Patent ID: 7031403

Claim:
A phase shift keying modulation apparatus for modulating a phase of a carrier signal by an input signal to produce a phase-shift-keying-modulated wave, said phase shift keying modulation apparatus comprising: a data converter, supplied with an input data signal having 3 bits long as said input signal, for converting said input data signal into first and second ternary converted data signals which are mapped on first and second phase planes, respectivley, said first ternary converted data signal having one of first through third values, said second ternary converted data signal having one of said first through said third values when said first ternary converted data signal has either said first value or said second value, said second ternary converted data signal having either said first value or said second value when said first ternary converted data signal has said third value; and a ternary phase shift keying modulator for modulating, in synchronism with a clock signal, the phase of said carrier signal by said first and said second ternary converted data signals to produce, as said phase-shift-keying modulated wave, first and second ternary phase shift keying modulated signals, respectively, said first ternary phase shift keying modulated signal on the first phase plane having one of first through third angles of the carrier signal that are predetermined in response to said first through said third values of said first ternary converted data signal, respectively, said second ternary phase shift keying modulated signal on the second phase plane having one of fourth through sixth angles of the carrier signal that are predetermined in response to said first through said third values of said second ternary converted data signal, respectively.