Class 379/390.04 - Hybrid circuit

Subclass of Class 379 - Telephonic communications
Definition: Subject matter including a two-wire to four-wire converter.
No. of patents: 33
Last issue date: 11/23/2010

Number	Title	Issue Date
7839993	Echo canceling arrangement In a line driver/receiver circuit where the line driver is connected with its output terminals to a load for supplying a transmit signal thereto and where the receiver is connected with its input terminals to the load for simultaneously receiving a receive signal th...	11/23/2010
7409195	Wireless modem A modem includes a base unit for transmitting a data signal, and a communication card which receives the data signal from the base unit over a wireless medium and which performs echo canceling on the data signal. The base unit is in communication with a telephone li...	08/05/2008
7397914	Multiple path hybrid for subscriber line services A hybrid with a plurality of selectable hybrid input paths each having an associated hybrid input path filter is provided. The hybrid includes a plurality of selectable receive paths each having an associated receive path filter. The hybrid further includes a hybrid...	07/08/2008
7386119	Filtered transmit cancellation in a full-duplex modem data access arrangement (DAA) An improved data access arrangement device for use in full-duplex two-wire communication systems having a transmission impedance characteristic. The DAA includes a transmit amplifier and a receive amplifier adapted for connection to a two-wire line, a codec connecte...	06/10/2008
7233659	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 party during speakerphone operation as if it were a normal receive s...	06/19/2007
7227944	Echo reduction for a headset or handset The present invention provides an echo reduction apparatus, system, and method that advantageously reduces echo when communicating over packet-switched networks. An echo reduction apparatus, including echo reduction circuit, operably couples a headset or handset dev...	06/05/2007
7212627	Line interface with analog echo cancellation A line interface performs echo cancellation without the use of a hybrid filter network and includes a transmit path having a line driver, a single matching network terminating the line, and a single transformer. The transformer uses split windings on both the primar...	05/01/2007
7127062	Hybrid circuit for a broadband modem A hybrid circuit that couples a broadband modem to a POTS or ISDN telecommunication line (TL) and includes a transformer bridge circuit (TBC) that includes a bridge circuit (BC). The bridge circuit includes four legs formed by impedance matching networks and parts o...	10/24/2006
7123897	Directional receiver coupling arrangement with frequency selectivity and gain control for DSL A directional coupler for a modem has a high common mode noise rejection characteristic with low transmit signal leakage, and reduced distortion of components mixed with a received signal. A primary filter network is connected to a communications circuit. The primar...	10/17/2006
7113590	Method and apparatus for a differential feedback in an active impedence feedback circuit A method and apparatus is provided for performing an active impedance differential current feedback. A signal is received. A current feedback of an output signal in an active feedback synthesis mode is performed based upon the signal. The active current feedback inc...	09/26/2006
7054279	Method and apparatus for optimizing signal transformation in a frame-based communications network A method of and apparatus for optimizing signal transformation from a twisted pair transmission line to a combination transmitter and receiver for a frame-based communications network, the transmitter having a transmit output pair port for transmitting signals onto ...	05/30/2006
7039179	Echo reduction for a headset or handset The present invention provides an echo reduction apparatus, system, and method that advantageously reduces echo when communicating over packet-switched networks. An echo reduction apparatus, including echo reduction circuit, operably couples a headset or handset dev...	05/02/2006
6978011	Enhanced low pass filter An ADSL POTS splitter includes an enhanced low pass filter. The enhanced low pass filter includes a first filter capacitor, a first non-isolated inductor, a second non-isolated inductor, a first isolated inductor and a common mode choke. The second non-isolated indu...	12/20/2005
6973182	Differential echo cancellation receiver with dynamic cancellation of excess DC output current Differential echo cancellation receiver circuitry with dynamic cancellation of excess DC output current. Differential input circuitry provides for cancellation of incoming DC voltage and the incoming transmit signal echo while passing the receive signal. Excess DC c...	12/06/2005
6931120	Telephone-computer interface An electronic circuit for connecting a standard analog telephone to the analog microphone and loudspeaker connections on a personal computer and for separating the talk signal from the combined talk/listen signal occurring at the telephone, effectively minimizing un...	08/16/2005
6931122	Single transformer hybrid system and method A hybrid matching system is disclosed for use with a transmitter and receiver. The hybrid matching system includes a pair of transmitter output nodes, a pair of receiver input nodes, and a pair of terminals for interfacing to a transmission line. The system further ...	08/16/2005
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 amplifier, a receiver circuit including a receiver output coupled to a...	08/02/2005
6898280	Line card and method for supporting pots, asymmetric DSL and symmetric DSL services A line card and method is provided which supports symmetric and asymmetric telecommunication services, such as symmetric and asymmetric DSL services. The line card may support concomitantly POTS and asymmetric DSL services or support DSL services. A xDSL interface p...	05/24/2005
6804349	Hybrid transceiver circuit A hybrid circuit forming an interface between a transmission line and heads of transmission-reception of signals in bands of different frequencies in transmission and reception, including a line transformer, and means for separating bands combined with echo cancella...	10/12/2004
6795548	Method and system for data communication A system for data communication is disclosed that comprises a hybrid circuit (220) that receives a signal. A switched gain circuit (204) coupled to the hybrid circuit (220) receives the signal from the hybrid circuit (220). A receiver cir...	09/21/2004
6771770	Hybrid circuit for a broadband modem A hybrid circuit that couples a broadband modem to a POTS or ISDN telecommunication line (TL) and comprises a transformer bridge circuit (TBC) that includes a bridge circuit (BC). The bridge circuit is constituted by four legs of which a first (A) and a second (B) n...	08/03/2004
6748076	Method for separating narrowband and broadband services on a transmission link and a splitter element The invention relates to the separation of narrowband and broadband services in a telecommunications network. Signals belonging to a narrowband service are transferred in a first frequency range below a given threshold frequency and signals belonging to a broadband ...	06/08/2004
6731752	Method and circuit for echo-cancellation in two-way communications A hybrid circuit models a plurality of attributes of a communication system including a subscriber line coupled to a line interface circuit. The plurality of attributes includes subscriber line impedance, and impedance of a coupling transformer. The attributes are b...	05/04/2004
6681012	Directional receiver coupling arrangement with frequency selectivity and gain control for DSL A directional coupler for a modem has a high common mode noise rejection characteristic with low transmit signal leakage, and reduced distortion of components mixed with a received signal. A primary filter network is connected to a communications circuit....	01/20/2004
6647116	Current sensing circuit and ADSL interface circuit A current sensing circuit (50) for use in an ADSL interface circuit senses an input current (IL) flowing through a resistor (R1) and provides an image output signal at an output which is an image of the input current. The circuit comprises an input stage ...	11/11/2003
6570985	Echo canceler adaptive filter optimization The Least Mean Square (LMS) and Normalized LMS (NLMS) algorithms commonly employed in adaptive filters of echo cancelers are further optimized. Finite impulse response (FIR) filters are used to estimate a transfer function of an echo channel in a communic...	05/27/2003
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 path of a second differential polarity....	09/03/2002
6370245	Full duplex communication circuits with bilateral T hybrid and balanced impedance configurations Full duplex circuits provide a bi-directional signal path at one port for transmit and receive signals and also provide separation between the transmit and receive signals at their respective ports. To accomplish this, the circuits employ amplifiers arran...	04/09/2002
5172410	Conference telephone system and method A speaker telephone comprising a microphone outputting an electrical signal, and a loudspeaker is disclosed. An amplifier has its output coupled to the loudspeaker. This amplifier has non-inverting and inverting inputs. A switch having two positions coupl...	12/15/1992
4723276	Two-module telephone terminal A telephone terminal whose structure separates the high voltage and the low voltage functions in separate modules; the high voltage module being specific to the telephone network and the low-voltage module being in conformity with the service provided by ...	02/02/1988
4567332	Four-wire telephone system with self-test means A four-wire "hoot-and-holler" telephone system provides full duplex conference communication. Four-wire desksets are provided for individual users, being connected by a four-wire telephone circuit. Repeaters at each end of the four-wire circuit provide in...	01/28/1986
4293740	Hands free answer intercom A hands free answer feature is provided in a key telephone system which includes an intercom lead pair for providing intercommunication between key telephone station sets and a signalling path for providing audible signals via a loudspeaker circuit in the...	10/06/1981
4251689	Loudspeaker telephone apparatus The loudspeaker telephone apparatus consists of a hybrid circuit which interconnects a telephone line and its line balance impedance with receive and transmit amplifiers. These amplifiers are connected to a bridge circuit, the arms of which are formed fro...	02/17/1981

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Class 379/390.04 - Hybrid circuit