YUSHI YUT-2620 Manual page 47

YUSHI INSTRUMENTS
Appendix II
Terminology
This appendix lists the special terms used in ultrasonic nondestructive testing. Knowing the
accurate definition of them will help users have a better understanding of this operator's manual.
Flaw: Wrong sizes, shapes, orientations, positions or property which may damage the workpieces or the
incontinuity which fails to meet the acceptance criteria.
Horizontal Linearity: A measure of the proportionality of the positive relationship between the signals
displayed on the space or distance shaft on the screen of the ultrasonic defectometer and the signals
received by the receiver. The received signals can be obtained through the time generator or through the
multiple echoes of the panel whose thickness is already known.)
Vertical Linearity: A measure of the proportionality of the positive relationship between the screen
time of the ultrasonic defectometer or the signals shown on the distance shaft and the signal amplitude
input into the receiver.
Dynamic Range: The ratio between the maximum and minimum reflection area which can be identified
on the screen of ultrasonic defectometer.
Pulse Repetition Frequency: the pulse frequencies produced per second when the impulsator drives the
probe wafer in order to generate ultrasonic waves.
Inspection frequency/Test frequency: the frequency used when ultrasonic defectometer detecting
flaws. The average frequency is 0.4 MHz ~15MHz.
Sensitivity: A measure of the minimum ultrasonic signal which can produce identifiable instructions on
the screen of ultrasonic defectometer.
Surplus sensitivity: the difference value between the standard flaw detection sensitivity and the
maximum detection sensitivity represented by certain power level in the system of ultrasonic flaw
defection.
Resolving power: The power for the ultrasonic flaw detecting system to differentiate the closest
neighboring flaws of certain sizes in the direction of horizon, length and depth
Suppression: the means to suppress or reduce the signals of low amplitude (the noises of electricity or
materials) to amplify the higher signals in the ultrasonic defectometer.
Gating: an electronic method to monitor the flaw detecting signals or to select a time range for further
processing
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