Abstract: Systems and methods for reducing crosstalk are provided. In one implementation, a method is provided. The method includes applying a pilot signal to a disturber twisted pair and measuring near end crosstalk of a victim twisted pair. The coupling characteristics between the disturber and the victim twisted pair are determined. A far end crosstalk function is derived for estimating the far end crosstalk in the victim twisted pair using the determined coupling characteristics. A crosstalk reduction signal is determined using the estimated far end cross talk. The crosstalk reduction signal is injected into the victim twisted pair to reduce crosstalk in the victim twisted pair.

Abstract: In an audio system having a microphone, a speaker coupled to a source of audio output, and an echo canceller coupled to the speaker and microphone, latency between the source of audio output and the speaker may be compensated in echo cancellation performed by the echo canceller. The echo canceller may use a reference signal derived from a signal from the source of audio output in echo cancellation. The latency may be compensated by measuring the latency between the signal from the source of audio output and the speaker, determining a delay amount from the latency, delaying the reference signal by the delay amount to produce a delayed reference signal, and using the delayed reference signal as the reference signal in the echo canceller.

Abstract: A multi-function communications device has a processor that generates a user interface audible tone signal. The device also has a downlink digital signal processor, and an uplink digital signal processor. A mixer has an input to receive the downlink signal and another input to receive the user interface tone signal. The uplink processor has an acoustic echo canceller having an input to receive the uplink signal and another input to receive an output from the mixer. The echo canceller may reduce the amount of both the far-end user's speech and the user interface tone that may be present in the uplink signal. The mixer may be positioned within the chain of audio signal processors, or it may be positioned outside the chain. Other embodiments are also described and claimed.

Abstract: Systems and methods for envelope-based acoustic echo cancellation in a communication device are provided. In exemplary embodiments, a primary acoustic signal is received via a microphone of the communication device, and a far-end signal is received via a receiver. Frequency analysis is performed on the primary acoustic signal and the far-end acoustic signal to obtain frequency sub-bands. An echo mask based on magnitude envelopes of the primary and far-end acoustic signals for each frequency sub-band is generated. A noise mask based on at least the primary acoustic signal for each frequency sub-band may also be generated. A combination of the echo mask and noise mask may then be applied to the primary acoustic signal to generate a masked signal. The masked signal is then output.

Abstract: In an example embodiment, a control connection is introduced between an adaptive jitter buffer (AJB) and an adaptive bulk delay (ABD) buffer of an echo canceller (ECAN) in an Internet Protocol (IP) conference bridge. The control connection allows the AJB to control the amount of delay inserted by the ABD in the ECAN convolution processor (CP) signal path. The adjustment in ABD delay restores the time alignment of the ECAN internal echo estimate and offsets variations in echo tail delay introduced by network induced AJB delay changes. Time-invariance is preserved in the echo tail path.

Abstract: Techniques to characterize and reduce acoustic echo are described. For example, a mobile computing device may comprise an audio characterization module to send a first signal to a first component and receive a second signal from a second component. The first signal may be a deterministic audio training sequence and the second signal may be a recovered audio training sequence. The audio characterization module compares the first signal and the second signal to determine an audio echo path. Other embodiments are described and claimed.

Abstract: A multimedia conferencing system includes a loud speaker system, one or more microphones for receiving a local audio signal and a remote audio signal, a state machine and an echo canceller that operates in conjunction with two reference signals to remove substantially all of a feedback signal component in the local audio signal that results from reinforcing and playing the local audio signal over the loud speaker system. The state machine operates to detect that only the local audio is active, and if so controls the operation of the echo canceller such that only the feedback component of the local audio signal is removed and the local audio signal is not suppressed.

Abstract: A system and method for identifying minor echoes present in an input signal in the situation where a set of major echoes has already been identified from the input signal. The method includes: computing a spectrum F corresponding to a sum of the major echoes; computing a weighted power spectrum SM of the spectrum F; subtracting the weighted power spectrum SM from a weighted power spectrum PIN of the input signal to obtain a difference spectrum; performing a stabilized division of the difference spectrum by a conjugate of the spectrum F to obtain an intermediate spectrum; computing an inverse transform of the intermediate spectrum to obtain a time-domain signal; and estimating parameters one or more of the minor echoes from the time-domain signal. The echo parameters are usable to remove at least a portion of the one or more estimated minor echoes from the input signal.

Abstract: A method and mobile stations for performing a zone switch, are discussed. According to an embodiment, the method includes: receiving, at the mobile station and from a target base station configured to operate in accordance with a first and a second protocol, a ranging response message of the first protocol including zone switch parameters used to perform zone switch from a first zone of the target base station corresponding to the first protocol to a second zone of the target base station corresponding to the second protocol; and performing, at the mobile station, the zone switch from the first zone to the second zone using the zone switch parameters.

Abstract: In one embodiment, a local network device may determine an inability to establish a connectivity verification protocol (e.g., Bidirectional Forwarding Detection, “BFD”) session to a remote network device, such as from unreturned control messages. In response, the local network device may send at least one connectivity verification protocol echo message to the remote network device destined to be returned to the local network device and forwarded using a forwarding protocol. In response to receiving or not receiving the echo message, the local network device may thus determine whether the forwarding protocol is functioning between the local and remote network devices. In this manner, the local network device may determine whether an inability to establish a connectivity verification protocol session is due to an inability to forward packets between the devices, or due to the connectivity verification protocol not working (or not being configured) on the remote network device.

Abstract: Certain aspects of the present disclosure provide a method for performing interference suppression in spatial division multiple access (SDMA) systems. When the number of receive antennas of a receiver is equal or larger than the number of spatial streams intended for the receiver, the receiver may perform interference suppression on the signals received on all of its antennas. In addition, certain aspects of the present disclosure present a flexible SDMA technique in which a plurality of channel estimates that may be received from an explicit feedback or estimated implicitly, are combined. The combined channel estimate may be used in calculating the SDMA weights.

Abstract: A signal selector enhancer suitable for portable electronic devices and base stations is disclosed. In one embodiment, the enhancer can include: a filter for receiving a signal from a first node, and for providing a filtered signal output therefrom, where the first node is coupled to a signal selector; and a noise canceller for receiving the filtered signal output, and for providing an adjusted filtered signal at a second node, where the second node is coupled to the signal selector, and where an operation of the signal selector is enhanced by the filter and the noise canceller arrangement.

Abstract: Embodiments of a method and apparatus for generating an estimated non-linear echo signal are disclosed. One method includes receiving a plurality of data inputs. The plurality of data inputs are partitioned into subsets. A weight vector is computed for each of the subsets. A vector of addresses to memory locations is computed for each of the subsets. Values of interpolants are accessed at the memory locations (interpolation sites) based on the vector of addresses for each of the subsets. The estimated non-linear echo signal based is calculated on the values of the interpolants and the weight vector corresponding to each subset.

Abstract: A communication device and receiving method thereof are disclosed in embodiments of the present invention. The communication device includes an extra digital to analog converter, an inverse partial response filtering circuit and an analog to digital converter. The extra digital to analog converter receives a first digital signal and generates a pulse shaped analog signal. The inverse partial response filtering circuit receives a first difference signal, and adjusts a response of the inverse partial response filtering circuit to generate an adjusted signal, wherein the first difference signal equals the result of subtracting the pulse shaped analog signal from a receiving signal. The analog to digital converter converts the adjusted signal to generate a second digital signal.

Abstract: This invention proposed an Echo Suppressor which can efficiently suppress both echoes and background noise without introducing “choppiness”. The Echo Suppressor System includes said two adaptive gains Gr(RSR) and Gn(NSR), said one adaptive zeros-filter A1(z) and said one adaptive poles-filter A2(z); wherein, thr gain Gr(RSR) is controlled by RSR (Residual echo level to Signal level Ratio); the gain Gn(NSR) is controlled by NSR (Noise signal level to current Signal (Tx) level Ratio); the filter A1(z) is converted from LSF1 obtained from the first modification of LSFTx (Line Spectral Frequencies of Tx signal); the filter A2(z) is converted from LSF2 obtained from the second modification of LSFTx.

Abstract: A satellite communication system comprised of a hub and plurality of remote terminals, wherein the system is configured for frequency reuse, a method and apparatus for signal cancellation are disclosed. The disclosed method and apparatus enable the hub to extract return link signals overlaying a transmitted forward link signal, wherein the forward link signal is transmitted at a power level higher than that of the overlaying return link signals.

Abstract: A cancellation system is disclosed for processing incoming and outgoing signals in a transform domain to create a cancellation signal for reducing or removing unwanted interference. Data is ordered based on Good-Thomas indexing into a two dimensional array in a buffer. The two dimensional array may have lr rows and lw columns. From the buffer, the columns of data undergo a Winograd small transform. The rows of data undergo a Cooley-Tukey operation to complete the transform operation into the frequency domain. Multipliers scale the transformed data to generate a cancellation signal in the frequency domain. Inverse (Cooley-Tukey) and Winograd transforms perform inverse processing on the cancellation signal to return the cancellation signal or data to the time domain. Re-ordering the data and combination of the cancellation signal or data with incoming or outgoing signals achieve interference cancellation.

Abstract: A system, method, and program product are provided for filtering sound from a selected application on a computer without interrupting voice communications on the computer. The method comprises: monitoring a selected program for an outgoing digital audio signal from a selected application; detecting said digital audio signal; and filtering an analog microphone input with the digital audio signal.

Abstract: A method for enhancing Ethernet channel impairment comprises the steps of sending a sequence to a receiver in a slave transceiver by a master transceiver, and training cancellation filter coefficients of an echo canceller and a near-end cross talk canceller in the master transceiver before the receiver of the slave transceiver converges.

Abstract: Duplex audio is provided for a mobile communication device and an accessory. In some embodiments, the accessory can selectably operate in a duplex audio mode, concurrently sending audio to and receiving audio from the mobile communication device, or in another audio mode. In duplex audio mode, the accessory can enable its internal audio processing operations (e.g., echo cancellation) while the mobile communication device disables its corresponding internal operations or vice versa. The mobile communication device can control when the accessory transitions into and/or out of duplex audio mode.

Abstract: A communication apparatus capable of echo cancellation is provided. The apparatus is configured to be provided with an input signal receiving interference. The input signal has a frequency range. The interference includes an echo component and a noise component. The apparatus has a first interference eliminator configured to reduce an echo component included in the input signal so as to produce an intermediate signal. The apparatus has a selector configured to select one of the input signal and the intermediate signal. The apparatus has a second interference eliminator configured to reduce at least one of a noise component and an echo component included in one of the input signal and the intermediate signal selected by the selector.

Abstract: The present invention is related to methods and systems for reducing or canceling echoes during fax communications. In an embodiment, during a fax call, a first fax signal from a first fax device intended for a second fax device is detected. Based at least in part on detecting the first fax signal from the first fax device or on the termination of the first fax signal, an echo audio packet is muted, wherein the echo audio packet is at least partly the result of the first fax signal being transmitted over a network, the network including at least a data network.

Abstract: The present invention provides a method and apparatus for finding an estimate of the delay of a signal travelling between two points. A quantity is evaluated from the signal at a final number of time instants, at both a reference point and a reception point. The values are quantized by comparison with a threshold adapted to a typical magnitude of the quantity. If the quantized values from the reception point are shifted back by the true delay with respect to the quantized values from the reference point, then certain co-occurrences of quantized values have very low probability. Hence, the best delay estimate is that shift which yields the least number of low-probability co-occurrences.

Abstract: A network component comprising a transmitter configured to transmit data at a transmitter phase, a receiver configured to receive data at a receiver, and a phase delay component coupled to the transmitter and the receiver and configured to control the transmitter phase relative to the receiver phase to maintain distortion in the transmitted data below a threshold, wherein the threshold is less than a maximum possible distortion in the transmitted data.

Abstract: Embodiments of a method and apparatus of reducing transmit signal components of a receive signal of a transceiver are disclosed. One method includes generating a transmit signal by passing a pre-driver transmit signal through a transmit driver. An echo cancellation signal is generated by passing the pre-driver transmit signal through an echo cancellation driver. A residual echo signal is generated by passing a pre-driver residual echo cancellation signal through a residual echo cancellation driver. The transceiver simultaneously transmits the transmit signal, and receiving the receive signal. At least a portion of an echo signal of the receive signal is canceled by summing the echo cancellation signal with the receive signal. At least another portion of the cancellation echo signal of the receive signal is canceled by summing the residual echo cancellation signal with the receive signal.

Abstract: The present invention provides a method and apparatus for finding an estimate of the delay of a signal travelling between two points. A quantity is evaluated from the signal at a final number of time instants, at both a reference point and a reception point. The values are quantized by comparison with a threshold adapted to a typical magnitude of the quantity. If the quantized values from the reception point are shifted back by the true delay with respect to the quantized values from the referenced point, then certain co-occurrences of quantized values have very low probability. Hence, the best delay estimate is that shift which yields the least number of low-probability co-occurrences.

Abstract: Techniques for multi-channel acoustic echo cancellation include adaptive filtering. An adaptive filter can use a lattice predictor of order M coupled to an adaptive LMS/Newton filter of length N, wherein M<N. The lattice predictor can provide decorrelation of the input to the LMS/Newton filter and can provide faster convergence for the LMS/Newton filter. Efficient operation of the LMS/Newton filter can also be provided by using output from the lattice predictor to provide low complexity update of weights for the LMS/Newton filter.

Abstract: In one implementation, a transceiver is provided that includes a precoder to pre-equalize a data signal transmitted from the transceiver. The transceiver further includes an interference cancellation system to substantially cancel interference from a data signal received by the transceiver. The precoder and the interference cancellation system share at least one common input signal.

Abstract: A linear full duplex system and method for acoustic echo cancellation is disclosed. In one embodiment, a method includes calculating a residual echo after subtraction of an echo estimate from a near end signal associated with a communication, refining a far end and a residual signal associated with the communication, updating, based on the far end signal, the echo estimate of an echo associated with the communication, subtracting the echo from the near end signal based on the echo estimate to cancel the echo associated with the communication, updating, based on the refined far end and refined residual signal, the adaptive filter module used for echo estimation, and detecting a steady state and, during the steady state, dynamically detecting internal substates and switching between the internal substates and detecting and managing double talk associated with the communication.

Abstract: A communication line having a plurality of twisted wire pairs connects a plurality of transmitters, one transmitter at each end of each twisted wire pair, with a plurality of receivers, one receiver at each end of each twisted wire pair. Each receiver receives a combination signal including a direct signal from the transmitter at the opposite end of the twisted wire pair with which the receiver is associated and a plurality of far-end crosstalk (FEXT) impairment signals, one from each of the remaining transmitters at the opposite end of the communications line. A plurality of FEXT cancellation systems, one associated with each receiver, provides a replica FEXT impairment signal. A device associated with each receiver is responsive to the combination signal received by the receiver and the replica FEXT impairment signal provided by the FEXT cancellation system associated with the receiver for substantially removing the FEXT impairment signals from the combination signal.

Abstract: Methods and apparatus describe techniques for reducing interference signals in a communication signal. An apparatus includes, in at least one aspect, a transceiver circuit to receive a communication signal that includes one or more interference signals and a compensation circuit to generate a compensation signal to compensate for the one or more interference signals in the communication signal based on one or more cancellation coefficients and one or more data symbols.

Abstract: Integrated echo cancellers in a telecommunications system are tested using a test apparatus connected to the main communications trunk where a large number of individual signals are multiplexed together. The signals are de-multiplexed in the test apparatus and specific amounts of echo delay, echo magnitude, and line delay can be introduced for any selected signals within the group on the trunk. The signals are then re-multiplexed and returned to the trunk in a direction back toward the echo canceller.

Abstract: A system for transmitting and receiving a wideband speech signal includes an A/D converter for receiving an analog speech signal to convert it into a digital speech signal, encoding a difference between a baseband speech signal and a standard baseband between a synthesized standard baseband signal, and an IP network interface for multiplexing the coded standard and additional baseband signals and enhancement residual band signal.

Abstract: A system that incorporates teachings of the present disclosure may include, for example, a network device to transmit interactive TV services using minimally twisted or non-twisted pair cables including a controller to receive a very high digital subscriber line (VDSL) signal at the minimally twisted or non-twisted pair cable and adapt the VDSL signal for transmission over the minimally twisted or non-twisted pair cable to form an adapted VDSL signal which can subsequently be used for presentation of interactive TV services. Other embodiments are disclosed.

Abstract: Embodiments of a method and apparatus of reducing transmit signal components of a receive signal of a transceiver are disclosed. One embodiment of an apparatus includes a transceiver that simultaneously transmits a transmit signal and receives a receive signal. The transceiver includes a transmit DAC that generates the transmit signal based on a transmit digital signal stream. The transmit DAC includes a plurality of transmit DAC circuit elements, and a plurality of transmit DAC switches that control which of the plurality of transmit DAC circuit elements contribute to generating the transmit signal. The transceiver additionally includes an echo cancellation DAC that generates an echo cancellation signal based on the transmit digital signal stream.

Abstract: Managing packet data network jitter is disclosed. A first call data associated with a mobile network communication session is received. A second call data that is older than the first call data is dropped from a buffer if required to make room in the buffer for the first call data.

Abstract: A multi-channel full-duplex transceiver is disclosed. The transceiver comprises: a clock generator for generating a first clock and a second clock based on a control code; a plurality of transmitters for transmitting a plurality of outgoing signals onto a plurality of channels, respectively; a plurality of receivers for receiving, sampling, and equalizing in parallel a plurality of incoming signals from said plurality of channels, respectively, to generate in parallel a plurality of equalized signals, respectively; a sampling rate converter for converting in parallel said equalized signals into a plurality of refined signals, respectively. In a first operation mode, the control code is established by detecting a timing difference between an output clock of the clock generator and a reference clock. In a second operation mode, the control code is established by detecting a timing embedded in one of said refined signals.

Abstract: An information processing apparatus includes a storage unit including plural memory banks, a wireless communication unit for executing the wireless communication process, a communication quality information storage unit for storing the communication quality information indicating the communication quality of the wireless communication unit in the case where one of the plural memory banks is used, a memory bank selection unit for selecting the memory bank based on the communication quality information stored in the communication quality information storage unit in the case where the wireless communication process is executed by the wireless communication unit, and a memory bank switching unit for switching to the memory bank selected by the memory bank selection unit.

Abstract: A reception device includes reception antennas and an address generation unit that converts a write-in or read-out order of channel estimation values according to a rearrangement rule. A storage unit writes in or reads out channel estimation values in the converted order, and an address generation unit converts a data sequence write-in or read-out order according to the rearrangement rule. A signal storage unit writes in or reads out data sequences in the converted order, and a replica generation unit generates a replica signal by re-modulating the data sequence according to the channel estimation value. A cancel unit successively generates a stream signal in which a data sequence interference signal is cancelled, by using the channel estimation value, the data sequence, and the replica signal.

Abstract: A method and apparatus for removing an echo signal in a signal transmission/reception apparatus of a communication system are provided. A signal transmission/reception apparatus determines an echo channel impulse response using a reception signal, generates an echo signal removing coefficient using the echo channel impulse response, removes an echo signal from the reception signal using the echo signal removing coefficient, and transmits a signal in which the echo signal is removed.

Abstract: Disclosed herein are conferencing products implementing an acoustic echo cancellation system that utilizes converging coefficients and a detector of turn-off and/or turn-on events of push-to-talk microphones, and, further, that mitigates against divergence and/or drift of coefficients and other variables of an echo canceller. A push-to-talk detector may be used that includes a high-pass filter, a transient detector, or an adjustable high-pass filter. An echo canceller may be disabled as to a push-to-talk microphone that has been turned off.

Abstract: One embodiment of the present invention relates to an adaptive filtering apparatus comprising first and second real valued adaptive filters, respectively configured to receive an adaptive filter input signal based upon a transmission signal in a transmission path. The first real valued adaptive filter is configured to operate a real valued adaptive filter algorithm on the input signal to estimate a first intermodulation noise component (e.g., an in-phase component) in a desired signal and to cancel the estimated noise. The second real valued adaptive filter is configured to operate a real valued adaptive filter algorithm on the input signal to estimate a second intermodulation noise component (e.g., a quadrature phase component) in the desired signal and to cancel the estimated noise. Accordingly, each filter operates a real valued adaptive algorithm to cancel a noise component, thereby removing complex cross terms between the components from the adaptive filtering process.

Abstract: In a speech communication device capable of bidirectional communication, a clock deviation between the speaker side (the receiving side) and the microphone side (the transmitting side) is detected, and based on the above deviation, either a first frequency signal (speaker signal (reference signal)) or a second frequency signal (microphone signal) is frequency-shifted in the frequency domain, and therefore, an influence caused by the clock deviation can simply be corrected without an increased processing amount, and thus, an echo can be suppressed effectively.

Abstract: A system and a method for canceling an echo is disclosed. In accordance with the system and the method, a plurality of independently and variably delayed adaptive algorithm blocks are selectively applied to a delayed feedback signal to generate a plurality of echo components in parallel, thereby canceling the echo component from an input signal.

Abstract: A technique of echo cancellation in a communication system. A method and/or apparatus of echo cancellation that may be suitable for performing echo cancellation under single talk and double talk conditions. A method and/or apparatus of echo cancellation that may significantly reduce a residual echo in a single talk environment (e.g. present in many telecommunications systems) without distorting a near end signal in a double talk environment. A method and/or apparatus of echo cancellation that may reduce a residual echo in single talk and double talk environments by applying a post-processing technique to an ECLMS algorithm.

Abstract: A method and apparatus for removing interference from a UpLink (UL) signal in a Time Division Duplex (TDD) system are provided. The method includes determining whether a section for receiving an UpLink (UL) signal from the MS overlaps with sections for sending a DownLink (DL) signal of neighbor BSs in service, the neighbor BSs sending the DL signal to another MS, when the UL signal section overlaps with the DL sections of the neighbor BSs, detecting DL transmit signal information from the neighbor BSs transmitting in the overlapping sections, and removing interference from the UL signal using the detected transmit signal information. Accordingly, the accuracy of detecting the signal from the MS can be raised without having to adopt the complex resource allocation scheme to avoid the interference of the neighbor BSs.

Abstract: An apparatus and method for interference cancellation is provided to cancel the interference such as echo and cross-talk received by a receiver of a communication system. The apparatus includes a digital cancellation signal generator, a first canceller, and a second canceller. The digital cancellation signal generator can generate a digital cancellation signal, which includes a first and a second portion and represents an interference signal within a received signal. The first canceller can perform an analog cancellation on the received signal to output a partially-interference-canceled received signal according to the first portion of the digital cancellation signal. The second canceller can perform a digital cancellation on the partially-interference-canceled received signal according to the second portion of the digital cancellation signal.

Abstract: A mobile communication apparatus usable for voice communication exchanging a received sound and a spoken sound is provided. The mobile communication apparatus includes a first section, a second section movably connected to the first section in an ordinary mechanical mode or an extra mechanical mode, a detector configured to detect the mechanical mode, a speaker included in the first section and configured to produce the received sound, and a microphone included in the second section and configured to pick up the spoken sound. The mobile communication apparatus includes an echo canceller configured to cancel an echo caused by leakage of the received sound, an AGC circuit configured to produce a gain-controlled signal, and a controller configured to provide the AGC circuit with a first input/output characteristic and a second input/output characteristic in the ordinary mechanical mode and in the extra mechanical mode, respectively.

Abstract: A method and apparatus are disclosed for canceling cross-talk in a frequency-division multiplexed communication system. The disclosed frequency-division multiplexed communication system employs multiple carriers having overlapping channels and provides an improved cross-talk cancellation mechanism to address the resulting interference. Bandwidth compression is achieved using n level amplitude modulation in each frequency band. An FDM receiver is also disclosed that decomposes the received broadband signal into each of its respective frequency bands and returns the signal to basehand in the analog domain. Analog requirements are relaxed by removing cross-talk from adjacent R-F channels, from image bands, and minimizing the performance degradation caused by In-phase and Quadrature-phase (I/Q) phase and gain mismatches in modulators and demodulators. The disclosed transmitter or receiver (or both) can be fabricated on a single integrated circuit.

Abstract: A large amount of user information is transmitted with good efficiency by means of a high-speed downlink by making transmission rates of an uplink circuit and a downlink asymmetrical. The radio communication system includes a plurality of base stations, a plurality of terminals, an uplink established between each of the base stations and each of the terminals for the purpose of radio transmission of prescribed information from a terminal to a base station, and a downlink circuit established between each of the terminals and each of the base station for the purpose of radio transmission of prescribed data from a base station to a terminal.