Patent ID: 6934523

Claim:
A tuner handling a radio frequency signal, the tuner comprising: (a) a first mixer operable to receive a first radio frequency signal split from the radio frequency signal; (b) a second mixer operable to receive a second radio frequency signal split from the radio frequency signal; (c) a local oscillator operable to provide the first and the second mixers with a local oscillating signal; (d) a first phase-shifter operable to provide the oscillating signal with a 90° phase-shift, the first phase-shifter being coupled between the local oscillator and the first mixer; (e) a first filter coupled to an output portion of the first mixer; and (f) a second filter coupled to an output portion of the second mixer, wherein a first operating mode comprises outputting a quadrature detection signal from the first and the second filters, wherein a second operating mode comprises adding an output signal from the second mixer to an output signal from the first mixer that undergoes a 90° phase-shift by a second phase-shifter, and outputting an intermediate frequency signal from the second filter, wherein the first operating mode and the second operating mode are switch-selectable, and wherein the first filter is a first low-pass filter, and a first changeover-switch is coupled with the output portion of the second mixer, by which the second filter can be switched between a second low-pass filter and a band-pass filter.