| 摘要 |
PURPOSE:To make a changeover between an in-use and standby key devices whose failure occurrence rates are high by a signal indicating the abnormal state of a system provided inside of the system. CONSTITUTION:While in-use oscillator 1 is operating normally, an oscillation output is transmitted from terminal (1) of waveguide change-over circuit to directional coupler 5 via terminal (2). Some of the oscillation is detected by detection diode 7 to judge that it level is normal. If in-use oscillator 1 gets out of order owing to the misleading- in of the oscillation frequency or the breakdown of an IMPATT diode, Gunn diode, or the like, the detection level of derection diode 7 decreases and the abnormality of the system is detected. After the detection of the abnormality of the system, waveguide change-over swtich circuit is rotated to connect standby oscillator 2 and directional coupler 5 together and the output of oscillator 2 is transmitted to main system body 6. |
