TRACKING CONTROL METHOD AND MAGNETIC TAPE

摘要

PROBLEM TO BE SOLVED: To perform a proper tracking correction by leading tracking signals based on a primary measurement value to be detected from the control track of a data part and a secondary measurement value to be detected from the additional control tracks of a leading area and forming a tracking control signal from the tracking signals. SOLUTION: In a starting area 22, a tracking signal of the one side and a tracking signal of the other side are determined only from a servo track 18a and only from three servo tracks 18a to 18c respectively. Both tracking signals are distinguished based on the nonuniformity in the case that a data track is optically projected on the photosensitive area of a CCD element. This difference is stored as the value of a difference and it indicates the measure of the nonuniformity. Then, only one of the servo tracks is evaluated instead of evaluating three servo tracks under the assumption that an effective area 23 has the same nonuniformity as that of the starting area 22 and the result can be added to the value of the difference.