Patent ID: 7295941

Claim:
A method for correcting a characteristic curve, the method comprising: determining whether a characteristic curve having phase angle values corresponding to displacement between a magnetic sensor element and a magnetic ruler of a magnetoresistive (MR) sensor within a range of displacement has a jump discontinuity by comparing a first phase angle value at a first end of the range to a second phase angle value at a second end of the range and by comparing phase angle values between the range ends; wherein the characteristic curve is determined to have a jump discontinuity if the second phase angle value is lower than the first phase angle value and if the phase angle values between the range ends are generally rising; wherein the characteristic curve is determined to have a jump discontinuity if the second phase angle value is higher than the first phase angle value and if the phase angle values between the range ends are generally falling; upon determining that the characteristic curve has a jump discontinuity; determining the value of the magnitude of the jump discontinuity; defining a phase angle decision threshold (PADT) to have a value lying between the first and second phase angle values; identifying the phase angle values within the range having values lower than the PADT value; identifying the displacements within the range corresponding to the identified phase angle values; and offsetting the identified phase angle values by the value of the magnitude of the jump discontinuity such that the characteristic curve is corrected to eliminate the jump discontinuity, whereby subsequent measurements made by the MR sensor for the identified displacements take into account the jump discontinuity magnitude offset.