Patent ID: 6909760

Claim:
A synchronization data detection unit in a communication system for detecting predetermined synchronization data of a transmission frame in a communication signal, said synchronization data including a sequence of identical binary symbols which are transmitted after scrambling, comprising: a descrambler for descrambling the received communication signal and producing output data symbols having multi-level signal values, wherein the descrambler includes: a binarization portion for converting a received multi-level input signal into a binary signal, a delay portion delaying the binary signal in accordance with a redefined descrambling rule, and a multiplication portion for multiplying the multi-level input signal with the binary signal output from the delay portion and outputting a descrambled signal; a filter means for smoothing the descrambled output data symbols, and a threshold means for comparing the smoothed output of said filter means with a predetermined threshold value and indicating a detection of said synchronization data if the output of the filter means exceeds said predetermined threshold value.