Patent ID: 6865052

Claim:
A method to calibrate a servo sensor disposed on a tape head disposed adjacent a moving magnetic tape, wherein said magnetic tape includes at least one servo edge comprising an interface between a first recorded signal and a second recorded signal, wherein said servo sensor detects said first recorded signal and said second recorded signal, and wherein a servo detector provides a servo signal comprising the ratio of the detected first recorded frequency and the detected second recorded frequency, and wherein an independent position sensor provides an IPS signal comprising the lateral position of said tape head with respect to the tape path, said method comprising the steps of: sampling said servo signal and said IPS signal to form servo signal/IPS signal data as said tape moves adjacent said servo sensor; determining (N) measured datapoints using said servo signal/IPS signal data, wherein each of the DP ACT(i) members of said (N) datapoints comprises a measured servo signal and a corresponding measured IPS signal, wherein (i) is an integer greater than or equal to 1 and less than or equal to (N); calculating a transfer function using said (N) datapoints and an (n)th order curve fitting algorithm, wherein (n) is greater than or equal to 1 and less than or equal to about 6; forming a first calibration curve comprising (N) calculated datapoints DP CAL(i) using said transfer function; setting a value for the maximum allowable residual error RE MAX ; computing (N) residual error values, wherein the residual error RE (i) for the (i)th one of said (N) calculated datapoints DP CAL(i) equals DP ACT(i) −DP CAL(i) ; adjusting said first calibration curve to form a second calibration curve based upon said (N) residual error values.