Recording The Jisdac Curve - GE Ultrasonic USM Go Operator's Manual

3.16.1 Recording the JISDAC Curve

JISDAC Curve points are typically taken from a standard with equally-sized reflectors (holes) located at various material depths. The
primary echo from each of these points, for a total of up to 15 echoes, are recorded. When JISDAC is active, the instrument displays a line
that represents echo peaks for constant reflectors at varying material depth. This line is drawn as either a curved (linear in gain) line based
on a series of collected JISDAC points or a series of straight line segments that join these JISDAC points. Only one JISDAC curve can be
stored at a time. To program the JISDAC Curve:
Access the JISDAC menu, and select the RECORD submenu .
1.
2. Couple the probe to the first reference point and adjust Gate A so that it is broken by the primary echo. If necessary, use the Gain Toggle
to adjust the gain so that the echo crosses Gate A and the highest peak in Gate A is at approximately 80% of full-screen height. The
highest peak must not be higher than 100% full-screen height.
Note: The AUTO 80 function automatically adjusts the gain to set the Gate A triggering echo to 80% of full screen height. If desired, select
the AUTO 80 function in the RECORD submenu.
While the Gate is lined up over the first reference echo, activate the RECORD function. When the value of the RECORD function
3.
changes from 0 to 1, you have recorded the first JISDAC Curve point. Note that the first JISDAC point is treated as the reference echo.
The amplitude value at which this point is recorded becomes the "reference amplitude" value.
USM Go Operator's Manual
Chapter 3. Making Measurements
107