| 摘要 |
PURPOSE:To avoid the occurrence of beat noises although a switch has a fault, by using a resonator at an area corresponding to the switch. CONSTITUTION:When local oscillators 1 and 2 are in normal operation, the voltage of a resonator 13 is controlled by a controller 12 so that the output of the oscillator 1 is delivered to an output terminal 11. While in case a variable capacity diode of the resonator 13 has a fault, the output of the using oscillator 1 is reflected by the oscillator 1 to be terminated to the terminator of an isolator 3 although the applied voltage of the controller has a change and since the resonance frequency of the resonator 13 is different from the frequencies of the oscillators 1 and 2. The output of a stand-by local oscillator 2 is reflected by the resonator 13 and delivered to the terminal 11. In case the controller 12 has a fault, the applied voltage differs from the preceding voltage with the resonance frequency different from the frequencies of the oscillators 1 and 2. As a result, only the output of the oscillator 2 is delivered to the terminal 11. In such a way, only the output of the oscillator 2 is delivered to the terminal 11 even in the case resonator 13 has a fault. Thus the beat noise is suppressed with no lowering of the transmitting performance. |
