“…A binary periodic orthogonal sequence which takes 1 or −1 is only (1, 1, 1, −1) of period 4. On the other hand, the general solution of real-valued periodic orthogonal sequences take real numbers has already been proposed [4], and the periodic sequence of various periods can be generated. The real-valued periodic orthogonal sequence of period 2 ν with positive integer ν derived from a real-valued Huffman sequence (shift-orthogonal finite-length sequence) [5], [6] of length 2 ν +1 whose aperiodic autocorrelation function has no sidelobes except at left and right shift-ends exists, has fast correlation algorithm [7].…”