| 摘要 |
<p>The present Patent Application relates to a recording device for recording on a record carrier (4; 4 min ) an information pattern of recording areas (8) having first optical properties, which recording areas alternate with intermediate areas (11) having second optical properties. The recording device comprises write means including means for scanning the record carrier (4; 4 min ) with the aid of a write beam (13; 107a), modulation means (107) for switching, in conformity with a bivalent signal (Vefm) having a specific duty cycle, the intensity (I) of the write beam (13, 107a) between a low intensity (Il) which does not bring about a change in optical properties of the record carrier (4; 4 min ) at the scanning location and a high write intensity (Is) which brings about an optically detectable change of the record carrier (4; 4 min ) at the scanning location. The recording device further comprises optical read means, including means for scanning the recorded information pattern with a read beam (53, 107a), the read beam being modulated by the information pattern being scanned, a radiation sensitive detector (64, 106) for converting the modulated read beam into a corresponding read signal (Vl, Vl sec ). An analysis circuit (65) derives from the read signal (Vl, Vl sec ) an analysis signal (Va) which is indicative of the deviation of the average ratio between the lengths of the recording areas (8) and the intermediate areas (11) from an optimum ratio defined by the duty cycle. Depending upon the analysis signal (Va) the write intensity (Is) is set to a value for which the ratio between the lengths of the recording areas (8) and the intermediate areas (11) substantially correspond to the optimum ratio defined by the duty cycle. The analysis signal indicates whether the dc component (DC) of the read signal (Vl) occupies a specific position, relative to the minimum values (A1) and the maximum values (A2) of the read signal (Vl, Vl sec -), which position is defined by the duty cycle.</p> |
