Patent ID: 8855589

Claim:
A tuner which down-converts an RF signal to an IF signal and performs signal processing, comprising: an IF filter which filters a down-converted signal centering around a center frequency F 0 to take out the IF signal; a pseudo sine wave generation circuit which generates a pseudo sine wave having a level change of at least two steps respectively on both positive and negative sides; a switch circuit which supplies the pseudo sine wave to the IF filter instead of the RF signal; and an F 0 adjustment circuit which adjusts the center frequency F 0 of the IF filter, wherein the pseudo sine wave is made to pass through the IF filter by the switch circuit, and in this state, the F 0 adjustment circuit compares a phase of the pseudo sine wave with a phase of the signal after passing through the IF filter and adjusts the center frequency F 0 in the IF filter according to an obtained comparison result.