Time-domain bucking circuit for landmine detection

[Altra]

Anyone know how this might be applied in a real circuit? A "gyrator" circuit (active inductor) is able to null the early exponential decay. I'm wondering if it would before/after the preamp or part of the integrator?

pulse-induction metal detector with time-domain bucking circuit for landmine detection


https://phys.org/news/2015-01-landmi...nsitivity.html

http://ieeexplore.ieee.org/document/7014440/

[Davor]

It is compensating the Coil tau by virtue of subtracting the approximation of its response. What remains is a target response, and because subtraction gets rid of the relatively high voltage, you may sample earlier, and you may apply more gain. Quite a clever approach, but not a panacea because gyrators tend to be noisy.

[pustareka]

beter rx bucking coils come
http://www.hyiq.org/downloads/guidel...ng%20Coils.pdf

who use haos sig.ge. detekt gold ?
http://www.sensorsportal.com/HTML/DI...163/P_1812.pdf

[Altra]

It is compensating the Coil tau by virtue of subtracting the approximation of its response. What remains is a target response, and because subtraction gets rid of the relatively high voltage, you may sample earlier, and you may apply more gain. Quite a clever approach, but not a panacea because gyrators tend to be noisy.

I understand the concept, the article vaguely explains it. My question is how would this be done in a practical circuit. For instance would this replace the back to back diodes on the pre-amp input?

Found this on gyrators as filters

http://sound.whsites.net/articles/gyrator-filters.htm

[Davor]

The Elliot page lacks the best gyrator circuit of them all, the Antoniou. All other gyrators suffer from residual resistance.
This compensation circuit may omit the back to back diodes only if some sort of analogue switch is used prior to the preamp, because flyback voltage is still a few hundreds volts. But sampling may start much sooner.

[Teleno]

Very good review of gyrator circuits: https://sites.google.com/site/roelarits/home/gyrator