Digital data modulating method

Claim 1

A digital data modulating method comprising the steps of: dividing a series of binary bits into groups of at least three binary bits: and allotting each of the sequential group to a corresponding predetermined period-and-phase discriminating signal, therein providing a series of different period-and-phase discriminating signals representing a given digital data wherein the digital data is related with the period-and-phase discriminating signals as follows: if the three sequential digital data bit combination (b 1 , b 1+1 and b 1+2 ) is L, L and L, it is allotted to a first period-and-phase discriminating signal having a short period T s , appearing synchronous with the leading end S of the intermediate bit b 1+1 ; if the three sequential digital data bit combination (b 1 , b 1+1 and b 1+2 ) is L, L and H, it is allotted to a second period-and-phase discriminating signal having an intermediate period T M , appearing synchronous with the leading end S of the intermediate bit b 1+1 ; if the three sequential digital data bit combination (b 1 , b 1+1 and b 1+2 ) is H, L and L, it is allotted to a third period-and-phase discriminating signal having an intermediate period T M , appearing synchronous with the intermediate point C of the leading bit b 1 ; if the three sequential digital data bit combination (b 1 , b 1+1 and b 1+2 ) is H, L and H, it is allotted to a fourth period-and-phase discriminating signal having a long period T L , appearing synchronous with the intermediate point C of the leading bit b 1 ; if the three sequential digital data bit combination (b 1 , b 1+1 and b 1+2 ) is H, H and -, it is allotted to a fifth period-and-phase discriminating signal having a short period T s , appearing synchronous with the intermediate point C of the leading bit b 1 , where L and H stand for binary digits "0" and "1", and - stands for either binary digit.