| 摘要 |
<p>PURPOSE:To keep the synchronization protection with a control signal by generating a PN pattern and adding a control logic signal representing the detection to the generated PN pattern in detecting a prescribed pattern having a shorter period than that of an M series. CONSTITUTION:When a synchronization protection controller 7 decides the synchronizing state, a selector 6 is used to form a synchronizing loop by a PN pattern generator 1, a pattern computing elements 2 and an adder 4. All outputs from the PN pattern generator 1 are fed to a focing pattern generator 3, from which a logic signal F having a shorter period than the period of the PN pattern M series is generated. In this case, an output of the pattern computing element 2 differs from the input frame pattern and the F pattern is added by the adder 4, resulting that the coincidence of the pattern outputted from the computing element 2 and the frame input is detected by a comparator 5, and a synchronizing protection signal is kept from the synchronizing protection controller 7 to repeat the identical pattern for the both.</p> |
