Ultrasonic measurement evaluation system - compares logarithmic digital amplitude signals from each ultrasonic detector with two limit values

摘要

The evaluation system for signals derived from ultrasonic measurements consists of a comparator (1) in which the logarithmic digital amplitude signals from each ultrasonic detector are compared with two limit values (GAC, GAD). The signals pass to a subtraction unit (3) fed with reference levels held in a store (2). The amplitude-difference signals are then passed to the comparator. For monitoring the reference amplitude, a second register (6) holds the amplitude values of a test sample, having the same time-slot addresses, in the form of a further reference signal. These reference signals are called up by the subtraction unit which then provides a difference signal from the two references. This signal (USDR) is then compared with the two pre-determined limit values. A programmar (4) controls the complete sequence.