Oliinyk Y. Methods of ultrasonic thickness measurement using phase-manipulated signals and their implementation

The dissertation is devoted to the solution of the scientific and technical problem of ultrasonic pulse-echo thickness measurement improvement due to the use of phase-manipulated test signals and their processing by methods of phase measurement. The amplitude-phase method of ultrasonic thickness measurement is proposed and investigated. It based on the use of modified by phase-manipulated initial signal and subsequent analysis of the phase characteristics of the testing and echo signals. The method involves the use of short-term (two to four periods of signal-carrier) phase- manipulation signals to reduce the error of allocation of the ultrasonic thickness measurement signals. The considered implementation of the method is based on the use of the discrete Hilbert transformation of ultrasonic signals. Improvement of the amplitude-phase method of ultrasonic thickness measurement with the use of phase-manipulated signals is proposed by clarifying the received time delay by measuring and taking into account phase shifts of the carrier signal. The method ultrasonic pulse-echo thickness measurement is investigated and improved. It based on the determination of time intervals between bottom impulses in the position of time r-statistics, which is determined by the phase characteristic of the carrier signal. Based on the results of the simulation, algorithmic and software software was implemented that implements the proposed ultrasonic techniques. The laboratory sample of the precision system of the ultrasonic pulse-echo thickness measurement that implements the developed methods is developed.