| 摘要 |
PURPOSE:To prevent a phase of a reference signal in its own station from being deviated early by using a signal from a closed loop circuit of a phase synchronizing oscillation circuit in place of an input reference signal for the time being at the momentary interrupt of the input reference signal of a transmission line. CONSTITUTION:When a reference signal is momentarily interrupted due to the disturbance of a transmission line, it is detected by an input momentary restoration detection control circuit 5 to allow a selection circuit 2 to select an output from an inverting circuit 4 and a reset circuit 6 resets a counter of an input frequency division circuit 1 for the preparation of restoration. A signal extracted from a phase synchronizing oscillation circuit 3 is inverted by the inversion circuit 4, its output signal is given to the phase synchronizing oscillation circuit 3 via the selection circuit 2 to allow the signal to act like an input reference signal IN of a master station tentatively. Thus, when the phase synchronizing oscillation circuit 3 is available for self-running, because of the presence of the signal from the inverting circuit 4, a comparatively longer time is required for the occurrence of a phase shift. |
