Patent attributes
The present invention is to reduce the maximum magnetization reversal interval of a trellis code. A trellis diagram for the trellis code takes into consideration a constraint condition on the DSV of a code and an inter-symbol-interference for three bits. The minimum squared Euclidean distance is 4. When a non-interleaving encoder and a non-de-interleaving code detector are constructed using the trellis diagram, the maximum magnetization reversal interval of a trellis code to be used is reduced to half of that in a known case while having the error rate and circuit size approximately equal to those in the known case. The trellis diagram has a basic repeating unit for two bits. In the actual apparatus, the trellis diagram is repeatedly used. The present invention is applicable to a read/write apparatus.
