Sampling of Physically Feasible Signal Spectrum

Signal spectrum can be sampled only under the condition that the signal contains a periodic component. Spectrum sampling includes its expansion in series on equidistant orthogonal functions with some weight. These functions have minimum-phase real and imaginary parts having spectrum moduli equal to Fourier transformation moduli of real and imaginary parts of the spectrum being sampled, respectively. Signal spectrum orthogonalization procedure is given below