field test unit no 001 "model T"

[moodz]

Paul



could you unhook your special circuit and put the damping resistor back in, so we can really see how much of an improvement their is. all timing being equal of course

Philip



I'm not ready to put my white Pyjamas up on a stick yet.......I'll let ya know

Its a sim as I am not near the bench .... the params are for a 18 inch minelab mono coil.


PS ....

we dont want any naked developers ... this is a clothes on thread however you are permitted to run around screaming and pulling your hair out.

moodz

[hdphilip]

Paul

...I am afraid its all over for the monocoil PI development .....

1. faster damping.
2. Automatic coil damping.
3. increased target sensitivity
4. near full depth discrim
5. Its a monocoil so it goes deeper

what more do you want .... ( oh yeh ... the cct )

I don't have to explain the picture below do I ???

could you unhook your special circuit and put the damping resistor back in, so we can really see how much of an improvement their is. all timing being equal of course

Philip

what more do you want .... ( oh yeh ... the cct )

I'm not ready to put my white Pyjamas up on a stick yet.......I'll let ya know

[Tinkerer]

The different waveforms are pretty clear for each case.

I'm afraid you do have one thing to explain for a Junior. Was it a very small Fe target and a very large non-Fe one? It does not seem right (but would be wonderful I suspect for mineralized ground) that the Non-Fe target response was larger than Fe if they were of similar size/ geometry.

It seems you have the principles right, real waveforms (not sims) and the circuit to match. I look forward to the circuit.

Chudster

The discriminating effect is always present as long as there is current flowing in the coil.

With a ferrite target, that has no conductivity, the response signal is exactly 180 degrees from the response of a purely conductive target. (in the picture DOWN)

The response of a gold nugget will be UP.

A steel target has magnetic permeability like the ferrite, but also has conductivity like a non magnetic metal.

While there is varying current flowing in the coil (and the corresponding magnetic field of course) the response of the steel target will be both ways, DOWN and UP.

The amount of either UP or DOWN, will depend on the shape of the steel target. In very thin often rusty fragments of steel sheet, the 2 responses often cancel, or the resistive response is of higher amplitude. This is what makes the discrimination of these targets difficult.

With such targets, orienting them in line with the magnetic field lines, will enhance the reactive response and help therefore identifying them as ferrous.

Since the field lines on the edge of the coil have a different vector angle, this can be used to help discriminating for near targets.

Tinkerer

[chudster]

...I am afraid its all over for the monocoil PI development .....

1. faster damping.
2. Automatic coil damping.
3. increased target sensitivity
4. near full depth discrim
5. Its a monocoil so it goes deeper

what more do you want .... ( oh yeh ... the cct )

I dont have to explain the picture below do I ???

[ATTACH]21043[/ATTACH]

The different waveforms are pretty clear for each case.

I'm afraid you do have one thing to explain for a Junior. Was it a very small Fe target and a very large non-Fe one? It does not seem right (but would be wonderful I suspect for mineralized ground) that the Non-Fe target response was larger than Fe if they were of similar size/ geometry.

It seems you have the principles right, real waveforms (not sims) and the circuit to match. I look forward to the circuit.

Chudster

[chudster]

The longer tail is a feature of prior art ... just lower level ... I am not sure it is a claim as such since patents should be focussed on methods that exploit phenomena not the phenomena itself ( since you cant invent physics or maths ). According to my advice even a sim could be challenged since it is only the result of mathematical manipulation of numbers by a CPU.

moodz

No you are right. I think you mentioned that minelab switch out the damping resistor so it would be prior art and the benefit of no damping resistor has been tried/ claimed before. I never suggested it should be a claim but explaining benefits (even if the benefit has been claimed before) helps convince the examiner that the patent has legs.

Chudster

[moodz]

Aziz .. I would really like to tell you what it is ....but I am trying to....actually I am not sure what I am trying to do LOL ......
Paul.

[Aziz]

No its not prior art ...you have not seen the claims in the patent ...the inventor of the car does not claim an improvement over the inventor of the wheel.

Sorry Paul,

but the idea is based on the same principle. I would love you to get the patent. As long as it isn't from Candy, it's OK for me!

Go for it. Looking forward to see some improvements.

Aziz

[moodz]

The interrupted TEM or the interrupted LC resonant circuit:

http://www.geotech1.com/forums/showpost.php?p=112156&postcount=840

The slight residual coil energy (due to imperfect zero-current-switch and parasitic capacitance) is damped with damping resistor in the above application. If you remove the damping resistor in the application above, you get the same behaviour.

The coil energy in the capacitor can be recycled back or burnt into heat in a resistor.

The big quiz:
So where comes the "huge target" response???
Where comes the timing change (for discrim)???


Aziz

...you did not follow the thread ... you are using critical damping .. you should be using laplace / heaviside

[moodz]

No, it's a prior art.

I'm just curious, whether the patent examiner is dumb or unskilled. Let's see, what he is going to do with the patent application.

Aziz

No its not prior art ...you have not seen the claims in the patent ...the inventor of the car does not claim an improvement over the inventor of the wheel.

[Aziz]

The interrupted TEM or the interrupted LC resonant circuit:

http://www.geotech1.com/forums/showpost.php?p=112156&postcount=840

The slight residual coil energy (due to imperfect zero-current-switch and parasitic capacitance) is damped with damping resistor in the above application. If you remove the damping resistor in the application above, you get the same behaviour.

The coil energy in the capacitor can be recycled back or burnt into heat in a resistor.

The big quiz:
So where comes the "huge target" response???
Where comes the timing change (for discrim)???


Aziz

[Aziz]

Nice Try.

No, it's a prior art.

I'm just curious, whether the patent examiner is dumb or unskilled. Let's see, what he is going to do with the patent application.

Aziz

[moodz]

GAME SET & MATCH

...I am afraid its all over for the monocoil PI development .....

1. faster damping.
2. Automatic coil damping.
3. increased target sensitivity
4. near full depth discrim
5. Its a monocoil so it goes deeper

what more do you want .... ( oh yeh ... the cct )

I dont have to explain the picture below do I ???

[moodz]

Makes perfect sense.

BTW the benefit of your circuit in having high impedance with no damping resistor to give a higher peak output and a longer 'tail' to aid ADC digitisation (and as shown in my sims) is given for free and I hope you have noted it add to your patent's background for the application as it strengthens the benefits of the approach while not being part of the claims. It allows for slower ADC sampling which is another practical benefit for a detector. You were probably aware of the peak but maybe not the 'tail' which I assume is due to coil and circuit self-capacitance with a high resistive circuit (no damping resistor). It increases the time constant. Having authored a few patents I know the deal.

On the subject of ADC. You mentioned a 'DSP version' of the circuit. Are you saying there is yet a different circuit for DSP purposes?

Chudster

The results I have presented come from the analogue version of the circuit ... there are some limitations ... the DSP version should / can produce perfect damping into an open circuit for all practical purposes .. but the timing is extremely tight so I am working on it
The longer tail is a feature of prior art ... just lower level ... I am not sure it is a claim as such since patents should be focussed on methods that exploit phenomena not the phenomena itself ( since you cant invent physics or maths ). According to my advice even a sim could be challenged since it is only the result of mathematical manipulation of numbers by a CPU.

moodz

[Aziz]

Occam's Razor Principle:
If there would be an effect to exploit, it would have been exploited by the early pioneers or from Candy.

There is no free lunch.

Sorry guys, I'm not convinced. Even I don't have the circuit, I know where it comes. And this is going to be a nice quiz game.
So, where comes the apparent "huge target" response???

Cheers,
Aziz

[chudster]

It's all a matter of balance ..... You want to store as much energy in the target as you can then stop storing and start measuring as fast as you can ... However if you are storing energy still ... No matter how small your measurement will be reduced. Radar is a very bad analogy for PI ... It implies that you send then wait for a recieve .... The target is never invisible to the coil not during transmit , flyback or immediately after in recieve. With radar until you get a reflection the target is invisible.
Moodz

Makes perfect sense.

BTW the benefit of your circuit in having high impedance with no damping resistor to give a higher peak output and a longer 'tail' to aid ADC digitisation (and as shown in my sims) is given for free and I hope you have noted it add to your patent's background for the application as it strengthens the benefits of the approach while not being part of the claims. It allows for slower ADC sampling which is another practical benefit for a detector. You were probably aware of the peak but maybe not the 'tail' which I assume is due to coil and circuit self-capacitance with a high resistive circuit (no damping resistor). It increases the time constant. Having authored a few patents I know the deal.

On the subject of ADC. You mentioned a 'DSP version' of the circuit. Are you saying there is yet a different circuit for DSP purposes?

Chudster