Phase-change optical recording method using pulse width modulation technique
US5761179A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 1996 |
| Grant date | Jun 2, 1998 |
| Priority date | — |
| Expiry date | Apr 12, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/006
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
When recording data according to the PWM recording system by modulating signals, pulse modulation for pulse modulation for recording for recording a 0 signal or the like having a signal width of nT (T: Clock time) after modulation is a continuous electro-magnetic wave at a power level e, a record signal pulse array for recording a 1 signal or the like having a signal width of nT after modulation comprises a pulse section fp having a time width x and a power level a, a multi-pulse section mp in which a low level pulse at a power level b and a high power pulse at a power level c having a time width T in total alternately appear (n-n') times in all with a duty ratio y, and a pulse section op having a time width z and a power level d, and x, y, z are integers satisfying the conditions of 0.5 T.ltoreq.x.ltoreq.2 T, 0.4.ltoreq.y.ltoreq.0.6 and 0.5 T.ltoreq.z.ltoreq.1 T, and n' is a positive integer which is equal to or smaller than n, and controls are provided so that the condition of (a and c)>e >(b and d) is satisfied.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.