A tuner which is adapted to down-convert an RF signal to an IF signal and perform signal processing, comprising: an IF filter which is adapted to filter a down-converted signal centering around a center frequency F0 to take out the IF signal; a pseudo sine wave generation circuit which is adapted to generate a pseudo sine wave having a level change of at least two steps respectively on both positive and negative sides; a switch circuit for selectively supplying the pseudo sine wave and the RF signal to the IF filter; and an F0 adjustment circuit which is adapted to adjust the center frequency F0 of the IF filter and includes a phase comparator, the pseudo sine wave is made to pass in use of the tuner through the IF filter by the switch circuit in a first state, and in said first state, the F0 adjustment circuit is adapted to adjust the center frequency F0 in the IF filter by comparing a phase of the pseudo sine wave with a phase of the signal after passing through the IF filter characterized in that the F0 adjustment circuit further includes a logic circuit and a DAC (digital/analog converter) for F0 adjustment, the logic circuit is adapted to receive a signal of a comparison result from the phase comparator and is adapted to rewrite data inside the DAC for F0 adjustment on the basis of the comparison result, and the DAC for F0 adjustment is adapted to supply the signal based on the rewritten data to the IF filter to change the center frequency F0 of the IF filter, the tuner further comprising an S meter which is adapted to detect a signal level of an IF signal that is output of the IF filter; and an S meter adjustment circuit which is adapted to adjust output of the S meter, wherein in use of the tuner a detection level of the S meter is adjusted using the S meter adjustment circuit depending on a level of an output signal of the S meter. an IF filter which is adapted to filter a down-converted signal centering around a center frequency F0 to take out the IF signal; a pseudo sine wave generation circuit which is adapted to generate a pseudo sine wave having a level change of at least two steps respectively on both positive and negative sides; a switch circuit for selectively supplying the pseudo sine wave and the RF signal to the IF filter; and an F0 adjustment circuit which is adapted to adjust the center frequency F0 of the IF filter and includes a phase comparator, the pseudo sine wave is made to pass in use of the tuner through the IF filter by the switch circuit in a first state, and in said first state, the F0 adjustment circuit is adapted to adjust the center frequency F0 in the IF filter by comparing a phase of the pseudo sine wave with a phase of the signal after passing through the IF filter characterized in that the F0 adjustment circuit further includes a logic circuit and a DAC (digital/analog converter) for F0 adjustment, the logic circuit is adapted to receive a signal of a comparison result from the phase comparator and is adapted to rewrite data inside the DAC for F0 adjustment on the basis of the comparison result, and the DAC for F0 adjustment is adapted to supply the signal based on the rewritten data to the IF filter to change the center frequency F0 of the IF filter, the tuner further comprising an S meter which is adapted to detect a signal level of an IF signal that is output of the IF filter; and an S meter adjustment circuit which is adapted to adjust output of the S meter, wherein in use of the tuner a detection level of the S meter is adjusted using the S meter adjustment circuit depending on a level of an output signal of the S meter.