Patent ID: 6088308
Filing Date: 2000-07-11
Classification: G11B

Abstract:
A tracking circuit for providing an indication of laser source position relative to embedded tracks in an information-containing media from which laser light has been reflected while said laser light has been moved oscillatorially back and forth across edges of said tracks, said tracking circuit comprising:photodetector means for receiving said reflected light and for producing therefrom an electrical signal in response to light incident upon said photodetector;threshold detector means for detecting when said electrical signal from said photodetector exceeds a threshold value so as to provide an indication of which side of an embedded track said light is reflected from;waveform detector for providing a signal indicating distance between a track on said medium and points on said medium from which said laser light is reflected based on an output form said threshold detector means; andcounter means responsive to changes in said distance greater than a predetermined value and also responsive to said threshold detector for indicating relative position with respect to a plurality of successive tracks across which said laser light crosses.