Digital data duplication apparatus

Claim 1

A digital data duplication apparatus for reproducing digital primary data stored in a master recording medium and recording the reproduced primary data in a slave recording medium, comprising: a data recording device for recording the digital primary data on the master recording medium, said recording device comprising formatting means for formatting the primary data when the primary data is to be recorded on the master recording medium, adding means for adding secondary check data including at least a master parity code to the primary data employing each fragment of the primary data as a unit, and first recording means for recording said primary and secondary check data on the master recording medium in opposite directions comprising a forward direction and a reverse direction; and a data reproducing device for reproducing at the same time both the primary data and secondary check data recorded on the master recording medium in both the forward and reverse directions, said reproducing device comprising forward data take-in means for taking in the primary and secondary check data recorded in the forward direction to detect an error in said take-in primary data using a generator polynomial, reverse data take-in means for taking in the primary and secondary check data recorded in the reverse direction to detect an error in said take-in primary data using a reciprocal polynomial, forward master reproduction processing means connected to the forward data take-in means for correcting said detected error, reverse master reproduction processing means connected to the reverse data take-in means for correcting said detected error, and second recording means connected to both the forward and reverse master reproduction processing means for recording at the same time on the slave recording medium the corrected primary data recorded in both the forward and reverse directions.