| 摘要 |
PROBLEM TO BE SOLVED: To suppress the mutual modulation of local oscillation frequencies regardless of a relationship of two receiving frequencies in a receiver of a heterodyne system capable of simultaneously receiving two waves. SOLUTION: In the receiver of the heterodyne scheme provided with a simultaneous two-wave receiving function having local oscillation circuits 200A and 200B, frequency mixer circuits 210A and 210B, intermediate frequency band pass filters 220A and 220B and following processing circuits in two systems A and B, the filter of the system A is switched to two kinds of different frequency bands having a prescribed frequency difference and when the oscillation frequencies of the local oscillation circuits in two systems are proximate within a preset frequency difference during receiving while switching the switching band pass filter 220A to one passing frequency band, the passing band of the switching band pass filter 220A is switched to the other passing band. At the same time, the oscillation frequency of the local oscillation circuit 200A in the system A is shifted for the prescribed frequency difference. COPYRIGHT: (C)2004,JPO
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