Optical disk reproducing device

An optical disk reproducing device comprising:

• a channel rate process data demodulation part for performing a process of demodulating digital data from an optical recording medium on which the data is digitally recorded in a form of recording codes having a restriction that at least three of the same code continue, by mainly employing a channel bit frequency;
• a half rate process data demodulation part for performing a process of demodulating the digital data from the optical recording medium by employing a frequency half as high as the channel bit frequency;
• and
• a process rate switching part for switching a data demodulation part for performing digital data demodulation between the channel rate process data demodulation part and the half rate process data demodulation part, thereby switching a process rate at data demodulation, wherein
• the process rate switching part has a retrial information detection part for detecting retrial process information which indicates a re-reading process for a part where demodulation of data from the optical recording medium has failed, and
• generates the process rate switching signal so that the half rate process data demodulation part is selected in a normal reproduction state;
• and
• that the half rate process data demodulation part is switched to the channel rate process data demodulation part when the retrial information detection part judges that a retrial process occurs.

An optical disk reproducing device comprising:

• a channel rate process data demodulation part for performing a process of demodulating digital data from an optical recording medium on which the data is digitally recorded in a form of recording codes having a restriction that at least three of the same code continue, by mainly employing a channel bit frequency;
• a half rate process data demodulation part for performing a process of demodulating the digital data from the optical recording medium by employing a frequency half as high as the channel bit frequency;
• and
• a process rate switching part for switching a data demodulation part for performing digital data demodulation between the channel rate process data demodulation part and the half rate process data demodulation part, thereby switching a process rate at data demodulation, wherein
• the process rate switching part generates a process rate switching signal so that:
• the half rate process data demodulation part is selected in the case of a favorable data demodulation state;
• and
• the channel rate process data demodulation part is selected in the case of a deteriorated data demodulation state, and wherein
• the process rate switching part has a retrial information detection part for detecting retrial process information which indicates a re-reading process for a part where demodulation of data from the optical recording medium has failed, and
• generates the process rate switching signal so that the half rate process data demodulation part is selected in a normal reproduction state;
• and
• that the half rate process data demodulation part is switched to the channel rate process data demodulation part when the retrial information detection part judges that a retrial process occurs.