| 摘要 |
<p>The invention relates to an apparatus and method of modulating/demodulating. The problem of the invention is recording and playing back data with high line density. According to the invention, the apparatus comprises a block for determining/inserting the DSV control bit (11), which inserts DSV control bits for making the DSV control, into an input data sequence and supplies a modulation block (12) with the data sequence, including DSV control bits. The modulation block (12) converts the data sequence with a basic 2-bit length into codes of variable length, with basic a 3-bit code length, according to a conversion table, and transmits the code resulting from the conversion to a conversion block NRZI (13). According to the invention, the method comprises conversion stages for the input data conversion into codes, according to a conversion table used by the modulation block (12) and which comprises substitution codes for limiting the number of consecutive occurrences of the minimum run number at a pre-determined value and substittion codes for keeping a limit for the running length. Additionally, the conversion table establishes a conversion rule, according to which, the rest of the division by 2 of the number of "1" values of an element of the data sequence, having a value of 0 or 1, will always be equal to the rest of the division by 2 of the number of "1" values of an element in the sequence of code words, resulting from the data sequence conversion.</p> |
