Device for deriving a synchronizing signal.

摘要

The device for deriving a synchronizing signal comprises a synchronizing signal detector (1), an output (3) of which is coupled both directly and via a delay unit (18) to inputs (4 and 19, respectively) of a signal combination unit (5). The output (6) thereof is coupled to an input (7) of a flywheel counter (8). One output (9) of the flywheel counter (8) supplies the synchronizing signal. Another output (9) is coupled to an input (11) of the signal combination unit (5). The first input (4) and the second input (11) of the combination unit (5) are coupled to inputs of a time slot circuit (12). The first input (4) and the third input (19) of the combination unit (5) are coupled to inputs (20, 21) of a further combination unit (14). The output of the time slot circuit (12) is also coupled to an input (13) of the combination unit (14).The delay time (T) of the delay unit (18) is equal to n times the period of the synchronizing signal. Therefore the device is less sensitive to "false lock" and can capture the synchronization rapidly again after a loss of synchronization.