| 摘要 |
PROBLEM TO BE SOLVED: To cover a local oscillation frequency band for high-band reception and a local oscillation frequency band for low-band reception by common oscillation transistors and a resonance circuit. SOLUTION: A local oscillation circuit is provided with an integrated circuit 10 in which the oscillation transistors 11 and 12 are formed and which has first and second terminals 10a and 10b connected to bases and collectors of the oscillation transistors 11 and 12, respectively and with the resonance circuit 30 provided outside the integrated circuit 10 and connected between the first and second terminals 10a and 10b. In the integrated circuit 10, protective diodes 19 and 20 for preventing dielectric breakdown are provided, wherein cathodes are connected to the respective terminals 10a and 10b and anodes are grounded, and voltage is not applied to the cathodes of the protective diodes 19 and 20 at the time of VHF low-band reception but voltage for a reverse bias is applied at the time of high-band reception. COPYRIGHT: (C)2006,JPO&NCIPI
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