What is the purpose of modulation analysis in eddy current testing?

The purpose of modulation analysis in eddy current testing primarily revolves around enhancing the ability to localize defects within the material being tested. By using modulation techniques, inspectors can exploit variations in the eddy current response that occur due to changes in material properties or impedance related to flaws. This can improve sensitivity to small defects and allow for more precise identification of their location.

Modulation analysis involves adjusting the amplitude or frequency of the excitation signal which helps in distinguishing the signals from flaws versus the background or noise from the material itself. By doing so, it becomes easier to characterize defects, ascertain their size, and determine their potential impact on the integrity of the material or component being assessed.

In contrast, other options relate to different aspects of eddy current testing but do not align with the specific role of modulation analysis in enhancing defect localization.