Patent ID: 6201778
Filing Date: 2001-03-13
Classification: G11B

Abstract:
A method for manufacturing an optical disc with a groove for defining serial data containing a plurality of bits, said method comprising the steps of:generating modulated signal by phase modulating the serial data such that a first time interval for a high logic level is equal to a second time interval for a low logic level;generating a second modulated signal by frequency modulating said first modulated signal such that at least one frequency cycle representing a portion of a high bit of said serial data, and at least one frequency cycle representing a portion of a low bit of said serial data, each corresponds in duration to one of said high logic levels combined with one of said low logic levels of the first modulated signal, and such that a first frequency component in each said frequency cycle corresponds to said high logic level and a second, different frequency component in each said frequency cycle corresponds to said low logic level; andproviding said groove on said optical disc in accordance with the generated second modulated signal.