Relation between Signal Quality and Groove Shape in Magneto-Optical Disk(2)

Calculations and experimental results are described which clarify the relation between signal quality (C/N) and groove shape of magnetic recording media. Calculation indicated a tendency for the C/N ratio to be favorable the wider and shallower the groove, and the experiment results supported this conclusion well. At a groove depth of 15nm there was no appreciable difference in C/N over the disk with no groove, but at a depth of 59nm, C/N was 2 to 4dB smaller. On a disk with a 0.8¿m wide, 15nm deep groove, at a recording frequency of 0.24MHz, C/N was 61.3dB, and at 1MHz it was 58.7dB, providing extremely good signals.