1.2.14
Discontinuity
Anything within a material that will cause a detectable interruption in an
ultrasonic beam.
1.2.15
Distance-Amplitude Correction Curve
Curve showing the relationship between signal amplitude and equal-sized
reflecting surfaces at various distances from the transducer. Reference
standards are used to obtain such curves.
1.2.16
Dynamic Range
Ratio of maximum to minimum size of reflective areas that can be adequately
distinguished on the cathode ray tube at a constant gain setting.
1.2.17
Effective Depth of Penetration
Maximum depth at which the sensitivity is satisfactory for the quality of
test desired.
1.2.18
Examination
Within the context of this specification, the word "examination" is
equivalent to the word "inspection."
1.2.19
Gain Control
Circuitry designed into the ultrasonic system to vary reflection amplitude.
This control is usually calibrated in decibels. It is also called the
sensitivity control.
1.2.20
Gross
Background displacement of the trace on the cathode ray tube from the
established baseline due to the gain setting, the characteristics of the
test equipment, or the material under examination.
1.2.21
Hertz
One complete set of recurrent values of a periodic quality comprises a
cycle. In other words, any one set of periodic variations starting at one
condition and returning once to the same condition is a cycle. A hertz is
a unit of frequency equal to one cycle per second.
1.2.22
Immersion Techniques
Test methods in which the part to be tested and the search units are
immersed in water or other suitable liquid couplant. A mechanical device
is used to firmly hold and direct the wave angle of the search unit. The
search unit does not contact the item being inspected.
1.2.23
Indication
Visual presentation on the cathode ray screen resulting from a sound beam
reflection from a boundary surface or discontinuity.
SECTION 05092A
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