Method and apparatus for interference cancellation in a high speed modem

Apparatus for interference cancellation in a high-speed modem comprising:

• a first coupler for receiving a differential signal including a received data signal in response to a transmitted signal;
• a second coupler for deriving a common mode signal for the transmitted signal;
• a phase-shift circuit coupled to the second coupler for deriving orthogonal signals from the common mode signal;
• first and second multipliers for correlating the orthogonal signals with the received data signal;
• first, second, and third integrators for integrating the mixed orthogonal signals and the common mode signal to produce orthogonal signal level measurements and a common mode signal level measurement, respectively;
• a controller for deriving orthogonal correction signals from measurements;
• multipliers for applying the corrections signals to the orthogonal signals;
• and
• an adder for combining the corrected orthogonal signals with the differential signal for cancelling interference therein and deriving the received data signal.

Apparatus for interference cancellation in a high-speed modem comprising the steps of:

• means, responsive to a transmitted signal, for receiving a differential signal including a received data signal and deriving a common mode signal;
• means for deriving orthogonal signals from the common mode signal;
• and
• means for deriving orthogonal correction signals in dependence upon the received data signal, orthogonal signals and the common mode signal;
• means for multiplying respective orthogonal signals by the orthogonal correction signals;
• and
• means for adding the combined orthogonal signals to the received data signal for cancelling interference therein.