| 摘要 |
PROBLEM TO BE SOLVED: To remove image signal components in an intermediate frequency signal without fail. SOLUTION: An oscillator 2 generates a reference image signal having a predetermined image frequency, and an antenna 1 receives a radio signal having a predetermined radio frequency. An amplitude phase adjustment circuit 30, which responds to an adjustment start signal C0 from a controller 200 so as to control a switch SW1 to set it to a contact a side, adjusts the signal voltage of a gain control signal CA for controlling the gain of a variable gain amplifier 11 and a signal voltage of a phase-shift amount control signal CP for controlling the phase-shift amount of a phase shifter 9 so as to minimize the signal voltage of an output signal S1 from a radio receiving circuit 100, and outputs the gain control signal CA and the phase-shift amount control signal CP that have the adjusted signal voltages to the variable gain amplifier 11 and the phase shifter 9, respectively. In addition, the amplitude phase adjustment circuit 30 controls the switch SW1 so as to switch it to a contact b side. COPYRIGHT: (C)2008,JPO&INPIT
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