Patent ID: 8311155

Claim:
A high-frequency receiver comprising: an electronic tuner for receiving a digital broadcast signal; a demodulator for demodulating an output signal from the electronic tuner; and a driving circuit; the electronic tuner comprising: an input terminal to which the digital broadcast signal is input; first and second mixers adopting a direct conversion system to which the digital broadcast signal is supplied to their one inputs and an oscillation signal of an oscillator is supplied to their other inputs via a phase shifter, the first and second mixers outputting output signals with different phases to each other; first and second output terminals to which outputs of the first and second mixers are supplied, respectively; a DC offset control loop for detecting first and second DC offset voltages in the output signals of the first and second mixers, the DC offset control loop outputting first and second cancel signals for canceling out the first and second DC offset voltage, respectively; a first compositor connected between the first mixer and the first output terminal, the first cancel signal being input to the first compositor; and a second compositor connected between the second mixer and the second output terminal, the second cancel signal being input to the second compositor; and the demodulator comprising: a demodulating circuit connected between an output of the electronic tuner and an output terminal of the high frequency receiver, the demodulating circuit including, a reception quality detecting circuit for detecting a quality of a received signal; and a reception quality evaluation circuit for evaluating a detected signal output from the reception quality detecting circuit by comparison with a first reference value, and outputting an evaluation signal to the driving circuit; wherein power supply to the DC offset control loop is stopped by the driving circuit when the reception quality evaluation circuit evaluates that the quality of the received signal is acceptable.