A new mathematical apparatus is proposed for monitoring the adequacy of the choice of signal sampling interval from the point of view of taking into account the main high-frequency components and identifying the possibilities of increasing it. It is based on the construction of special aliasing grams based on measured signal samples. Aliasing grams are graphs of standard deviations of the amplitude spectra of a conventionally reference discrete signal, specified with the highest sampling frequency, and auxiliary discrete signals obtained over the same observation interval, but with lower sampling frequencies. By analyzing such graphs, it is easy to identify sampling frequencies that lead to the appearance of the aliasing effect in the case of sampling, and, consequently, to distortion of the signal spectrum. To speed up and simplify the construction of aliasinggrams, it is proposed to use as auxiliary signals obtained from the reference one by thinning. It has been shown that this device is also effective in the case of the spectrum spreading effect. It can be used in self-learning measuring systems.
Keywords: sampling interval, aliasing, amplitude spectrum, aliasing-gram, sample decimation, spectrum spreading