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CTX 3030 Signal Processing...
- Thread starter HumblePie
- Start date
earthmansurfer
Active member
Jim, This question has been avoided by Minelab as they probably don't want to give out their secrets.
That said, Carl from White's (lead engineer?) answered me this question regarding BBS anyway on another forum a while ago:
This would be similar to the two used by the Fisher CZ detectors (except they use 5kHz and 15kHz I think). The real magic I hear is in how the E-Trac does it's ground balancing which is more like ground removal - thing of beauty imo.
Albert
That said, Carl from White's (lead engineer?) answered me this question regarding BBS anyway on another forum a while ago:
Carl said:
This would be similar to the two used by the Fisher CZ detectors (except they use 5kHz and 15kHz I think). The real magic I hear is in how the E-Trac does it's ground balancing which is more like ground removal - thing of beauty imo.
Albert
Chris(SoCenWI)
Well-known member
Long ago I believe Charles(Upstate NY) posted oscilloscope shots of the FBS transmit. Also two different square waves. The 17 or 28 or whatever number of receive frequencies are generated from these two frequencies. Noise cancel shifts the frequency of one of the waves very slightly.
And if I remember correctly one of the patents or white papers published by Minelab discussed ignoring receive frequencies that fell on or close to 50/60 Hertz powerline harmonics. Seems that there where between 13 and 22 different frequency channels monitored depending on which of the noise cancel channels was currently being used. Don't remember the exact numbers. Long story short the machines probably never monitor 28 frequencies at any given time, and the exact number is dependent on the noise channel, AND that as a user it probably doesn't make any difference to us; the fact that the machines are looking at several frequencies across a fairly wide spectrum makes the magic happen. Choosing a lower channel for heightened sensitivity to certain objects is basically BS.
Chris
And if I remember correctly one of the patents or white papers published by Minelab discussed ignoring receive frequencies that fell on or close to 50/60 Hertz powerline harmonics. Seems that there where between 13 and 22 different frequency channels monitored depending on which of the noise cancel channels was currently being used. Don't remember the exact numbers. Long story short the machines probably never monitor 28 frequencies at any given time, and the exact number is dependent on the noise channel, AND that as a user it probably doesn't make any difference to us; the fact that the machines are looking at several frequencies across a fairly wide spectrum makes the magic happen. Choosing a lower channel for heightened sensitivity to certain objects is basically BS.
Chris
earthmansurfer
Active member
Chris. Nice to hear a bit more onthe subject. To add to what you said, is it even remotely possible for the chips in the FBS or BBS machines for that matter, to monitor/process 28 frequencies? I think not even close. the processors available now though, that is another story.
I'dreally like to know how Minelab does their GB, which seems better than any other machine. Critter touched on this in another thread.
Albert
I'dreally like to know how Minelab does their GB, which seems better than any other machine. Critter touched on this in another thread.
Albert
digital144
New member
First of all comparing the 3030 to any other machine out there is simply not happening ... whether you love the machine or hate the machine there is no other quite like it ... The CTX3030 transmits and receives 28 freq simultaneously ... It processes all of them at the same time and produces a dramatic and accurate Composite . This is why the coil is not interchangeable with any other ML machine ... The smart coil assists with the processing . Its closest relative is the ETRAC which processes 16 . ... The CTX processor and transmitting computer is one of a kind and Not molded from the existing processors that are out there
See the discussion on geotech1.com, CTX noise cancel thread. The signal is a repetitive pulse train. The NC setting affects the nature of this such that frequency/ies of interest can shifted out away from EMI so it has less negative effect. It apparently does affect detectability of small targets upon how it is set - but this was not the design intention. It really is a unique/patented approach to detection and can't be compared to a typical two frequency detection scheme. A lot of similarities between CTX and Etrac though.
I know how Minelab portrays the coil as having some kind of preprocessing function of the RX signal but I find that doubtful - perhaps it does A/d conversion? Not much written about it by 3rd parties.
The processor is a standard part and Minelab posts its Linux code they participated in the open source approach. There are a few guys out there that can look at it and tweak it if they wanted to - wish I had that kind of smarts!
I know how Minelab portrays the coil as having some kind of preprocessing function of the RX signal but I find that doubtful - perhaps it does A/d conversion? Not much written about it by 3rd parties.
The processor is a standard part and Minelab posts its Linux code they participated in the open source approach. There are a few guys out there that can look at it and tweak it if they wanted to - wish I had that kind of smarts!
Jason in Enid
Active member
bklein said:
That is what it's doing. The detector sends a digital signal to the coil, then the chip in the coil converts it to analog. It takes the analog return and converts it to digital before sending it back to the control unit.
chip is in the coil to stop aftermarket coil manufacturers making coils for the high end minelabs , pretty sad really that they don't get that more coil options sells detectors, anyway minelab remains the spoilt brat who wont share there toys or offer a kid who has no lunch a banana.
poor form really only people it hurts is its customers !!
AJ
poor form really only people it hurts is its customers !!
AJ
How can I get in touch with Charles from up state ny. Since I live in the upper portion of New York.
I would like to talk to him. I have taken the ctx apart and have had the boards separated from one another.
I can tel you there is a battery on one of the boards most likely to retain programming data. I don't no for sure if replacing the battery would lose the
normal internal information where you would have to reformat and reload the MLB fire or other information.
So if you have a dead ctx3030 I would recommend having a technician take it apart and change the internal battery.
There is a small plastic clip that holds a ribbon cable in place if you break it you won't be able to secure the ribbon cable and most definitely you will be sending it to minelab for repair. The repair places in the US only fix level one troubles. They don't even no there is a battery in there.
So I can understand why they are coming back NOT FIXED. They do not have repair schematics because of the patents minelab holds they won't release any info to other party's.
Guys we have to figure this shit out for our self. We need to help one another to make this unit better.
Anyone notice the Normal and the Smooth and the Long Settings. The Long is way to long. We need to be able to change the delay ourself s.
That's why we need to figure out how to modify the internal program. The display is way to dim. Lots of problems with this detector. If you don't want to have things changed that we need a CLASS ACTION LAW SUIT.
I would like to talk to him. I have taken the ctx apart and have had the boards separated from one another.
I can tel you there is a battery on one of the boards most likely to retain programming data. I don't no for sure if replacing the battery would lose the
normal internal information where you would have to reformat and reload the MLB fire or other information.
So if you have a dead ctx3030 I would recommend having a technician take it apart and change the internal battery.
There is a small plastic clip that holds a ribbon cable in place if you break it you won't be able to secure the ribbon cable and most definitely you will be sending it to minelab for repair. The repair places in the US only fix level one troubles. They don't even no there is a battery in there.
So I can understand why they are coming back NOT FIXED. They do not have repair schematics because of the patents minelab holds they won't release any info to other party's.
Guys we have to figure this shit out for our self. We need to help one another to make this unit better.
Anyone notice the Normal and the Smooth and the Long Settings. The Long is way to long. We need to be able to change the delay ourself s.
That's why we need to figure out how to modify the internal program. The display is way to dim. Lots of problems with this detector. If you don't want to have things changed that we need a CLASS ACTION LAW SUIT.
IDXMonster
Well-known member
My tiny brain always thought that the e-series and CTX were advertised as 28 freq machines,so...1 freq for the ground balancing/tracking and a low,medium and high channel with 9 "harmonics" apiece...voila! 28 freqs. Any takers?
Jason in Enid
Active member
IDXMonster said:
Not sure about the freq for GB, but I have seen others post what they have observed from oscilloscopes and the CTX. It does appear that there are a handful of actual transmission freqs and the remaining ones are actually harmonics.
treasure_hunter
New member
mypenneys said:
Repair techs do know the battery is there, I imagine it is there for the bios and clock settings when power is turned off just like on desktop and laptop computers... Labor charges for Level 3 repairs would be very expensive.and would cause an even longer back log of repairs.
Post the photos of the boards please. I don't want to take mine apart until it dies. Such a battery usually has a design life of 5 years. They are in lots of things and the best you can do for battery backup. I suspect that you put another in, load the default config. firmware and finally load anything unique that you stored with the Xchange software. Music synths have these too and patches get lost when they get too low voltage. You can replace them usually with the product running - usually main battery power supplements this battery but might be no big deal if not. I'm not worried about it - I'm sure we'll be talking about it when it becomes an issue and there will be youtube videos on what to do.
Such ribbon cable designs are typical. A good tech can replace it from parts off Digikey. Should only become an issue from sloppy disassembly - not from normal use.
Looking forward to when these die and Minelab won't fix them as you suggest. I'd love to spend my spare time repairing them if Minelab doesn't care to (unemployed right now). I don't anticipate major issues in such repairs. Things that go bad in 5+ year old electronics are usually connections, bad traces due to the environment, bad capacitors, bad crystal/resonators. True of any detector that age. The parts count likely is reducing in detector designs as time advances - a lot of designs are using ARM processors with standard architectures around them.
For me on the beach, all the detection modes still detect the targets I come across. I've stood there and tested several targets. They exist to help your brain process the sounds - pick one that is best for you and you have to adapt to it. I'd love to see the code open up so we could tweak our own versions but I think the results would still be rejected by some people and confuse many - so it would need to be an advanced mode option kind of thing. I mainly dislike the menu system and feel it could be greatly improved.
What is the interest in the TX/RX signal frequencies? What are your intentions?
I mean I'm digging small nuggets and gold pieces of jewelry as deep as I care to dig. I wouldn't be interested in upgrading to a detector with more depth.
I think the problem with the display is not brightness - it is darkness. The darkness of an LCD black in the sun is light gray at best. An LCD is low power - a OLED display or whatever is not. My Iphone5 display is worse in the sun than the CTX's. I don't know if I have seen a better low power color screen technology than what it has (but I'd like better too). LCD's will start dying eventually. We may need to look into generic replacements. I went through that with my Whites Spectrum XLT.
Some discussion of the CTX TX/RX waveforms: http://www.geotech1.com/forums/showthread.php?20621-Multi-Frequency&highlight=ctx-3030
I have never seen a CTX for sale not working or even damaged. If it doesn't work right after being returned you should be able to describe the issue and have Minelab see it and fix it. I wish Minelab sold replacement parts though - that might take some of their repair load off too.
Such ribbon cable designs are typical. A good tech can replace it from parts off Digikey. Should only become an issue from sloppy disassembly - not from normal use.
Looking forward to when these die and Minelab won't fix them as you suggest. I'd love to spend my spare time repairing them if Minelab doesn't care to (unemployed right now). I don't anticipate major issues in such repairs. Things that go bad in 5+ year old electronics are usually connections, bad traces due to the environment, bad capacitors, bad crystal/resonators. True of any detector that age. The parts count likely is reducing in detector designs as time advances - a lot of designs are using ARM processors with standard architectures around them.
For me on the beach, all the detection modes still detect the targets I come across. I've stood there and tested several targets. They exist to help your brain process the sounds - pick one that is best for you and you have to adapt to it. I'd love to see the code open up so we could tweak our own versions but I think the results would still be rejected by some people and confuse many - so it would need to be an advanced mode option kind of thing. I mainly dislike the menu system and feel it could be greatly improved.
What is the interest in the TX/RX signal frequencies? What are your intentions?
I mean I'm digging small nuggets and gold pieces of jewelry as deep as I care to dig. I wouldn't be interested in upgrading to a detector with more depth.
I think the problem with the display is not brightness - it is darkness. The darkness of an LCD black in the sun is light gray at best. An LCD is low power - a OLED display or whatever is not. My Iphone5 display is worse in the sun than the CTX's. I don't know if I have seen a better low power color screen technology than what it has (but I'd like better too). LCD's will start dying eventually. We may need to look into generic replacements. I went through that with my Whites Spectrum XLT.
Some discussion of the CTX TX/RX waveforms: http://www.geotech1.com/forums/showthread.php?20621-Multi-Frequency&highlight=ctx-3030
I have never seen a CTX for sale not working or even damaged. If it doesn't work right after being returned you should be able to describe the issue and have Minelab see it and fix it. I wish Minelab sold replacement parts though - that might take some of their repair load off too.
Jason in Enid
Active member
I have only seen one "as-is, not working" CTX for sale, ever. It was on ebay and it was a detector found by a kayaker in a river. He COMPLETELY disassembled it, and had pics of everything apart. Said he took it apart to check for water leaks or something. He knew absolutely nothing about detectors. I think it still sold for quite a bit.
The problem with all modern electronics is the miniaturization of all the circuits. There is really not much for a tech to "repair". Its just replacing boards, cables and components. Yeah, it would be nice if minelab would sell these parts but we all know that is never going to happen.
The problem with all modern electronics is the miniaturization of all the circuits. There is really not much for a tech to "repair". Its just replacing boards, cables and components. Yeah, it would be nice if minelab would sell these parts but we all know that is never going to happen.
IDXMonster
Well-known member
Jason in Enid said:
I remember that discussion about the wayward CTX over on another forum awhile ago...seemed a bit sketchy but maybe he found it...wonder where the original owner went or if someone really got that disgusted with his machine!