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312 views
18:53 Jul-09-2009

Abbas Bombaywala

NDT Inspector
Free Lance,
India,
Joined Jul 2007
91
Lateral Wave

The Code says that your Lateral Wave should be 40% of your full screen height, and as TOFD is a RF wave so when its 20 % above and below ur center line its actually on 40% full screen height. Can i Scan with the 20 % FSH, cause all the clients they say that your Lateral Wave should be 40% FSH which is in actual is 80%. I would like to clear this doubt in my mind cause when i am scanning with high frequency probe and if i am adjusting the gain so that my lateral wave goes to 40% then i am having to much noise from the grain structure because of the high sensitivity. please provide me ur thoughts on this.


Regards

 
05:03 Jul-15-2009
Bill Blanshan
Re: Lateral Wave In Reply to Abbas Bombaywala at 18:53 Jul-09-2009 (Opening).

Your statement is incorrect. A 40% lateral wave in RF mode is the same as in rectified. Remember, when you rectify an RF signal, you take the negitive plotted waveform and add it to the positive potted waveform......so in RF mode what you can do is measure the amplitude of each of your negitive and positive cycles and note the side which is higher in amplitude, then adjust your gain to where this signal is reading 40%FSH. Example: Say your positive cycle of your lateral wave is reading 35%FSH and your negitive cycle is at -25%FSH. All you would need to do is adjust your gain to where your higher amplitude cycle (35%FSH) reads 40%FSH. The same goes if the negitive cycle was higher than the positive cycle; pick the one higher and then adjust your gain to where this signal is at +40FSH or -40%FSH, it is all the same. I hope this helps.

Bill

 


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