| 摘要 |
<p>PURPOSE: To obtain the concrete constitution of a synchronized switching device capable of switching line without hit. CONSTITUTION: An active-side data signal DATAI is directly inputted to a switching circuit-7 and a reserving-side data signal DATAIS is delayed by a FIFO memory 12 to be a data signal DATAR and inputted to the switching circuit 7. A counting circuit 5 detects the relative delay time difference between both data signals inputted to the switching circuit 7 from a frame pulse generated by frame synchronization circuits 3 and 4. A control circuit 6 controls the frequency dividing rate N of an N-frequency divider 12 so as to eliminate the relative delay time difference. When a frequency dividing rate N is made larger than the frequency dividing rate M of an M-frequency divider 11, the delay quantity of the FIFO memory 12 is increased but when being made smaller, the delay quantity is reduced. This control eliminates the relative delay time difference between both data signals inputted to the switching circuit 7 to attain syncronized switching.</p> |
