Abstract: A method for modulating digital data and apparatus therefor is capable of determining a digital data stream coded by Run Length Limited swiftly and precisely so as to record data in a recording medium. The digital data modulating method includes the steps of comparing a preset critical value and DSV (Digital Sum Value) of a certain digital data stream, computing the penalty of the digital data stream by multiplying the number of the time that the DSV of the digital data stream is larger than the critical value by a preset weight value of the critical value, comparing the penalty of the digital data and a penalty of another digital data stream and selecting a digital data stream with a smaller penalty as the digital data stream. Therefore, with the method for modulating digital data and apparatus therefor, the digital data stream which will be modulated among a number of digital data streams can be selected precisely and swiftly.

Abstract: A method for modulating digital data and apparatus therefor is capable of determining digital data stream coded by Run Length Limited (hereinafter as RLL) swiftly and precisely so as to record data in a record medium. To achieve the method and apparatus, the digital data modulating method includes the steps of comparing a preset critical value and DSV of a certain digital data stream, computing the penalty of the digital data stream by multiplying the number of the time that the DSV of the digital data stream is larger than the critical value by a preset weight value of the critical value and comparing the penalty of the digital data and a penalty of another digital data stream and determining a digital data stream with a smaller penalty for the digital data stream.