| 摘要 |
PURPOSE:To shorten leading-in time and to prevent mislocking by sampling a burst signal to input one or several-wave components to a circulation type memory and circulating them continuously in one horizontal period to form a burst continuous wave and synchronizing the burst continuous wave with the burst signal in every horizontal period correctly. CONSTITUTION:Since a changeover switch 17 is connected to the A side in the pulse period of a signal SSW, the digital data of a burst signal SSC from an A/D converter 16 is supplied as input data to a memory 18 during this period and is written there successively. Since the changeover switch 17 is connected to the B side when the pulse period of the signal SSW elapses, the circulating state where the output data of the memory 18 is supplied as input data to the memory 18 is set after the elapse of the pulse period of the signal SSW till the next pulse period of the signal SSW. Thus, a burst continuous wave SSC is obtained as the output data from the memory 18 and is converted to an analog data by a D/A converter 19 and is supplied to a PLL circuit 20.
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