Sync signal detection system in a memory system for recording and reproducing block unit data

Claim 1

A synchronization (sync) signal detection system for detecting sync signals respectively provided at each period of data blocks occurring at equal time intervals, each of the data blocks including serial digital data having added thereto one of said sync signals, an auxiliary code, a block address code indicating an address value of each block period, and an error detection code obtained by performing a predetermined computation on the auxiliary code and the block address code, said sync signal detection system comprising: (a) sync signal detection means for (i) receiving said data blocks, (ii) determining a coincidence between each of said sync signals and a predetermined sync signal pattern and (iii) responsive to a determination of said coincidence therebetween, outputting a sync signal detection signal; (b) means for performing said predetermined computation on the auxiliary code and the block address code to produce a computed parity code signal; (c) error detection means for (i) inputting the error detection code included in the received data block and the computed parity code signal produced by said computation means, (ii) comparing said inputted error detection code with the computed parity code signal and (iii) responsive to an anti-coincidence comparison result between said inputted error detection code and said computed parity code signal, providing an error detection signal; and (d) means for outputting said sync signal detection signal responsive to simultaneous (i) presence of the sync signal detection signal output by said sync signal detection means and (ii) absence of said error detection signal provided by said error detection means, thus indicating that there is no synchronization error existing.