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Minelab does not have patent on multifrequency? Or apex has different approach? I was thinking that xp can do multifreq but is limited by law. I don’t know exactly how this patent rules work.
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These are the key patentsOriginally posted by ionut_mtb View Post
Poole UK2,004,069 1970's
David Johnson US4,868,504 1980's
Bruce Candy US4,942,360 1990's
Carl Moreland US2018/0372904 A1 2018
XP does not use simultaneous frequencies. You can switch between single frequencies.
The key patents have all expired. So it is wide open for all manufactures. Carl's patent is an improved method of doing multi-frequency, but not on the broad use of multi-frequency.Comment
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thanks, i will take a look,Originally posted by Altra View Post
sorry, i use the wrong worlds to explain, i know how deus works, i mean to say why xp does not come to the market with multifrequency? It is more than 10years from the first release of deus.Comment
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I'm sure Xp and Nokta are working on multi-frequency detectors. With the added complexities of multi-frequency, water proofing and the trend in low pricing. It takes a few years to develop a new detector.Originally posted by ionut_mtb View PostComment
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Carl Moreland US2018/0372904 A1 2018 This number is correct?Comment
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A patent cover a particular method of doing something, and expires after 20 years. There are several methods for doing MF, and the patents that cover the basic methods have expired. It remains to be seen how Garrett implemented their MF but I would guess it is similar to the White's DFX which, ironically, was never patented. XP has been working on MF for some time now (according to rumor) but I don't know what the technical glitches have been. Possibly trying to get it to work within the confines of their wireless system?Comment
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It's an application that I have not an issued patent numberOriginally posted by Taktyk View Post
http://appft.uspto.gov/netacgi/nph-P...al+detector%22Comment
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True, but their wireless system works on direct sampling and everything-in-DSP. That's hard to do with MF, although Minelab did it with the Equinox. But I suspect Minelab has a lot of engineering horsepower. An easier approach is to use analog demods, but that won't fit in a wireless coil.Originally posted by Taktyk View Postwirelessly, there is only audio and control in XP
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Exactly. 3F are band filters for frequency separation + 6 ground filters. I don't know how they do it.Originally posted by Carl-NC View Post
I'm thinking of another solution. MD 1F and 3 different ground filters working simultaneously: 5Hz, 10Hz, 15H. And the CNN neural network for classification. That's what I'm doing now.
TAKTYKComment
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Garrett Apex
Hi there,
I am a French user of metal detectors and I agree with Guru's post above,a digital machines produced nowadays is not better than an analogic produced in the 80's.About the Garrett Apex,I disagree with frequencies of that model.Is there a valuable difference in depth and ground exclude between a 5/10,10/15 and 15/20 KHZ? In my opinion,a 5/15/30 KHZ simultaneously or not is the best choice...
Maybe field tests made by owners will tell us the truth!Comment
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Hi,
This is the current flow in APEX, in MF mode:
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For single F= 5, 10, 15, 20kHz amplitude is optimized (1.3-1.0App):
MS mode:
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Analysing the MS mode, it looks like the lowest freq component is 5.5 kHz ( 3 cycles in 545 microsecs ) , and there are definitely 4 cycles of a higher freq for every single cycle of the fundamental, so 4 x 5.5 = 22 kHz.
That's all, I reckon, the only other 'strong' signal is just the 3rd harmonic of the 5.5 kHz, which isn't going to be used, and nothing above 22k is relevant.
The MF mode looks basically the same, but with a stronger level of 22 kHz.
So is MS mode a 5.5k detector with 22k used to suppress ground signal, and MF a 22k detector, with the 5.5k used for ground suppression ?Comment
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It's hard to say... There is a direct sampling.Comment
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