METHOD AND APPARATUS FOR ENCODING AND DECODING DIGITAL INFORMATION

摘要

Digital data formed of binary bits of first and second values occupying consecutive bit cells of predetermined intervals are encoded such that successive binary bits of the first ox second values are represented by predetermined separations between succeeding transitions. A first transition is produced at a first reference point in a bit cell when a binary bit of the second value changes over to a binary bit of the first value. When successive binary bits of the first value are sensed, a respective second transition is produced at a second reference point in a bit cell after sensing every 2 or 3 binary bits of the first value. When successive binary bits of the second value are sensed, a respective second transition is produced at the second reference point in a bit cell when at least two successive binary bits of the first value are followed by a binary bit of the second value and also after sensing every 3 or 4 successive binary bits of the second value, such that the last-mentioned second transition at the second reference point is separated from the closest first transition thereto by at least 1.5 bit cell intervals but no more than 4.5 bit cell intervals and successive ones of the second transitions are separated from each other by no more than 4 bit cell intervals.