FLAW DETECTING SIGNAL BALANCING METHOD OF ELECTROMAGNETIC INDUCTION FLAW DETECTION

摘要

PURPOSE:To automatically balance all detecting elements without influenced by a change of energizing frequency, by filtering a phase discriminating signal, and applying it, A/D conversion, and obtaining a balancing quantity automatically. CONSTITUTION:An output of an oscillator 1 is fed to a detecting element 2 through an electronic switch 3, and a flaw detecting signal is converted to a pulse by a phase discriminator 4, and it is sample-held 11 through an LPF10, and is subjected to A/D-conversion 12, and is applied to an adder 13. Subsequently, a value of a storage element 14 is added through a register 15, and an added output is stored in the element 14 as a new balancing quantity. In this way, it is possible to automatically balance all channels without influenced by a change of energizing frequency.