Signal processing technique for ultrasonic inspection

Abstract

Disclosed is a correlation receiver for processing an elctrical signal derived from an acoustic signal in a test object, including a signal generator for producing a reference waveform, a multiplier for combining the electrical signal and the reference waveform, an inegrator for integrating the combined signal, and a sample and hold circuit for detecting and holding the output of the integrator. In another embodiment, the signal generator also produces a second reference waveform in quadrature with the first reference waveform, and the receiver further inclues a second multiplier for combining the electrical signal and the second reference waveform, a second integrator for integrating the combined signal, and a means for combining the integrated first and second combined signals to produce an output indicating the structural integrity of the test object.