a center frequency f 0 of an if filter is effectively adjusted . the if filter filters a down - converted signal centering around the center frequency f 0 . a pseudo sine wave generation circuit generates a pseudo sine wave having a level change of at least two steps respectively on both positive and negative sides . the pseudo sine wave is made to pass through the if filter by a switch circuit , and in the state , an f 0 adjustment circuit adjusts the center frequency f 0 in the if filter 14 by comparing a phase of the pseudo sine wave with a phase of a signal after passing through the if filter .