Samsung Electronics Co., Ltd.

Khoa Bui

Bac V Pham

Kingston Lin

The present invention is a method and apparatus for removing transient DC level shifts caused by thermal asperities. A read signal is generated by a transducer in response to proximate contact between the transducer and magnetic flux fields recorded on a magnetic media surface. The read signal is provided to a continuous time filter and a sampler. During normal operation, the output of the sampler is provided directly to a fixed delay tree search detector. Upon encountering a thermal asperity, the output of the sampler is first provided to a 1-D sampled filter which removes the DC shift caused by the thermal asperity and then to the fixed delay tree search detector, which provides signal recovery. A multiplexer provides selection of the output signal from between sampler and the 1-D sample filter.

Method and apparatus for providing thermal asperity compensation in a

A method and apparatus is disclosed for removing transient DC level shifts caused by thermal asperities (TAs), thereby reducing TA induced errors. Read signal generated by a Magneto resistive (MR) is input to a continuous time filter and a sampler. Sampler output is input to a 1-D sampled filter which performs level equalization to remove DC Shift cased by TA disturbance. Sampled filter output is input to MUX along with sampler outputs. MUX selects sampled filter output during TAs. MUX output is input to a FIR filter and Viterbi decoder. Gain and Timing loop tracking and acquisition blocks receive sampler and FIR filter output and output correction signals for use by VGA and phase/frequency Detector.

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San Jose, CA, United States of America

Khoa Bui