Ultrasonic fault detection by processing of signals from fixed transceiver system

An ultrasonic nonscanning method of flaw detection employing coded excitation with a new approach to the signal processing is investigated. An ultrasonic M-sequence signal is transmitted through the medium under investigation and reflections from faults are received by plural receivers at different positions. The cross correlation function between the original M-sequence and the reflected signal is used to detect any reflection, and based on it, the fault is located. To suppress the self-noise of the system, a new approach to the design of an inverse filter is described. The concept of coincident peak enhancement can be very useful in some cases of ultrasonic NDT to remove false peaks from the correlator´s output