Abstract: The present invention provides for echo cancellation circuitry and variable rate encoding circuitry to cooperate with one another to effectively provide comfort noise in an effective and efficient manner. The echo cancellation circuitry will use far-end signals to generate estimated echo signals, which correspond to the actual echo signals appearing in near-end signals. The estimated echo signals are essentially subtracted from the near-end signals in an effort to remove the actual echo signals from the near-end signals. The echo cancellation circuitry will monitor any residual echo signals in the resulting processed near-end signals and provide residual echo control signals that are indicative of whether the residual echo signals should be replaced with comfort noise. The residual echo control signals are used at least in part by the variable rate encoding circuitry to determine the encoding rate to use for encoding different portions of the processed near-end signals.

Abstract: A voice packet dynamic echo cancellation system includes an input/output unit configured to communicate over a packet network and a storage unit configured to store network performance information associated with node segments on the packet network. The system also includes a processing unit in communication with the input/output unit and the storage unit and configured to: set-up a call from an originating call device to a terminating call device; determine the network performance of the call between the originating call device and the terminating call device; locate an echo signal of the call to the originating call device based on the network performance; produce a echo cancellation signal based on the echo signal; and cancel the echo signal with the echo cancellation signal.

Abstract: A network device including a port configured to exchange packets of data with one or more networks. The network device further includes a rule storing circuit is configured to store a plurality of event classification rules. Each of the event classification rules describes at least one event characteristic for an event in the network device. At least one of the event classification rules includes a change in state of the at least one port of the network device. The change in state of the at least one port is generated by a change in spanning tree mode. The network device further includes an event classifier is configured to identify events having the at least one event characteristic described by any of the event classification rules, and a plurality of event counters configured to count the events identified by the event classifier for a respective one of the event classification rules.

Abstract: In a data processing system, a method includes receiving samples of a send path input signal (Sin) and samples of a receive path input signal (Rin); in response to receiving each sample of the send path input signal, providing a double-talk indicator to indicate whether or not double-talk has been detected; using the double-talk indicator to determine a double-talk density within a predetermined number of samples of the send path input signal or the receive path input signal; and using the double-talk density to provide a heavy double-talk indicator which indicates whether or not heavy double-talk has been detected. In response to the heavy double-talk indicator indicating that heavy double-talk has been detected, a heavy double-talk mode may be entered.

Abstract: An audio/video (AV) processor is coupled to a media access controller (MAC) to generate a composite packet having an optimized format for carrying audio, video, and data traffic with fields in a header of the composite packet specifying video-specific information. A physical device interface (PHY) is coupled to the MAC. The PHY encodes and decodes between a digital signal and a modulated analog signal. The PHY comprises a high rate physical layer circuit (HRP) and a low rate physical layer circuit (LRP). A radio frequency (RF) transmitter is coupled to the PHY to transmit data.

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: In a system having an adaptive filter block for receiving a reference signal and adapting to an input signal, and a block for detecting corruption of the input signal by an interference signal and in response limiting adaptation of the adaptive filter block, the improvement comprising delaying and applying the input signal to the adaptive filter block while applying the input signal to the block for detecting corruption without delay.

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: An apparatus for routing data packets includes a network interface, a memory, a general purpose processor and a flow classifier. The memory stores a flow structure. Every packet in one flow has identical values for a set of data fields in the packet. The memory stores instruction that cause the processor to receive missing flow data and to add the missing flow to the flow structure. The apparatus forwards a packet based on the flow. The flow classifier determines a particular flow and whether it is already stored in the flow structure. If not, then the classifier determines whether that flow has already been sent to the processor as missing data. If not, then the classifier stores into a different data structure data that indicates the flow has been sent to the processor but is not yet included in the flow data structure, and sends missing data to the processor.

Abstract: A second output transmission signal (“TX2”) added to a line driver is a scaled version of the main output transmission signal (“TX1”). TX2 is scaled from TX1 by a variable scale factor K. An adaptive hybrid circuit subtracts TX1 and TX2 from a line signal carrying both a line transmission signal and a line received signal (“RX”). A programmable impedance Ztune is coupled between the TX2 output of the line driver and the RX output of the adaptive hybrid circuit. A transmission echo in the output RX signal is measured. K and Ztune are then adaptively tuned to minimize the transmission echo. The hybrid in this case becomes a 4-port network, one port specifically added to adaptively cancel the transmission echo in the RX output of the adaptive hybrid circuit. Alternatively, the hybrid may be a 3-port hybrid including variable impedances to cancel the line transmission signal.

Abstract: A packet based display interface arranged to couple a multimedia source device to a multimedia sink device is disclosed that includes a transmitter unit coupled to the source device arranged to receive a source packet data stream in accordance with a native stream rate, a receiver unit coupled to the sink device, and a linking unit coupling the transmitter unit and the receiver unit arranged to transfer a multimedia data packet stream formed of a number of multimedia data packets based upon the source packet data stream in accordance with a link rate between the transmitter unit and the receiver unit.

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: 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 Local Mobility Anchor/Agent (LMA), on seeing a Proxy Binding Update (PBU) with a same Network Access Identifier (NAI) but with a different access technology indication or interface identifier can assign a unique prefix to a mobile node (MN) via a PBAck message. The unique prefix avoids the creation of a duplicate address that would conflict with the address assigned to another interface that was configured using a prefix provided by the LMA. This solution can enable an MN to attach to different Mobility Access Gateways (MAGs) that are in different access networks of differing technologies but attached to the same LMA (i.e. the MAGs and the LMA are in the same PMIP6 domain) and not cause conflicts in prefix assignment or confuse the LMA into thinking that the MN had performed a handover (HO).

Abstract: During initial formation of an adjacency, two neighboring PIM speakers exchange, in their hello messages, information as to whether each supports a non-stop forwarding (NSF) capability. When one of the PIM speakers restarts, the PIM neighbor senses this event, and responds by immediately forwarding its entire relevant Tree Information Base (TIB) to the restarting PIM speaker, followed by an End Of TIB (EOTIB) marker. Once the restarting PIM speaker has received TIB contents and EOTIB markers from each of its PIM neighbors, it can immediately finalize its multicast routes. In a group of routers participating in this non-stop forwarding capability, it may be possible to significantly reduce the configuration delay time currently required before purging stale multicast entries from the line card forwarding tables. Other embodiments are also described and claimed.

Abstract: Various embodiments of a wireless multimode receiver having an off-chip duplex filter associated with a multimode band, and a blocker cancellation circuit disposed on a semiconductor chip are described in the present disclosure.

Abstract: A method for synchronizing audio signals of a communication device includes determining whether a downlink thread or a uplink thread is running, pausing the downlink thread or the uplink thread, and executing the downlink thread or the uplink thread by directing a scheduler. A system and storage medium with instructions for performance of the system also provided.

Abstract: Duplex audio communications over a network use compressed audio data, with linear prediction coefficients (LPCs) and variances by which sample values differ from predictions. A adaptive echo canceller for a transceiver develops finite impulse response filter (FIR) coefficients characterizing an echo path between its local audio output and audio input. The received/decompressed audio data is applied to the FIR coefficients, and the predicted echo is subtracted from the uplink signal. Echo is detected as cross-correlation of the receive signal versus the uplink/send signal over time. In one embodiment, the cross-correlation is determined using a pre-whitened receive signal, obtained by adopting the variance values received over the network by the downlink Codec. Apart from the uplink Codec, no speech analysis filter or process is needed. The technique is apt for GSM, AMR and similar compressed audio communications.

Abstract: A method for eliminating DSL crosstalk is provided. The method includes steps of a coordinated transceiver device notifies an existing online opposite device of a signal sent to a new online opposite device; the coordinated transceiver device receives a calculation result that is obtained by the existing online opposite device based on a detected error signal and the signal sent to the new online opposite device, the coordinated transceiver device updates the coefficient of a vector pre-encoder according to the calculation result. A computer program tangibly embodied on a computer-readable storage medium, computer-readable storage medium, DSL opposite device, DSL coordinated transceiver device and system for eliminating the DSL crosstalk are also provided to implement the method. The provided method may reduce the duration of the crosstalk that the new online opposite device generates on the existing online opposite device, and enable the new online opposite device to join a vector group faster.

Abstract: The present invention discloses a method for improving channel estimation in a communications network.

Abstract: Disclosed is a non-linear echo canceller and method for cancelling echo during full duplex communication in a hands free communication system. An input signal from a far-end talker and an input signal from the output from an echo canceller are received. K spectral subbands are created for each input signal. The spectral echo residual power at each subband is estimated and compared to a clean signal power to calculate a signal to echo ratio. Gains are calculated based on each calculated ratio and non-linear echo is cancelled based on the calculated gains.

Abstract: A system and method is described for determining a distance to a desired target via correlating a pulse modulated signal with its corresponding reflected signal, while compensating for noise error in the reflected signal to allow for a more precise distance determination. The system and method determine a phase shift of an echoed signal in response to a transmitted signal incident onto an object to thereby determine a distance, wherein the system analyzes an overlap region between a second signal that is a reflection of a first signal incident on the object. The first signal is modulated by one or more pulses having a defined modulation frequency. Further details and features are described herein.

Abstract: In one embodiment, a path computation client (PCC) generates a path computation request and transmits the path computation request to a path computation element (PCE). The PCC receives from the PCE a response including path segments defining a path, at least one of the path segments being an encrypted path segment that has been encrypted according to an encryption algorithm associated with a remote domain. The PCC then generates a path reservation message that includes the encrypted path segment. This is done without decrypting the encrypted path segment at the PCC. The PCC transmits the path reservation message to one or more nodes along the path, which may be capable of decrypting the encrypted path segment.

Abstract: A system and method for provide a stable gain from an adaptive gain control device in a signal path. An echo canceller is also located in the signal path, and is used to provide performance information regarding losses in the signal. This performance information is fed to the automatic gain control device via a connection. The automatic gain control device thereafter uses the performance information to determine a maximum gain that might be provided based upon losses cause by echo conditions. The gain however is limited in order to provide for a stable system. The performance information includes a loss rate that includes a combination of the echo return loss and the echo return loss enhancement.

Abstract: A method and apparatus for determining reachability of a device connected to a computer network by receiving from a requesting device at least one ICMP echo request, the at least one ICMP echo request having a destination address associated with a non-echoing device; in response to the received ICMP echo request, sending a ping to the non-echoing device; receiving from the non-echoing device a reply to the sent ping; issuing from a routing device a subsequent at least one ICMP echo request to the non-echoing device and determining that no response is received to the issued at least one ICMP echo request; receiving at least one subsequent ICMP echo request from a requesting device, the at least one subsequent having a destination address associated with the non-echoing device; and in response to the received reply to the additional ping, sending a proxy ICMP echo reply to the requesting device.

Abstract: Devices, softwares and methods are provided for redundantly encoding a data stream into frames for network transmission as packets. A main encoder encodes a data stream into main frames, while a redundant encoder encodes it into redundant frames. The redundant frames have a redundant-coding delay from the main frames that is adjustable to accommodate many different sets of network conditions.

Abstract: Duplex audio communications over a network use compressed audio data, with linear prediction coefficients (LPCs) and variances by which sample values differ from predictions. A adaptive echo canceller for a transceiver develops finite impulse response filter (FIR) coefficients characterizing an echo path between its local audio output and audio input. The received/decompressed audio data is applied to the FIR coefficients, and the predicted echo is subtracted from the uplink signal. Echo is detected as cross-correlation of the receive signal versus the uplink/send signal over time. In one embodiment, the cross-correlation is determined using a pre-whitened receive signal, obtained by adopting the variance values received over the network by the downlink Codec. Apart from the uplink Codec, no speech analysis filter or process is needed. The technique is apt for GSM, AMR and similar compressed audio communications.

Abstract: A quadrature modulator divides a part of a transmitted signal to generate a cancel signal. A signal comparator compares the amplitude and phase of the cancel signal which is generated by the quadrature modulator with those of a received signal, and outputs signals corresponding to the comparison results to the quadrature modulator. The quadrature modulator generates the cancel signal on the basis of the output signals of the signal comparator, and these components perform feedback control such that the cancel signal has the same amplitude as the leakage signal and is in phase with the leakage signal. A combiner combines the cancel signal with an antiphase cancel signal, which is made to be in opposite phase with the cancel signal outputted from the quadrature modulator, to cancel out the leakage signal.

Abstract: In a method for echo suppression or cancellation, a reference voice packet is selected from a plurality of reference voice packets based on at least one encoded voice parameter associated with each of the plurality of reference voice packets and the targeted voice packet. Echo in the targeted packet is suppressed or cancelled based on the selected reference voice packet.

Abstract: Classifying signals includes receiving signals from communication devices, where each signal is received from a communication device. The following is repeated for each signal: a received signal from the communication device is encoded, whether the encoded signal is an undesirable auditory signal is determined, and the encoded signal is modified if the encoded signal comprises an undesirable auditory signal. The received signals are combined.

Abstract: A system and method for estimating a channel spectrum. The method includes: (a) receiving an input signal from a channel, where the input signal includes one or more major echoes and zero or more minor echoes introduced by the channel; (b) identifying the one or more major echoes present in the input signal; (c) identifying the minor echoes from a filtered autocorrelation function of the input signal in response to a determination that there is only one major echo; (d) identifying the minor echoes from a filtered power spectrum of the input signal in response to a determination that there is more than one major echo; (e) computing a channel spectrum estimate from the major echoes and minor echoes; where the channel spectrum estimate is usable to remove at least a portion of the one or more major echoes and one or more minor echoes from the input signal.

Abstract: The present invention refers to a passive echo cancellation device for use in a full-duplex communication system and its signal transceiving method. The full-duplex communication system comprises a transmitting end for sending a transmit signal to a wiring interface, and a receiving end for accepting a receive signal from the wiring interface. The passive echo cancellation device comprises an offset-signal-generating circuit and a passive echo cancellation circuit composed of a plurality of passive components. The offset-signal-generating circuit generates an offset signal according to the transmit signal. The passive echo cancellation circuit is serially connected between the wiring interface and the receiving end, and is connected with the offset-signal-generating circuit.

Abstract: A system and method facilitating acoustic echo cancellation convergence detection is provided. The invention includes an acoustic echo cancellation convergence detector having a center clipping component, a convergence calculator, a convergence filter and a convergence statistic component. The invention provides for the acoustic echo cancellation convergence detector to provide an output regarding convergence of an adaptive filter based, at least in part, upon a filtered convergence statistic. Optionally, the acoustic echo cancellation convergence detector can provide an output associated with convergence history.

Abstract: A communication circuit includes a replica circuit that generates first and second single-ended replica transmit signals. When one of the first and second single-ended replica transmit signals is asserted, the other of the first and second single-ended replica transmit signals is not asserted. A converter circuit includes a differential amplifier including first and second inputs that receive the first and second single-ended replica transmit signals, respectively. The converter circuit converts the first and second single-ended replica transmit signals to a differential replica transmit signal. A receive circuit generates a differential receive signal based on a differential composite signal and the differential replica transmit signal.

Abstract: A demodulator cancels out the echo signal properties in the received signal to generate a primary signal, and cancels out the primary signal properties in the received signal to generate a separate echo signal. In addition, the demodulator may combine the primary signal and the echo signal in a comparison/combination operation to generate a third combined signal. Error correction operations may then be performed on all three of the primary signal, echo signal and combined signal, with the results of those error correction operations being used to select which of the three signals will serve as the transport stream.

Abstract: A device and method for a full-duplex transceiver is disclosed. The transceiver includes a transmitter DAC coupled to a transmission channel. The transmit DAC converting a digital transmission signal into an analog transmission signal. The transceiver further includes a receiver connected to the transmission channel. The receiver receives a desired signal and an echo signal, in which the echo signal includes at least a portion of the analog transmission signal. The receiver includes a receiver ADC, a programmable delay line for adjustably delaying a clock signal of the ADC, and a receiver processing circuit for adjusting the delay of the clock signal based at least in part upon the echo signal.

Abstract: The present invention provides a method, apparatus, and computer implemented instructions for computer-based onboard noise suppression devices with remote web-based management features. The present invention detects noise within a computer. A noise canceling signal is generated based on parameters. These parameters may include, for example, the percentage of noise to suppress. The noise canceling signal is broadcasted to reduce or eliminate noise. Additionally, the present invention provides the ability to remotely manage noise suppression within computers.

Abstract: Bidirectional differential point to point simultaneous high speed signalling is provided between integrated circuits with highly effective echo canceling. Each integrated circuit comprises a transmitter for transmitting a first signal to another integrated circuit and a receiver for receiving a second signal from the other integrated circuit. The transmitter has an output buffer; a receiver has a receiver buffer and is co-located on the same integrated circuit; and a differential buffer is coupled between the input of the transmitter buffer and the output of the receiver buffer. To increase the quality of receiving the second signal, a third signal adjusted in phase and amplitude is coupled at the output of the receive buffer, so that the echoing of the first signal is canceled. Preferably, the rise time of the third signal is also adjusted.

Abstract: A method of determining residue-echo threshold for the trans-hybrid echo path of a loop start (LS) trunk line, comprising the steps of estimating the impulse response of the trans-hybrid echo path, passing a speech-like signal through the LS trunk circuit and collecting the echo signal. The collected echo signal is compared to the convolution of the speech-like signal with the estimated impulse response. The difference between the convolution result and the collected echo signal is the residue echo, which represents the effect of nonlinearity. With different levels of excitation signal, a curve of residue echo power level against input signal level is obtained, and the distortion characteristics are derived from this curve.

Abstract: Techniques for suppressing large echo due to nonlinearity, instable adaptive filter, and so on. An echo cancellation system includes an echo canceller unit, a nonlinear echo detection unit, and a nonlinear echo suppression unit. The echo canceller unit (e.g., an adaptive filter) receives a reference signal and a near-end signal, derives an echo estimate signal based on the reference and near-end signals, cancels a portion of echo in the near-end signal based on the echo estimate signal, and provides an intermediate signal having residual echo. The nonlinear echo detection unit detects for large nonlinear echo in the echo estimate signal. The nonlinear echo suppression unit suppresses large nonlinear echo in the first intermediate signal based on a variable gain, which may be adjusted lower if large nonlinear echo is detected and higher otherwise.

Abstract: The invention relates to an interference cancellation method and a receiver including interference canceller for suppressing a narrow-band interference signal from a received signal, converter for performing an orthonormal conversion of the signal into subspace components of a desired subspace, a decoder connected operationally to the output of the interference canceller, in which decoder an estimate for the received signal is obtained. The output of the decoder is operationally connected to the interference canceller, and the converter is arranged to determine an estimate for narrow-band interference properties, in which determination the estimate obtained from the output of the decoder is subtracted from the received signal before the orthonormal conversion is performed. By using the determined estimate, the interference canceller is arranged to reduce effect of the subspace components including narrow-band interference signals from the received signal.

Abstract: A method and system are disclosed for improving the performance of a multiline transmission system by using one or more split-pair receivers in a multiline communications system to identify crosstalk on a pair of transceivers coupled to the split pair receivers, wherein each split pair receiver receives a signal including the crosstalk from each transceiver and provides a corresponding signal vector to a post processing unit, and performing MIMO post-processing on signal vectors received at a receiver from each transceiver and each split-pair receiver while minimizing crosstalk on pairs of lines in the multiline communications system with a frequency equalizer.

Abstract: Devices, softwares and methods send a warning signal when a periodic signal is present in the audio content of a VoIP connection. In response to the warning signal, an acoustic echo canceller of an IP telephone discontinues its adapting process. A signaling network switch detects when a periodic signal is present in the audio content, and issues a warning signal. A signaling call manager device, when it transmits a tone that has periodicity, it also transmits a warning signal.

Abstract: JPEG-2000 data is formatted into RTP packets for transmission through the Internet. A priority field is provided in the format, and a value indicating the importance of a code stream included in a packet is stored therein. A type field indicates a payload type of a JPEG-2000 code stream. An mh_id field is provided as an identifier of a main header of the JPEG-2000 code stream and indicates a change in the main header. An mh_length field indicates the length of the main header and a fragment offset field stores the number of offset bytes from the start of an image of the packet.

Abstract: A system includes multiple packet-based communication devices that support audio output and other suitable functionality and an acoustic space management device that manages these devices to provide telephony services within acoustic spaces. These devices can coordinate their actions to provide audio services, such as conferencing, paging, broadcasting, and other appropriate audio services.

Abstract: A path change is detected by multiplying the energy of a signal on the output of a summation circuit in one channel of a telephone by a constant to produce a product. The product is compared with the energy of a signal on the input of the summation circuit. A path change is indicated when the energy of the product exceeds the energy of a signal on the input of the summation circuit. The comparison is made in successive frames of an audio signal and a path change is indicated when the energy of a signal on the input of the summation circuit is exceeded in two or more successive frames.

Abstract: The present invention relates to a method and apparatus for detecting voice activity in a communication signal, wherein filter means are provided for estimating or suppressing an offset component of the level of the communication signal. A filter parameter is controlled based on the output of the filter means. Furthermore, the estimation or suppression of the offset component is limited in response to the output of the filter means. The filter means may be based on a non-linear adaptive notch level filter or a noise floor tracking filter. Thereby, the tracking behavior of noise floor estimation to sudden rises in noise floor can be improved and the voice activity detection can work efficiently over a wide dynamic range.

Abstract: A method and apparatus for identifying echo sources in a communication path. A system that incorporates teachings of the present disclosure may include, for example, an echo measurement device (EMD) having a transmit module to transmit an echo canceller deactivation signal in a communication path of the communication system, wherein the echo canceller deactivation signal deactivates one or more echo cancellers in said communication path. The transmit module can also transmit a test signal in the communication path which is looped back at an end point identified as having an echo problem, wherein the test signal is transmitted at a remote location from the end point. The EMD can further include a detection module to detect one or more echo signals associated with the test signal. Additional embodiments are disclosed.

Abstract: A method of canceling an echo in a signal of a communication network may include filtering an input signal and a corresponding reference signal of an echo path so as to produce vectors of N subband signals corresponding to the input signal and N subband reference echo signals corresponding to the reference signal. Vectors corresponding to a subset of the N subband signals may be adaptively adjusted to form modified vectors of the subset which approximate the corresponding N subband reference echo signals. Based on the modified vectors, subband errors related to a residual echo for each of the subband signals of the subset may be determined. The subband errors may be synthesized to generate a full-band signal with a synthesized residual echo.