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8121260 |
Method and apparatus for retraining of echo cancellation
A method of determining if an echo canceller comprised in a communication channel that is used to transmit at least one tonal signal and characterized by a model echo path of the channel, is...
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8090077 |
Testing acoustic echo cancellation and interference in VoIP telephones
Described is automatically testing the quality of an audio coupling between juxtaposed first and second digital telephones, e.g., VoIP telephones, such as to quantitatively determine the quality of...
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8090078 |
Systems and methods for half-duplex speakerphones and other two-way communication devices
An apparatus to enable half-duplexing capabilities in a two-way communication device is disclosed. The apparatus estimates the signal power and background noise of a first input signal and a second...
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7881459 |
Acoustic echo canceller using multi-band nonlinear processing
An echo canceller (106) can include a first multi-band filter (152) which receives a first input signal (108) and generates a first plurality of sub-band signals (110, 111, 112), and a second...
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7856087 |
Circuit method and system for transmitting information
Disclosed is an echo suppresser or cancellation circuit including a speech signal extrapolation unit. The speech extrapolation unit may provide extrapolated signal segment approximations to an echo...
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7817797 |
Method and apparatus for detecting echo path changes in an acoustic echo canceller
An echo canceller comprising a first adaptive filter having N_long coefficients for converging to an echo path, a non-adaptive filter representing a direct echo path portion captured by the first...
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7787597 |
Automated tools for testing echo cancellers using natural speech excitations
There are provided methods and systems for automated testing of echo cancellers using natural speech excitations and evaluating an echo canceller by transmitting a first signal to the echo...
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7733949 |
Wireless communications system with reduced sideband noise and carrier leakage
A wireless communications system is provided with reduced sideband noise and carrier leakage. In the system, at least one transmitter modulates at least one input signal with a first carrier to...
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7702004 |
Simultaneous bidirectional differential signalling interface
Bidirectional differential point to point simultaneous high speed signalling is provided between integrated circuits with highly effective echo canceling. Each integrated circuit comprises a...
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7620172 |
Method and system for eliminating noises and echo in voice signals
Techniques for simultaneously and efficiently eliminating echo and noise mixed in voice are disclosed. According to one aspect of the present invention, an adaptive filter system for eliminating...
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7548599 |
Method and apparatus for reducing cross-talk with reduced redundancies
A method and apparatus are disclosed for reducing cross-talk in an unbalanced channel with a reduced number of redundancies. A cross-talk canceller is disclosed that uses a multi-dimensional finite...
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7480367 |
Fault characterization using information indicative of echo
A fault associated with a communication medium is analyzed by correlating a first set of information indicative of echo associated with the communication medium with a second set of information...
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7359489 |
Method and apparatus for inclusive echo canceller testing
A testing and performance analysis methodology applies a series of test vector pairs to the input ports of an echo canceller under test. The test vector signal pair may represent a particular...
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7330500 |
Adjustable electronic duplexer
A duplexer for a communication device having a transmission unit, a reception unit and a shared antenna is disclosed. The duplexer comprises a first signal path between the transmission unit and...
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7269211 |
Residual echo reduction for a full duplex transceiver
A hybrid circuit within a full-duplex transceiver transmits an outgoing signal outward on a communication channel at the same time it receives an incoming signal arriving via the communication...
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7120130 |
Seamless redundant echo canceller replacement in a multi-channel echo canceller
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...
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7095720 |
Trunk level echo canceller test system
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...
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7068611 |
Method and apparatus for performing diagnostic tests using an assisting transceiver
A method and system for performing diagnostic tests on a communications system. Diagnostic test signals are generated by a transceiver included within the communications system. Diagnostic data...
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7065056 |
Transceiver circuit including an echo canceller
A circuit for transmitting and receiving communications. The circuit includes a transmit block, a receive block, and an echo canceller, coupled to the transmit block and to the receive block, for...
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7042934 |
Crosstalk mitigation in a modem pool environment
In a modem pool system capable of mitigating alien crosstalk, a system including a first modem pool including at least two modems, at least one protected line connected to one of the modems, at...
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7027562 |
System and method to reduce echoes in voice communications
A system and method to reduce echoes in voice communications are described. Input data containing return loss values of a communication trunk within a communications network is received, the return...
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6999560 |
Method and apparatus for testing echo canceller performance
A test system measures performance of telephone network echo cancellers using a primary criterion of estimated user annoyance due to audible returned echo. The invention generates live telephone...
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6940830 |
Method and apparatus for echo cancellation
The present invention relates to an improved method and apparatus for echo cancellation in a communication system utilizing a bidirectional transmission medium. The invention significantly reduces...
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6931101 |
Method and apparatus for inband testing of an echo canceller
Provided is a method and apparatus for inband testing of an echo canceller. The apparatus includes a signal generator for generating an excitation signal including a preamble portion and a test...
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6891809 |
Background communication using shadow of audio signal
Data is transferred by delaying an audio signal less than fifty milliseconds to produce a shadow signal and combining the shadow signal with the audio signal. The shadow represents the data to be...
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6856653 |
Digital signal sub-band separating/combining apparatus achieving band-separation and band-combining filtering processing with reduced amount of group delay
An apparatus having a band-separating filter bank for separating a digital signal into a plurality of sub-band signals, to be processed or transmitted, and a band-combining filter bank for...
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6748050 |
Method and apparatus for performing either tone analysis on a local looped-back communications path or utilizing a hybrid reflection based looped-back test to test integrity
In one embodiment, a test tone is placed in an outbound path of a full-duplex transmission system. An echo cancellation capability is disabled, enabling an echo signal of the test tone to pass...
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6744885 |
ASR talkoff suppressor
A system and method provide ASR talkoff suppression in a prompt-and collect voice transaction system in which a prompt signal is sent and an input signal is received. A comparison is made of a...
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6614879 |
Method and apparatus for intra-bundle signaling
A communications system includes first and second subscriber lines, a first device, and a second device. The first device has a first negotiation unit coupled to the first subscriber line. The...
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6611593 |
Call control of ancillary telecommunications equipment using continuity tests
System and method for controlling an ancillary telecommunications device such as an echo canceller within a telecommunications system. The system and method include and involve a switching system...
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6563863 |
Computer modem
A service chip for use with a computer. The chip includes a CPU interface, a transceiver interface, an adaptive echo cancellation filter, a monitor, and first and second data synthesizers. The CPU...
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6516050 |
Double-talk detecting apparatus, echo canceller using the double-talk detecting apparatus and echo suppressor using the double-talk detecting apparatus
A first pseudo-echo signal approximating an echo of a reception signal superposed on a transmission signal is produced from a delayed reception signal corresponding to a past time according to...
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6501830 |
Method of and device for measuring echo parameters on telephone lines
A test signal is injected on the line (L) and the corresponding return signal produced by the line itself as an effect of the echo is detected. A signal having lenticular envelope is used as test...
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6480824 |
Method and apparatus for canceling noise in a microphone communications path using an electrical equivalence reference signal
In a technique for canceling noise from a microphone communications path, an electrical equivalence circuit which is positioned close to and electrically matched to the microphone produces a signal...
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6452967 |
Method and device for reducing coupling effects between neighboring telephone devices
A method for reducing disturbing effects of coupling between a first transmission/reception device and a second transmission/reception device that are each connected to a subscriber line. According...
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6411656 |
Echo cancelling softmodem
A method and apparatus for aligning a received echo signal. The method operates by determining a memory address pointer value that directs which transmit data is to be transmitted. The pointer is...
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6400802 |
Method and apparatus for performing transmission line testing
A method and apparatus for testing and measuring transmission line parameters, such as the post-dial delay, the line rate, the noise level and the signal level, among others. The method comprises...
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6215854 |
Digital signal processor-based telephone test set analyzing and displayed multiple signal parameter data for terminal mode and line monitor mode operation
A digital signal processor-based test set is configured and programmed to enable a craftsperson to monitor, receive and process signals of a variety of formats that may be present on a line under...
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6185280 |
Line impedance matching using dynamically generated transfer functions
A system and method for determining the impedance of a telephone transmission line are disclosed. A test signal is transmitted through a telephone switch to the telephone line and corresponding...
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6154639 |
Handsfree unit
The present invention provides a cheap handsfree unit which can prevent the howling phenomenon and reduce the input sound from the loud-speaker into the microphone in both the analog and digital...
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6111949 |
Method of rapid automatic hybrid balancing
The present invention provides a two-wire line conditioning apparatus having an improved calibration and cancellation circuit and provides an improved calibration method using a multitone...
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6078645 |
Apparatus and method for monitoring full duplex data communications
A modem monitor for monitoring full duplex communications comprises one receiver for each data stream and an echo canceler for canceling "far" echo. Prior to each receiver decoding the data stream...
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5987098 |
Method and system for sparing echo cancellers
A telephone communications switching system incorporating echo cancellers that may be replaced by other echo cancellers, and a method for replacing such echo cancellers are disclosed. The system...
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5943392 |
Device for measuring echo return loss in a two-two wire line system
The present invention is directed to an adaptor for measuring an echo return loss in a communication system. The adaptor includes two transformers, each having a primary winding and two secondary...
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5933797 |
Adaptive dual filter echo cancellation
A digital signal processor that is used for echo cancellation computations is disclosed, which includes parallel multiplier/adders, an input signal sample memory, and a plurality of accumulators...
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5912966 |
Enhanced echo canceller for digital cellular application
An echo cancelling system for communication systems. The system includes an adaptive filter that processes the speech signal re-constructed by a voice decoder to generate an echo estimate. The echo...
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5790632 |
Method and apparatus for echo canceling accounting for companding induced quantization error
An improved method and apparatus for canceling echo is disclosed. The echo canceller of the present invention compensates for the existence of quantization error in the echo signal that does not...
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5745549 |
Line break detection device and modem comprising such a device
A modem for transmission and reception of data samples over a transmission line includes a transmission line break detection device having a correlation meter for providing a measure of the degree...
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5717736 |
Testing circuit and method for a codec hybrid balance network
A telephone system coder/decoder (CODEC) having improved access for testing CODEC components and a method of testing a CODEC in which a test signal is not contaminated by passage through CODEC...
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5689556 |
Method of detecting narrow-band signals in an echo canceller
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...
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