Phase Wrap: What do YOU call it?

[Eddy Current]

Hi all,

you know the situation when the TID on a VLF bounces
between Iron and Silver, because of phase wrapping...

I was wondering what you call this effect?

Please vote in the above poll, and if you have any other
name for this phenomenon, please feel free to post it...

Happy Hunting
Eddy

 

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[Jason in Enid]

None of those, because they all contain the word wrap. Nothing is "wrapping" around. Targets, especially highly corroded ones often give different signals, not just the original.

 

[woof!]

Eddy is correct, the effect is real. I just call it "wraparound" one word. However with certain models I use the phrase "false high tones" since that is what the user experiences.

--Dave J.

 

[Jason in Enid]

Eddy is correct, the effect is real. I just call it "wraparound" one word. However with certain models I use the phrase "false high tones" since that is what the user experiences.

--Dave J.

Of course the EFFECT is real, it's just NOT wrap. Wrap implies a circular spectrum where the bottom is connected to the top. This does not exist in detecting. "false high tone" is the best descriptive and most correct.

 

[woof!]

Jason, you are correct that "wrap" [around] implies a circular spectrum where the bottom is connected to the top. The phase circle diagram is so basic to VLF metal detector engineering that it's the first thing I teach to new engineers, and insist that they learn it until they can draw it and explain it from memory.

--Dave J.

 

[Eddy Current]

cheers for your replies guys
much appreciated...

I'm aware that highly corroded iron targets can cause different signals due to Iron bleed/leach (Halo Effect), but these terms describe what causes the phenomenon, rather than them being a label for the technical bit happening in the discrimination circuit due to these causes.

What I mean is, what is it called when the phase shift happens to exceed -TT or +TT ?

I usually call it iron wrap, Dave calls it wraparound
was wondering what everyone else calls it?

HH Eddy

 

[Carl-NC]

Usually "wrap around", occasionally I use "phase wrapping".

 

[Eddy Current]

cheers Carl-NC much appreciated

HH Eddy

 

[JohninNC]

Well, really...

If we combine a VLF and PI machine and examine the VLF phase shift to a bit more of a finer detail and also examine the PI frequency return to a finer detail then combine the results of both, we will get a bit more depth with fewer 'false' readings. JMHO
John