| 摘要 |
PURPOSE: A redundant synchronization fields to improve disc drive read performance is provided to improve the capacity of interpreting a disc driver by using a redundant synchronization fields within contiguous data blocks used to store user data. CONSTITUTION: A channel(160) which employs partial response, maximum likelihood(PRML) signal processing which as will be recognized involves time-domain equalization and self synchronization of the read signal provided by the head(118), is recognized that additional components and features typically be provided in the read channel(160) and further, selected operations of several of the components disclosed in FIG.3 are controlled with inputs provided from and the pre-amp(162) monitors the variations in magnitude of voltage across the MR element of the head(118) and provides indications when the voltage exceeds a predetermined threshold bounding the nominal read voltage, and through the filter the result signal from the pre-amp(162) is provided to a variable gain amplifier(VGA)(164), which typically includes automatic gain control(AGC) to maintain a nominal signal amplitude for the remainder of the read channel(160). The output from the Viterbi decoder(176) l comprises a digitally expressed data sequence corresponding to the encoded data originally written to the selected track. This output data sequence is provided to a sync word detector(178) which, when enabled by the sequencer of the interface circuit(152), proceeds to examine each successive set of bits in the output data.
|
