New Quasi P.I detector coming onto the market.

[Altra]

This 2.2 microfarad capacitor implies a full ( or half ) bridge driver and this capacitor is connected in series with the transmission coil. detectormods , can you please us with a video about the current through the transmission coil ? Half-sinusoidal pulses have been used for many , many years for geophysical surveys.
Yesterday I removed some nails (I needed them for tests) from the wood ash on the stove before I threw it away. The nails stuck a little weakly (but I could be wrong) to the magnet, but the whole magnet got covered with the ash... the sticking power of the ash to the magnet (neodymium, from a computer hard drive) is the same as that of Roman floor brick dust .

I don't think its a half-sine. If you watch Detectormod's videos closely, he flips the pcb over and you can see the tx mosfet and electrolytic capacitors. In another video he shows the tx wave form on his oscilloscope, three narrow pulses and one wide. It's a modern take on the SD2000

[detectormods]

One thing about this unit catches my eye, and that's the "obscene" of any apparent shielding.
something tells me the whole plastic work is impregnated with graphite, otherwise, the capacitive coupling of the fingers on the UI would cause trouble, it's right on the preamp, The LCD cover looks suspiciously different, so much graphite made it rough.
Woody, can you meter the plastics? if you have 30sec on hand.
thank you.

I do not have the detector anymore, it possibly may be a conductive composite, I never tested it though.

[Riss]

ok, but where is the link to this another video?

[detectormods]

I don't think it’s a half-sine. If you watch Detectormod's videos closely, he flips the pcb over and you can see the tx mosfet and electrolytic capacitors. In another video he shows the tx wave form on his oscilloscope, three narrow pulses and one wide. It's a modern take on the SD2000

My first though was a SD2000 rebuilt with modern technology.

[Altra]

Woody if you get to try one again. I would like to see a scope shot of the tx signal again but during a noise cancel. To see how the timing changes. Thanks for the videos.

[Altra]

ok, but where is the link to this another video?

https://www.youtube.com/watch?v=kbz9bnvFhRM&t=7s

https://www.youtube.com/watch?v=M0RPhQINWWA&t=659s

[Sean_Goddard]

I am currently playing with an FFT on a bipolar PI Drive stage (Moodz one) and a digital "Bit pattern" waveform. Depending on the bit pattern used, you can see differences in the returned spectrum. It's NOT a combination of different square waves, it IS different square waves, a mixture of long and narrow pulses but in a VERY specific pattern with changes over a few seconds. Results are VERY promising. Depth sucks at the moment as I'm only using 8 bits as proof of concept.

Please don't ask for details, it would take WAY too long to explain. so the above is all I will say. HINT Think ARINC data stream used as a metal detector transmit signal...Figure the rest out.

[Riss]

Finally! (you reap what you sow ) such an impulse mish-mash (mess) was hanging around in my empty head at the end of 2019, but I didn't have time left to implement it - I don't understand microprocessor programming. about 90% of the time it takes me to make a prototype (ready for a field test ) is an assembly activity... BIG suffering things could be more rational (the third sentence of the post above) - I'm sure you'll get what I'm implying...