Combined magnetic channel signal sensor and servo control track following system and method.

摘要

Servoing is accomplished utilizing the same read head and the same data track by utilizing a differentially sensitive magnetic sensor. The sensor is utilized as the data read back head sensitive element but separate outputs from the differential sensor are supplied to separate track following amplifiers isolated from the data signal amplifier. The separate amplifiers for the servo information utilize the inherent differential sensitivity of the sensor. As one-half or the other of the differentially sensitive sensor drifts over the edge of a recorded data track, its signal output level will follow. This differential between the left and right halves of the sensor in the form of a change in signal level at the output can be amplified, referenced to common ground for high common mode noise rejection, and a differential signal derived from the difference between the left and right halves of the sensor. The differential is proportional to the distance off track that the sensor has wandered provided that at least a portion of the sensor remains over the track. A servoing system utilizing the differential output between the left and right and driven by the magnitude of the difference between left and right half signal components is utilized to force the head positioning system back in the appropriate direction to center the head over the data channel.