The paper presents one of the methods of digital processing of diagnostic signals such as cepstral analysis and the possibility of its application in the investigations of sources of wave disturbances. In order to solve the problem, simulation and diagnostic research was performed. The simulation experiment consisted in generating different sample signals (by special software) containing known frequency-related information, which aimed at exploring the information generated and presented in the cepstrum characteristics and its reliability. The diagnostic experiment was carried out on an mechanical device – a Ford Transit minivan. The object was a basis for the determination of the possibilities of practical application of the cepstrum characteristics.