An apparatus, method, and system for providing asymmetric signal
correction in a HDD system using magneto-resistive (MR) heads for reading
information stored thereon. The MR head produces a signal that is
asymmetric, and an asymmetric correction circuit corrects the asymmetric
signal for further processing. The asymmetric correction circuitry
comprises a differential amplifier having a variable gain for producing a
current proportional to the asymmetric signal. The differential amplifier
is coupled with two high speed switches for producing an output signal
having only positive polarity. When the asymmetric correction output
signal combines with the input signal, the resultant signal approximates
the inverse distortion of the asymmetric input signal.