Abstract: IP network communication device which allows facsimile communication conforming to ITU-T recommendation V.34 in the network conforming to ITU-T recommendation T.38. This IP network communication device comprises a call controller for setting the call connection of a voice channel with another communication device, a voice controller which generates packets from voice data and facsimile data, sends the packets to the other communication device, and restores voice data or facsimile data from the packets received from the other communication device, and a digital signal processor which mediates the communication of voice data and facsimile data between an accommodated terminal and the voice controller. The digital signal processor turns ON the facsimile tone detecting function, echo canceling function, and fluctuation absorption buffer function if voice data is communicated, and turns these functions OFF if facsimile data is communicated.

Abstract: A first physical layer device of a first network device includes a sense circuit that senses activity on a medium and with the first physical layer device. An autonegotiation circuit attempts to establish a connection with a second physical layer device of a second network device within a first period after the sense circuit senses activity. An energy saving circuit selectively provides power to the first physical layer device based on the sensed activity and connection with the second physical layer device, and that while attempting to establish the connection resets a timer associated with the first period when the sense circuit senses activity.

Abstract: Methods and apparatus of managing a communication system, wherein a decision regarding a level of activity at a first end is made based at least in part on the level of activity at the second end. In one embodiment, the energy level of a first-end audio signal is measured. The first end is declared voice-active if the first-end energy level is greater than or equal to a first threshold value. The first end is declared voice-inactive if the first-end energy level is less than the first threshold value. To determine the value of the first threshold value, the energy level of a second-end audio signal is measured. If the second-end energy level is greater than or equal to a second threshold value, the second end is declared voice-active, in which case the first threshold is maintained at a relatively high level. If the second-end energy level is less than the second threshold value, the second end is declared voice-inactive, in which case the first threshold is maintained at a relatively lower level.

Abstract: A method of and apparatus for noise reduction for a transceiver transmitting frames over a transmission medium in a frame-based communications network. A transceiver transmit path and a transceiver receive path is provided. A blocking switch is located in the transceiver transmit path, the blocking switch allowing transmit signal propagation when enabled, while preventing both transmit signal propagation and circuit device noise coupling from the transceiver transmit path to the transceiver receive path when the blocking switch is disabled. The blocking switch is disabled when the transceiver transmit path is not transmitting frames over the frame-based communications network.

Abstract: A transceiver for echo and near-end crosstalk cancellation without a loop timing configuration. The transceiver comprises a receiver, a timing recovery circuit, a same-channel phase interpolator, an echo canceller, a near-channel phase interpolator and a near-end crosstalk (NEXT) canceller. The same-channel phase interpolator and the near-channel phase interpolator receive a phase choosing signal from the timing recovery circuit to determine a specific phase from different phases. The same-channel phase interpolator generates a same-channel phase-modified signal with the specific phase and outputs the phase-modified signal to the echo canceller to cancel an echo in the received signal. The near-channel phase interpolator generates a near-channel phase-modified signal with the specific phase and outputs the near-channel phase-modified signal to the NEXT canceller to cancel a NEXT signal in the received signal.

Abstract: According to one embodiment of the invention, a method for managing communication impairments between Internet Protocol devices is provided. The method includes determining a transmission of a signal comprising a comfort noise, where the signal is transmitted from a first endpoint to a second endpoint. The method also includes sending a notice signal from the first endpoint to the second endpoint indicating that the signal is transmitted. The method also includes suppressing the signal at the second endpoint in response to the notice signal. According to another embodiment of the invention, a method for managing communication impairments between an Internet Protocol (“IP”) phone and an IP device is provided. The method provides sending a status signal to the device indicating that the phone is operating as a speakerphone. The method also includes suppressing the transmission of any comfort noise to the phone in response to the status signal.

Abstract: A radio apparatus, to be used as a first ending node of a communication network, is connectable to a hands-free apparatus by a local radio link to form a hands-free system. A call made on the hands-free apparatus for an second ending node in the communication network is sent to the radio apparatus through a control channel on the local radio link. The radio apparatus and the hands-free apparatus arrange a voice channel to be established on the local radio link. The call is then sent to the second ending node. In a case where no voice channel is established within a predetermined time period after arranging the voice channel, the radio apparatus cancels the call to prevent a connection between the radio apparatus and the second ending node from being kept and charged.

Abstract: An echo cancelling system comprises a system controller for directing inbound and outbound PCM signals to one of two echo canceller modules. The system controller receives status information from the echo cancellers and maintains state information pertaining to the active echo canceller, in order to allow seamless switchover from one echo canceller to the other without interrupting service.

Abstract: A repetitive burst-mode input signal that has a dark time portion, a preamble portion, and a payload portion is converted into a limited output signal in accordance with a decision threshold level, which is controlled by selectively coupling an averaged value of the burst-mode data amplitude to the decision threshold level. The timing sequence for selectively coupling the averaged signal value is controlled such that the average value of the burst-mode signal acquired during the preamble portion of the burst-mode signal is applied to the decision threshold level during substantially all of the payload portion. The control circuit may incorporate a phase-locked loop, which locks onto the repetitive dark time frequency and in response synthesizes a switchable track enable signal that controls the timing sequence of the decision threshold level. The phase-locked loop can employ all-digital, analog, and/or hybrid digital/analog circuitry.

Abstract: A wireless endpoint employs frequency hopping for communicating signals in a wireless communications system. Over a time period T, the wireless endpoint performs pseudo-random selection of a frequency from a hopping set of N frequencies such that over at least a portion of the time period T, the frequency selection is constrained to less than the N frequencies.

Abstract: An apparatus and method for echo cancellation is presented. The echo canceller comprises an adaptive filter that tracks the impulse response of the echo path and produces an estimate of the echo. Filter adaptation is controlled by a controller based on the rate of the far-end speech signal, the rate of the near-end signal, an acoustic loss measure, and a double talk hangover indicator. The controller may also comprise a step size adaptation unit for determining the adaptation step size of the adaptive filter. In addition, the controller may comprise a noise replacement unit, which controls replacement of the echo residual signal with comfort noise to ensure echo is completely rejected when only the far-end speaker is talking.

Abstract: An energy saving circuit is connected to a receiver of a first physical layer of a first network device. The energy saving device has first and second energy saving modes. In the first energy saving mode, a sense circuit generates a receive signal when connection activity is detected by the receiver. The energy saving circuit powers down the physical layer when the receiver does not detect the connection activity. An autonegotiation circuit powers up the first physical layer and negotiates a connection with a second physical layer of a second network device when the sense circuit generates the receive signal. In a second energy saving mode, a second timer periodically powers a transmitter and generates a link pulse. After the transmitter generates the link pulse, the transmitter is turned off.

Abstract: An echo cancellation system measures an average delivery rate of a reference data signal and an average capture rate of an input data signal. From the measured data rates, the system converts the reference data signal to a domain of the input data signal. An echo canceler cancels an echo that may be present in the input data signal based upon the converted reference data signal.

Abstract: An echo cancelling system for cancelling echoes in a communication path includes an echo locator and an echo canceller. The echo locator is coupled to the communication path and locates the positions of echo signals received from the communication path. The echo canceller is also coupled to the communication path and cancels echo signals received therefrom. During echo cancellation, the echo canceller becomes active in regions corresponding to the positions of echo signals in response to the echo locator.

Abstract: A network gateway is configured to facilitate on line and off line bi-directional communication between a number of near end data and telephony devices with far end data termination devices via a hybrid fiber coaxial network and a cable modem termination system. The described network gateway combines a QAM receiver, a transmitter, a DOCSIS MAC, a CPU, a voice and audio processor, an Ethernet MAC, and a USB controller to provide high performance and robust operation. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Abstract: A startup protocol is provided for use in a communications system having a plurality of transceivers, one transceiver acting as a master and another transceiver acting as slave, each transceiver having a noise reduction system, a timing recovery system and at least one equalizer. The operation of the startup protocol is partitioned into three stages. During the first stage the timing recovery system and the equalizer of the slave are trained and the noise reduction system of the master is trained. During the second stage the timing recovery system of the master is trained in both frequency and phase, the equalizer of the master is trained and the noise reduction system of the slave is trained. During the third stage the noise reduction system of the master is retrained, the timing recovery system of the master is retrained in phase and the timing recovery system of the slave is retrained in both frequency and phase.

Abstract: A startup protocol is provided for use in a communications system having a communications line with a master transceiver at a first end and a slave transceiver at a second end, each transceiver having a noise reduction system, a timing recovery system and at least one equalizer all converging at startup of the system. The operation of the startup protocol is partitioned into stages. The first stage includes the step of converging the equalizer and the timing recovery system of the slave while converging the noise reduction system of the master. Upon completion of the first stage the protocol enters a second stage which includes the step of converging the equalizer and the timing recovery system of the master, converging the noise reduction system of the slave, freezing the timing recovery system of the slave, and resetting the noise reduction system of the master.

Abstract: An apparatus (200) checks voice quality when in a vocoder bypass mode. If the voice quality level is beyond an acceptable range, the apparatus (200) ends the vocoder bypass mode and returns to tandem vocoding. For example, a vocoder bypass controller (206) includes a speech quality detector (225) that determines the speech quality level of speech information based on at least one of detected volume level, echo level and noise level of the speech information. The vocoder bypass controller (206) with the speech quality detector (225) outputs a speech quality-based vocoder bypass control signal (236) to selectively activate or deactivate a vocoder bypass operation in response to the speech quality-based vocoder bypass control signal (236). In another embodiment, a network element for communicating speech packets includes an incoming decoder (512) and a speech quality detector (514) operative to determine the speech quality level of incoming speech packets.

Abstract: A method of improving convergence of an echo canceller in a full duplex speakerphone, wherein the echo canceller includes LEC (Line Echo Canceller) and AEC (Acoustic Echo Canceller) portions, comprising the steps of capturing LEC coefficients during operation, storing the coefficients, and utilizing the stored coefficients as default values during start-up of a subsequent call. The method of the present invention reduces the overall convergence time of the echo canceller by alleviating the requirement to wait for a suitable reference signal in order to converge the LEC.

Abstract: Embodiments of the present invention relate generally to receivers. One embodiment relates to a digital FM receiver having multiple sensors (e.g. antennas). In one embodiment, the digital receiver includes a baseband unit having a channel processing unit. In one embodiment, the channel processing unit is capable of calculating or estimating a phase difference between the incoming signals prior to combining them. One embodiment uses phase estimation method for diversity combining the signals while another embodiment utlizes a hybrid phase lock loop method. Also, some embodiments of the present invention provide for echo-cancelling after diversity combining. An alternate embodiment of the channel processing unit utilizes a space-time unit to diversity combine and provide echo cancelling for the incoming signals.

Abstract: An echo cancellation device for reducing a magnitude of an echo occurring in a voice signal propagating in a channel of a communication system. The echo cancellation device is capable to selectively acquire an active operative mode and an inactive operative mode in response to a condition indicative of a level of echo present in the voice signal. In the active operative mode the echo cancellation device performs echo cancellation on the voice signal. In the inactive operative mode the echo cancellation device allows the voice signal to propagate without performing any echo cancellation.

Abstract: An apparatus and method for echo cancellation is presented. The echo canceller comprises an adaptive filter that tracks the impulse response of the echo path and produces an estimate of the echo. Filter adaptation is controlled by a controller based on the rate of the far-end speech signal, the rate of the near-end signal, an acoustic loss measure, and a double talk hangover indicator. The controller may also comprise a step size adaptation unit for determining the adaptation step size of the adaptive filter. In addition, the controller may comprise a noise replacement unit, which controls replacement of the echo residual signal with comfort noise to ensure echo is completely rejected when only the far-end speaker is talking.

Abstract: An echo cancellation system measures an average delivery rate of a reference data signal and an average capture rate of an input data signal. From the measured data rates, the system converts the reference data signal to a domain of the input data signal. An echo canceler cancels an echo that may be present in the input data signal based upon the converted reference data signal.

Abstract: A communication apparatus and its control method which assure an execution of a polling communication in a state that an ECM transmit inhibition is selected while an ECM receive inhibition is not selected for communications in the ITU-T Recommendation V.8, V.21, V.27ter, V.29, V.17, or V.34, by executing a V.17 or lower transmission without executing a V.34 transmission if the ECM transmit inhibition is selected, by executing a V.17 or lower reception without executing a V.34 reception if the ECM receive inhibition is selected, and by executing a V.8 protocol for a reception so as to execute a V.34 reception if it is a receive operation or to shift to a V.17 or lower polling transmission if it is a polling operation and executing a V.17 or lower transmission for a transmission in a state that the ECM transmit inhibition is selected while the ECM receive inhibition is not selected.

Abstract: A communication integrated circuit, such as a full-duplex speakerphone circuit, includes a double-talk detector that operates in combination with an echo canceller. The echo canceller includes an adaptive filter with filter coefficients that are regularly adjusted to train to a received echo. The double-talk detector includes an ERLE detector for measuring the current ERLE of the echo canceller and a logic circuit for determining a best ERLE value over a plurality of measurements. The double-talk detector also includes a power estimator and noise estimator for determining a noise level. The noise level attained when the ERLE value is the best ERLE value is saved as a benchmark noise level. Filter coefficients of the echo canceller are updated or updating is blocked based on several considerations including a comparison of ERLE value to best ERLE value, the noise level in comparison to the benchmark noise level, whether the circuit is operating in half-duplex or full-duplex mode, and detection of a tone.

Abstract: Improved data communication for modems having digital identification information capability.

Abstract: In a full duplex PCM modem system, a method and apparatus is provided for robust measuring of the communications channel in which the digital modem's transmitter is silenced during generation of training signals by the analog modem, with the silencing of the digital modem's transmitter eliminating problems associated with echo during channel measurement at the digital modem. The above method thus eliminates echo during channel estimation and removes any dependencies on the performance of the echo canceller normally used.

Abstract: In a data communications system, a first node transmits an output digital signal to a second node through a transmission line and receives an input digital signal from the second node through a reception line, a signal processing amplification block of the data communications system compensates an attenuation in the input digital signal and prevents a crosstalk between the transmission line and the reception line, and a regulating block for preventing a crosstalk receives a branch signal and generates a control signal based on a capacity of the branch signal.

Abstract: A method is described for reducing computational requirements during idle transmission in remote access systems incorporating digital subscriber line (DSL) modems, including asymmetrical DSL (ADSL) systems. Processing power is saved during idle transmission by generating an idle signal using low-complexity techniques. The generated idle signal is made spectrally compatible with xDSL systems, and a non-disruptive signaling scheme is used to indicate to the far-end receiver the transition between idle to active or active to idle status. A technique is presented that modulates the phase of the pilot tone to signal status transitions to the remote receiver. The computational complexity at the receiver is reduced because fill demodulation and decoding is not required to determine that an idle signal is being transmitted.

Abstract: A startup protocol is provided for use in a communications system having a plurality of transceivers, one transceiver acting as a master and another transceiver acting as a slave, each transceiver having a noise reduction system, a timing recovery system and at least one equalizer. The operation of the startup protocol is partitioned into three stages. During the first stage the timing recovery system and the equalizer of the slave are trained and the noise reduction system of the master is trained. During the second stage the timing recovery system of the master is trained in both frequency and phase, the equalizer of the master is trained and the noise reduction system of the slave is trained. During the third stage the noise reduction system of the master is retrained, the timing recovery system of the master is retrained in phase and the timing recovery system of the slave is retrained in both frequency and phase.

Abstract: An echo canceler (10) includes an idle code density detector (12) that measures an idle code density over a period of time. The idle code density detector (12) includes an idle code detector (30) that identifies idle codes and non-idle codes. An idle code integrator (32) increments an idle code count (36) by a first weight factor (38) for each idle code identified by the idle code detector (30). The idle code integrator (32) decrements the idle code count (36) by a second weight factor (40) for each non-idle code identified by the idle code detector (30). A threshold detector (34) continuously compares the idle code count (36) to a threshold value (42). When the idle code count (36) exceeds the threshold value (42), the threshold detector (34) generates a control signal (22) to disable an adaptive filter (14) and a processor (18) of the echo canceler (10).

Abstract: A method and device for managing the communication of high speed analog data across a communications line. If the communications line is not authorized for communication of high speed analog data, line conditioning applied (e.g., at a digital line unit or subscriber line interface circuit) to the communications line is varied. The line conditioning may include echo suppression and/or hybrid balancing. If the line conditioning unit is a digital signal processor, the line conditioning is varied by varying coefficients or line types. If the line conditioning unit is a circuit, the line conditioning is varied by varying a control signal to a selection element of the analog circuit.

Abstract: The problem of tracking rapid changes in the echo signals associated with modems is eliminated by using an echo canceler consisting of cascaded adaptive filters. Each filter in the structure contributes to the modeling of the overall echo path impulse response, with a longer filter providing the ability to model long echo path impulse responses and a shorter filter providing the ability to track changes in the echo path impulse response over time.

Abstract: The computational load imposed by a software modem executed on a general purpose processor can be significantly reduced by exploiting periods during an active connection when no data is being received by the software modem. In particular, execution of many receive path signal processing algorithms can be disabled when no data is being received by the software modem. The transmit path continues output modulation as with a normal connection, so as to trick the remote modem (which may or may not be a software modem) into believing the connection is still normal. However, substantial portions of the software modem's receive path can be disabled, thereby reducing computational load on the general purpose processor and freeing additional compute cycles for application and/or operating system program use.

Abstract: A multistage interconnect network (MIN) capable of supporting massive parallel processing, including point-to-point and multicast communications between processor modules (PMs) which are connected to the input and output ports of the network. The network is built using interconnected switch nodes arranged in 2 .left brkt-top. log.sub.b N .right brkt-top. stages, wherein b is the number of switch node input/output ports, N is the number of network input/output ports and .left brkt-top. log.sub.b N .right brkt-top. indicates a ceiling function providing the smallest integer not less than log.sub.b N. The additional stages provide additional paths between network input ports and network output ports, thereby enhancing fault tolerance and lessening contention.

Abstract: An improved echo removing system by which it is possible to more effectively remove echoes which occur during a wireless communication between a mobile communication subscriber and a fixed communication subscriber in a CDMA type mobile communication exchange system, which includes a signal input unit connected between the remote network/station interface unit and the first time switch connection unit for receiving a transmitting and receiving audio signal, an echo removing processor for detecting a difference between the transmitting audio signal and the receiving audio signal outputted from the signal input unit and for removing an echo component from the receiving audio signal in accordance with the control signal from the time switch connection/disconnection controller, and a second time switch connection unit for time-switching in order for the output signal from the echo removing processor to be transmitted to the mobile communication subscriber through the system inside connection unit in accordance wit

Abstract: A phase-splitting T/3 equalizer and echo canceller structure is computationally efficient because only one point per baud is calculated. However, there are two drawbacks to the structure: (1) since the equalizer performs both the phase-splitting function and channel response equalization, its convergence is slow, and (2) when training the echo canceller during half-duplex training, an answering modem needs an assumed equalizer in its receive path to train its echo canceller, because the adaptive equalizer has not yet been trained; however, after equalizer training the echo canceller needs to be retrained because equalizer coefficients have changed. In contrast, a fixed phase splitting filter can be used during training.

Abstract: A multi-channel transcoder with rate adapter converts the data rate of GSM and PSTN network data in a multi-channel network. A transcoder having echo-cancellation features uses the robust voice activity detection functions of the GSM transcoder functions to enhance the accuracy of echo-cancellation of near-end signals. A method for decoding a GSM signal in which the transmission of the audio data over the network is commenced prior to the completing of the decoding process. A transcoder unit having rate adaption and echo-cancellation with improved decoding is implemented in a single DSP and processes multiple traffic channels simultaneously.

Abstract: The problem of tracking rapid changes in the echo signals associated with modems is eliminated by using an echo canceler consisting of cascaded adaptive filters. Each filter in the structure contributes to the modeling of the overall echo path impulse response, with a longer filter providing the ability to model long echo path impulse responses and a shorter filter providing the ability to track changes in the echo path impulse response over time.

Abstract: A circuit in which driver units are associated with data networks that are coupled through at least two single transmission channels is provided. The driver units have a logical signal input and a logical signal output on their sides facing away from the data network, with the signal input or signal output of one driver unit being connected with the signal output or signal input of the other driver unit through a signal transmission channel in each case for coupling each of two data networks. A logical coupling control unit is looped into the coupling signal transmission channels. The unit blocks the signal path to the other signal transmission channel when predetermined blocking signal information appears on one signal transmission channel. This ensures that feedback and oscillation effects are suppressed during the transmission of signals over the transmission channels. The circuit can be used for coupling CAN data networks in motor vehicles.

Abstract: In a TDMA mobile-to-mobile connection, the end-to-end audio signal quality as well as system performance can be improved by providing digital signal processors the capability to automatically switch configuration such that each digital signal processor in a mobile-to-mobile communication connection can automatically identify a TDMA mobile-to-mobile connection and bypass the speech encoding and decoding processes within the digital signal processors. The two digital signal processors are virtually connected at the channel codecs.

Abstract: A method of detecting narrow-band signals in an echo canceller to control the coefficient update process, echo suppression process, and the disablement of the echo canceller is provided. The method includes the steps of searching for the presence of a generic tone, searching for DTMF tones, searching for a 2100 Hz tone and, if a generic tone is found, searching for a dial tone. If a generic tone is detected on the far end signal, a tone flag is set which triggers the disablement of the echo canceller coefficient update process and the enablement of the echo suppressor process. If a 2100 Hz tone is detected, the echo canceller is disabled. If a DTMF signal is detected, DTMF flags are set which are used by the echo suppressor for suppressing the near end echo. Finally, if a dial tone is detected, dial tone flags are set which cause the disablement of the echo suppressor.

Abstract: A double-talk detector for an echo canceller includes power estimators (60) and (62) which are utilized to measure the ERLE value in a calculator (64). This ERLE value is stored in a register (70) when it is the largest value generated. This register (70) is updated whenever a new and better ERLE occurs. A fraction of the value in register (70) is utilized as an input to a comparator (88), and then compared to the current ERLE value. If the current ERLE differs from the SERLE in register (70) an inhibit signal is generated for blocking the updates of an adaptive filter (40). The value stored in the register (70) is periodically decremented to reduce the value thereof. This decrement operation is performed in response to detection of an utterance from the far-end.