| 摘要 |
PURPOSE:To improve reliability by multiplexing an oscillator, switching frequency-dividing rate when a fault occurs in either oscillation systems or frequency-dividers and oscillation stops so as to obtain the oscillation output of the same frequency. CONSTITUTION:The frequency dividers 2-1 and 2-2 frequency-divide frequency signals from the oscillators 1-1 and 1-2 in a mode switching them to prescribed first and second frequency-dividing rates so as to transmit the prescribed oscillation output. Multipliers 6-1 and 6-2 mutually multiply the frequency signals which have been frequency-divided by the frequency dividers 2-1 and 2-2. Supervisory circuits 5-1 and 5-2 supervise whether the oscillation of the frequency signals inputted to the multipliers 6-1 and 6-2 has stopped or not. When they have detected stop, they switch the frequency-dividing rate of either of the frequency dividers 2-1 and 2-2 and they control to output almost the same frequency signal. Thus, correspondence to the fault of the frequency dividers is attained. |
