FAST INITIALIZATION METHOD AND APPARATUS OF ECHO CANCELLER BASED ON CIRCULAR CONVOLUTION TECHNIQUE

摘要

PURPOSE: An apparatus and a method for quickly initializing an echo removing unit using a circular convolution technique are provided to improve an initialization speed and thereby improve performance of the apparatus, by making a transmission signal and a coupling signal different from each other, and performing an initialization operation using only a real number signal through circular convolution. CONSTITUTION: A modulator modulates a symbol to be transmitted, using a carrier wave with the same frequency as that of a transmitter. An output from the modulator is converted to a transmittable analog signal via a signal process part(22), a digital-to-analog converter(23) and a low pass filter(24). The low pass filter(24) is an analog filter for removing an image spectrum from the converted analog signal. A hybrid coupler(25) sends the analog signal output from the low pass filter(24) to an opponent modem, and receives a signal via an echo path. A band pass filter(26) filters the signal received via the echo path in order to remove a part except for the spectrum of a signal band from the received signal. An analog-to-digital converter(27) converts the output of the band pass filter(26) to a digital signal.