Patent ID: 7974168

Claim:
A data storage medium reproducing device for reproducing data recorded on a data storage medium, comprising: signal detection means for reading out the data storage medium, and for detecting a reproduction signal, which is modulated in accordance with recorded data, the reproduction signal being modulated according to repeating of a sub data having the same content and being added to the recorded data; data detection means for (i) generating a valid detection data, which is an obtained detection result of the recorded data, by using one or more specific parts of the reproduction signal, and (ii) allowing an accuracy of the detection data to become higher, as the total time length of the accumulation of a modulation amount(s) of the one or more specific parts in the reproduction signal, the total time length being to be used for generating the detection data becomes larger; and control means for, when the recorded data is reproduced, controlling the total time length of the accumulation of the modulation amount(s) of the one or more specific parts of the reproduction signal by dividing each of the sub-data into a cyclic signal indicating a positive or negative sign of the detection result of the reproduction signal, the total time length being to be used by the data detection means, for generating a valid detection data.