Instruments and Systems: Monitoring, Control, and Diagnostics Annotation << Back Spectrum Transformations in the Classical Haar Basis V.V. GURENKO, B.I. BYCHKOV The paper analyzes the classical non-normalized Haar basis as a target system for transforming the spectrum of a discrete signal from harmonic bases. Fourier kernel matrices are analyzed for transforming a deterministic spectrum from the trigonometric basis and the Hartley basis into the Haar basis. The structure of the Fourier kernel matrices in both cases makes it impossible to select groups of nonzero elements. Based on this fact, as well as an insignificant proportion of zero elements in the matrices, it is concluded that it is impossible to reduce the computational complexity of the spectral transformation and that it needs to be moved to the setting up stage of simulation algorithms. The resulting linear operators are intended for the development of new signal simulation algorithms for preparatory calculations on energy characteristics, and can also be generalized to multidimensional signals. Keywords: Haar function, basis, spectrum, spectrum transformation, spectrum transformation operator, Fourier kernel, simulation. DOI: 10.25791/pribor.11.2022.1368 Pp. 01-07.