Signal Processing for 15/27 GB Read-Only Disk System

In order to realize 15/27 GB read-only disk systems using blue laser, new signal processing is required. The technology of large-scale integrated circuits has advanced considerably. Hence we can use a complicated circuit with a big gate size without increasing the system cost significantly when we fabricate the blue laser disk system. We have realized the 15/27 GB system using the two-dimensional equalizer and the limit equalizer. The two-dimensional equalizer was composed of the cross-talk cancel system and the asymmetry compensation type tangential adaptive equalizer. And could improve the deterioration due to the inter symbol interference and the cross-talk from the adjacent tracks. The limit equalizer could improve the deterioration due to the disk noise. Using these signal-processing systems, we could reduce the bottom jitter by more than 3% and expand the tilt margin.