Anyone know PI ground balance methods?

[Pennyweight]

Hi all,
just wondering if anyone can offer any innovative or even basic ground balance methods to add to a PI project? Perhaps a simplified form of
Eric Foster's manual Goldscan idea, a ground tracking system or something new? A schematic, component speak or just plain English language would do Anyone out there with ideas? Cheers, Dwt

[Unregistered]

Take an sample early in the TX and a later sample in the TX and amplify the late sample to the same amplitude as the early sample and then invert the late sample and send to a difference op amp together with the early sample so that the result is a null signal for the ground. As the ground changes the amplification of the late sample will have to be changed (ie re ground balanced) to maintain a null signal. This is a very big over simplification as filtering is also very important but it will give you the general idea.

[Geo]

Good idea but.... any ground balance work with change of the gain (or sensitivity). we want a ground balance without to change the sensitivity. At manual ground balance i locate a soda can at 75 cm on air but at auto only at 40... 50cm . So we need a more clever GB
Regards

[Pennyweight]

PI ground balance methods

Hi Geo,
exactly correct! We are playing with a couple of GB ideas but they appear
to sacrifice too much performance. PI ground tracking seems to offer the best idea but they are firmware driven. Another easier form of GB has to be out there somewhere? Cheers, Dwt

[Esteban]

At the end, GB is other sensibility control.

[B^C]

Maybe any recieve signal that is Linear can be cancelled out automatically pressumed as ground noise, the response from magnetic soil would seem to be Linear where the response from targets are not.

I have an old graph somewhere i will find it & post it, may spark some ideas?

[B^C]

Heres that Graph.

[porkluvr]

Hello B^C

Thank you for that fantastic graph. Simple, understandable. If it's accurate then it means there may even be hope for a poor technician like myself to devise a system of ground cancelling that doesn't seriously affect sensitivity. (Yeah I like to dream.)

Do you remember where it came from?

[Unregistered]

Hello B^C

Thank you for that fantastic graph. Simple, understandable. If it's accurate then it means there may even be hope for a poor technician like myself to devise a system of ground cancelling that doesn't seriously affect sensitivity. (Yeah I like to dream.)

Do you remember where it came from?

US Patent 6583625 - Metal detector and method in which mineralization effects are eliminated

[Pennyweight]

PI ground balance methods

Hi Unreg,
jeeeez, thanks for that! Some really useful stuff there and I like the fact that the GB method can be utilized without sensitivity loss. The Fe ID sounds good too, a bit better than ours! Oh Dear....MORE R & D !!!!
Cheers, Dwt

[Brucethegoose]

Looks like this one is now public property.

http://www.invisionplus.net/forums/i...=post&id=11453

[Rov]

Looks like had been Public for quite some time ,before from how I read?an we not aware of it!

[Unregistered]

Thanks

Thanks for the info Guys. I was crazy for thinking I might be able to cram mineral cancellation into my first PI project. Unless I have a sudden burst of ambition real soon, I think I'd better skip it.

Sooo, it looks like my channel three will remain "unassigned".

Porkl.