METHOD FOR DETERMINING THE GENERATION CYCLE OF RANDOM DATA, A RANDOM DATA GENERATOR USING THE SAME METHOD, AND A DATA SCRAMBLER ADOPTING THE SAME UNIT, PARTICULARLY FOR GENERATING A STABLE SERVO SIGNAL AND PROVIDING AN ADVANTAGE OF DC-SUPPRESSION IN MODULATING

摘要

PURPOSE: A random data generation cycle determining method, a random data generator using the method, and a data scrambler adopting the random data generator are provided to correspond to a capacity of data, entering the innermost and the outermost circumference track, varied according to the size of a data sector, the size of an error correction block, and a change in a disk radius. CONSTITUTION: The random data generator comprises registers(r0-rn-1), multipliers(40.0-40.n-1) and XOR gates(41.0-40.n-2). The n value is determined according to a random data generation cycle which corresponds to a data capacity within the outermost circumference track and the size of the first and the second data frame. The registers(r0-rn-1), serially structured, perform a shift left operation on inputted data. The multipliers(40.0-40.n-1) bypass the output of each register inputted via one input end if structure values inputted via the other end are 1, and determine survival of a corresponding path by the structure values which depend on the random data generation cycle. The most significant one of the XOR gates(41.0-40.n-2) receives the output of the most significant multiplier via one end and the output of the second significant multiplier via the other end. Remaining ones of the XOR gates(41.0-40.n-2) offer the outputs of corresponding multipliers via one ends, and receive the outputs of upper adjacent XOR gates via the other ends. The least significant one of the XOR gates(41.0-40.n-2) feedbacks an output value to the least significant multiplier.