| 摘要 |
<p>An information-bearing record medium (10) (magnetic tape, disk, or an equivalent thereof) includes a stream of binary bits (26, 28, 32,...) in which a binary 1 bit is normally represented by a signal transition at the middle of its corresponding bit cell and a binary 0 bit is normally represented by a signal transition at the trailing edge of its corresponding bit cell so long as the immediately following bit cell contains a binary 0 bit, whereby the spacing between successive normal signal transitions is at least one bit cell and is no greater than two bit cells. The binary bit stream includes an address mark byte (30), for identifying a future substream of data bits, defined by a unique pattern of signal transitions having at least one normal signal transition missing, whereby at least one pair of successive signal transitions is separated by more than two bit cells and less than four bit cells.</p> |
