Drive device
AssigneeSony Corporation
InventorShigeo Yamaguchi
Life of this patent
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Abstract
A drive device having an improved capability of reproducing data is disclosed. If an error occurs during a reproducing operation, reproduction is retried after changing amplitude reference values depending on whether the recording laser power is adequate. This makes it possible for the retrying operation to successfully read data that the previous reproducing operation failed to correctly read owing to an inadequate recording laser power. The determination as to whether the recording laser power is adequate is performed on the basis of the degree of asymmetry of the waveform of a data signal read by head means.
Claims7
A drive device comprising:
- head means for reading a data signal recorded on a recording medium by illuminating said recording medium with a laser beam;
- decoding means for performing a Viterbi decoding process upon the data signal read by said head means;
- determining means for determining, from the data signal read by said head means, whether or not the recording laser power used to record said data signal is adequate;
- and
- control means for controlling a reproducing operation such that when said decoding means fails to correctly reproduce data from the data signal read by said head means, if said determining means determines that the recording laser power associated with said data signal is inadequate, the reproducing operation is retried after changing an amplitude reference value used in said Viterbi decoding process.
Dependencies are inferred from the claim text.