CHANNEL SHORTENING EQUALIZER

PURPOSE: A channel shortening equalizer is provided to reduce the total impulse response by equalizing a channel having a long impulse response, such as a telephone line, in a time domain. CONSTITUTION: A channel shortening equalizer is composed of a correlation matrix operation unit(310), a coefficient updating unit(320) and a digital filter(330). In process that DMT(Discrete MultiTon) block columns(Xn-2,Xn-1,Xn,Xn+1,Xn+2,...) go by way of a communication channel, received signals(Yn-2,Yn-1,Yn,Yn+1,Yn+2,...) are inputted to the correlation matrix operation unit(310) and the digital filter(330) sequentially. If the received signals(Yn-2,Yn-1,Yn,Yn+1,Yn+2,...) are inputted sequentially, the correlation matrix operation unit(310) calculates correlation matrix components ry(m)=ry(0), ry(1), ry(2),..., ry(M-3), ry(M-2), ry(M-1) and provides them to the coefficient updating unit(320). If the correlation matrix components are inputted, the coefficient updating unit(320) generates filter coefficients using a Durbin algorithm and provides them to the digital filter(330). The digital filter(330) filters the received signals based on the filter coefficients and removes interference between DMT blocks.