Data reproduction control method and apparatus, and optical disk unit
AssigneeFujitsu Limited
InventorsToru Fujiwara, Akira Nanba, Masakazu Taguchi
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Abstract
The present invention realizes stable and more proper data reproduction even when a reproduced signal varies locally due to a noise or includes a steady distortion. In a data reproduction control method and apparatus, and an optical disk unit that adjust sampled values, in sampling a signal reproduced from a recording medium recorded with data, the frequencies of the levels of quantized data are counted, a histogram of the frequencies of the levels is created based on the counting results, and more accurate reproduced data is obtained by means of a distribution of the frequencies of the levels in the histogram.
Claims15
A data reproduction control method controlling a distribution characteristic of quantized data by adjusting a waveform equalization characteristic at a time of performing quantization and waveform equalization on a signal reproduced from a recording medium recorded with data in accordance with a given recording code, wherein:
- frequencies of levels of the quantized data are counted;
- and
- the waveform equalization characteristic is adjusted so that a distribution of the counted frequencies of the levels approaches a distribution that is to be obtained based on the given recording code.
A data reproduction control apparatus controlling a distribution characteristic of quantized data by adjusting a waveform equalization characteristic of a waveform equalizer when a signal reproduced from a recording medium recorded with data in accordance with a given recording code is subjected to operations in quantization means and the waveform equalizer, the data reproduction control apparatus comprising:
- counting means for counting frequencies of levels of the quantized data;
- and
- equalization characteristic adjustment means for adjusting the waveform equalization characteristic of the waveform equalizer so that a distribution of the frequencies of the levels obtained in said counting means approaches a distribution that is to be obtained based on the given recording code.
An optical disk unit having a reproduction system including processing means for performing quantization and waveform equalization on a signal reproduced from an optical disk medium recorded with data in accordance with a given recording code, and maximum likelihood detection means for determining, in accordance with a maximum likelihood detection process corresponding to the recording code, reproduced data from waveform-equalized quantized data obtained in the processing means, the optical disk unit comprising:
- counting means for counting frequencies of levels of the quantized data;
- and
- equalization characteristic adjustment means for adjusting a waveform equalization characteristic in the waveform equalization so that a distribution of the frequencies of the levels obtained in said counting means approaches a distribution that is to be obtained based on the given recording code.
Dependencies are inferred from the claim text.