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7483420 |
DSP circuitry for supporting multi-channel applications by selectively shifting data through registers
Digital signaling processing (DSP) circuitry that supports multiple channel or time division multiplexing (TDM) applications is provided. For example, the DSP circuitry can process one or more...
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7471670 |
Method and apparatus for reducing echo and crosstalk in a communication system
Methods and apparatus describe techniques for reducing interference signals in a communication signal. A communication signal is received through a receiver. The communication signal contains an...
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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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6947395 |
Locating network echos
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...
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6744887 |
Acoustic echo processing system
A system and method of Acoustic Echo Cancellation includes a digital filter used to estimate the echo path is split into 2 filters: one fixed infinite impulse response (IIR) filter and one adaptive...
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6694020 |
Frequency domain stereophonic acoustic echo canceller utilizing non-linear transformations
The invention is a multiple channel teleconferencing system employing a stereophonic acoustic echo canceler that exploits the coherence between multiple channels. In accordance with the invention a...
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6671374 |
ADAPTIVE FILTER FOR ECHO CANCELLATION, METHOD FOR OPERATING AN ADAPTIVE FILTER FOR ECHO CANCELLATION, AN ARTICLE OF MANUFACTURE FOR DETERMINING TAP WEIGHTS AND A LENGTH FOR AN ADAPTIVE FILTER FOR ECHO CANCELLATION AND A COMPUTER IMPLEMENTED CONTROL SYSTEM FOR DETERMINING TAP WEIGHTS AND A LENGTH FOR AN ADAPTIVE FILTER FOR ECHO CANCELLATION
An adaptive filter for echo cancellation includes a segmented sparse transversal filter having an input, the filter having an adjustable length, adjustable lengths for the segments and adjustable...
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6661895 |
Zero-delay structure for sub-band echo cancellation
A zero-delay structure to be used in sub-band echo cancellation systems. In telecommunications, a delay is usually introduced in sub-band decomposition and/or sub-band reconstruction. This...
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6498850 |
Multichannel echo canceller with a compander
A compander circuit ( 20 ) for echo cancellation in telecommunications apparatus with an estimator module ( 21 ) for estimating an echo coupling and a delay of a line echo and a characteristic...
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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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6426979 |
Adaptation control algorithm for echo cancellation using signal-value based analysis
The present invention addresses signal noise problems associated with telecommunications. In particular, echo cancellation is addressed by the present invention, which employs an inventive adaptive...
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6404809 |
Method and apparatus for training equalizer structures in a digital communication system having periodic digital impairments
An improved two-point equalizer training technique for use with V.90 modem systems utilizes a number of scaling parameters to enable the compensation of robbed bit signaling (RBS) effects in a...
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6381272 |
Multi-channel adaptive filtering
A multi-channel adaptive filter system for use, for example, in echo cancellation for generating an echo estimate for each channel is described. The system includes a forward and backward...
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6256383 |
IIR filter of adaptive balance circuit for long tail echo cancellation
An automatic balance system for a transmit signal of a wireless local loop communication system. The automatic balance system includes a finite impulse response (FIR) filter system, the FIR filter...
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6246444 |
Digital and analog TV common-use receiver having single ghost canceler and ghost cancellation method
A digital/analog TV common-use receiver having a single ghost canceler, and a ghost cancellation method are provided. The single ghost canceler includes a first filter coefficient generator for...
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6219334 |
Receiving apparatus for receiving orthogonal frequency division multiplexing signal and receiving method thereof
A coherent detection type OFDM receiver is disclosed. The coherent detection type OFDM receiver demodulates a digital data sequence. The OFDM receiver obtains a channel frequency response with a...
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6181794 |
Echo canceler and method thereof
An echo canceler for canceling an echo signal mixed in an input signal received from a hybrid circuit. The echo canceler has a double filter structure comprised of an adaptive filter and a fixed...
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6130943 |
Method and apparatus for suppressing echo in telephony
A method and an apparatus suppresses echo in telephone communication systems having a send path and a receive path. A first filter is coupled to the send path carrying a voice signal. The first...
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6009083 |
Cascade echo canceler arrangement
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...
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5940455 |
Adaptive filter with disabling circuit for fast tap weight convergence
An input signal is supplied to a tapped-delay line adaptive filter to produce tap signals which are equally divided into groups. The tap signals are selectively coupled on a per group basis through...
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5923708 |
Decoding circuit for a read signal from a magnetic recording and reading system using partial response
A decoding circuit for a magnetic recording and reading system enables the implementation of an AGC loop with a relatively simple configuration and further enables easy clock extraction and high...
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5920548 |
Echo path delay estimation
An echo cancellation apparatus (20) and method involves an operation AEPR for analyzing echo path response and thereafter an operation CR for configuring an adaptive FIR filter (52). The...
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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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5889857 |
Acoustical echo canceller with sub-band filtering
The echo canceller is designed to be placed between a hands-free acoustical interface and a communications network. It comprises a plurality of processing paths connected in parallel and each...
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5831880 |
Method for processing a signal in a CSD filter and a circuit therefor
A method for processing a signal in a CSD filter includes the steps of obtaining real coefficients optimized to desired filter characteristics, calculating scaling factors for each real coefficient...
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5818945 |
Subband echo cancellation method using projection algorithm
A received signal is output to an echo path and, at the same time, it is divided into a plurality of subbands to generate subband received signals, which are applied to estimated echo paths in the...
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5809058 |
Code division multiple access signal receiving apparatus for base station
A CDMA signal receiving apparatus for a base station includes a spread-spectrum demodulation section which has a plurality of channel-signal processing sections and a common-signal processing...
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5796819 |
Echo canceller for non-linear circuits
A system and a method for echo suppression which use two or more microphones for beamforming of an echo signal corresponding to an incoming speech signal that is output by a loudspeaker. The...
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5796820 |
Recovery of previous filter coefficients with smaller capacity memory
The echo canceler includes an N-tap FIR filter and a coefficient controller. Previous filter coefficients which were generated before an estimation error occurrence when the transmitting output...
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5764753 |
Half-duplex controller
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 is stored in a register (70) when...
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5752229 |
Intelligent near-end speech detection
The detection and cancellation of echo in a communications system is enhanced by taking advantage of the accumulated knowledge relating to the echo path delay that an adaptive filter acquires as a...
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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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5737410 |
Method for determining the location of echo in an echo canceller
A method for adaptation to an echo location in an echo canceller comprising an output port, an input port, an adjustable delay unit (43) compensating for the pure delay component in the echo path...
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5691978 |
Self-cancelling full-duplex RF communication system
A method is presented herein whereby both transceivers of a full-duplex RF communications system can use the same spectrum at the same time. Self-interference is cancelled using a combination of...
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5663955 |
Echo canceller system with shared coefficient memory
An echo canceller system includes first and second echo cancellers. Each echo canceller includes a foreground filter and an adaptive background filter, with the foreground filter providing the...
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5649012 |
Method for synthesizing an echo path in an echo canceller
A method of synthesizing an echo path in an echo canceller is provided. The method includes the steps of obtaining near end and far end signal samples at an echo canceller, locating the echo in a...
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5644596 |
Method and apparatus for frequency selective adaptive filtering
A method and apparatus for performing subband adaptive filtering is proposed. A signal is prefiltered by a set of complementary filters to provide corresponding subbands of the input signal. The...
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5631899 |
Acoustic echo canceler
Acoustic echos are canceled by employing a first echo canceler having a comparatively short first impulse response synthesis capability which is connected between a transmit path and receive path...
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5610909 |
Multistage echo canceler including time variation compensation
Acoustic echos are canceled by employing a first echo canceler having a comparatively long first impulse response synthesis capability which is connected between a transmit path and receive path...
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5572545 |
Process for starting up a modem containing a variable-phase echo canceller and modem in which such a process is implemented
A start-up method for a data modem having an echo cancelling loop between the send port and receive port, the loop including a transversal filter having adjustable coefficients, adjustable...
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5477535 |
Method of preventing a divergence of an adaptive echo canceller in a noisy signal environment
A method of preventing an adaptive echo canceler from diverging in a noisy environment, including determining an average noise level (-45 dBmO) in the echo path, determining an attenuation (A e )...
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5418778 |
Local and remote echo canceling apparatus particularly adapted for use in a full duplex modem
An echo cancellation apparatus is included in a variable rate modem. The echo cancellation apparatus includes a local echo canceler, a remote echo canceler and a quadrature echo canceler unit. The...
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5406552 |
Device and method for linear listener echo cancellation
A device and method utilize a linear feedback/feedforward configuration to estimate and cancel a listener echo wherein equalizer (202) and listener echo cancellation (204 and 208) units are jointly...
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5404397 |
Conference system with automatic speaker detection and speaker unit
A conference system comprises speaker units (12) coupled to a central unit (14). The speaker unit (12) comprises an echo canceller (20) with an adaptive filter (38) having an impulse response of...
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5351291 |
Adaptive echo cancellation method and device for implementing said method
The echo cancellation method includes starting with an arbitrary set of echo filter coefficients. The coefficients are first sequentially re-estimated using a fast converging method. These...
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5343522 |
Adaptive sparse echo canceller using a sub-rate filter for active tap selection
With the presently described echo canceller, a sparse adaptive transversal filter is used to model and cancel only the active regions of the echo impulse response. Since the tap coefficients, in...
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5329587 |
Low-delay subband adaptive filter
A subband adaptive filter is disclosed that retains the computational and convergence speed advantages of subband processing while eliminating delay in the signal path. The technique has...
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5305307 |
Adaptive acoustic echo canceller having means for reducing or eliminating echo in a plurality of signal bandwidths
An echo cancelling device for reducing acoustic feedback between a loudspeaker and microphone in a full duplex communication system such as a telephone conferencing system. The device includes a...
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5303228 |
A far-end echo canceller with a digital filter for simulating a far end echo containing a frequency offset
A far-end echo path may be simulated at a terminal which utilizes QAM by processing the in-phase and quadrature data symbols by a pulse shaping filter whose transfer function may be a raised cosine...
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5278900 |
Digital echo canceller comprising a double-talk detector
A digital echo canceller has a receive path (2) and a send path (3) and comprises combining apparatus (10) for forming a send output signal [r(k)] as the difference between the signal [z(k)]...
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