White's TDI jumper

[Mark-VA]

What is the jumper on the bottom of the TDI board for?

[eclipse]

Like the 50% rest of the TDI SL circuit - it does nothing and it very well may be just traces (if you're thinking you can use this to alter the device).
Too much "service traces" and unsoldered components pads (without elements) and if you remove all those you get Gold Scan 5 with different audio stage, well okay and improved integrator which doesn't need components matching.

[Carl-NC]

It's a header for a Sunray-style probe that I designed but never released. The intent was to add a second coil connector to the box that plugged into the header (remove the jumper). The probe then plugged into connector. The probe had a push-button switch; you press/hold the switch and the probe was active. Release the switch and the main coil was active. I built one, it all worked very well.

[Mark-VA]

It has became quite obvious you had a lot of plans for the TDI. All the vacant component areas and then there are several marked upgrades that never got implemented. You must have had a lot of ideas on the table when you left for 1st Texas.
I read where Reg stated you couldn't use battery voltage above 16.8. Is that true?

[Carl-NC]

Yes, the missing components were to implement ground tracking and some other features. However, I had largely abandoned the TDI work because I had developed another platform that beat the TDI by a good margin.

I think the TDI is limited to maybe 16.8v, don't recall. The SL could go higher, that info is somewhere on the forums but now I can't recall. 20V, maybe higher.

[Orbit]

It's a header for a Sunray-style probe that I designed but never released. The intent was to add a second coil connector to the box that plugged into the header (remove the jumper). The probe then plugged into connector. The probe had a push-button switch; you press/hold the switch and the probe was active. Release the switch and the main coil was active. I built one, it all worked very well.

Hi Karl is Coil Sunray in the same housing ? I think the main and second coils are in the same plastic case ? And another question does the processor support Blanking I think about what this function should be for, but if you can explain, and next whether the processor record contains a pulse width function or components have been added for the next version of the new hex code?

[Carl-NC]

I'm not sure I understand your questions. Sunray mostly made VLF probes and they had the TX and RX coil in the probe. A probe for the TDI would only be a mono coil.

I don't know what you mean by "blanking." Some VLF detectors once had target blanking but no one does that anymore.

[Orbit]

I was thinking of what you wrote above tdi with the coil Sunray ? ( It's a header for a Sunray-style probe that I designed but never released) ....And as for blanking obviously I was looking at the wrong scheme.. And I thought that from the processor pins 21 the signal goes to the base tr 3904 and from the collector on pin 5 U12 ..I don't understand what it is for because there is no signal on the oscilloscope on pin 21 of the processor ?It should serve I guess for the detector to lock the gate at the time of turning on maybe?

[Carl-NC]

A "Sunray-style" probe means a probe similar to the ones Sunray used to make for the Sovereign & other detectors. They did not make one for the TDI. I was going to make one at White's but never did.

Yes, pin 21 is a blanking signal used at start-up. It disables the back-end signal until the SAT circuits stabilize and prevents a loud *BONG* audio.

[Orbit]

Thanks Carl it's much clearer now !

[Mr.Jaick]

Yes, the missing components were to implement ground tracking and some other features. However, I had largely abandoned the TDI work because I had developed another platform that beat the TDI by a good margin.

I think the TDI is limited to maybe 16.8v, don't recall. The SL could go higher, that info is somewhere on the forums but now I can't recall. 20V, maybe higher.

Hello Carl
how does the ground tracking work?
TDI has two channels, gold and ground
do you average the gold channel output then servo adjust the ground channel to get almost Zero average value on gold output?
I want to know how this is done in analog domain, I've been scratching my head for some time
came up with some ideas but at the end they all needed DSP

[Carl-NC]

Hello Carl
how does the ground tracking work?
TDI has two channels, gold and ground
do you average the gold channel output then servo adjust the ground channel to get almost Zero average value on gold output?
I want to know how this is done in analog domain, I've been scratching my head for some time
came up with some ideas but at the end they all needed DSP

I don't remember but whatever it was would be done in DSP. The difference signal is fed to an ADC channel on the PIC and the PIC then controls a digital pot. In thinking about this some more you probably want to sample the channels individually.

[Mr.Jaick]

yes that was the solution I was thinking of, we need a PID control or maybe just the PI portion.
I need to invest more time in stm32's.
thanks.

[bklein]

I’ve been playing around a little with a ADAU1701 sigmadsp eval board at work. Didn’t think about doing a detector with it but wondering if someone is? The stm32’s use just Audioweaver or sigmadsp? I spoke with an Analog Devices support guy that said they are working with ST with a SigmaDSP eval board - anyone know more?

[Carl-NC]

That looks really interesting for a direct sampling system. Wish I had more time to look into it, also the eval board is $234 which is pricey.