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Match Document Document Title
8077856 Driver circuit and method for driving a signal  
Driver circuit for driving a transmit signal for a line comprising a signal amplifier which delivers a transmit signal, present at a signal input of the signal amplifier, amplified with a gain to a...
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,...
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...
7139528 RF coupled data access arrangement circuit for telephony customer premise equipment  
A data access arrangement (DAA) circuit for an item of customer premise equipment (CPE, i.e., telephone terminal equipment) utilizes RF coupling across an isolation barrier between two sides of the...
7054439 Differential input stage for electronic equipment, comprising means for reducing interference caused by a voltage or current in common mode  
According to the invention, means for reducing the interference caused by a voltage or a current in common mode, comprise adders (S3; S4) in each path for adding a first counter-reaction voltage...
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...
6917682 Method and device for echo cancelling  
Echo cancelling in a communication line system, particularly an ISDN or XDSL system, is performed with a tunable hybrid having tunable passive elements. The tunable hybrid is integrated in the...
6792105 Current-mode differential active hybrid circuit  
In at least one embodiment, a current mode differential active hybrid circuit having an H-bridge output driver with a first output resistor coupled across a transmission medium output. Drive...
6754341 External resistor and method to minimize power dissipation in DC holding circuitry for a communication system  
A CMOS implementation for a DC holding circuit in direct access arrangement (DAA) circuitry is disclosed that provides desirable inductive behavior while minimizing power dissipation required by...
6735302 DSP based SLIC architecture with current-sensing voltage synthesis impedance matching and DC feed control  
A CODEC and a SLIC assembly perform current-sensing-voltage synthesis impedance matching and DC feed control functions. Signal processing that does not require high voltage, such as impedance...
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...
6633642 Balance network directional coupler system and method  
A balance network directional coupler (BNDC) allows for effective coupling to sources of transmitted signals, communication lines, and devices that process received signals. The BNDC includes a...
6563926 Resetting surge protection in telephone line interface circuits  
A surge reset circuit used to automatically reset a surge protection circuit within a telephone line interface circuit. A sensor (e.g., a zenering device) advantageously generates a voltage level...
6560333 MOS transistors substitute circuit having a transformer/data interface function, particularly for ISDN networks and corresponding control and driving switch configuration  
The invention relates to a MOS transistors substitutive circuit having a transformer/data interface function, in particular for ISDN networks, comprising first (11a) and second (11b) power...
6477249 Communications signal splitter and filter  
A splitter separates telephony traffic (POTS) from digital subscriber line (ADSL) traffic occupying a higher frequency band. The splitter comprises a low-pass filter for passing the telephony...
6473507 Apparatus and method for isolating transients associated with a digital subscriber line  
A communication apparatus includes circuitry operable to facilitate communication over a digital subscriber line. The apparatus also includes a filter operable to be coupled between the circuitry...
6456712 Separation of ring detection functions across isolation barrier for minimum power  
A communication system of the present invention utilizes ring detection circuitry on both sides of an isolation barrier. More particularly, the ring detection circuitry may include ring burst...
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...
6359983 Digital isolation system with data scrambling  
A method and apparatus are provided for reducing the amplitude of signals that often are inadvertently coupled to a telephone line from an isolation barrier system, or that cause undesirable...
5822426 Balanced hybrid circuit  
Large signal swings are obtained for the transmitted signal of a telephone line modem using differential drivers. Compensation for the complex nature of line impedance is provided without affecting...
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...
5774541 Optically-coupled data access arrangement and transhybrid  
Isolation and interconnection of a telephone network of tip and ring lines and the analog ports of a modem are achieved with a transhybrid that incorporates optically-coupled isolation stages....
5768351 Method and apparatus for connecting a telephone to a voice capable modem  
A circuit for providing an interface between a telephone set and a modem having voice processing capabilities that allows digitization of the voice to occur and provides an improved capability for...
5734703 Hybrid circuit and data communication apparatus  
The balancing bridge circuit is provided between a four-wire circuit and a two-wire circuit, to provide a thin-type balancing bridge circuit having satisfactory transmission characteristics and a...
5671272 Current mode ring trip detector  
A circuit and method for sensing in current mode when a telephone has been answered in a telephone system in which an answer is indicated when a dc component of a signal across a resistor exceeds a...
5602912 Telephone hybrid circuit  
A method and apparatus for providing a telephone hybrid function is provided. The present invention maximizes dynamic range while providing a receive signal without interference from a transmit...
5586181 Metallic channel unit network  
A channel unit network having a two-wire port for interconnecting a two-wire, bidirectional signal transmitting means with a four-wire digital transmitting means in a communication system to create...
5574404 Optical coupler galvanic isolation device, and modem incorporating it  
A galvanic isolation device having a light-emitting diode and a photo-transistor. A control circuit, which is coupled to the light-emitting diode and which controls the light-emitting diode, is...
5528683 Method and circuit for implementing an impedance, in particular for DC telephonic applications  
The invention relates to a method and circuit for implementing an impedance associated with a monolithically integrated telephone subscriber circuit connected to a telephone line having a pair of...
5528685 Transformerless hybrid circuit  
An electronic hybrid useful in telephone line-powered Data Access Arrangements. The hybrid has a transmit amplifier with an output driving the base of a bipolar transistor. The emitter of the...
5528686 Transformerless hybrid circuit having direct powered line-side amplifiers  
A telephone line-powered Data Access Arrangement having amplifiers therein directly powered from the telephone line without voltage regulators or filters. The amplifiers, such as the amplifier...
5517565 Integrated ringer relay circuit and method  
A circuit and method for isolating a subscriber line interface circuit ("SLIC") from the ringer generator in a telephone system. The circuit uses a gain blocking device to provide a signal gain...
5515433 Resistance forward telephone line feed circuit  
A line feed circuit employing a low-inductance transformer, and providing a major portion of the terminating impedance as line feed resistors connected between a telephone line and the transformer...
5500895 Telephone isolation device  
An isolation circuit for a telephone line interface includes a pair of capacitors that differentially couple analog transmit and receive channels in full duplex communication across an isolation...
5500894 Telephone line interface with AC and DC transconductance loops  
A method and apparatus for providing a telephone line interface having selectable termination characteristics, such as impedance parameters, is provided using AC and DC transconductance loops. The...
5481606 Opto-coupling device between a modem and a telephone line  
An opto-coupling device lies between an analog input circuit, such as a telephone line, and a processing apparatus, such as a modem. The device has a high impedance circuit; this is, its impedance...
5479504 Low voltage balanced hybrid circuit with operational amplifiers  
A hybrid circuit applies a data sending signal and an inverted data sending signal to the ends of a primary coil, so that the primary coil receives voltages based on the sum of the voltages of the...
5347577 Battery feed circuit for supplying feed current to telephone set  
A battery feed circuit supplies a feed current to a telephone set via a 2-wire telecommunication line formed of a TIP line and a RING line. The battery feed circuit includes a first voltage...
5341108 Amplifier biasing circuit  
This amplifier biasing circuit is used in a telecommunication ring trip circuit to control the bias of a sense amplifier (SA) having input terminals (I1, I2) coupled to output terminals (A, B) of a...
5295186 Termination circuit for a two-wire transmission line  
A low-pass filter is inserted between a two-wire line and a four-wire transmitting line for transmitting a transmission signal supplied from the two-wire line. Input and output signals of the...
5289537 On-hook transmission circuit in cable line  
In an on-hook transmission circuit provided in a subscriber circuit connected between a subscriber terminal and an exchange, a constant-current source unit causes a constant current to flow in...
5287406 Hybrid circuit having a two-wire/four-wire converting function  
A hybrid circuit includes a two-wire/four-wire conversion unit for forming an interface between a two-wire line and a four-wire line, and a digital balancing unit for canceling a return echo...
5280526 Transformer-less hybrid circuit  
An improved transformer-less electronic isolating transformer is obtained with an output subcircuit that outputs a controlled current rather than voltage. Specifically, the improved hybrid...
5260995 Electric power circuit for telephone set use  
An electric power circuit for telephone set use utilizing a power source drawn from a telephone circuit line. Alternating current components superimposed on a supply voltage, which is taken out by...
5133007 Side tone correction circuit  
A conversion circuit for connecting a two-wire circuit and a four-wire circuit to each other comprises a transformer having a primary side and a secondary side, the primary side being connected to...
5050210 Metallic current limiter  
A circuit for the non-linear limiting of the metallic current flowing in telephone line conductors. The circuit senses the metallic current flowing in the conductors. If that current exceeds a...
5034978 Universal channel unit switchable between two wire and four wire configurations  
The universal channel unit includes a channel interface circuit that uses a pair of fixed ratio transformers to terminate both two wire and four wire analog transmission facilities on a selectable...
4995111 Ring trip circuit for subscriber telephone  
An improved ring trip circuit for a subscriber telephone, for detecting an on-hook state or an off-hook state of the telephone. The ring trip circuit can be formed in a small size and can be formed...
4993063 Channel unit interface circuit  
A channel unit interface circuit for interconnecting a two-wire, bidirectional signal transmitting path and a four-wire signal transmitting path in a communication system includes a tip terminal...
4961222 Apparatus in a telecommunication system for supplying power to a telephone set  
A subscriber line circuit (1) is connected via a subscriber line (3a, 3b) to a telephone set (2). For a raised receiver the subscriber line (3a, 3b) is supplied with a line current (Is) by speech...
Matches 1 - 50 out of 132 1 2 3 >