Multi-channel equalization for PWM channels in magneto-optical recording

We show by modeling and simulations that multitrack readback and equalization can lead to significant increases in the track density in magneto-optical recording without performance degradation due to two dimensional interference. We assume an architecture in which an isolated set of closely spaced tracks is read simultaneously. In an earlier paper, we described a multi-channel zero-forcing equalizer and a two-dimensional decision-feedback equalizer for this architecture, and presented their performance for PPM (pulse position modulation) optical recording channels. Since PWM (pulse width modulation) recording is more popular in magneto-optic (MO) disks, we model the PWM channel in this paper and show simulation results for the performance improvement obtained by using multi-channel equalization for data recorded in PWM format.