Patent ID: 7212476

Claim:
An optical disk reproducing device comprising: a channel rate process data demodulation part operable to demodulate 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 consecutive data have a same value, by employing a channel bit frequency; a half rate process data demodulation part operable to demodulate the digital data from the optical recording medium by employing a frequency that is half of the channel bit frequency; and a process rate switching part operable to switch between the channel rate process data demodulation part and the half rate process data demodulation part, thereby switching a process rate of data demodulation, wherein the process rate switching part is operable to generate a process rate switching signal so that, when data demodulation is performed with rotation of the optical recording medium kept constant, the channel rate process data demodulation part is selected for an inner circumference side where a channel frequency is low, and the half rate process data demodulation part is selected for an outer circumference side where a channel frequency is high.