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Single / Selectable / Multi-Frequency.

April 01, 2019 04:00PM avatar
Quote
glabelle
Couple of comments. This is from Minelab's site:
"Multi-IQ is Minelab’s next major innovation and can be considered as combining the performance advantages of both FBS and VFLEX in a new fusion of technologies. It isn’t just a rework of single frequency VLF, nor is it merely another name for an iteration of BBS/FBS. By developing a new technology, as well as a new detector ‘from scratch’, we will be providing both multi-frequency and selectable single frequencies in a lightweight platform, at a low cost, with a significantly faster recovery speed that is comparable to or better than competing products."

This is of course marketing speak, but the bottom line is that Multi-IQ is a little different than their FBS/BBS. The signal coming out of the transmit coil has been measured, and it is indeed simultaneous multi-frequency. It appears that FBS/BBS used a square wave (which naturally contains odd harmonics of the fundamental). I think the V3i also worked on this principle. The trick is now how you analyze the received signal at various frequencies. The V3i seems to analyze each of the frequencies, then reports what each returned, and a VDI based on the combination of these. The processor must be very fast in order to do this as you swing the coil. I had one, and the recovery time between targets was too slow for me, compared to a single frequency machine.

Multi-IQ outputs a complex waveform consisting of multiple frequencies in square wave form. It should result in a transmit signal that is just as strong at the low freq., as it is at the high. Whatever they do in analyzing the return signal, it is fast. To start, probably a faster µ Processor. In practice, it is fast enough to give you a satisfactory quick recovery time between targets. They claim to give you better ID of targets at depth. Many are reporting that this is true, I have yet to test it. However, in theory, it makes sense that if you can compare the phase of the return signal at different frequencies that you will at least have more information with which to work than with a single frequency machine.

I agree. Lots of possibilities for analyzing the signal with multiple frequencies to look at.

I've not seen the actual wave forms on an oscilloscope and would be interested to see if Minelab is actually varying the transmit signal between the 5 different frequencies determined by the selected mode OR if they are always sending out the same waveform and simply changing their signal analysis depending on the selected mode.

I think that Monte described the 'waveform' correctly as sequential, meaning that the 5,10,15,20,40kHz Tx signals ARE NOT transmitted at the same instant, but in a series. i.e. x number of cycles of 5kHz followed by x number of cycles of 10kHz (not necessarily in ascending order) and so forth to 40kHz and then repeat.

My non-scientific experience with my 800 over the last year demonstrated superior audio and visual ID at depth while offering improved target separation compared to my previous FBS machines. My 800 is a different beast than my FBS machines but I can certainly tell that it is a member of the Minelab family.

Aloha
Subject Author Views Posted

Some 'traveling thoughts' on Single or Selectable Frequency Vs Simultaneous Multi-Frequency.

Monte 200 March 30, 2019 11:05AM

Surprise, surprise! Attachments

glabelle 139 April 01, 2019 04:55PM

What frequency am i really anyway?

UtahRich 96 April 02, 2019 08:06AM

Re: What frequency am i really anyway? Attachments

glabelle 101 April 02, 2019 11:08AM

Frequencies and Analysis

UtahRich 94 April 02, 2019 03:28PM

OOOOPS N/T

UtahRich 74 April 02, 2019 08:06AM

Surprise!

UtahRich 83 April 01, 2019 08:35PM

Re: Surprise, surprise!

WM6 78 April 01, 2019 06:27PM

Re: Surprise, surprise!

glabelle 67 April 01, 2019 09:55PM

Re: Some 'traveling thoughts' on Single or Selectable Frequency Vs Simultaneous Multi-Frequency.

glabelle 94 April 01, 2019 10:02AM

Single / Selectable / Multi-Frequency.

UtahRich 117 April 01, 2019 04:00PM

Re: Some 'traveling thoughts' on Single or Selectable Frequency Vs Simultaneous Multi-Frequency.

WM6 95 April 01, 2019 12:52PM

Re: Some 'traveling thoughts' on Single or Selectable Frequency Vs Simultaneous Multi-Frequency.

NWCindy 88 April 01, 2019 06:00PM

Re: Some 'traveling thoughts' on Single or Selectable Frequency Vs Simultaneous Multi-Frequency.

Kickindirt 126 March 30, 2019 09:01PM

Why i like multi frequency

zincoln 135 March 30, 2019 03:07PM

Re: Why i like multi frequency Hey Brian

Kickindirt 126 March 30, 2019 09:11PM

Re: Why i like multi frequency Hey Brian

zincoln 125 March 31, 2019 07:37AM

My name is Rich and I’m a multi-freq’r. thumbs up N/T

UtahRich 81 March 31, 2019 09:04PM

My name is Monte and I'm a multi-frequency user, too!

Monte 103 April 01, 2019 02:33AM

Re: Why i like multi frequency Hey Brian

Kickindirt 100 March 31, 2019 11:24AM

Interesting topic N/T

UtahRich 92 March 30, 2019 01:48PM

Re: Some 'traveling thoughts' on Single or Selectable Frequency Vs Simultaneous Multi-Frequency.

jmaryt 141 March 30, 2019 12:36PM

My old standby of single freak 6.59 kHz works for meWhite's Electronics N/T

Hombre 109 March 30, 2019 11:39AM



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