Abstract: A detector and tracker using a three coil sensor for is disclosed. The detector detects eddy current variations caused by differences in electromagnetic characteristics in two adjacent materials. The eddy current variations are measured and compared to determine the magnitude and direction the detector may be from the center of one of the adjacent materials. The magnitude and direction determination by the detector can be used to drive a process controller to position the sensor.

Abstract: A system for selectably electrically pulsing each of a plurality of ultrasonic transducers in a testing apparatus in rapid sequence to produce a pattern of ultrasonic energy transmitted into and subsequently received from a test piece comprises a plurality of transducer pulsing circuits, each connected to a different associated one of the transducers. Each pulsing circuit includes a silicon control rectifier connected to ground and a capacitor, connected between the rectifier and the associated transducer, that is dischargeable to pulse the associated tranducer. The rectifier is switchable to an "on" condition to rapidly discharge the capacitor to ground. The rectifier maintains the "on" condition until current conducted through it drops below a characteristic holding current and thereafter switches to an "off" condition.

Abstract: A system for non-destructively acquiring and processing information about a test piece includes an array of ultrasonic transducers each adapted to transmit ultrasonic energy into the test piece and to receive ultrasonic energy transmitted back thereto to produce a response signal capable of representing deviation from the expected condition of the test piece. The transducers are mounted on a carriage to be transported relative to the test piece and a transducer control sequentially pulses the transducers while so transported to ultrasonically inspect the test piece and produce a set of response signals representing the inspection. A plurality of transducer monitors, one for each transducer, sequentially monitor each of the response signals and an analogue-to-digital converter converts each monitored response signal to a single set of digital data.