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8085945 |
Communication machine room wideband noise suppression system
In a communication machine room wideband noise suppression system, a sensing unit detects a noise source produced by a fan during the operation thereof and generates a noise input signal and a...
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7881456 |
Music phone, station, and system and method of using same
An audio system including an audio-enhancing station including at least one speaker and an audio-enhancing station docking connector, a music phone configured to play audio files and function as a...
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7734034 |
Remote party speaker phone detection
A system and method are provided for detecting acoustic echo in a telecommunications transmission. Detected acoustic echo is analyzed to determine if the acoustic echo includes characteristics...
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7706525 |
Systems and methods for side-tone noise suppression
A side-tone circuit comprises a microphone configured to generate a reverse link audio signal and a side-tone noise suppressor. The side tone noise suppressor is configured to receive the reverse...
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7573839 |
Line driver for an adaptive hybrid circuit
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 adap...
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7457405 |
Enhanced low pass filter
An ADSL POTS splitter includes low pass filter. The low pass filter includes a first inductor portion in communication with the line interface and a second inductor portion isolated from the line...
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7450715 |
Transceiver for bidirectional frequency division multiplexed transmission
The present invention relates to a transceiver for bidirectional frequency division multiplexed transmission, a communication system including one or more transceivers. Optionally, the...
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7333603 |
System and method for adapting an analog echo canceller in a transceiver front end
There is disclosed an echo canceller circuit for use in a full duplex transceiver of the type comprising a line driver capable of sending analog transmit signals through a cable and comprising a...
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7330739 |
Method and apparatus for providing a sidetone in a wireless communication device
A wireless communication device is disclosed that provides a sidetone to the device user. The device converts an outbound analog audio signal to an outbound audio bitstream from which a sidetone...
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7224794 |
Transmitting message playback concurrent with speakerphone operation
A digital telephone answering device having speakerphone capability allows a recorded message to be played back and heard by the far-end party as well as over the local speakerphone by the near-end...
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7149305 |
Combined sidetone and hybrid balance
A combined sidetone and hybrid balance apparatus and method of operating same are disclosed. An embodiment of the present invention may provide both a hybrid balance mode of operation and a...
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7050574 |
Telephone line interface circuit and method
A hybrid circuit is disclosed for effectively communicating information over a telecommunications line to which a transmitter and receiver are connected. The hybrid circuit is configured as a...
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7023984 |
Automatic volume adjustment of voice transmitted over a communication device
A system and method for adjusting the volume level of a communications device in response to a voice volume/ambient noise relationship. Ambient noise and voice volume are sampled and compared to a...
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7020277 |
DSL line interface having low-pass filter characteristic with reduced external components
A line interface couples a data transceiver to a transmission line via a transformer, the data transceiver transmitting signals in a first frequency range and receiving signals in a second...
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7003096 |
Full duplex telephone set using echo cancellation and side tone management for high gain stability
A full duplex telephone set for hearing impaired users includes a digital signal processor incorporating a pair of adaptive transversal filters to cancel line and acoustic echo feedback from the...
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6993126 |
Apparatus and method for detecting far end speech
Method and apparatus for detecting far end speech in a telephone apparatus. A speaker (14) produces far end sound from a far end signal, when received by the telephone apparatus. A microphone (12)...
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6993125 |
Variable sidetone system for reducing amplitude induced distortion
The variable sidetone system provides an enhanced method for inducing the subscriber maintain the amplitude of their voice at an appropriate level by exaggerating the amplitude characteristics of...
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6925172 |
Line interface with gain feedback coupled matching impedance
A transceiver system is disclosed for use in a telecommunication system. The transceiver system includes a transmission circuit including a transmitter input coupled to an input of a transmission...
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6870928 |
Line interface, apparatus and method for coupling transceiver and transmission line
A line interface couples signals between a data transceiver and a transmission line having a load impedance Z. The line interface includes a transformer, a driver circuit for supplying a transmit...
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6850617 |
Telephone receiver circuit with dynamic sidetone signal generator controlled by voice activity detection
A telephone receiver circuit with sidetone signal generation controlled by voice activity detection in accordance with the present invention uses the voice activity detector (VAD) to detect the...
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6842517 |
Meter pulse filtering circuit for analog modems
A filtering circuit is described for filtering out meter pulses of analog telephone communication, for example in analog modems. The circuit is mainly composed of resistors and capacitors and is...
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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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6819761 |
Programmable constant current “off hook” circuit
An apparatus and method for interfacing a communication device, such as a Customer Premise Equipment (CPE) to different telephone networks. The telephone networks typically provide a voltage of 48...
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6801623 |
Software configurable sidetone for computer telephony
Techniques for software configurable sidetone are provided. A user can select one or more characteristics of the sidetone and the sidetone signal will be generated according to an input signal and...
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6792104 |
Transformer-coupled matching impedance
A system for matching impedance in the circuitry of an xDSL communication device to improve noise cancellation resulting from signal leakage between transmit and receive signals. The system for...
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6768795 |
Side-tone control within a telecommunication instrument
A side-tone control unit for a telecommunication instrument is configured to include a side-tone amplifier having a transfer function selectively controlled in accordance with a set of amplifier...
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6741700 |
Low insertion loss current sense circuit
A current sense circuit for sensing a current in a subscriber loop comprising a transformer having a first and second winding coupled for sensing a differential current in a loop, a sense winding...
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6711259 |
Method and apparatus for noise suppression and side-tone generation
An audio processing module, in accordance with the invention, includes an input for receiving input signals. A side tone generator is included for receiving the input signals and for generating a...
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6704414 |
Telephone line extension
A system comprising a base unit and a remote unit for transmitting telephonic data on AC power lines is disclosed. The base unit includes a transmitter section, a receiver section, a power line...
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6700976 |
Noise canceler system with adaptive cross-talk filters
A known cross-talk adaptive noise cancellation apparatus uses two adaptive filters for suppressing the correlated noise in the main signal, which contains wanted voice and unwanted noise, by a...
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6661892 |
Method and apparatus for decreasing distortion in a line powered modulator circuit
A method and apparatus for a telephone line interface or data access arrangement (DAA) which includes a shunt regulator in series with a line modulator. A first sense resistor is placed in series...
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6628779 |
Method and system for scaleable near-end speech cancellation for tip and ring tone signal detectors
A method and system for providing suppression of near-end speech energy for tone signal detectors. In accordance with the invention a system or device is connected between the tip and ring on a...
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6594359 |
Circuit for eliminating echo and side tones in a switching system
A circuit able to attenuate echo and side tones in a switching system connecting the first and second subscribers, comprises a first linear converter for converting pulse code modulated data...
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6445791 |
System and methods for modem interface
An interface for coupling a modem port with a transmission line includes a hybrid converter having a variable gain amplifier coupling a transmit path of a first differential polarity and a received...
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6377680 |
Method and apparatus for noise cancellation
A method and system for reducing background noise during a telephone call. When a caller begins dialing a telephone number, the system receives an ambient noise level measured near the caller's...
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6369650 |
Impedance synthesis and DC biasing method and architecture for DSL/cable line drivers
A low noise, low distortion, power efficient DSL/cable line driver has a double Wheatstone impedance bridge network that functions to prevent contamination of DSL signals that are received by and...
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6151391 |
Phone with adjustable sidetone
A telephone with a selectable level of sidetone for use in noisy environments. The selectable level of sidetone is achieved by forming a switch-controlled feedback path including a gain setting...
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6058165 |
Telephone apparatus with recording function
A 1st telephone apparatus comprises a transmission system for transmitting a transmission voice SIG to a network, a receiving system for receiving a reception voice SIG from the network, a...
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6041118 |
Architecture for telephone set
The invention concerns digital processing of analog signals in a telephone set. A signal path runs between a telephone line and the handset of the telephone. A digital signal processor is...
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5946391 |
Telephones with talker sidetone
A telephone, particularly a portable handset operable in a digital radio telephone system, has a sidetone gain circuit 28 which applies one of two levels of gain G1 G2 dependent on whether a...
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5940498 |
Electronic voice circuit configuration
An electronic voice circuit configuration can be connected through a first and a second line terminal to a telephone line. The electronic voice circuit configuration has a calling part, a...
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5909489 |
Method of and circuit arrangement for improving the transmission properties of an echo affected transmission link in a telecommunications network
When telecommunications systems with analog and digital circuit technology are interconnected, the two-wire/four-wire transitions are achieved with hybrid circuits in which mismatches cannot be...
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5896450 |
Automatically variable circuit of sound level of received voice signal in telephone
In an apparatus of adjusting a sound level of a reception voice in a telephone, an audio signal including a transmission voice signal and a peripheral noise is inputted through a microphone. A gain...
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5896451 |
Adaptive telephone interface
The present invention relates to an adaptive telephone interface for use in a telephone apparatus comprising a telephone terminal including signal amplifier means, and audio/input device. The...
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5878132 |
High-frequency noise elimination for use in telephone systems
A noise elimination scheme is disclosed which enables the prior established telephones or telephone exchange modules linked thereto to eliminate high-frequency noises as applied from outside...
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5774536 |
Balanced network for use in a keyphone system
A balanced network in a keyphone system has a filtering unit which is composed of: first and second filtering circuits, formed on the transmission path and having an inverted-phase feature, for...
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5734714 |
Subscriber line interface circuit capable of realizing by a C-MOS circuit
A balanced amplifier delivers a detection voltage in order to carry out power supply control. A level shift circuit shifts the level of the detection voltage to a level shift voltage for a +5 Volts...
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5710811 |
Speech circuit for subscriber telephone apparatus
The speech circuit matches the impedance of the telephone line by synthesizing a complex impedance using a positive feedback loop which has a single resistor (11), and cancels out the side tone...
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5692042 |
Speakerphone controlled by a comparator with hysteresis
A speakerphone which employs non-linear amplifiers to compress transmit and receive signals, and level detectors to determine levels of the compressed transmit and receive signals. Compressed...
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5675641 |
Dual-mode speaker telephone
An apparatus and method for operating a speaker telephone in either full-duplex mode or half-duplex mode. In the absence of an earphone connection, the speaker telephone operates in half-duplex...
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