A time-domain equalizer includes a delay circuit, a weighting circuit, a controller and a summation circuit. The delay circuit receives an equalized signal and accordingly generates M delayed signals for an equalized signal. The weighting circuit applies an mth weighting of M weightings to an mth delayed signal of the M delayed signals to generate an mth weighted signal. The summation circuit sums up the M weighted signals, according to which the equalized signal is updated. The controller iteratively updates the M weightings according to a vector {right arrow over (e)}n,p=[en,p,1 . . . en,p,M], where the symbol en,p,j is defined as en,p,j=Σk(z[k]*z[k−Dp,j]*), the symbol n is an iteration index, k is a sample index, z[k] is a kth sample of the equalized signal, j is an integer index between 1 and M, and Dp,j represents a time delay amount corresponding to a jth delayed signal of the M delayed signals.