More Speed

[Carl-NC]

This is described in the construction manual of the Sandbanks.

Change of frequency, reduction of the integration capacitor ...

Is this also possible with other detectors?

Reducing the integrator cap increases the target response speed (allows a faster sweep speed) but also decreases SNR. Increasing pulse frequency generally improves SNR. Neither of these help with a faster sample time, if that is your goal.

[Andi68]

Tanks Carl, but what is the SNR?

[rickb]

snr = signal to noise ratio.

[Andi68]

Thank you

[dbanner]

The sandbanks(I did make it)stock circuit has exceedingly slow response speed and recovery, there are mods at the end of article to help to improve the circuit. I did such mods and now my sandbanks is very good. But it has poor sensitivity to small gold items. No surprise there.

[6666]

The sandbanks(I did make it)stock circuit has exceedingly slow response speed and recovery, there are mods at the end of article to help to improve the circuit. I did such mods and now my sandbanks is very good. But it has poor sensitivity to small gold items. No surprise there.

I still have my 1979 copy of PW with the sand banks article, I did not make it as finding the inverter transformer was a problem.
Wow 39 years ago.

[dbanner]

Yes, the transformer, I replaced with other power supply circuit. The 709 I replaced with 5534, with some small changes to the original circuit. It works very good indeed.
Actually I did a series of mods to timing and prf.
I will try to find the file and post it. It has been a while.

[Funfinder]

The answer to the main question is:

Don't think 1-dimensional if you can do it 3-dimensional.
Or:
Use more persons to get the work faster done.

OK, this is now some riddle but this makes it more motivating and interesting.


Real?! Use different frequencies in between the pulse cycles.
You can't double the construction/vanishing of the field itself
if you wanna reach some useful power and depth.
Same as a cap needs its time to discharge.

[dbanner]

The answer to the main question is:

Don't think 1-dimensional if you can do it 3-dimensional.
Or:
Use more persons to get the work faster done.

OK, this is now some riddle but this makes it more motivating and interesting.


Real?! Use different frequencies in between the pulse cycles.
You can't double the construction/vanishing of the field itself
if you wanna reach some useful power and depth.
Same as a cap needs its time to discharge.

.
Man, send me some of that joy juice you've been having lately, I could use a good trip down to la la Land.

[dbanner]

"More Speed" (lithium)anyone?
But seriously though, improvements to pulse technology has been really snails pace over the years, little has changed to original design. I think it has more or less close to the limit. Sort of like 9.58 seconds world record. Does it really matter 9.57?

[dbanner]

I think the next generation of metal detectors might be autonomous machine with AI for distinction between metals. Sort of a learning pulse / VLf hybrid.

[dbanner]

I saw.nice opamp for pi that has excellent parameters for front end, but problem is I observed that others were disappointed with the testing. It doesn't live up to expectations.
This is key for good fast recovery of device and no. drift
Next thing I observed was Miller effect. A feedback resistor between source and gate of MOSFET. This is expert territory I know little about.

[dbanner]

Also noise is great enemy of any Pulse circuit. Need to be kept very quiet. Designers of circuit Alway keep snr as low as possible.

[dbanner]

Also high quality components of sufficient tolerance to do the business. Heat is enemy of a circuits efficiency, must be kept in check. MOSFET in some cases must be heat sinked,

[dbanner]

Very important aspect that is often neglected is power supply and bypass caps. Rails must be kept as clean as possible. Placement of bypass caps of CORRECT value az close as possible to chips power pins is very important to be effective.