Patent ID: RE43338

Claim:
A method for modulation, comprising the steps of: regularly subjecting an input digital signal to first modulation and second modulation to convert the input digital signal into a pair of a baseband I signal and a baseband Q signal, the first modulation and the second modulation being different from each other and regularly applied ; and outputting the pair of the baseband I signal and the baseband Q signal; wherein the first modulation is at least 8-signal-point modulation, and the second modulation is phase shift keying; wherein the phase shift keying provides periodically-spaced symbols which represent corresponding portions of the input digital signal in terms of differences between phases of the periodically-spaced symbols; and wherein the at least 8-signal-point modulation assigns logic states of the input digital signal to respective signal points for a first symbol in response to a signal point used by a second symbol of the phase shift keying which precedes the first symbol.