| 摘要 |
PURPOSE:To recover the synchronization in a comparatively short period even in case a synchronizing signal has the start-stop shifting, by resetting a synchronization period while the synchronizing signal is stable at the outside of a window. CONSTITUTION:When data are sent to a synchronization detector 1, the synchronizing signal is sent out. This synchronizing signal usually resets a free-running counter 3 and a front side protecting counter 4. A window generator 2 estimates the position of the next synchronizing signal and sends the window output to the counter 3. A synchronization counter detector 5 monitors the position of the synchronizing signal and then decides that the positions of the past signals i+2, i+3 and i+4 are cynchronous with the position of the signal i+5 at a time point the signal i+5 is supplied and that a signal trains is stable at the outside of the window in case the signal i+2 has the start-stop shifting. Then the detector 5 delivers a hunting signal. With this hunting signal, a synchronizing period is reset at a time point the signal i+7 is supplied. The synchronization period is cut down to five frames in an asynchronization period. |
