Method and apparatus for positioning a read head to a selected track on a record disc

A method for recovering recorded information from a selected target track of a plurality of recorded information tracks on an information carrier, the recorded information including location identification data, said method including the steps of:

• rotating the carrier;
• scanning a reading beam of radiation upon the carrier to produce a reflected beam which is modulated by the recorded information on the tracks;
• selecting the target track, to thereby initiate a search operation;
• moving said reading beam across the carrier towards said selected target track;
• monitoring said modulated, reflected beam to periodically detect said location identification data, during said search operation;
• intermittently redetermining, in response to said monitoring step, the position of said reading beam relative to said selected target track;
• determining, in response to said intermittently redetermining step, when said reading beam has reached a predetermined position relative to said selected target track;
• and,
• in response to said determining step, moving said reading beam, in one increment, during less than a single revolution of the carrier, from said predetermined position to said selected target track, during less than a single revolution of the carrier.

A method for recovering recorded information from a selected target track of a plurality of recorded information tracks on an information carrier, the recorded information including location identification data, said method including the steps of:

• rotating the carrier;
• scanning a reading beam of radiation upon the carrier to produce a reflected beam which is modulated by the recorded information on the tracks;
• selecting the target track, to thereby initiate a search operation;
• moving said reading beam across the carrier towards said selected target track;
• monitoring said modulated, reflected beam to periodically detect said location identification data, during said search operation;
• determining, in response to said monitoring step, when said reading beam is positioned at a location less than a predetermined number M, greater than three, of tracks from said selected target track;
• further determining, in response to the firstrecited determining step, the exact number, defined as N, of tracks between said location and said selected target track;
• and,
• in response to said further determining step, moving said reading beam from said location, in one increment, during less than a single revolution of the disc, across said determined, exact number N of tracks, to arrive precisely at said selected target track, even when said determined, exact number N is greater than one.