Deus II: About the oscillogram

[Riss]

Any assumptions about the oscillogram of the current through the transmitter coil of DEUS II ? I think XP have used Direct digital synthesis (DDS) and having worked hard to reduce phase noise during synthesis . I don't think they used successive bundles of sinusoidal signals with different frequencies , nor full oscillation (360 degrees) with low frequency, followed by full oscillation with medium and high frequency - -it's quite unprofitable...In a promotional video on YouTube XP show the oscillogram - a complex sinusoidal oscillation resembling an audio signal . Broadcasting more than 3 frequencies only causes headaches and is practically meaningless . Of course - they do not use odd harmonics . I waited long enough someone to raise the topic , but my curiosity did not endure .I will ask to be added to the title of the topic ,, DEUS II “ - I made a mistake and I can't edit the title- to add DEUS II

[Carl-NC]

What video shows an oscillogram? I would expect that Deus2 uses square wave drive for both MF and SF modes as that is the easiest and most fuel-efficient. DDS would waste a lot of power.

[Skippy]

This 'waveform' topic was briefly touched upon on the DetectorProspector forum.
Things that could influence what it transmits include:

*What patents are now available for XP to use.

*What techniques are suitable for low-power consumption, to give good battery life.

DDS of a pseudo-sine-wave is possible. So is a 're-make' of Minelab's BBS, with different frequencies/ratios. I think it's unlikely to be a sophisticated square-wave system, similar to Tarsacci's method. Though having the coil AND the coil electronics inside the coil together means the issues with matching the coil to the electronics is made easier.

[surfdetector]

...In a promotional video on YouTube XP show the oscillogram - a complex sinusoidal oscillation resembling an audio signal .

In fact the video is indeed of the audio as seen here at time 1:07

https://youtu.be/27N9_3h4ZDk

[Qiaozhi]

In fact the video is indeed of the audio as seen here at time 1:07

https://youtu.be/27N9_3h4ZDk

At 1:07 minutes it shows a title: "Audio Options" with "Pulse Width Modulation" underneath.
But strangely (in the pull-down on the left) it says "PMW".

[ivconic]

At 1:07 minutes it shows a title: "Audio Options" with "Pulse Width Modulation" underneath.
But strangely (in the pull-down on the left) it says "PMW".

"Puked Medium Wave"!?
"Put Me in Water"!?
"Pleasant Mood Wave"!?
"Professional Mortal Wreck"?!
...
Keep in mind those are French!
At least now we know in advance the main reason for the very next update!
Tomorrow you buy Deus 2 and just a day after tomorrow you get free update with "PMW" corrected to "PWM"!
Eagle eyes Q. Congrat!

[ivconic]

Just checked this with the XP "insider".
Actually "PMW" stands for:
"Peeshy Mahoosive Waft" !!!??
As non native English speaker i can't tell what the heck is that?
Any ideas?

[ivconic]

[Carl-NC]

OK, I've seen that video. Riss, that waveform means absolutely nothing, it's just a bunch of cool-techy-looking-CGI. It's meant to portray the audio signal but does not even correlate with the audio that's being heard.

I'd wager that the Deus2 uses a square/rectangular TX drive exactly like every other MF detector that's been produced so far. Back in the 90s White's designed a sequential sinusoidal system (non-DDS) that proved to be unmanufacturable. People (including me) have investigated DDS drive but it's a power hog. White's had a securlty walk-thru design that used a DDS TX drive but power consumption was not a concern. It can be done, but is not a good choice for a battery-operated device.

P.S. -- PMW is Parisian Motor Works, a fancy car that Alain Loubet drives. When you rev the engine it sounds a lot like a Deus passing over a big silver coin.

[ivconic]

OK, I've seen that video. Riss, that waveform means absolutely nothing, it's just a bunch of cool-techy-looking-CGI. It's meant to portray the audio signal but does not even correlate with the audio that's being heard.
I'd wager that the Deus2 uses a square/rectangular TX drive exactly like every other MF detector that's been produced so far. Back in the 90s White's designed a sequential sinusoidal system (non-DDS) that proved to be unmanufacturable. People (including me) have investigated DDS drive but it's a power hog. White's had a securlty walk-thru design that used a DDS TX drive but power consumption was not a concern. It can be done, but is not a good choice for a battery-operated device.
P.S. -- PMW is Parisian Motor Works, a fancy car that Alain Loubet drives. When you rev the engine it sounds a lot like a Deus passing over a big silver coin.

Yes, of course, it's just a nice graphic presentation for the site.
...
Well, you worried me a bit with that,
quite by coincident these days I'm waiting for the AD9833 module to arrive:



I thought that by using that module I would save resources on Atmega for other use.
...

"Waft" term closely correlates to what's announced to be the main Deus 2 feature, so i rather tend to accept previous explanation!
(malicious native English speaking minds would understand the term as "quiet, fine and imperceptible fart")

[Riss]

FMF – fast multi frequency –this directs to sequential transmission of different frequencies . If they are not bundles of oscillations , then maybe one low frequency oscillation, then one medium frequency oscillation and another high frequency oscillation . Probably not by the method DDS -sinus , and the current in the coil is triangular . As far as I know, this has not been done so far . BBS –MINELAB uses one full low frequency oscillation followed by 8 high frequency oscillations . I think the consistent approach suffers from a decrease in the signal-to-noise ratio - at 3 frequencies we have 3 times less samples per second . XP prefer a micropower oscillator and fantastic gain in the receiver…

[Carl-NC]

FMF is just a marketing term -- like BBS, FBS, and Multi-IQ -- and doesn't convey any information about how they designed the circuit. It could be sequential, it could be simultaneous. We'll know before long. It's unlikely to be a single low cycle followed by a single high cycle; Minelab did 1 low + 8 high in order to boost the weaker high response. Even then, BBS/FBS is not very hot on small low conductors, but it is on deep silver. Suggesting that even 8:1 wasn't enough.

[ivconic]

In direct sampling systems; high gain is almost mandatory. Having in mind the Deus 1 configuration. Maybe is not the same at Deus 2.
High gain at receiving part usually comes with lower power at transmitting part, for many reasons, most significant is to avoid unwanted saturation and increase of noise at receiving part.
Also much faster recovery is easier achievable if power is not high.
Sequential or simultaneous; usually the highest frequency will determine the absolute number of samples.
So i tend to believe that number of samples must be fixed during the whole TX period. Especially if they again used direct sampling method as at Deus 1.
Otherwise is hard for me to understand how to process variable number of samples when switching fast to another frequency and especially what would be the trade off in such case.
It is not impossible at all, but will need a beast of ADC and later processing. I highly doubt it is the case here.
Main trade off would be less accuracy as the frequency arises. Which is quite the opposite from what we want in multi-f system.
Meaning that we will have much more samples at lowest f and much less at highest f, if variable number of samples. I don't see any benefit in such case, on contrary.
So i assume the number of samples is fixed and determined by highest f in a row.
But we can only assume until we see if the Deus 2 configuration is the same as at Deus 1... or quite different. Is it direct sampling, is it the same chip, what is the ADC and specs...

[Carl-NC]

My guess is they used the same approach as the Equinox, which is also direct sampling. Simultaneous multifrequency, probably with a fixed sample rate.

[Riss]

Here - ivconic you have an insider in the company ? Ask him about the oscillogram, please . Once the detector is already on sale, this is not confidential information . Otherwise, when the first units arrive in Sofia , I will go to the store with my portable oscilloscope