| 摘要 |
PURPOSE:To attain a data density equal to that of the 3PM system and to shorten a maximum signal inversion interval and to reduce a constrained length by determining inversion position of the signal or not inverting the signal in accordance with arrangement of codes when binary data is converted to a two- bit code. CONSTITUTION:One of ''0'' and ''1'' is denoted as A, and the other is denoted as B. The signal is inverted in the center of the data bit of B if B follows A, and the signal is inverted on the boundary between two As if two As follow B and the signal is not inverted on the boundary between B and A (figures A-J). Upper numbers indicate encoded bits, and mark * indicates optional data or bit. The signal is inverted on boundaries of data bits at intervals of 4T if 5 or more As are continuous (figure A'), and the signal is inverted on boundaries of data bits at intervals of two bits from the last B if 4-7 Bs are continuous (figures B'-E'). If 8 or more Bs are continuous, the first signal inversion intervals is 1.5T, and thereafter, the signal is inverted on boundaries at intervals of 2T (figure F'); and if odd Bs are continuous, data is so converted that the last signal inversion interval goes to 2T and the just preceding inversion interval goes to 3T (figure G'). |
