Optical disc having small access units and address information modulation method therefor

Abstract

An address information modulation method includes using a first characteristic of a first modulation method and a second characteristic of a second modulation method to modulate address information and/or additional information. Accordingly, a data amount of information, to access a disc, in a predetermined space of the disc is increased, and the modulated information is formed in a form of a wobble signal in a track. Here, the first characteristic of the first modulation method can be physical location information of an MSK-modulated signal, and the second characteristic of the second modulation method can be sign information of a second harmonic wave obtained by an HMW modulation, which synthesizes a cosine function of a basic frequency of a wobble signal with a sine function having a frequency that is a multiple of the basic frequency of the wobble signal. Therefore, where the address information is modulated, a plurality of information bits are loaded on a predetermined number of wobble or carrier signals to increase the amount of the information in the predetermined space, such that a physical length of the information needed in accessing the disc and reading the additional information thereof is shortened. Also, where a defect occurs, the resulting loss can be reduced such that addressing specifications for a small-sized high density disc can be satisfied.