ON A CLASS OF ORTHOGONAL SEQUENCES
Brian E. White · 1969
Abstract : The work was motivated by studies proposing the use of binary continuous-phase frequency-shift-keying (FSK) (with a frequency spacing of 1/2T, where T is the signalling interval corresponding to one data bit) for high-power low-frequency communications in military applications. Of interest here are mutually orthogonal N-ary continuous-phase FSK waveforms composed from mutually orthogonal signals equally spaced in frequency by any odd number of half cycles per signalling interval T.