| 摘要 |
PURPOSE:To detect step-out of the phase synchronous oscillator, by generating the step-out alarm only when the true step-out is detected. CONSTITUTION:Dangerous region detecting circuit 41 has monostable circuit 43 which outputs the first monostable pulse, monostable circuit 44 which outputs the second monostable pulse, and the first and the second D type FFs 45 and 46 which detect coincidence of each other. NOR gate 42 outputs normality detecting signal dE when signals dC and dD do not exist simultaneously. When detecting signals are received in the order of dC dD dE dC or dD dE dD dC, order deciding circuit 47 finds two sequences respectively to output true step-out alarm signal ALM. |
