The Discriminating (to iron) Pulse Induction. - Fantasy? .....Facts.!

[metalpopper]

Hello, to readers of the Technology forum.

This 'separate post' is offered to readers who may have been confused by the controversial differences of opinions that ensued from Ringzapper's initial post and my (metalpopper).'s reply. That thread subsequently attracted a contradictory point of view, principally from Dave J.... and further supplemented with his supporter’s retaliatory posts, in response to my robust rebuttal of his mystifying lack of understanding of what I had written; especially as Dave is noted for his experience in the art.

The Discriminating (to iron) Pulse Induction. - Fantasy? (Pages: 1 2)
by Ringzapper
1,632 18 05/07/2015 11:47PM
Last Post by Dave J.


In this post, I simply, paste relevant copies of articles from MINELAB’s KNOWLEDGE BASE.

URL:- http://www.minelab.com/emea/consumer/knowledge-base/terminology.

If you explore the KNOWLEDGE BASE, I believe that you will find conclusive evidence as to what
VLF and PI are intended to infer when using those abbreviation in metal detecting discussions.

Note the endorsements regarding PI and VLF which are dispersed in the relevant sections; especially those accredited to BRUCE CANDY.....A qualified physicist, who, by applying his academic knowledge of mathematics and electromagnetics, to the physics involved in metal detecting in highly ferro-mineralised soils, transformed primitive pulse technology into a sophisticated science that can operate over environments where VLF technology struggles to compete.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^​

[size=x-large]With acknowledgement of MINELAB'S proprietorial rights[/size]

PULSE INDUCTION (PI)
Pulse Induction (PI) is a type of metal detecting technology. Pulse induction operates by sending short pulses of voltage to the metal detectors coil. These short pulses cause a magnetic field to be generated which quickly dissipates at the end of each pulse. Any metal targets that induce the magnetic field remain magnetised for a short time after the end of a pulse. The target’s decaying magnetism is then detected by the detector’s coil. (Also see “Multi period sensing (MPS)” & “Dual Voltage Technology (DVT)”)

MULTI PERIOD SENSING (MPS)
MPS (Multi Period Sensing) is Minelab’s advanced Pulse Induction (PI) technology that transmits pulses of different time periods. MPS also samples the receive signal at multiple time periods allowing target signals and ground signals to be separated. This effectively removes the ground signal from even the most highly mineralised ground while still being sensitive to both small and deep gold. This achieves superior depth in extremely mineralised ground.



DUAL VOLTAGE TECHNOLOGY (DVT)
DVT (Dual Voltage Technology) is Minelab’s advanced Pulse Induction technology that uses pulses with two voltage levels to further enhance MPS. The two voltage levels work in combination with the different time period pulses transmitted by MPS to increase the amount of power transmitted into the ground. DVT also allows more of the ground signal to be removed, further increasing detection depth and sensitivity. This achieves ultimate depth in extremely mineralised ground.



1. Minelab Technologies | Minelab Knowledge Base
... VFLEX technology ... signal processing to enhance conventional single frequency (VLF) metal detector technology ... EX transforms conventional single frequency metal detection technology by including two micro-controllers (miniature computers), on ...
consumer/knowledge-base/minelab-technologies
2. Terminology | Minelab Knowledge Base
... Double-D coil (DD) Dual Voltage Technology ... or VFLEX VLF ... Continuous wave is a type of metal detecting technology ... Dual Voltage Technology (DVT) DVT (Dual Voltage Technology) i ...
consumer/knowledge-base/terminology
VLF (VERY LOW FREQUENCY)
VLF is a type of metal detecting technology. VLF metal detectors create an electromagnetic field that is applied to the ground in a continuous sine wave.

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Thanks for reading.....matt​

 

[Dave J.]

Matt, we already figured out what you are in the last thread. Your quest to make double-sure that we know what you are has succeeded, your new thread reinforces it. But you left out the stamping-your-feet emoticon.

And since you're interested in (if badly confused by) metal detector technology, I suggest that you take another trip to Australia. And while there, beg humbly with about a million dollars in your hand for Bruce Candy to educate you. After all, he, too has designed and built stuff that works.

 

[Carl-NC]

Matt, I'm guessing your real name is John Heenan. If it's not, then I know your brother.

If it means so much to you to believe that BBS/FBS and V3 are all PI machines, then I think that's exactly what you should believe. I ran the engineering dept at White's during the tail end of the V3 development, so I can say with certainty you don't know squat about how it works. And if you ask Bruce Candy whether BBS/FBS is really pulse induction... well, like Dave said, an education is there if you want it.

 

[Dave J.]

[copied from Metal Detecting Forum,,,,,]

No..you are wrong...Ace 250 is a Beat Frequency Oscilator detector....the Teknetics is a VLF....

Striderida sounds like a reincarnation of Metalpopper.

 

[mudpuppy]

Poindexter Fight!

Grab your oscilloscopes and drop your Simpson 101 and get down here fellas! Pocket protectors and slide rules are a flying!

The rest of you, keep digging tabs!
Mud

 

[Dave J.]

Hey, Mud, I resemble that remark! Still use a slide rule now and then, and use analog multimeters too. My "laptop computer" is a copy of the stone age ARRL reactance chart on a clipboard, it's not as as accurate as PSPICE but it's a helluvalot faster. Half my electronic engineering is done with that reactance chart.

The worst part around here is oscilloscopes. All the young guys (i.e. less than retirement age) use digital 'scopes. They struggle and struggle to get the damn things to actually show what's going on in the circuit, what they actually get is some combination of no or false triggering and/or DSP aliasing artifacts, and no ability to see weak signals. They try to show me something happening in the circuit and I cringe while they get stuff to show up on the display but it's not telling them what's happening in the circuit and they don't even know that what they're seeing is not what's going on in the circuit. I beg them to spend $400 of the company's money to get a 2-channel analog scope (technology basically unchanged for 40 years) so they can actually see what's going on in the circuit, but it's big and clunky and they decide they don't have room on their workbench for it.

There are times when a good grid-dip meter would really come in handy, too, but when's the last time you saw a grid dip meter at Radio Shack? ......... On an electronics forum I was recently lamenting that when I was a kid I could (and did) buy a good all-band portable radio receiver, and nowadays nobody makes good radios any more at any price. Turned out I wasn't the only fogie who's noticed the same discrepancy. For every technology gained, another one is lost.

--Dave J.

 

[Carl-NC]

I got one foot in FogeyLand and one foot in FutureLand... I use both an analog scope and a digital scope. At least I do schematics in CAD, rather than 3-foot sheets of graph paper.

 

[metalpopper]

Carl, it's encouraging to read that you at least are endeavouring to move into the 21 century of electronics.

Well done; don't let old age be an excuse for loosing your mental dexterity.

If you can pass on your expertise to the younger generation of DETECTING enthusiasts, then I'm sure you will stay 'young at heart, and young in the head'.

Slide rules etc., have had their day; Fabulous Texas Instruments and Casio calculators etc have made them redundant (until their batteries go flat !).....Digital is in.

My dip-meter, 'scope etc., are all still functioning, and called upon when circumstances call for their need; mostly for my Ham radio interests.

Maturing trees in my garden, have somewhat restrained active global communications, but local LF can still make the trip.

I have a few country-wide farmers who are also radio hams, and it's very handy to be able to contact them for permission to visit and detect.

[size=large]Regarding present discussions on what's implied by PI.[/size]

For me, it designates the type of transmission used to STIMULATE the TARGET.

NOT the subsequent METHOD USED TO ANALYSE the consequential/resultant reaction from the target.

Typically, MINELAB etc., use TIME DOMAIN analysis methodologies in their RECEIVER section; whereas WHITES, in the V3 series employ the alternative approach,

which is FREQUENCY DOMAIN analysis.......BOTH manufacturers, use PULSE transmission, ( i.e. Whites...for the Best Data mode).

I hope that you at least can understand the point I originally was trying to make, to the initiator of this thread.

I repeat my assertions; That mid 20 century PI detectors ( Using old 'All metal' receiving technology) have now been superseded by Pulse Induction

using more sophisticated receiver technologies, which enable discrimination.

Best regards....Matt.

 

[trojdor]

I repeat my assertions; That mid 20 century PI detectors ( Using old 'All metal' receiving technology) have now been superseded by Pulse Induction

using more sophisticated receiver technologies, which enable discrimination.

Best regards....Matt.

Matt,

I believe even a cursory examination of either Minelab or White's current catalog show this statement to be inaccurate.
(Both obviously still sell models based on that 'old all metal tech' from the 20th century.)

Discriminating multifreq vlfs (like the CTX) aren't even Minelab's flagship models.

As far as getting Carl to understand your original point...I think what you perhaps missed, is that everyone clearly and concisely understood your point...we just don't agree with it.

hh,
mike

 

[trojdor]

Matt,
I think it may boil down to an attempt to arbitrarily redefine how some already arbitrary terms are generally/historically accepted.

We've seen this throughout the history of the metal detector.

The original term 'T/R' is used to designate an early transmit/receive unit that doesn't ground balance.
It's already inaccurate, in that the correct term is 'induction balance'...but we'll gloss over that, and simply state that because the majority of us accept that T/R means an older non-GB detector, we all understand it.

The later term 'VLF', generally used to distinguish a ground balancing unit, is by it's own wording totally arbitrary. 'Very Low Frequency'...totally nebulous term...has nothing to do with GB...but we all accept what it means.
(Note that the VLF still utilizes the same type of inductance balance to get a signal as the TR...only the processing is different...but that term was already used for the IB/TR, so we needed something else.)

Now you would like to take the term 'PI' and redefine it's generally accepted usage. You might even be correct in that your terminology is grammatically more accurate...but it doesn't matter.
Like the terms T/R and VLF, the generally accepted definition of PI has been in use for some time, and you can't undo history. It's already in use as a generally accepted term throughout the industry.

It's kind of like the joke; "They had to call it PMS because Mad Cow Disease was already taken."


mike

 

[Carl-NC]

Matt, I agree with Mike, we understand what you're trying to say, but you're just plain wrong. It ain't my job to try to convince you of that, I have better things to do. Maybe Bruce will back you.

 

[Dave J.]

Matt, I agree with Mike, we understand what you're trying to say, but you're just plain wrong. It ain't my job to try to convince you of that, I have better things to do. Maybe Bruce will back you.

Offering Bruce a million dollars will improve the odds of that happening. I don't know his price, though-- if you want guaranteed results, be prepared to offer more.

 

[Dave J.]

Matt, I agree with Mike, we understand what you're trying to say, but you're just plain wrong. It ain't my job to try to convince you of that, I have better things to do. Maybe Bruce will back you.

Offering Bruce a million dollars will improve the odds of that happening. I don't know his price, though-- if you want guaranteed results, be prepared to offer more.

What the hell am I thinking? Bruce is used to high livin', I'm not. Offer me $500K cash on the barrelhead and let's talk!

 

[Frank-S]

I dis-agree VLF and pulse detectors tansmite and receave different, the coils are different the only
thing that they have in common depending on how the circuits are connected, they both when a target
is detected non-ferrous goes negative for a second then goes positive, if you are smart enough a simple
pluss and minus meter with O center, will tell you if its ferrous or non ferrous.if the meter is connect to
right circuit.
Frank-s

 

[metalpopper]

I repeat my assertions; That mid 20 century PI detectors ( Using old 'All metal' receiving technology) have now been superseded by Pulse Induction

using more sophisticated receiver technologies, which enable discrimination.

Best regards....Matt.

Matt,

I believe even a cursory examination of either Minelab or White's current catalog show this statement to be inaccurate.
(Both obviously still sell models based on that 'old all metal tech' from the 20th century.)

Discriminating multifreq vlfs (like the CTX) aren't even Minelab's flagship models.

As far as getting Carl to understand your original point...I think what you perhaps missed, is that everyone clearly and concisely understood your point...we just don't agree with it.

hh,
mike

****************************************************************​

"Hello Mike", and thanks for your opinion on the subject matter.

Before I begin, I wish you and all forum readers and contributors, " A successful 2016 in the hobby".

Now; I will try and address each facet of your reply, to hopefully understand from what viewpoint you make your personal assertions.

QUOTE:- [size=large]I believe even a cursory examination of either Minelab or White's current catalog show this statement to be inaccurate.[/size]

""""""""""""""""""
Mike, I'm not sure if I'm acquainted with the 'current' catalogue you mention...so to avoid ambiguities of reference....

(1) Can you specifically identify each Minelab unit you include in your generalization, and then tell me and other readers,

(A) The Transmission class used.....( you speak of ' multi-frequency, vlf's ...) No mention of Pulse Induction...

So how do Minelab generate the relevant drive for each, Mike ?......and your definition of each voltage drive waveform.

Any simple / rough diagram you can provide, of the voltage driving-waveform to the current amplifier, energising the search-coil, will demonstrate your logic/understanding

of what is involved.....(Hint; 'copy Minelab's own published diagrams; or Patents.)

Once you've done that, then I may be able to better appreciate why you interpret Minelab's methodology differently than I do.


(B) Mike, (or Dave, or Carl....as you both are ex design engineers for Whites)...can you simply explain to the readers, how Whites

for example, achieved 'Frequency domain' analysis of their 'BEST DATA' multi-frequency, Pulse-train transmission

(I am aware that White's 'Multi Frequencies' modes, and 'Single Frequency' modes, do utilise FREQUENCY DOMAIN methodology for their RECEIVER section.)

If you will share that knowledge with the readers, then we will all be better informed, and maybe more able to appreciate the pros and cons of Frequency Domain versus

Time Domain receiver processing.

*************************

Thanks again Mike, for your input......Matt

 

[Dave J.]

MP, if ya wanna know how the White's multifreakers work, just give Kenny White a call and ask him. If ya wanna know how Minelabs work, just call Mr. Codan and ask him. And if ya wanna write a book on how metal detectors really work...... well, before embarking on that quest, first ya might wanna see how many people post here saying they're looking forward to reading it.

 

[metalpopper]

Good evening Dave..........Glad to see you are alive and kicking, despite what mother-nature is throwing down.

There's been enough rain to float an ark; so the outcome for metal detectorists, is potentially intriguing.

I have a test-bed in my garden, and known targets that have been 'stable' for over 45 years, are now taking on different characteristics.

I suspect the water has penetrated sufficiently such, that dormant, deep, dry, ferrous items local to my 'non-ferrous' .ones, are now 'oxygenated.

It will be interesting to hear from others, whose own set-up shows any such changes.

............................

So you think I should write a book ?..!!!!!!!

Would you give me permission to use your forum contributions to illustrate some of the technicalities we've endeavoured to discuss on the Technology forum ?

Knowledge is initially born as a statement of someone's ideas. Whether they are accepted by the majority, is dependant on two things; the originator's communication skills, and the ability of the recipients to analyse what's offered.

Offering an opinion, right or wrong, is in itself not the most important aspect of such; but rather the stimulus it provokes by attracting constructive debate on WHY each participant thinks differently.

So in that spirit Dave, can you add your technical thoughts as well as your entertaining bluster.

I'm sure, all input will be eagerly followed, especially when donated by a man of the trade.

Matt.

 

[Dave J.]

I think you should write a book.

 

[Hastings]

Does anybody know about any new developments in this area?

 

[kt315]

Dave Jonson is active in geotech and you can ask him directly http://www.geotech1.com/forums/member.php?6331-Dave-J
Biography:chief engineer FTP-Fisher..... Please don't PM me asking for information about metal detectors, that's what the forum is for. Beeping on metal is my day job, and anything beyond that is entertainment.Location:El Paso TX, Citizen of the Universe.Interests:Surviving Lou Gehrig's Disease & sharing howOccupation:Feeding hungry people. Worst sin known to man.