| 摘要 |
PURPOSE:To reduce generation probability of an erroneous synchronization by using plural cascade-connected time filters inputting a synchronizing pattern bed from a correlation detector. CONSTITUTION:A correlation detector 2 receives a receiving data train 101 and a clock signal 102, detects a synchronizing pattern from the receiving data train, and inputs it to a time filter 10. The time filters 10-12 are cascade-connected, and a clock signal of 1 frame length counted by a frame counter 1 is inputted to the filters 10-12 in order. An output of the counter 1 is inputted to a decoder 3, the decoder 3 decodes its contents and generates a frame pulse 106, and applies it to a control signal generating circuit 13. In case when a control signal 203 to the filters 10-12 from the circuit 13 is ''write'', the filters 10-12 store contents of the counter 1 in order in a memory whenever a pulse comes into an input. In case when the signal 203 is ''read-out'', the filter 10 generates a forecasting pulse whenever the contents of the counter 1 coincide with the stored contents, outputs only a pulse whose time has coincided with the forecasting pulse in the input pulse, and generation of an erroneous synchronization is reduced. |
