Patent ID: 8619384

Claim:
A servo system configured to determine a relative lateral movement and velocity between a tape and a tape head, the tape having at least one longitudinal defined servo track, the servo track including a longitudinal series of identical servo pattern frames, each servo pattern frame including two pairs of non-overlapping parallel magnetic transitions, the transitions of each pair being spaced apart an equal distance d, the transitions of the first pair forming an azimuth angle Î· to the longitudinal axis of the tape, the transitions of the second pair forming the azimuth angle Î· to the longitudinal axis of the tape but at an opposite slope about the lateral axis of the tape, the servo system comprising: a tape head including a servo read head configured to read the servo pattern frames in the at least one servo track and produce servo signals at times T A and T B , corresponding to the times that the servo read head detects the first and second transitions of the first pair of parallel transitions of a servo pattern frame, and times T C and T D , corresponding to the times that the servo read head detects the first and second transitions of the second pair of parallel transitions of the servo pattern frame; a servo channel configured to receive the servo signals and determine a relative lateral movement LM AB or LM CD between the tape and the tape head between times T A and T B , or times T C and T D , respectively, at least according to the relationships ( T D - T C ) ( T B - T A ) = sin â¡ ( Î· ) â¢ cos â¡ ( Î± ) - cos â¡ ( Î· ) â¢ sin â¡ ( Î± ) sin â¡ ( Î· ) â¢ cos â¡ ( Î± ) + cos â¡ ( Î· ) â¢ sin â¡ ( Î± ) , and LM AB = Î± * d sin â¡ ( Î· ) - ( Î± * cos â¡ ( Î· ) ) or LM CD = Î± * d sin â¡ ( Î· ) + ( Î± * cos â¡ ( Î· ) ) , respectively.