A method for generating a substantially sinusoidal waveform containing encoded digital data having one of a first value and a second value at selected phase angles _n comprises generating the waveform having an amplitude Y defined by a first function at phase angles lying outside of regions having a range beginning at each phase angle _n, said first function being Y=sin ; generating the waveform having an amplitude Y defined by the first function at phase angles lying inside the regions having a range of beginning at each phase angle _n where data of the first value is to be encoded; and generating the waveform having an amplitude Y defined by a second function at phase angles lying inside the regions having a range of associated with each phase angle _n where data of the second value is to be encoded, the second function being different from Y=sin .