Patent ID: 7515371

Claim:
A disk drive system comprising: a controller for writing data symbols as received from an associated I/O interface; a read channel circuit which encodes and decodes data symbols and converts digital signals to analog signals to be written to the recording media of one of a plurality of hard disk platters in the disk drive system; a preamplifier coupled to said read channel, which amplifiers the analog signals and generates a write current signal containing data information and applying the write current signal during a write operation and terminating the write current signal at the end of a write current operation; a write transducer coupled to receive the write current signal from the preamplifier and configured to apply the write current signal to one or more drive coils wound on a yoke which has associated magnetic pole tips in which a magnetic signal is induced in order to write to said recording media; and said read channel having an adjustable oscillator configured to generate a transitioning signal which is applied to the preamplifier at the end of a write operation, and the preamplifier thereby passing a decaying write current signal with polarity transitions at the end of a write operation, to degauss the pole tips and yoke of the write transducer during a predetermined de-gaussing interval.