Optical information recorder and reproducer

Abstract

Abstract PURPOSE: To obtain the optimum recording exposure conditions, by reproducing the previously recorded address signal on a guide track provided to an information carrier and controlling the laser output with the reproduced address signal. CONSTITUTION: An address signal SI is separated by a signal separating circuit 34 from signals SAWSD received a photoelectric conversion through a photodetector 17. The signal SI is a code signal modulated by a PE or an MFM and demodulated by the clock supplied from a clock reproducing circuit 37 through an address signal reproducing circuit 36. A modulated series address signal (a) is stored in a series- parallel converting circuit 38 and turned into an analog signal through a D/A converting circuit 39 to be applied to a laser driving circuit 35 through a bias switching circuit 40. Thus the bias current of a semiconductor laser 3 is controlled. As a result, a proper laser output is ensured although the speed is different between the inner and outer circumferences of an information carrier 1. COPYRIGHT: (C)1982,JPO&Japio

Inventors

• 👤 Isao Sato
• 👤 Tomio Yoshida
• 👤 Shunji Harikae
• 👤 Kenji Koishi

Bibliographic Details