Patent ID: 6891445

Claim:
A phase modulator for generating digital signals of phase-modulated carriers in response to changes in an input binary digital signal by using a waveform which, when it is changed in the increasing direction, has “0” level in a first period of T/12 (T corresponding to one-half cycle of the binary digital signal), is changed as a waveform of (h/2)(1+cos(3πt/T)+π/4) in the next period of 4T/12 (−5T/12≦t≦−T/12) and has an h (constant) level in the remaining period of T/12, and when it is changed in the reducing direction, has the h level in the first period of T/12, is changed as a waveform of (h/2)(1+cos(3πt/T)−π/4) in the next period of 4T/12 (T/12≦t≦5T/12) and also has “0” level in the remaining period of T/12.