| 摘要 |
PURPOSE:To prevent the abrupt change of a phase in a synchronous signal by controlling the passage of a second pulse by means of the AND of a decision output and the output of a first latching means, controlling a counting means by means of the outputs of a first and a second latching means and changing an output frequency. CONSTITUTION:A detection window signal S12 including the rise of an external synchronous signal S1 is generated. A gate means 4 controls the passage of a second pulse by the AND of the decision output of a decision means 11 and the output of the first latching means 13 and controls the alteration of the output frequency of the counting means 6 by the output of the first latching means 13 and the output of the second latching means 14. Thus, the phase of the synchronous signal output is prevented from being abruptly changed since the output frequency of the counting means 6 gradually changes and the phase of the synchronous signal output is locked in a state approximated to the phase of the external synchronous signal S1 even if the external synchronous signal S1 is switched to second, third... external synchronous signals different in the phase. |
