| 摘要 |
PURPOSE:To control an average output frequency equal to that just before the occurrence of input trouble even after the occurrence of input trouble by reading out temporarily stored digital control signals to calculate an average value at the time of the occurrence of trouble of an input signal and generating and sending a digital control signal for free running. CONSTITUTION:When trouble occurs in the input signal, a computing element 30 stops the operation to generate a new digital control signal from the digital phase difference signal from an A/D converter 2. Past digital control signals temporarily stored in a storage device 70 are read out to generate the digital control signal for free running. Thus, the digital control signal very approximating that just before the occurrence of trouble in the input signal is generated even after the occurrence of trouble in the input signal, and the average output frequency for free running is very approximated to that in the synchronous state. |
