Patent ID: 7106235

Claim:
An active hybrid circuit for a full duplex channel, comprising: a transmit digital-to-analog converter having a positive output port and a negative output port for generating an analog transmit signal; a receive analog-to-digital converter having a positive input port and a negative input port for receiving an analog receive signal; a duplicated voltage digital-to-analog converter having a positive output port and a negative output port for generating a duplicated voltage, the duplicated voltage including a duplicate of the analog transmit signal of the transmit digital-to-analog converter; a plurality of signal combiners each electrically connected at a first input thereof to the positive output port and negative output port of the transmit digital-to-analog converter and at an output thereof to the positive input port and the negative input port of the receive analog-to-digital converter, the plurality of signal combiners each connected at a second input thereof to the positive output port and the negative output port of the duplicated voltage digital-to-analog converter, the plurality of signal combiners each subtracting the duplicated voltage from the analog transmit signal; and a digital signal processor coupled to the receive analog-to-digital converter and responsive to a digital signal therefrom to provide a digital control signal, wherein the duplicated voltage produced by the duplicated voltage digital-to-analog converter is adjusted in accordance with the digital control signal.