Tuner with calibration of center frequency of IF notch filter and calibration of S-Meter

摘要

A center frequency F0 of an IF filter is effectively adjusted. The IF filter (14) filters a down-converted signal centering around the center frequency F0. A pseudo sine wave generation circuit (20) 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 (14) by a switch circuit (22), and in this state, an F0 adjustment circuit (24) adjusts the center frequency F0 in the IF filter (14) by comparing a phase of the pseudo sine wave with a phase of the signal after passing through the IF filter (14).