Patent ID: 7239660

Claim:
An adaptive filter, the adaptive filter comprising: a feed-forward filter for providing a filtering coefficient to filter an input signal and to output an output signal, wherein the filtering coefficient is a sum of power-of-two; and an adaptive module electrically connected to the feed-forward filter for adaptively adjusting the filtering coefficient of the feed-forward filter according to a Group Signed Power of Two (GSPT) Least Mean Square (LMS) algorithm, the adaptive module comprising: an error detector for receiving a desired signal and the output signal to output an error signal; an updating term decision module electrically connected to the error detector for receiving the error signal and the input signal to output an updating term signal, wherein the updating term signal is a Carry-in signal or a Borrow-in signal; and a coefficient updater electrically connected to the updating term decision module for receiving the updating term signal to output an updated filtering coefficient to the feed-forward filter; wherein when the updating term signal is the Carry-in signal, the coefficient updater executes a Carry-in operation for updating the filtering coefficient; when the updating term signal is the Borrow-in signal, the coefficient updater executes a Borrow-in operation for updating the filtering coefficient; when the updating term decision module does not output any signal, the coefficient updater does not update the filtering coefficient.