| 摘要 |
PURPOSE:To improve working stability of control devices connected to a frequency deviation detector, by a method wherein a frequency deviation detector generates DC output depending on deviation between input signal frequency and setting frequency, timer element and AND element are provided in control signal transmission line of the frequency deviation detector, and output is held zero at interruption of input signal. CONSTITUTION:In output line of control circuit 16 to connect FF26 and switches 22, 23, a time element 34 with time setting longer than period based on input signal frequency and AND elements 36, 38 are connected. If input signal is interrupted and FF26 of the control circuit 16 does not become setting state and time tau elapses, the time element 34 outputs lock signal. Thereby input condition of AND elements 36, 38 is not effected, control signal of FF26 prevents AND elements 36, 38 from passing. Switches 22, 23 are opened, input signal to a filter amplifier 20 becomes zero and ouput E0 of the amplifier is held zero. |
