Method for balancing the sensitivity of two channels in a differential detection apparatus

摘要

A method is provided for balancing the sensitivity of two channels comprising intermittently-appearing pulse waves, such as the signals generated by respective sensors in a detecting couple which is used in the so-called differential detection of flaws in materials. The balancing of the levels of the pulse signals is accomplished by the use of, essentially, a pair of sample and hold circuits, one or two variable gain amplifiers and the same number of comparison loops as variable gain amplifiers.