“…In quantum mechanics and quantum computer science, an important role is played by unitary operators in form of Hadamard matrices with complete orthogonal systems of Walsh functions in them. Hadamard operators are also widely used for spectral representations of signal vectors in the technique of noise-immune communication [Seberry, Wysocki, Wysocki, 2005], the sequency analysis of Harmuth [Harmuth, 1977[Harmuth, , 1989, the digital logical holography [Derzhypolskyy, Melenevskyy, Gnatovskyy, 2007;Morita, Sakurai, 1973;Soroko, 1974] and algorithms of quantum informatics [Nielsen, Chuang, 2010]. But the Hadamard matrices with their complete systems of orthogonal functions are not the only unitary matrices with complete systems of orthogonal functions in them.…”