Realtek Semiconductor Inc.

Chih-Wen Huang

Chen-Chih Huang

Pao-Cheng Chiu

Mu-Jung Chen

An apparatus for echo cancellation in a transceiver of a full duplex communication system, where the transceiver includes a transmitter for transmitting a transmit signal and a receiver for receiving a receive signal, includes: an echo cancellation signal generator, coupled to the transmitter, for receiving the transmit signal and for generating an echo cancellation signal according to the transmit signal, wherein the echo cancellation signal reflects an effect of an impedance of a channel and a parasitic capacitor of the transceiver; and a calculation module coupled to the transmitter, the receiver, and the echo cancellation signal generator for receiving the receive signal and for canceling the echo of the receive signal according to the echo cancellation signal to generate an echo-cancelled signal, wherein the effect of the impedance of the channel and the parasitic capacitor of the transceiver in the echo-cancelled signal is reduced.

Echo cancellation device for full duplex communication systems

An echo cancellation apparatus of a transceiver in a full duplex communication system is disclosed. The full duplex communication system includes a transmitter section for transmitting a transmit signal and a receiver section for receiving a receive signal. The echo cancellation device includes an echo cancellation signal generator coupled to the transmitter section for receiving the transmit signal and for generating an echo cancellation signal according to the transmit signal, a load resistor and a parasitic capacitor of the transceiver; and a calculation module coupled to the transmitter section, the receiver section, and the echo cancellation signal generator for receiving the receive signal and for eliminating at least high frequency components of the echo signal.

A network device comprises a hybrid-mode transmitter for transmitting a differential transmission signal at a first transmission rate or a second transmission rate. The network device includes a first mode channel and a second mode channel. The first mode channel includes a voltage mode driver and a current mode driver for outputting the differential transmission signal. The second mode channel includes a second mode driver, which is one of a voltage mode driver and a current mode driver. The network device transmits the differential transmission signal at the first transmission rate through the voltage mode driver of the first mode channel and the second mode driver. The network device transmits the differential transmission signal at the second transmission rate through at least one of the current mode driver and the voltage mode driverfirst mode channel.

Network device with hybrid-mode transmitter

A transceiver in a full duplex communication system includes a transmitting circuit coupled to a channel for transmitting a transmit signal to the channel, a cancellation signal generator coupled to the channel for generating a cancellation signal according to the transmit signal, and an echo cancellation device coupled to the transmitting circuit and the cancellation signal generator for attenuating an echo corresponding to the transmit signal with the cancellation signal.

Transceiver for full duplex communication systems

A network transmitter and an associated transmitting method are disclosed. The network transmitter includes a signal converter and a signal driver. The former can convert an input signal into a current signal, and the latter can output a differential transmission signal according to the current signal. The signal driver includes a feedback network which can switch between a first configuration and a second configuration.

Multi-rate network transmission circuit

An echo cancellation device for a full duplex communications system is provided. The full duplex communication system has a transmitter for transmitting a transmit signal and a receiver for receiving a receive signal. The echo cancellation device has a filter for outputting a filter signal according to the transmit signal, an echo cancellation circuit connected to the filter for outputting an echo cancellation signal according to the filter signal, at least one echo cancellation resistor connected to the transmitter, the receiver, and the echo cancellation circuit, and an echo cancellation detection circuit for outputting a control signal according to an echo residue at the receiver to control the filter.

A signal transmitting apparatus being used in a network device includes a voltage-controlled current source for outputting a current signal according to an input digital signal; a line driver for outputting a voltage signal according to the current signal; at least one impedance-matching unit, which is coupled to the line driver, for impedance-matching at the output of the line driver; and a first correction unit, which is coupled to the voltage-controlled current source, for outputting a first correction signal to adjust the current signal outputted from the voltage-controlled current source.

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Kao-Hsiung Hsien, Taiwan

Chih-Wen Huang