Preamp

[6666]

I never said there was a schematic. I've disclosed a method. Anyone can implement it as a circuit or in software, according to preference.

This is the method: http://www.geotech1.com/forums/showt...mit-time/page3

Thanks for finding the correct thread, unfortunately mathematical formulas are not my forte, looking at Q's description your idea seems to be to have 2 transmit pulses of different length and 2 samples for each transmit pulse is that correct ? is the sampling done with a single intergrater.

[Teleno]

TELENO

You said in a previous post in this thread that

If I search on your name 22 threads show up, I have looked in most of them, but so far I have failed to find any GB schematic
could you please give me a glue where to find this GB information , thanks.

I never said there was a schematic. I've disclosed a method. Anyone can implement it as a circuit or in software, according to preference.

This is the method: http://www.geotech1.com/forums/showt...mit-time/page3

[6666]

TELENO

You said in a previous post in this thread that

I have posted my novel GB scheme in another thread, should be tested in Aussie goldfields.

If I search on your name 22 threads show up, I have looked in most of them, but so far I have failed to find any GB schematic
could you please give me a glue where to find this GB information , thanks.

[Teleno]

Some questions that might be important for component selection and board layout for coil driver and preamp. Works with mono coil, IB coil or either? Peak coil current? Fast diode between Mosfet and coil? Snubber? EF cancel by two sample difference or bipolar pulsing(needs bipolar preamp)? Probably more.

Well, if you looked at my design you'll see it's monocoil, monopolar and no snubbing.

Since the purpose is to improve speed and signal/noise relative to Surfmaster and similar, I'm concentrating on the (pre)amplifier and keeping it simple. Further refinements can be considered once the concept is proven.

By the way, all further signal processing (GB, EF etc.) will be carried out by an MCU.

[green]

Some questions that might be important for component selection and board layout for coil driver and preamp. Works with mono coil, IB coil or either? Peak coil current? Fast diode between Mosfet and coil? Snubber? EF cancel by two sample difference or bipolar pulsing(needs bipolar preamp)? Probably more.

[WM6]

Great find! Diptrace for Linux has no time limit and 300 pins is more than enough or the project.

.

You can get 500pin/2 layer, free, by asking (registering to) editor per email. Not truly Linux, it can run under Wine.

[Teleno]

Is the STP11NM80 transistor selected for a purpose? (I.e perhaps it has the spice model built in), there are better trans if this is not the case.

Nope just because it's convenient for the sim. I've selected the IRFIBF30 which has a breakdown of 1,000V and Co < 300 pF above 25 Vds. Ron is about 4 ohm or a max current of 3 A at 12 V.

[eclipse]

Is the STP11NM80 transistor selected for a purpose? (I.e perhaps it has the spice model built in), there are better trans if this is not the case.

[Teleno]

Two boards, one for TX one for RX better noie isolation that way, to PLENTY of filtering on the Rx board.

Teleno, Express looks just fine. I didn't want to have to use another package, have you also tried DIPTRACE? http://diptrace.com/

Great 3D with it too. Limited yes, but it we do this as two boards then I can still do this as I have the full version. there is also a LINUX version - WOOT!!

Great find! Diptrace for Linux has no time limit and 300 pins is more than enough or the project.

Regarding the board question, noise is not caused by the Tx circuit. Do not mistake the flyback transient with noise. The transient is well handled by the Rx circuit, no need to separate boards.

[Sean_Goddard]

Is the plan, one board for the whole detector or maybe 2,3 or 4 sections with a board for each section?

Two boards, one for TX one for RX better noie isolation that way, to PLENTY of filtering on the Rx board.

Teleno, Express looks just fine. I didn't want to have to use another package, have you also tried DIPTRACE? http://diptrace.com/

Great 3D with it too. Limited yes, but it we do this as two boards then I can still do this as I have the full version. there is also a LINUX version - WOOT!!