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8160241 |
Communication terminal device with echo canceller and its echo canceling method
An uncomfortable feeling due to lack of the speech of a far end speaker and a convergence signal voice (sound) is prevented, and the echo of the far end speaker is removed. A pseudo signal...
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8094809 |
Frame-based level feedback calibration system for sample-based predictive clipping
A feedback calibration system and a method for controlling an electronic signal are disclosed. The feedback calibration system includes an input controller adapted to modify an input signal in...
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8023641 |
Spectral domain, non-linear echo cancellation method in a hands-free device
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...
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7844365 |
Field-mounted process device
A field-mounted process device with multiple isolated connections includes a connection that can be an input or an output. The given input or output can couple to multiple sensors or actuators,...
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7835774 |
Removal of local duplication voice on conference calls
The present invention provides mechanisms for removing duplicate signals during a communication session. More particularly an over-air signal is received at a given endpoint and a stream of...
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7672445 |
Method and system for nonlinear echo suppression
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...
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7480377 |
Dual adaptive filter apparatus and method
A method and apparatus for adapting dual filters is disclosed. In one aspect, a method may include transforming a signal, adapting a first adaptive filter based on the transformed signal,...
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7471671 |
Band signal detection and presentation for IP phone
A VoIP telephone operates in an IP environment wherein at least a portion of the signaling from a remote gateway is included within a media session real time protocol stream. The VoIP telephone...
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7151828 |
Circuit arrangement for the analogue suppression of echoes
A circuit arrangement for the analogue suppression of echoes, as in particular can be used in a hybrid-circuit for DSL-transmission systems, comprises a replica (8) for emulating the behaviour of...
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7062040 |
Suppression of echo signals and the like
In a microphone signal, the signal component corresponding to, e.g., echo is suppressed using an echo control scheme that estimates the spectral envelope of the echo signal, without having to...
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6912474 |
Method and apparatus for high-speed synchronous digital acquisition derived in real -time from analog samples
A method and apparatus for real-time derivation of precise digital clock edges and synchronous logic samples from a digital signal having a clock channel and at least one data channel acquires a...
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6836544 |
Sidestone reduction in full duplex transceivers
A method and apparatus enables echo reduction in a full duplex transceiver system. A replica current is subtracted from a receiver via a first differential circuit path that adaptively matches a...
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6744884 |
Speaker-phone system change and double-talk detection
A speaker-phone that is operable to perform system change detection, double-talk detection and if desired, optimal step-size control. The invention differentiates between system change and...
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6611601 |
Echo sound signal suppressing apparatus
An echo sound signal suppressing apparatus for suppressing an echo sound signal to ensure speech communication between a far-end speaker and a near-end speaker, comprising: first power value...
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6487178 |
Methods and apparatus for providing volume control in communicating systems including a linear echo canceler
In handsfree communications devices including a linear echo or noise canceler, both analog and digital gain factors are adjusted in response to user volume control inputs, the analog gain factor...
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6339642 |
Telephone apparatus with howling prevention function
A telephone apparatus having a howling preventing function is connected to a communication partner via a telephone exchange and is constructed by a communication unit, including a microphone and a...
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6278785 |
Echo cancelling process with improved phase control
An echo is cancelled from a composite signal by providing a coarse phase adjustment, a fine phase adjustment, an amplitude correction, and then subtracting the phase shifted signal from the...
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6157680 |
Audio distortion canceler method and apparatus
In a communications environment where it is desirable to allow the simultaneous transmission of digital data and conventional voice on a single communication line, an audio distortion canceler...
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5943319 |
Packet format interface for telecommunication instruments
Improved telecommunication apparatus is realized with a structure that is tailored to interact with the telecommunication network strictly in packet format. The apparatus includes circuitry for...
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RE35901 |
Solid state isolation device using opto-isolators
An improved solid state isolation device that uses opto-isolators to provide an electrical barrier between a telephone network and user telephone equipment includes a load and current control...
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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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5504778 |
Analog circuit for baseband modem
So as to be directly connected to the predefined logic circuit PLC to form a baseband modem, the analog circuit BBAC is monolithically integrated in accordance with the CMOS technology, using...
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5381475 |
Arrangement for suppressing echoes in a digital portable telephone
An echo suppression arrangement for use in a digital portable telephone prevents sidetone echo appearing in the base unit of the telephone from being coupled to and emanating at the handset unit of...
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5323458 |
Echo cancellation in a full-duplex speakerphone
A direct-path echo cancellation circuit includes a loudspeaker (12), first and second microphones (14, 16), and an in-phase signal cancellation circuit (21, 43). The first and second microphones...
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5206854 |
Detecting loss of echo cancellation
In a full-duplex modem, correlation of an echo estimate signal with an echo-canceled signal is used to determine the presence or absence of a remote signal.
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5204894 |
Personal electronic directory
A central office based service and apparatus whereby personal electronic directory (PED) subscribers may call a special number from any DTMF telephone to access their personal directory. Such users...
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5148427 |
Non-linear echo canceller
A method and apparatus for echo cancelling linear and nonlinear echo components from a received signal by temporally and spatially separating the overall echo canceller into a fast, transversal...
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5084866 |
Transversal filter echo canceller
A transversal filter apparatus having a shift register, an averaging circuit for averaging data stored in sequential shift registers, and a multiplier for multiplying the averaged data....
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5075687 |
Echo suppression with both digital and analog variable attenuators
An apparatus for effecting echo suppression facilitating communications between an analog device and a digital device comprising a transmit circuit for processing outgoing signals, a receive...
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5022074 |
Digital echo suppressor
A digital echo suppression circuit in a four-wire digital telephony circuit having an echo from a local or remote connection to a two-wire circuit or other echo source. The invention incorporates a...
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5016271 |
Echo canceler-suppressor speakerphone
An echo canceler-suppressor speakerphone arrangement effectively addresses the limitations of regeneration and reverberant return echo inherent in the design of speakerphones. The tendency for...
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4972406 |
Echo canceller
An echo canceller (1) for full duplex digital data transmission in a transmitter/receiver unit when connected via a hybrid circuit (2) to one end of a two wire line (3). In order to provide...
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4928308 |
Echo canceller circuit
An echo canceller circuit contains a network of capacitors binary-stepped in their capacitance, whose one set of plates, representing a center of the network, each are switchably connectable to a...
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4891801 |
Terminal for the transmission of data over a bidirectional analog channel with echo cancellation controlled by the reception rate
A terminal is provided for transmitting data over a bidirectional analog channel with echo cncellation coupled to the reception timing, wherein, between an emission circuit and a reception circuit...
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4696015 |
Echo correction especially for television broadcast systems
Echo cancellation is carried out on a received demodulated analog signal. The apparatus comprises an analog transversal filter, a computing circuit for generating the direct coefficients a1 to ar...
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4368360 |
Adaptive control type echo suppressor
An adaptive control type echo suppressor which compares the levels of voice signals of sending and receiving paths by a first comparator with each other and cuts off the sending path to suppress an...
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4215252 |
Video teleconference audio echo control unit
An audio echo control unit for a video teleconference system is provided with a suppression attack time which is a function of the microphone-to-audio speaker distance and a suppression hangover...
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4081616 |
Method of and apparatus for eliminating the side tone of a telephone station
Method and apparatus for use in telephone exchanges, such as time division multiplex exchanges, for eliminating the side tone of a telephone station by interruption of a restored input signal to a...
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4031338 |
Echo suppressor using frequency-selective center clipping
An echo suppressor for use in the send path of the four-wire part of a long distance telephone circuit employs frequency-selective center clipping. The bandwidth of the channel in which echo occurs...
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4012603 |
Echo suppressor having self-adaptive means
An echo suppressor employed in systems interconnecting a two-wire circuit with a four-wire circuit for substantially eliminating "talker's echo" and for selectively attenuating the calling party's...
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4005277 |
Echo controller comprising a mode switch for switching echo suppressor and canceller
An echo controller comprises a parallel circuit of an echo suppressor and a self-adaptive echo canceller near an echo path of a long-distance telephone network. The echo controller further...
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3935403 |
Device for developing a neutralization signal for an echo suppressor
The invention comes within the branch of digital data transmission on a telephone line having four wires comprising echo suppressors. In order to be able to neutralize these suppressors during a...
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3462561 |
BILATERAL SIGNAL TRANSMISSION SYSTEM HAVING A COMBINED DYNAMIC RANGE CONTROL AND ECHO SUPPRESSOR ARRANGEMENT
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