Patent ID: 8467435

Claim:
A bidirectional communication system, configured for full duplex communication, comprising: a communication channel; a main transmitter having an output for asserting a transmit signal; a transmit signal path electrically coupled between the communication channel and the output of the main transmitter; a receiver having an input for receiving a receive signal; a receive signal path electrically coupled between the communication channel and the input of the receiver, the receive signal path further coupled to the transmit signal path via cancellation resistors; and a transmit signal cancellation circuit electrically coupled to the receive signal path, the transmit signal cancellation circuit developing a cancellation signal, representing a transmit signal, and asserting the cancellation signal on the receive signal path so as to prevent the transmit signal from being asserted to the input of the receiver, the transmit signal cancellation circuit further comprising: a first replica transmitter having an output electrically coupled to the receive signal path between the main transmitter and the receiver; and a cancellation impedance circuit electrically coupled into the receive signal path between the output of the first replica transmitter and the output of the main transmitter, and between the output of the main transmitter and the input of the receiver.