The main purpose of performing normalization is to standardize sensitivity for an ECA probe. To do this, the operator scans a sample containing a calibration defect in order to generate the same eddy current signal for each channel. For most applications, a defect such as a long transversal notch will suffice (see illustration to the right). Using the calibration defect, the operator adjusts the gain and rotation of each channel so that the same phase and amplitude response is obtained for all channels.