Adaptive electronic transmission signal cancellation apparatus for full duplex communication

An adaptive transmission signal cancellation circuit for separating transmit data from receive data in a bidirectional communication system comprising:

• a transmit DAC having positive and negative output terminals for asserting differential analog transmit signals on a common signal path;
• a receive ADC having positive and negative input terminals for receiving differential analog receive signals from the common signal path;
• a first replica DAC having positive and negative output terminals for asserting a first differential analog cancellation signal, the positive terminal of the first replica DAC coupled to the negative terminal of the receive DAC, the negative terminal of the first replica DAC coupled to the positive terminal of the receive DAC;
• a second replica DAC having positive and negative output terminals for asserting a second differential analog cancellation signal, the positive terminal of the second replica DAC coupled to the positive terminal of the transmit DAC, the negative terminal of the second replica DAC coupled to the negative terminal of the transmit DAC;
• a first impedance element coupled between the positive terminal of the receive ADC and the common signal path;
• and
• a second impedance element coupled between the negative terminal of the receive DAC and the common signal path.

An adaptive transmission signal cancellation circuit for separating transmit data from receive data in a bidirectional communication system comprising:

• a transmit DAC having positive and negative output terminals for asserting differential analog transmit signals on a common signal path;
• a receive ADC having positive and negative input terminals for receiving differential analog receive signals from the common signal path;
• and
• a replica DAC having positive and negative output terminals for asserting a differential cancellation signal at the input of the receive ADC for cancelling the transmit signal from the receive signal.

A circuit for transmitting and receiving communication signals over a communication channel, comprising:

• a transmitter operable to assert a transmit signal on a transmit signal path electrically coupled between the communication channel and an output of the transmitter;
• a receiver operable to receive a receive signal from a receive signal path electrically coupled between the communication channel and an input of the receiver, the receive signal path being coupled in parallel fashion to the transmit signal path;
• and
• a transmit signal cancellation circuit electrically coupled to the receive signal path, the transmit signal cancellation circuit asserting a cancellation signal, representing the transmit signal, on the receive signal path so as to prevent the transmit signal from being asserted to the input of the receiver, wherein said transmit signal cancellation circuit is implemented in an Ethernet communication system capable of operating at a data rate of at least one gigabit per second.

An adaptive transmission signal cancellation circuit for separating transmit data from receive data in a bidirectional communication system comprising:

• a transmit DAC having positive and negative output terminals for asserting differential analog transmit signals on a common signal path;
• a receive ADC having positive and negative input terminals for receiving differential analog receive signals from the common signal path;
• a first replica DAC having positive and negative output terminals for asserting a first differential analog cancellation signal, the positive terminal of the first replica DAC coupled to the negative terminal of the receive DAC, the negative terminal of the first replica DAC coupled to the positive terminal of the receive DAC;
• a second replica DAC having positive and negative output terminals for asserting a second differential analog cancellation signal, the positive terminal of the second replica DAC coupled to the positive terminal of the transmit DAC, the negative terminal of the second replica DAC coupled to the negative terminal of the transmit DAC;
• a first impedance element coupled between the positive terminal of the receive ADC and the common signal path;
• and
• a second impedance element coupled between the negative terminal of the receive DAC and the common signal path;
• wherein the first and second replica DACs are implemented in an Ethernet communication system capable of operating at a data rate of at least one gigabit per second.

An adaptive transmission signal cancellation circuit for separating transmit data from receive data in a bidirectional communication system comprising:

• a transmit DAC having positive and negative output terminals for asserting differential analog transmit signals on a common signal path;
• a receive ADC having positive and negative input terminals for receiving differential analog receive signals from the common signal path;
• and
• a replica DAC having positive and negative output terminals for asserting a differential cancellation signal at the input of the receive ADC for cancelling the transmit signal from the receive signal, wherein the replica DAC is implemented in an Ethernet communication system capable of operating at a data rate of at least one gigabit per second.