Abstract: A channel estimation method is configured to estimate a channel length. The method includes the following operations: receiving an input signal; summing the input signal and an analog echo cancelation signal decrease an echo of the input signal, and generate a first signal according to a result of the summation; providing an analog gain value to the first signal to generate a second signal; performing an analog-to-digital conversion to the second signal to generate a third signal; obtaining a ratio according to an energy of a first frequency and an energy of a second frequency of the third signal; and estimating the channel length according to the ratio, and setting the analog gain value according to the estimated channel length.

Abstract: A channel estimation method is configured to estimate a channel length. The method includes the following operations: receiving an input signal; summing the input signal and an analog echo cancelation signal decrease an echo of the input signal, and generate a first signal according to a result of the summation; providing an analog gain value to the first signal to generate a second signal; performing an analog-to-digital conversion to the second signal to generate a third signal; obtaining a ratio according to an energy of a first frequency and an energy of a second frequency of the third signal; and estimating the channel length according to the ratio, and setting the analog gain value according to the estimated channel length.

Abstract: A decision feedback equalizer for generating an output signal according to an input signal includes: a feedforward equalizer, a feedback equalizer and a weight coefficient control unit. The feedforward equalizer includes a plurality of tapped delay lines and is controlled by a set of first weight coefficients. The feedback equalizer includes a plurality of tapped delay line and is controlled by a set of second weight coefficients. The weight coefficient control unit is employed to selectively adjust at least one of the set of first weight coefficients and determine a set of first boundary values for at least one of the set of second weight coefficients. When the at least one of the set of second weight coefficients does not exceed the set of first boundary values, the weight coefficient control unit increments the at least one of the set of first weight coefficients.

Abstract: A decision feedback equalizer for generating an output signal according to an input signal includes: a feedforward equalizer, a feedback equalizer and a weight coefficient control unit. The feedforward equalizer includes a plurality of tapped delay lines and is controlled by a set of first weight coefficients. The feedback equalizer includes a plurality of tapped delay line and is controlled by a set of second weight coefficients. The weight coefficient control unit is employed to selectively adjust at least one of the set of first weight coefficients and determine a set of first boundary values for at least one of the set of second weight coefficients. When the at least one of the set of second weight coefficients does not exceed the set of first boundary values, the weight coefficient control unit increments the at least one of the set of first weight coefficients.