A tuner is provided to remove harmonics in the received RF signal by including a tunable filter comprised of a passive filter. A low noise amplifier(110) amplifies the received RF(Radio Frequency) signal with the low noise. A tunable filter(130) filters the output signal of the low frequency amplifier by varying the central frequency according to a channel control signal. A local oscillator generates a local oscillation signal with a plurality of phases of the same frequency according to the channel control signal. A mixer generates an IF(Intermediate Frequency) signal of an I(In-phase) channel and a Q(Quadrature-phase) channel by mixing the output signals of the tunable filter and the local oscillator. An RSSI(Received Signal Strength Indicator)(120) detects the intensity of the output signal of the low noise amplifier and controls the amplification gain of the low noise amplifier according to the detected intensity.
