Distance amplitude correction (DAC) provides a means of establishing a graphic ‘reference level sensitivity’ as a function of sweep distance on the A-scan display. The use of DAC allows signals reflected from similar discontinuities to be evaluated where signal attenuation as a function of depth has been correlated.

A Distance Amplitude Correction (DAC) is a method of compensating for the fact that the pulse-echo response of a reflector will decrease as the distance of the reflector from the ultrasonic probe increases.

A DAC curve graphically compensates for material attenuation, nearfield effects, and beam spreading. In a DAC setup, the echo amplitude from reflectors of the same size as those used for calibration will match the curve height no matter what their depth or distance.

2023年2月11日 · Distance Amplitude Correction (DAC) Curve Calibration: The distance amplitude correction (DAC) curve is a graph that shows the relationship between the amplitude of an ultrasonic echo and the distance it has traveled through the material being tested.

The curve produced is called the Distance Amplitude Curve, or DAC for short. When a discontinuity echo appears, an immediate assessment can be made whether or not the discontinuity echo exceeds the DAC.

Plot the DAC Curve: Join the three points smoothly to draw the DAC curve, which represents the flaw sizes. This process is for normal straight beam ultrasonic testing using an FBH reference block. For angle beam testing, follow the same procedure …

The characteristics of an ultrasonic probe vary according to the size of the piezo-electric transducer and its frequency. It is therefore essential that each probe to be used to examine a welded component is individually calibrated and a DAC …