Ground Balance Theory

[robby_h]

The 1/t response from viscous ground has been verified by several different methods as reported in the many various papers on soil magnetism since the 1960's. It is acknowedged that it can be distorted by TX pulse shape, but for a rectangular pulse that remains at a constant level for a given time prior to switchoff, the decay is t^-1 +/- a small percentage, due to the spread of particle sizes in a real world situation. This decay does not depend on the method of signal processing. It can be observed directly on a scope straight off the preamplifier.

Eric.

Yes that's correct, the 1/t response is purely the response to a magnetic step and all contaminates must be removed or avoided or accounted for in order to achieve this, including delays in the electronics, but it is obvious that some here have assumed it's the case regardless of the pulse waveform.

Doug in his mindless attacks on Minelab has tried to prove Candy wrong by insisting the 1/t response is wrong and he quotes AU200247522 in one of his silly attempts, but the inventor mentions a rectangular voltage pulse and says his measurements don't approximate the 1/t response until the pulse length exceeds 1000us. This would make sense because the coil time constant would become short relative to increased pulse length, which would eventually result in the required rectangular current waveform if the pulse was long enough.

The ground response is said to be invariant with time but this is also subject to conditions and it helps to know what these are if a design encounters problems with GB.

Someone said I am a troll but the real trolls are those who are desperately trying to hide the elephant in the room. It seems the current boys club gets upset when someone contradicts their "belief".

It's interesting to note that Eric, Carl and myself (as PeterM) had a good discussion on the now defunct ZGUS forum with John H without the silly interjections from Doug's clowns or guys pretending to have achieved something that is clearly beyond their capabilities. I wonder if the boys club here would have learnt anything from that exercise.

[Paul99]

Now a question to the admin:
If Ufox (now obviously paul99) is allowed to post on Geotech then why should dougAEGP not be allowed to post?

Hey comeon, these (forum-) battles reveal a lot of interesting things and we are progressing towards WBGB...
Aziz

Where do you get that I am this UFox?

[Davor]

Someone said I am a troll but the real trolls are those who are desperately trying to hide the elephant in the room.

Bruce, there are only two elephants in the room. First one is the fact that none of the QED rigs apprehended by Minelab were returned to the owner. Second is the fact that Minelab trolls are infesting all forums that still tolerates that level of communication, and Minelab did not do anything to distance it's name and fame from such bigots. In effect they became one and the same. Minelab = whole lotta trolls on forums. So it is only appropriate to denounce such forumers as trolls they really are.

Apparently Minelab accepts the position where trolls are waving it's flag. That says a lot.

[WM6]

First one is the fact that none of the QED rigs apprehended by Minelab were returned to the owner.

Then, when they tried in vain to get QED GEB explanation through the courts, now obviously still awaiting for a QED user manual.

[Carl-NC]

Aziz, I removed your cross-posts from the AEIOU forum. I've kindly asked that people not cross-post or link to that forum. If Doug wants to ask Robby a question, he can ask on his own forum, and invite Robby for discussion, or a knock-down drag-out if he prefers. Banning Robby, then continuing to ask him questions, is just rude. No, I don't care to un-ban Doug, as his sole purpose is to antagonize people.

...and myself (as PeterM)

I didn't know that. I was just thinking about Mr. Heenan this morning. I don't remember why.

[Carl-NC]

And I'm gonna start deleting a lot more posts that try to pull this thread off-topic. Discussions about Minelab, QED, and trolls should be taken to another thread.

[Paul99]

Someone said I am a troll but the real trolls are those who are desperately trying to hide the elephant in the room. It seems the current boys club gets upset when someone contradicts their "belief".

It's interesting to note that Eric, Carl and myself (as PeterM) had a good discussion on the now defunct ZGUS forum with John H without the silly interjections from Doug's clowns or guys pretending to have achieved something that is clearly beyond their capabilities. I wonder if the boys club here would have learnt anything from that exercise.

Does anyone have screen captures of that exchange that they can produce so we might all gain something from it?

[mickstv]

Does anyone have screen captures of that exchange that they can produce so we might all gain something from it?

Whatever it is, I doubt the content will have any bearing on this thread. Maybe you can start your own thread and request the information.

For everyone

Personally I'm getting quite sick of Threads being butchered with off topic posts and as far as I'm concerned anyone who posts off topic is just another forum troll/spammer.

[Paul99]

Whatever it is, I doubt the content will have any bearing on this thread.

I had an email from one of the participants in that interchange, and it seems the content is very relevant to this thread.

It's interesting to note that Eric, Carl and myself (as PeterM) had a good discussion on the now defunct ZGUS forum with John H

Does anyone have a link to this discussion on the ZGUS forum, or a record of the email digest so we can review the discussion as I understand this discussion was of definite relevance to this thread!

[mikebg]

HOW THE SENSING SYSTEM WORKS
Look what happens when the balls of Newton's cradle have names :-)
What excites the "target"?
What excites the "RX coil"?

[mikebg]

THE ROLE OF THE BAD GROUND
The illustration below is valid for an elastic system.
What will happen when balls "input ground" and "output ground" make phase shift?
What will happen when balls "input ground" and "output ground" are unelastic?

[Ferric Toes]

THE ROLE OF THE BAD GROUND
The illustration below is valid for an elastic system.
What will happen when balls "input ground" and "output ground" make phase shift?
What will happen when balls "input ground" and "output ground" are unelastic?

How about an animated picture like Aziz's IQ meter in post 269?

Eric.

[mikebg]

Sorry Mikebg, I will refrase that.....Meant to say the less capable. Competent i was refering in general terms. Not directed to anyone.

Like i have said before, I cannot get access to Doug's Forum after requesting to join 3 times......so i cannot view most links you have posted.

BTW, most technological advances in most Engineering fields, past and present have come out of Australia. And i am not talking about Metal Detecting technologies.

Cheers Sid

Here is the first post:
The name of the best ground balance method is
DECONVOLUTION
http://www.dspguide.com/ch17/2.htm
" Deconvolution is the process of filtering a signal to compensate for an undesired convolution. The goal of deconvolution is to recreate the signal as it existed before the convolution took place. This usually requires the characteristics of the convolution (i.e., the impulse or frequency response) to be known..."

Measurements in frequency domain showed that OZ dirt has very different properties starting with conductivity as temperature dependent semiconductor and ending with magnetic decay law t^-4 ie 1/(t^4). However the ground properties are not important for signal processing algorithm. More important is the search head to deliver a GND signal. The signal processing should use it as reference to calculate deconvolution of TGT signal. I showed in the Geotech forum the block diagram for algorithm and the suitable loop configuration of search head.

The attached image illustrates that the TGT signal is twice convolution of targets impulse response h5(t) with impulse response functions h4(t) and h6(t) of ground.
CONCLUSION: To obtain pure information for target, the signal processing should make deconvolution of TGT signal.

[Aziz]

How about an animated picture like Aziz's IQ meter in post 269?

Eric.

My IQ went down to -4.24242E+98 and is still decreasing.
Thanks to UFox. It is permanently negative increasing.



Aziz

[mikebg]

How about an animated picture like Aziz's IQ meter in post 269?

Eric.

Eric, three men in this thread think that know the best algorithm for ground balance:
- a software ingeneer (Aziz),
- a professional (you) and
- a hobbyst (me).
My algorithm can not be patented because I showed it in this forum and in Doug's forum. However the fun is that the method is not mine. Search the WEB for "convolution" and "deconvolution", read textbooks and papers and you will see that the method has no alternative - all other methods are simplifications and speific cases of deconvolution..
Aziz started to explain his method in Doug's forum. The method of Aziz is suitable for a specific type soil, but Oz soils are very different in properties.
Remains somebody to show something better than deconvolution. This is impossible.