134610483 DAC Distance Amplitude Curve

DISTANCE AMPLITUDE CORRECTION CORRECTION CURVE(DAC) Initially cut out a transparent plastic with the same size as of the CRT screen and put or stick it on the CRT screen . 1.Position the probe targeting the the side drilled hole(!"# as shown below. $a%imize the echo & then  bring the echo to ')*"(*ull ')*"(*ull creen "eight# by turning turning the d+ control. $ark the peak of the echo on the screen. ,ote your d+ gain &e%. --d+. Reminder /se the formula +P0!2 +P0!2 cos 3 to estimate where where the echo should fall fall on the screen. 1T position

4.5mm3 !" ') *"

!

T

=%. of :$= !:C +lock use for materia l Thk. 4;mm and below

4.+ring the echo further down using the d+ control to 5) *".6ou can do this by subtracting a -db from your pre7ious d+ gain&ie --db8-db- d+.$ark the peak of the echo on the screen.

') *"

5) *"

9.:gain using the d+ control bring down the echo to 4)*".ubtract another -d+ from your last d+ setting.e%-8-;5 setting.e%-8-;5 db. 6ou ha7e now 9 point marks for the first probe position.

4) *"

5.Position the probe as in fig below. !o the same procedure as abo7e. Result will be another 9 point mark for the 4 nd probe position. To estimate the echo location on the screen&+P0 T2cos3 < d 2 cos 3

1st pos.

d 4nd pos.

Page 1 of 4

;.Position the probe in 9 rd position.!o the same procedure as abo7e. Result will be another 9 point mark for the 9 rd probe position. To estimate the echo location on the screen& +P0 T2cos3 < ! 2 cos 3 9rd pos. ') *"

!

5) *" 4) *"

-. To complete the !:C Cur7e >oin all the point mark as below.

') *"

5) *" 4) *"

?.,ow !:C cur7e is ready. Reminder also that the !:C block has a more smooth and shiny surface than a material that you are going to test& so to compensate for this &consider also the Transfer Correction *actor.( do this separately# @hate7er d+ result e%. 5d+&( depends on the roughness of the test material# you are going to get& add this to the d+ gain& e%. --<5? d+. This is now your Primary Reference 0e7el(PR=# or the ensiti7ity gain setting. !uring scanning add another -d+.canning d+ now is A--
?.Pro7ide !:C cur7e for each probe that you are going to use&?D&-D&5;D.

9.4mm diam. hole

Types of !:C +lock  9mm

& /se for T4;mm and abo7e

Page 4 of 4