Patent ID: 6256383
Filing Date: 2001-07-03
Classification: H04B

Abstract:
A method for echo cancellation comprising:using a finite impulse response (FIR) filter system operatively coupled to a 4-wire section of a 2 to 4 wire conversion system, the FIR filter system including at least one FIR tap for replicating a leading portion of an echo signal, the leading portion of the echo signal having a duration of about 1 ms;using a non-adaptive infinite impulse response (IIR) filter system, operatively coupled to the FIR filter system, to replicate a long-tail portion of the echo signal, the non-adaptive IIR filter system further including at least one amplifier, the at least one amplifier corresponding to a decay rate of the long-tail portion of the echo signal, the decay rate being about 0.9;using a first summer, operatively coupled to the FIR filter system and non-adaptive IIR filter system, to combine the output replicated portions of the echo signal from the FIR filter system and the IIR filter system to generate a replicated echo signal; andusing a second summer to combine an inverted replicated echo signal with the transmit signal so as to substantially negate an echo signal component of the transmit signal.