| 摘要 |
PURPOSE:To realize a local oscillator and a carrier oscillator with a stable oscillating frequency by providing a tuning amplifier receiving an oscillated wave, outputting selectively its 2nd order harmonic wave to a mixer, thereby suppressing the feedback of a signal to the oscillator. CONSTITUTION:This oscillator is provided with an oscillator 1a oscillating an oscillated wave at a prescribed frequency in response to the carrier frequency of a reception signal and a tuning amplifier 2a receiving the oscillated wave, outputting selectively its 2nd order harmonic wave to a mixer 5. Thus, the 2nd order harmonic wave is selected by giving the oscillated wave outputted from the oscillator 1a to the tuning amplifier 2a and inputted to a mixer 5. A part of a signal going to the mixer 5 is fed back to the oscillator 1a while being delivered in opposite direction through the tuning amplifier 2a and the signal of the same frequency as the oscillated frequency is sufficiently attenuated by the tuning amplifier 2a. Thus, the fluctuation in the oscillated frequency in the oscillator 1a is prevented. |
