Patent ID: 7003027

Claim:
A modem for establishing communication between a first device and a second device via a communication medium, said modem for passing a transmit signal generated by the first device via a transmitter to the communication medium and passing a receive signal from the communication medium to a receiver for processing by the first device, said modem coupled to the communication medium through a hybrid circuit, said modem comprising: a Farrow phase shifter positioned between the first device and the hybrid circuit to shift the phase of the transmit signal; an equalizer positioned between the hybrid circuit and the first device to minimize intersymbol interference in the receive signal, said equalizer having an adaptive input; a primary echo sub-canceler having an input coupled between the Farrow phase shifter and the hybrid circuit to receive the phase shifted transmit signal and an output coupled between the hybrid circuit and the equalizer, said primary echo sub-canceler adapted to remove a first portion of an echo in the receive signal; a post equalizer echo canceler having an input coupled between the Farrow phase shifter and the hybrid circuit to receive the phase shifted transmit signal and an output coupled between said equalizer and the first device, said post equalizer echo canceler adapted to remove a second portion of the echo in the receive signal, said post equalizer echo canceler having an adaptive input; and a slicer positioned between the output of the post equalizer echo canceler and the first device, said slicer having an output for producing a standard symbol value which is a representation of a current symbol value being supplied at an input of said slicer by the receive signal, the difference between the input and the output of said slicer being supplied to the adaptive input of said equalizer and to the adaptive input of said post equalizer echo canceler.