82results about "Transmission hybrid circuits" patented technology

There is provided a coupling circuit for a full duplex modem having a transmitter and a receiver. The coupling circuit includes (a) a first transformer having a primary winding and a secondary winding, where the primary winding is coupled to the transmitter, (b) a second transformer having a primary winding and a secondary winding, where the primary winding of the second transformer is coupled to a communications line, and (c) a resistance between a terminal of the primary winding of the first transformer and a terminal of the primary winding of the second transformer. The secondary windings of the first and second transformers are connected in series, with opposing phase, and coupled to the receiver to minimize a level of a signal from the transmitter from reaching the receiver.

An active hybrid circuit for a full duplex channel generates a duplicated voltage at the current output stage to reduce the energy of the transmitter transmitted to the receiver. The active hybrid circuit cancels the energy of the transmitter transmitted to the receiver when it is operated in a full duplex channel with high-speed transmission. The active hybrid circuit for full a duplex channel comprises a transmit digital-to-analog converter for generating an analog transmit signal, a receive analog-to-digital converter for receiving an analog receive signal, a duplicated voltage digital-to-analog converter for generating a corresponding duplicated voltage according to the analog transmit signal of the transmit digital-to-analog converter, and a plurality of signal combiners for subtracting the duplicated voltage from the analog transmit signal to cancel the influence of analog transmit signal to the analog receive signal.

A method and apparatus for isolating transmit and receive signals in a communication system utilizing a common channel for both incoming and outgoing signals. In one embodiment a tuned hybrid or isolation circuit is provided with a high-frequency pre-emphasis response. The tuned hybrid rejects the transmit signal from the receive port and is capable of isolating the low power receive signal. One or more filters within the hybrid provide the desired levels of attenuation and frequency specific processing. Outgoing transmit signals encounter minimal attenuation thereby reducing overall transmit power requirements while receive signals are isolated. The tuned hybrid may be configured with an all-pass network consisting of an attenuator and a delay element. Both of these devices or elements maybe tuned to tailor the frequency response to the channel.

An improved analog front end and methods for increasing the power efficiency of duplex signals on a transmission line are disclosed. The improved analog front end bifurcates a hybrid into a fixed portion and an adaptive portion. The adaptive portion combines a biquad and a summer to produce a filter transfer function suited to compensate for transmission line irregularities. A method for configuring a local transceiver to minimize power requirements at a remote transmitter is disclosed. Broadly the method entails, applying a transmit signal to a front end in the absence of a remote signal; optimizing the transmit signal power; recording the reflected transmit signal; applying an adaptive filter in response to transmission line irregularities; and controllably adjusting the adaptive filter to minimize the amplitude of the reflected version of the transmit signal in the receive path. A method for recovering a remotely generated signal is also disclosed. The method entails, applying a local transmit signal to the front end in the absence of a remote signal; recording a reflected version of the transmit signal in the receive path; controllably adjusting an adaptive portion of the front end to minimize the amplitude of the reflected version of the local transmit signal; and combining a scaled replica of the local transmit signal with a plurality of adaptive filter outputs to recover a remotely generated receive signal from the transmission line.

An electrical isolation barrier for use in a Data Access Arrangement uses a high frequency (HF) transformer 24 to provide isolation. An input signal, which may be analog or digital, is connected to a modulator. The analog output of the modulator is connected to the input of the HF transformer. The output of the HF transformer is connected to the input of a demodulator. Simple amplitude modulation can be used in the modulator to modulate the input signal to the frequency range of operation of the HF transformer. A simple low pass filter may be incorporated in the demodulator to remove harmonic distortion caused by the HF transformer. The output signal of the demodulator is substantially the same as input signal.

According to one exemplary embodiment, a communication device comprises a line driver, where the line driver provides an output signal. The communication device further comprises a digital echo canceller module coupled to the line driver, where the digital echo canceller module receives an echo reference signal determined by the output signal of the line driver, where the echo canceller module outputs an echo cancellation signal, and where the echo cancellation signal is capable of canceling linear and non-linear components of a composite signal. The communication device further comprises a summation module coupled to the digital echo canceller module, where the summation module receives the echo cancellation signal and the composite signal, and where the composite signal comprises a received signal and the linear and non-linear echo components. The summation module is configured to subtract the echo cancellation signal from the composite signal and to output the received signal.

A method and apparatus for outbound wave subtraction using a variable offset amplifier is described. The method includes calibration of a bi-directional signaling circuit in order to calculate one or more offset codes for cancellation of an outbound wave within a bi-directional communications link. Once the one or more offset codes are calculated, it is determined whether a dual inbound wave is received by the bi-directional signaling circuit. Once received, an offset code from the one or more calculated offset codes is selected according to a value of an outbound wave within the dual inbound / outbound wave. Finally, the outbound wave is cancelled from the dual inbound wave at an output of a variable offset amplifier using the selected offset code.

The interface comprises transmission cable and linker as well as impedance matching interface circuit. The cable and linker connects device at opposite device with the device in local device. Based on types of cable and id signal output from the linker, impedance matching is carried out for local device by the impedance matching interface circuit. First, the invention builds a mapping list between impedance of local device and matched impedance of cable and types. Impedance and type of cable is read out, and then matched value of impedance of local device is found out from the mapping list. Control of turning on / off resistance connected to the local device makes impedance of the local device match to impedance and type of cable. The invented interface and method can recognize impedance and type of cable with same impedance of opposite device so that different impedances are output in order to make impedances matched between opposite device and local device.

Bidirectional differential point to point simultaneous high speed signalling is provided between integrated circuits with highly effective echo canceling. Each integrated circuit comprises a transmitter for transmitting a first signal to another integrated circuit and a receiver for receiving a second signal from the other integrated circuit. The transmitter has an output buffer; a receiver has a receiver buffer and is co-located on the same integrated circuit; and a differential buffer is coupled between the input of the transmitter buffer and the output of the receiver buffer. To increase the quality of receiving the second signal, a third signal adjusted in phase and amplitude is coupled at the output of the receive buffer, so that the echoing of the first signal is canceled. Preferably, the rise time of the third signal is also adjusted.

An energy consumption meter includes a first input for providing a first input signal derived from a voltage, a first analog-to-digital (A / D) converter electrically connected to the first input to generate a first output signal based on the first input signal, a second input for providing a second input signal derived from a current, a second A / D converter electrically connected to the second input to generate a second output signal based on the second input signal, a multiplier to combine signals corresponding to the first and second output signals, and a phase evaluation block having two inputs that are electrically connected to the first input and to the second input. The phase evaluation block measures a phase difference that corresponds to a phase difference between the first input signal and the second input signal. A phase correction block corrects for the phase difference in one of the first output signal and the second output signal.

The present invention refers to a passive echo cancellation device for use in a full-duplex communication system and its signal transceiving method. The full-duplex communication system comprises a transmitting end for sending a transmit signal to a wiring interface, and a receiving end for accepting a receive signal from the wiring interface. The passive echo cancellation device comprises an offset-signal-generating circuit and a passive echo cancellation circuit composed of a plurality of passive components. The offset-signal-generating circuit generates an offset signal according to the transmit signal. The passive echo cancellation circuit is serially connected between the wiring interface and the receiving end, and is connected with the offset-signal-generating circuit. The passive echo cancellation circuit receives the offset signal in such a manner that an echo signal contained in the receive signal coming from the wiring interface is cancelled by mean of the offset signal, so as to generate an output signal containing merely the signal characteristics of the receive signal.

The cable interface unit in accordance with the invention allows use of the same wire in one cable both for base-band transmission of data between telecommunication equipment in full duplex form and also for transmission of an operating voltage (V) from one device to another. In the transmission unit, data is transmitted through a hybrid connection (41) to a cable (23). After the hybrid connection, the operating voltage (V) is also brought to the cable with the aid of a diplexer (44). The hybrid connection separates the arriving data and conducts it to the receiver, where the data is shaped in an analog manner by correcting level distortions and thereupon in the digital signal processing a DECISION is made on what the received symbol is.

The power amplifier mainly includes a main amplifier, two splitters, one combiner, one subtracter, two phase shifters, one attenuator and one error amplifier. The splitters, subtracter and combiner are designed in the form of 90-degree or quadrature hybrid couplers. A quadrature hybrid can be implemented with any lumped or transmission-line elements and has an important advantage compared to the in-phase splitter that at equal values of reflection coefficients from loads connected to the in phase and 90° phase shift terminals, the reflection wave is lacking at the main input terminal and, consequently, the input voltage standing wave ratio of a quadrature hybrid does not depend on the equal load mismatch level.

An XDSL system comprising a hybrid circuit in operative communication with a transmission line and an XDSL modem associated with a subscriber premises. The hybrid circuit comprises a plurality of selectable impedance circuits having different impedance values. A controller selectively engages each of the impedance circuits in-line with the XDSL modem and the transmission line. The controller records the performance of the modem with each circuit engaged, and selects the desired impedance circuit as a function of the performance characteristics associated with each of the impedance circuits. The impedance circuit which provides the best performance characteristic is selected as the impedance circuit for normal modem operation.

A system for improving the attenuation of an undesired signal found in a differential signal path through the use of inductive coupling. The system includes a primary inductor, a secondary inductor, and a filter. The primary inductor and the secondary inductor operably couple an input differential signal pair to an output differential signal pair, and the filter attenuates an undesired signal in the output differential signal pair.

In an active hybrid transformer circuit connected to both transmit and receive sides, a current driver is connected to a transmission path circuit through a common connection point of a load resistor and a replica resistor while a replica driver is connected to the replica resistor of which another connection point is directly connected to the receive side. The replica driver may be formed by a DAC of a current output type. A current ratio of the replica driver and the current driver is selected at a predetermined value so as to prevent a transmit signal from leaking into the receive side.

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 primary side and the secondary (line) side. Each half of the primary side is tapped to obtain a turns ratio of N1:N2, while each half of the secondary side of the transformer has N windings. The single matching impedance is coupled in parallel between the first winding and the second winding on each half of the primary side. Either the voltage across the matching impedance or the voltage across the receive terminals is bootstrapped to the receive signal through multiple negative feedbacks. The transfer function of the line driver is shaped as a first-order high-pass filter (HPF) to reject any out-of-band noise and distortion components.

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 analog front-end portion of the communication line system. The values of the tunable passive elements are digitally controlled by a microprocessor.

Systems and methods for remote control of an electronic device using a power cord are disclosed. A power cord that provides electric power to the device includes a module configured to receive wireless control signals originating from and / or transmit wireless signals to a remote device. The power cord includes one or more control wires for communicating signals between the module and the device. The module may be configured to translate information or signals received from the communications protocol of the remote device to the communications protocol of the device, and vice versa. The control wire(s) may extend along or within the power cord. Methods for wirelessly controlling a device comprise transmitting a command from a remote device to a module connected to the device's power cord, the module wirelessly receiving the command and transmitting the command to the appliance via control wires extending from the module to the device.

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 filter for filtering at the receiver input signals at predetermined frequencies appearing on the transmitter output and the telecommunications line. The filter circuit additionally forms a capacitive divider for scaling signals appearing at the transmitter output and canceling the scaled signals at the receiver input with related signals appearing on the telecommunications line. In one embodiment of the present invention for communicating using the ADSL protocol, the filter circuit is a first order high pass filter.

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 of the transformer, and a differential drive amplifier (DRV) that performs impedance synthesis. A secondary winding (TS) of the transformer is magnetically coupled to the first and the second primary windings and is electrically coupled to the telecommunication line. First and second impedance dividers (Zhin1, Zhout1 and Zhin2, Zhout2) are connected to the various nodes to provide outputs to a receive amplifier (RCV). The impedance matching networks (Zm1; Zm2) include various passive and reactive components that together provide an impedance value selected based upon the line impedance reflected into the primary windings (TP1; TP2) of the transformer. To perform the impedance synthesis, the drive amplifier (DRV) is a differential drive amplifier having feedback inputs (FB−, FB+) to which the third (C) and fourth (D) nodes are connected.

A 1000BASE-T transceiver linked to an unshielded twisted pair (UTP) through a transformer currently transmits and receives outgoing and incoming signals via the UTP. The transceiver employs an energy efficient class B or AB line driver supplying asymmetric output currents to the transformer's primary winding terminals so that the transformer's secondary winding induces the outgoing signal on the UTP. Resistors couple the transformer's primary winding terminals to inputs of separate amplifiers producing a differential output signal mimicking the incoming 1000BASE-T signal. Since both the incoming and outgoing signals contribute to voltages appearing at the transformer's primary winding terminals, echo cancellation circuits provide additional compensating signals to the amplifier inputs for canceling echo in each amplifier input due to the resistive and reactive loading on each driver output current and arising from the asymmetric nature of the class B or AB driver's output currents.

The invention discloses an electronic detonator control chip based on dual-mode communication and belongs to the technical field of initiating explosive devices and microelectronics. The electronic detonator control chip comprises a dual-mode communication receiving circuit used for processing and receiving wired signals and wireless signals, a dual-mode communication sending circuit used for sending the wired signals and the wireless signals, an instruction analyzing and data processing circuit used for analyzing instructions, processing data, packing sent data and generating various control signals, a delay control circuit used for generating a clock, locking the frequency and controlling counting, a discharge control circuit used for achieving discharge control, switching of high voltage and low voltage and starting of discharge, and a power source management unit used for achieving stability of a power source and generating high voltage. The electronic detonator control chip based on dual-mode communication can achieve wire communication and wireless communication and effectively ensure the communication success rate, and improves the reliability and safety of engineering blasting construction.