| 摘要 |
<p>The video information is formed into a frequency modulated signal which is used to vary the intensity of a lser writing beam which forms a track on the metallised surface of a video disc. The disc consists of non-reflective lengths of the track, corresp. to marks of the frequency modulated waveform, and reflective lengths of the track corresp. to the spaces of the frequency modulated waveform. The track can be read by use of a reading light beam and collecting light reflected from the reflective lengths as the beam moves over the track. There is feedback appts. for maintaining the average intensity of the writing light beam, and devices for monitoring the record after it has been formed by comparing it with the original waveform to be recorded.</p> |
