| 摘要 |
PURPOSE:To prevent an output signal from a coupler from being interrupted should a rubidium atomic oscillator belonging to an acting group be faulty. CONSTITUTION:A phase detector 3 detects a phase error between output signals of rubidium atomic oscillators 1,2 to provide an output of an error signal. The error signal is subject to low pass filtering by a low pass filter 7 and the resulting signal is used tp a frequency variable control signal of the standby group rubidium atomic oscillator 2. An output signal of the standby group rubidium atomic oscillator 2 controlled by the control signal is the same as an output signal of the active group rubidium atomic oscillator 1. The phase of the output signal of the rubidium atomic oscillator 2 has a prescribed difference from a phase of the output signal of the rubidium atomic oscillator 1 by a phase adjustment device 4 and the output signal of the rubidium atomic oscillator 2 is given to a 3dB coupler 5, in which the output signals are synthesized and the result is outputted. Through the constitution above, should the rubidium atomic oscillator 1 be faulty, an output signal from the 3dB coupler is not interrupted. Furthermore, the phase adjustment device 4 is used to set the phase difference between the output signals of the rubidium atomic oscillators to be 45 deg., then the output level of the 3dB coupler is unchanged even when either of the rubidium atomic oscillators is faulty. |
