A-scan: a method of data presentation utilizing a horizontal base line that indicates distance, or time, and a vertical deflection from the base line which indicates amplitude.
B-scan (parallel scan): scan that shows the data collected when scanning the transducer pair in the direction of the sound beam transversely across a weld.
C-scan: an ultrasonic data presentation which provides a plan view of the test object, and discontinuities therein.
decibel (dB): twenty times the base ten logarithm of the ratio of two ultrasonic signal amplitudes, dB = 20 log 10 (amplitude ratio).
attenuation: a factor that describes the decrease in ultrasound intensity with distance; normally expressed in decibel per unit length.
Distance Amplitude Response Curve (DAC): a curve showing the relationship between the different distances and the amplitudes of ultrasonic response from targets of equal size in an ultrasonic transmitting medium.
