Latest Minelab Patent - 11th Feb 2016

[Dave J.]

Some say it's impossible to discriminate iron in a PI. They're wrong, it's obvious to those skilled in the art that it can be done and the hard part is doing it well enough to get a marketable product out of the deal. Minelab's GPZ platform makes good iron discrimination a lot more achievable than with conventional PI, and that's where they're headed with it.

Moodz, got anything else that "some say is impossible" that those skilled in the art know in principle how to do?

[moodz]

I cant say that ferrous discrim is one of the claims or not however i cant tell you what else is "impossible" or i could be risking my primary claim .. but its odds even you will figure what it is

[Davor]

Dave, you forgot one step:

0. Voltage supplied to the coil produces change in current. Therefore to the rate of change of the transmit current is directly proportional to the applied voltage.
di/dt~e

1. The magnetic field produced by the transmitter is proportional to the transmit current. h~i, which is in fact useless, as you need dh/dt to get things going, again, dh/dt~di/dt~e

2. The voltage induced in a metal target located in the field is proportional to the rate of change of the field; and therefore to the rate of change of the transmit current. (e~dh/dt~di/dt)

3. The voltage induced in the receiver coil resulting from induction imbalance is proportional to the rate of change of the field. (e~di/dt)

4. Knowing what the voltage on the transmitter coil is, does not tell you the amplitude of the current flowing in the transmitter coil or even its polarity, and therefore does not tell you what the magnetic field is. It however does say it's derivative, which you already demonstrated as the only important factor here.

To the skilled in the art it boils down to the same thing, yet avoiding reverting to calculus - if avoidable - is easier thing to do, leading to more consistent result.

[Davor]

Once you get a current going in a coil you're stuck with a current problem, for it behaves as a current source. You got to remove that current quickly, not a voltage. Moodz uses a current sink as evidence that the problem can be treated efficiently in the current domain. You can even detect the target's decaying magnetic field as a current in a shorted Rx coil.

Of course you do, but unless you employ transimpedance amplifier at a frontend, which must not be a bad idea, your Rx will register induced voltage, reducing frequency dependence in the process.

[ivconic]

Except for occasional effusion of unnecessary arrogance by some people, I do not see anything special educational in this whole debate.
I think that it is precisely the presence of this arrogance prevents that the debate goes in the right direction.
Egocentricity and arrogance otherwise spoil the many topics on this forum.
So that all of this became very boring.
It all boils down to masturbation some of these arogant people who seem to have no other ways of pleasure in life.
Whichever professional achievements that man has; become completely irrelevant and void by the presence of such arrogance.
And such people are good for avoiding and ignoring.
The theme revolves around, nothing new has been said, nothing was found.
People from ML are probably lauhing to death reading this.
So this is all very comical and pathetic.
And those who were arrogant, and who think of themselves are worth more than others; better yourself sit down and learn something more than what you know.
It's one thing to know for real and another to be the turkey struts with colorful feathers, tossing empty words around.
When you can not find the right answers; then along comes this course of behavior and action.

Whether he was joking or not, KT315 gave here pretty sane and honest question and doubt.
In the spirit of this forum, it should be just tried to answer on that.
Several nice people tried to do that.
Some of not so nice people took advantage of the situation to show their arrogance which is also their weak point.
Now we know that from such can not expect any contribution here.
I can not participate in such a story, i'm sick of these kind of people.
And my last advice would be; do not continue to give cause ML people to laugh!
They did a job and now they taking a money for that... while you here are wasting your (and our) time by empty debating.



https://www.youtube.com/watch?v=XKk5KGp6Foo

[Dave J.]

Dave, you forgot one step:

0. Voltage supplied to the coil produces change in current. Therefore to the rate of change of the transmit current is directly proportional to the applied voltage.
di/dt~e

Nope. Voltage supplied to the inductive reactance is what does it. The physical coil has series resistance -- plenty of it-- and some of the voltage gets dropped across that. To make matters worse, in the case of a perfect inductor knowing the voltage at any point in time tells you nothing about the current because the two things are 90 degrees apart. If you want to know what the magnetic field is, you have to know the current. This is ordinary high school physics.

[moodz]

Except for occasional effusion of unnecessary arrogance by some people, I do not see anything special educational in this whole debate.
I think that it is precisely the presence of this arrogance prevents that the debate goes in the right direction.
Egocentricity and arrogance otherwise spoil the many topics on this forum.
So that all of this became very boring.
It all boils down to masturbation some of these arogant people who seem to have no other ways of pleasure in life.
Whichever professional achievements that man has; become completely irrelevant and void by the presence of such arrogance.
And such people are good for avoiding and ignoring.
The theme revolves around, nothing new has been said, nothing was found.
People from ML are probably lauhing to death reading this.
So this is all very comical and pathetic.
And those who were arrogant, and who think of themselves are worth more than others; better yourself sit down and learn something more than what you know.
It's one thing to know for real and another to be the turkey struts with colorful feathers, tossing empty words around.
When you can not find the right answers; then along comes this course of behavior and action.

Whether he was joking or not, KT315 gave here pretty sane and honest question and doubt.
In the spirit of this forum, it should be just tried to answer on that.
Several nice people tried to do that.
Some of not so nice people took advantage of the situation to show their arrogance which is also their weak point.
Now we know that from such can not expect any contribution here.
I can not participate in such a story, i'm sick of these kind of people.
And my last advice would be; do not continue to give cause ML people to laugh!
They did a job and now they taking a money for that... while you here are wasting your (and our) time by empty debating.



https://www.youtube.com/watch?v=XKk5KGp6Foo

...your assessment is a bit harsh ... in reality any tx or rx signal could be composed or decomposed from / to a finite number of unique sinus waves ... albeit that number could be very large ...however the fact remains. So all detector methods can be realised in a theoretical sinus machine. The original question that was asked was like lighting a cigar in the gunpowder house sometimes there will be an explosion and sometimes it will just be a cigar.

[Qiaozhi]

...and theres a real eyepopper coming in application 2015903535 ... it does what some say is impossible. Cant say anymore obviously ...;-)

ANTIRESONANCE DAMPING OF A COIL - AU2015903535

This provisional patent was filed on 31/08/2015

[kt315]

Yes, those are BBS/FBS TX voltage waveforms. Now, what does the TX current look like?

i see Carl you again... what is the pulse in PI. sacramental for ivconic Delta Impulse is FIRST pulse of current resonance impulses on a monocoil. be cause ANY monocoil has self resonance, even the basket coils with very low C factor. our aim is only to pump up the power as much as possible in the coil (for the depth - every beginner here is asking only 'give me mods for the depth' everytime) and
turn out the circuit by a key.

we take FIRST pulse of self coil resonance always while there them is MUCH, for measuring, just cause it has biggest amplitude and more easely for time domain. thats start point and first rule of any PI detector.

question. Fisher Impulse does THAT i tell above? NOT. that was described in the patent of Sir Johnson? NOT.
does Sir Johnston know about voltage resonance nature and USED? NOT. so why Fisher is PI if there is NOT
resonance first peak voltage at all called by me 'delta pulse'?

[Dave J.]

kt315, if you are interested in knowing how these things work, it's been explained repeatedly in this thread.

[Taktyk]

KT 315 so many years on the forum Geotech and you still do not understand the basics.....

T.

[kt315]

KT 315 so many years on the forum Geotech and you still do not understand the basics.....

T.

RTFM ITMD.

[Taktyk]

Carl M.

Plural frequency method and system for identifying metal objects in a background environment using a target model US 5642050 - why he did not see the light of day? I ask because
you worked in white's...

Does anyone have any other materials of this inventor?

Regards
TAKTYK

[Dave J.]

http://www.google.com/patents/US5642050
Shoemaker. I knew the guy, Carl probably never met him. His apparatus was a horribly complicated mess that was almost impossible to get working even on the bench, but he did prove that you could discriminate iron in the multiple frequency domain. Unfortunately the apparatus itself was not the basis of a manufacturable product, so to get an actual product they hired me to design the circuit that became the DFX, which is of the same general sort as the CZ although not in any sense a copy.

The story then takes an even stranger twist. The engineer on the DFX project was Rowan, and he'd absolutely insisted that iron couldn't be discriminated using multiple frequency methods--- despite Shoemaker's patent! I showed him how to do iron discrimination on the DFX platform, but he refused to do it because he'd already told Mr. White it couldn't be done.

The first swinging multifrequency machine I built approx. 1984 used multiple frequency methods to do iron ID, although under weak signal conditions it helped itself to the reactive signal single-frequency style. That particular platform was not sensitive enough or reproducible enough to become a manufacturable product, but it established the principles involved. It was all-analog, too-- no microprocessor. And on our freshwater beach test site with granite-derived sand containing a lot of magnetite, it did just about the same thing in the ground as in the air and you didn't dig any trash you didn't want to dig.

In this industry there's gobs of stuff that's been done and gobs of other stuff which folks have known how to do although they may not have actually done it, that never saw the light of day. The reason for that is that a commercial business has to decide what is most likely to actually produce a return on investment and then to invest in that, and those other possibilities (some of which might even be better investments but management doesn't know that) don't get funded. Business is guesswork.

[Taktyk]

Shoemaker. I know only patent 5900/6000.
I know your detectors Fisher CZ5 it is not simple Dave Thank you for your reply. Your projects are always an inspiration for me.
I was looking for a solution for the multifrequency detector but other than it is now - the emission signal based on the network reactive impedance - as the MXT (control signal TX by integrator). Only it works for the two frequencies 3kHz and 30kHz Program loop is 1mS - the project is based on the platform of Cortex M4.
Below prototype detector.
Regards