No abstract

No abstract

The multiple spaced (d, k) codes seem to have some application value for magnetic recording and magneto-optic reaiding systems. Recently it was shown that these codes have a performance advantage when a partial-response channel is considered. In this paper we will show that the multiple spaced (d, k) constraint has some interesting spectral properties. Certain choices of d and the spacing parameter will result in spectral nulls in the power spectrum. From these results it is shown that the previous choices of d and the spacing parameter are not optimal in terms of matching the spectral null of the sequence and that of the partial-response channel.

No abstract

Theorems relating characteristic equations and values of channel capacity of some classes of constrained sequences to other classes are presented. These results provide new characteristic equations which can be used for the calculation of channel capacity, and enable existing tables containing values of channel capacity for constrained sequences to be used to find previously unknown values of capacity for other classes of sequences. Algorithms for transforming DC-free line codes and their decoders to minimum bandwidth line codes, and vice-versa, are presented. These algorithms are then used to obtain two new minimum bandwidth line codes.