| 摘要 |
PROBLEM TO BE SOLVED: To prevent the level of an amplified oscillation signal from dropping by switching a tuning circuit of a buffer amplifier to two oscillation frequency bands in a simple configuration and stabilizing a tuning frequency. SOLUTION: Power is fed to a first oscillation transistor 1a and a second oscillation transistor 2a from an amplifying transistor 4a. A first switch transistor 6 whose connector is connected to a power terminal 5 and which applies a bias voltage from its collector to the base of the first oscillator transistor 1a, and a second switch transistor 9 whose emitter is connected to the power terminal 5 and which applies a bias voltage from its collector to the base of the second oscillation transistor 2a are provided. A capacitor 4c is connected between the collector of the first switch transistor 6 and the collector of the amplifying transistor 4a to switch the first switch transistor 6 and the second switch transistor 9 so as to make on/off of the first switch transistor to be reverse to on/off of the second switch transistor 9. COPYRIGHT: (C)2004,JPO
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