Digital data transmission system having error detecting and correcting

Abstract

In an information data recording and reproducing device which can record and reproduce input information data accurately, an error correction code of the product sign format is added to the input information data to form coded data. The coded data are then NRZI converted and recorded onto a recording medium together with identification data of a predetermined data pattern. Error detecting and correcting are performed on data reproduced from the recording medium so as to obtain the data recorded on the recording medium. The device comprises an NRZI converting circuit for outputting the identification data as they are, that is, without NRZI conversion, and for NRZI converting the coded data using the last bit of the identification data as an initial value, and a memory controlling circuit for controlling writing and reading of a memory, which is provided to convert the reproduction data from a series of inner codes into another series of outer codes, so that write address information for the memory which is obtained from the reproduction data may be compensated for when it is not obtained properly and outer code error detection and correction may be readily executed.