Method for seeking the center of a recorded data track

US5343341A · kind A · utility

Assignee

• Tandberg Data ASA · NO

Inventor

• Rolf Jahren · Oslo, NO

Key dates

• Filing date: Oct 15, 1992
• Grant date: Aug 30, 1994
• Expiry date: Oct 15, 2012

Classification

• Technology area (CPC G): Physics
• CPC primary: G11B5/584
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

A method for seeking the center of a data track recorded on a magnetic tape using a read head, having an accuracy which is not limited by the stepper mechanism which positions the read head relative to the tape, makes use of the discovery that the fundamental component of tape wander is independent of the tape cartridge vendor and the tape length, and therefore the tape wander can be averaged over an integral number of tape wander periods. In the method, the average output from a read head over an integral number of tape wander periods is found at the lower and upper edges of a data track. The read head output from the center of the track is then measured, and is used to calculate an output change versus head position when the read head is partially in the track. The output change versus head position is then used to scale the lower or upper edge position to a position which would result in an output equal to the output found for the opposite edge, and then the center of the track can be found by dividing the sum of one edge position plus the corrected position for the opposite edge by two.