Patent ID: 6594094
Filing Date: 2003-07-15
Classification: G11B

Abstract:
A read/write channel circuit to communicate with a magnetic head, the read/write channel circuit comprising:a mode controller to select one of a plurality of operating modes for the read/write channel circuit, the plurality of operating modes including a read mode, a write mode, and a servo mode; a read path through which a read signal from the magnetic head passes when the mode controller is in the read mode in order to read data in the read signal, the read path including: a thermal asperity compensation unit to reduce distortions in the read signal caused by thermal asperity; a variable gain amplifier to adjust an amplitude of the read signal; an asymmetry control unit to compensate for the distortions in the read signal caused by a non-linear transfer function of the magnetic head; a continuous time filter to attenuate high frequency noise in the read signal; a programmable finite impulse response filter configured to equalize the read signal for data sequence detection when the mode controller is in the read mode; an interpolated timing recovery unit to synchronize the read signal by resampling the read signal for data sequence detection; a sync byte detector to detect sync marks in the read signal; a Viterbi detector to detect data sequences in the read signal using the detected sync marks; and a decoder to decode the detected data sequences; a write path through which a signal carrying write data to the magnetic head passes when the mode controller is in the write mode in order to record the write data, the write path including: an encoder to encode the write data; and an output driver to provide a write current pattern for the magnetic head from the encoded write data; and a servo path through which a servo signal from the magnetic head passes when the mode controller is in the servo mode in order to find address marks in the servo signal, the servo path including: said variable gain amplifier to adjust an amplitude of the servo signal; said continuous time filter to attenuate high frequency noise in the servo signal; said programmable finite impulse response filter configured to equalize the servo signal for address mark detection when the mode controller is in the servo mode; and a servo block to detect address marks in the equalized servo signal.