function is incorporated into a coded-domain echo control system that also includes spectrally-matched noise injection for replacing echo frames with comfort noise. Using actual echoes recorded over a commercial mobile network, it is shown herein that the similarity function is robust against both codec non-linearities and additive noise. Experimental results further show that the echo-control is effective at suppressing echoes compared to a Normalized Least Mean Squared (NLMS)-based echo cancellation system.03-15-2012
20100329444Crosstalk Estimation and Power Setting Based on Interpolation in a Multi-Channel Communication System - An access node of a communication system comprises a plurality of transmitters adapted for communication with at least one receiver over a plurality of channels. The access node is operative to obtain estimated crosstalk coefficients between a joining channel and an active channel, and to set a power level of at least one signal transmitted over the joining channel based on the estimated crosstalk coefficients. The access node obtains the estimated crosstalk coefficients by first obtaining a subset of the estimated crosstalk coefficients and subsequently determining additional ones of the estimated crosstalk coefficients by applying an interpolation process to the estimated crosstalk coefficients in the subset. The access node sets the power level of the signal transmitted over the joining channel in a manner that ensures maintenance of a desired performance characteristic for the active channel.12-30-2010
20080219433FULL DUPLEX HANDS-FREE TELEPHONE SYSTEM - A telephone system comprising an analog telephone and a full-duplex speakerphone adapter is disclosed. The analog telephone comprises an ordinary analog telephone subscriber circuit for transmitting and receiving analog signals and a handset for users. The full-duplex speakerphone adapter is coupled between the analog telephone and a central office, uses a subscriber loop interface circuit through the first telephone line to couple to the ordinary analog telephone subscriber circuit of the analog telephone and uses a telephone hybrid interface circuit through the second telephone line to couple to a wall jack to communicate with the central office.09-11-2008
20100034374VECTORED DIGITAL SUBSCRIBER LINE SYSTEM HAVING MODULAR VECTORING ARRANGEMENTS - The present invention relates to a vectoring chip unit in a DSL system connectable to a plurality of DSL ports of a DSL chip comprising means for receiving data from each of the plurality of DSL ports, means for performing pre-coding/cancellation in order to reduce crosstalk and means for transmitting a result of the precoding/cancellation to the respective DSL port. Preferably, a system is provided comprising a plurality of said vectoring chips, whereby each vectoring chip is adapted to handle pre-coding/cancellation of a predetermined frequency range and the frequency ranges of each vectoring chip are non-overlapping.02-11-2010
20100195817Reducing the Feedback Overhead During Crosstalk Precoder Initialization - An apparatus comprising a receiver coupled to a digital subscriber line (DSL) between an exchange site and a customer premise equipment (CPE) and configured to send a feedback error message to train a precoder coupled to the exchange site, wherein the feedback error message comprises a plurality of error components and an indication of a quantity of bits per error component, a quantization accuracy per error component, or both. Included is a method comprising sending an error feedback message to a DSL crosstalk precoder to train the crosstalk precoder, wherein the error feedback message comprises an error vector and a quantization scaling factor of the error vector.08-05-2010
20100195816METHOD AND DEVICE FOR A DATA PROCESSING AND COMMUNICATION SYSTEM COMPRISING SUCH DEVICE - A method and a device are provided for data processing, including the steps of transmitting a first signal from a first instance to a second instance and sending a second signal from a third instance to the first instance, wherein the second signal corresponds at least partially to the first signal as received at the third instance.08-05-2010
20110051924VOICE AND DATA EXCHANGE OVER A PACKET BASED NETWORK WITH ECHO CANCELLATION - A signal processing system which discriminates between voice signals and data signals modulated by a voiceband carrier. The signal processing system includes a voice exchange, a data exchange and a call discriminator. The voice exchange is capable of exchanging voice signals between a switched circuit network and a packet based network. The signal processing system also includes a data exchange capable of exchanging data signals modulated by a voiceband carrier on the switched circuit network with unmodulated data signal packets on the packet based network. The data exchange is performed by demodulating data signals from the switched circuit network for transmission on the packet based network, and modulating data signal packets from the packet based network for transmission on the switched circuit network. The call discriminator is used to selectively enable the voice exchange and data exchange.03-03-2011
20100208882APPARATUS FOR PROCESSING ECHO SIGNAL AND METHOD THEREOF - An echo signal processing apparatus is disclosed. The echo signal processing apparatus is utilized for generating a cancellation signal by using group phenomenon of a frequency response of an echo signal to remove the echo signal. The echo signal processing apparatus has lower cost and is able to remove the echo efficiently.08-19-2010
20090147942Reducing Echo - Far-end audio signal data generated by a far-end device during voice cross-talk between the far-end device and a near-end device is received via a network. Energy levels of frequency components of the received far-end audio signal data are determined. Near-end audio signal data produced by a microphone array is received, the near-end audio signal data including components contributed by a loudspeaker playing at least some of the far-end audio signal data. Which frequency components of the near-end audio signal data to use to compute likely near-end sound source directions is controlled dynamically, where the controlling is based on the determined energy levels of the frequency components of the received far-end audio signal data.06-11-2009
20100278328SYSTEMS AND METHODS FOR SELECTING TONES FOR FAR-END CROSS TALK MITIGATION - Systems and methods are described for selecting tones for far-end crosstalk (FEXT) mitigation. In particular, systems and methods are described for performing far-end crosstalk (FEXT) mitigation within a digital subscriber line (xDSL) system. One embodiment is a method that comprises determining a first set of function values relating to a per-tone signal-to-noise ratio (SNR) for a user among a plurality of users for a number of tones, wherein the number of tones is less than or equal to a total number of tones available for transmission. The method further comprises estimating coefficients for performing FEXT mitigation for the number of tones, performing FEXT mitigation on the number of tones based on the estimated coefficients, and performing FEXT mitigation on a selected group of tones from among the number of tones, wherein the selected group of tones is less than or equal to the number tones.11-04-2010
20080205632PACKET VOICE SYSTEM WITH FAR-END ECHO CANCELLATION - A packet voice transceiver adapted to reside at a first end of a communication network and to send and receive voice packets to and from a second packet voice transceiver residing at a second end of the communication network. The transceiver includes a voice encoder, a packet transmitter, a packet receiver, a voice decoder and a far-end echo canceller. The voice encoder receives an ingress audio signal and encodes the audio signal to produce an ingress packet voice signal. The packet transmitter transmits the ingress packet voice signal over the network to the second packet voice transceiver. The packet receiver receives an egress packet voice signal transmitted over the network by the second packet voice transceiver. The voice decoder decodes the egress packet voice signal to produce an egress audio signal. The far-end echo canceller reduces echo that is present in the egress audio signal and that originated at the second end.08-28-2008
20110002458METHOD AND APPARATUS FOR ACOUSTIC ECHO CANCELLATION IN VOIP TERMINAL - A method of acoustic echo cancellation in the VoIP terminal using processing of the far-end signal with the digital adaptive filter in order to obtain the echo estimate that is subtracted from the microphone signal in which the far-end signal, before it is converted to the analog form and passed to the loudspeaker (01-06-2011
20100254528Configuring Virtual Noise Parameters of Very High-Speed Digital Subscriber Line - An apparatus comprising a transmitter configured to transmit a digital subscriber line (DSL) signal in a line from a plurality of subscriber lines according to a reference virtual noise power spectral density (PSD), wherein the reference virtual noise PSD is based on an upper bound for a worst-case far-end crosstalk (FEXT) PSD in the subscriber lines. Also included is an apparatus comprising at least one processor configured to implement a method comprising obtaining an upper bound for a worst-case FEXT PSD for a plurality of subscriber lines, obtaining a referred virtual noise PSD based on the worst-case FEXT PSD for the lines, and determining a bit-loading for the lines based on the referred virtual noise or a scaled version of the receiver-referred virtual noise.10-07-2010
20080219432Echo Delay Detector - An echo detector has a correlator for correlating between an incoming signal and an echo signal, the correlator being arranged to operate recursively, the detector being arranged to detect the echo and the length of its delay from peaks in the correlation. Recursive operation means the computational load can drop from being proportional to N*N, to being proportional to 09-11-2008
20130148801VOICE SWITCHING FOR VOICE COMMUNICATION ON COMPUTERS - A voice communication end device performs quality checks to determine whether acoustic echo cancellation would be ineffective, such as due to noise or clock drift or discontinuities between incoming and outgoing voice channels. In the case where echo cancellation would prove ineffective, the device falls back on a tri-state voice switching operation that includes a bi-direction state in which both channels are on in full duplex operation, which provides a smoother transition switching between active channels. The tri-state voice switching supports both voluntary transitions where the active user voluntarily stops to yield the active channel, and forced transitions where the active user is forcedly interrupted by the other user speaking more loudly.06-13-2013
20130208885METHOD AND DEVICE FOR DATA PROCESSING IN A DIGITAL SUBSCRIBER LINE ENVIRONMENT - A method and a device for data processing in a digital subscriber line environment, wherein a flat noise margin is determined based on an actual noise determined and based on a maximum noise expected. A device is initialized using the flat noise margin. Also, a communication system is described that includes such a device.08-15-2013

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