| 摘要 |
<p>PURPOSE:To use one clock reproducing circuit for an address part and a data part to shorten the time of an amble part, by selecting the interval of level inversion of a modulated signal due to the first modulating method from intervals of level inversion which appear on a modulated signal due to the second modulating method. CONSTITUTION:In case FM modulation is adopted as the modulating method of the address part and 4-5 converting modulation is adopted as the modulating method of the data part, the level is inverted in the center of a bit cell of data in case of data ''1'' and is not inverted in case of data ''0'' and is always inverted on boundaries of bit cells of data in FM modulation. In 4-5 converting modulation, data is divided to 4-bit units, and they are converted to 5-bit coded words, and the level is inverted in the center of a bit cell of bit ''1''. Intervals of level inversion of FM modulation are T1 and T2, and those of 4-5 converting modulation are T3, T4, and T5. If T1=T3 and T4=T2 are made true in accordance with relations of T2=2T1, T5=3T3, and T4=2T1, intervals of level inversion of FM modulation exist in intervals of level inversion of 4-5 converting modulation, and thus, the same reproducing clock signal is used for respective modulated signals.</p> |
