Patent ID: 6965578

Claim:
An echo cancellation method for a digital data communication system comprising a first device having a first transmitter and a first receiver, and a second device having a second transmitter and a second receiver, wherein said first transmitter is configured to transmit signals to said second receiver over a downstream communication channel, said first receiver is configured to receive signals from said second transmitter over an upstream communication channel, and an echo channel conveys echo signals between said first transmitter and said first receiver, said method comprising: generating an analog output signal by said first transmitter for receipt by said second receiver, the analog output signal including characteristics associated with a nonlinearity introduced by said first transmitter; sampling said analog output signal; performing echo cancellation based on said analog output signal that includes the characteristics associated with the nonlinearity, using an echo canceler having a transfer function that is based upon a transfer function of a line coupling between the first transmitter and the second receiver, wherein said echo cancellation cancels an echo signal conveyed by said echo channel; sampling a digital signal provided by a digital signal processor, said digital signal being operatively coupled to an input of said first transmitter; and performing a second echo cancellation based on said digital signal, wherein said second echo cancellation further cancels the echo signals conveyed by said echo channel.