Patent ID: 8456229

Claim:
A filter device comprising: a filter that separates a steady component and a non-steady component included in an input signal, the filter being an adaptive filter in which updating of a filter coefficient causes frequency response characteristics to adapt in an autonomous fashion; a synthesis unit that synthesizes the separated steady component and the separated non-steady component according to a given ratio; and an evaluation unit that evaluates, on the basis of a result of a frequency analysis performed on at least one of the input signal, the separated steady component, and the separated non-steady component, the magnitude of the amount of the non-steady component included in the input signal; wherein the synthesis unit sets the given ratio to a first ratio in an instance in which the evaluation unit determines the amount of the non-steady component to be equal to or less than a predetermined reference, and sets the given ratio to a second ratio, in which the proportion of the non-steady component is less than that of the first ratio, in an instance in which the evaluation unit determines the amount of the non-steady component to be greater than the predetermined reference.