Apparatus for and method of determining transverse position of a

Abstract

The transverse position of a magnetic head relative to reference positions defining even and odd numbered axes between concentric adjacent tracks of a magnetic disc is detected. Each track includes plural position determining, longitudinally extending, equal length cells. The cells have magnetic variations which cause the head to respond to variations in cells of a pair of abutting tracks to derive a series of waveforms respectively having first and second like amplitudes and shapes for even and odd numbered cells as the tracks are translated relative to the head. The waveforms for each of the odd numbered cells include successive equal first amplitude pulses of first and second different polarities. The waveforms for each of the even numbered cells include successive equal second amplitude pulses of first and second different polarities. The number of pulses and approximate shapes of pulses for the even and odd numbered cells are the same. The first and second amplitudes indicate the transverse position of the transducer relative to the axis. In response to a determination of whether the reference axis has an even or odd number and the waveforms, the pulses are altered so both pulses of the odd numbered cells have one of the polarities and pulses of the even numbered cells have the other polarity while substantially retaining the shape and amplitude of the pulses to derive a resulting waveform. The resulting waveform is integrated over an integral number of cells to derive an indication of the transverse position relative to the axis.