FLUKE 1630-2 Earth Ground Clamp for loop resistance

[HighVoltage]

I just came across this FLUKE 1630-2 Earth Ground Clamp for loop resistance.

This must be one of the most clever instruments I have come across in years.
It looks like a clamp meter but it measures impedance.

https://www.fluke.com/en/product/electrical-testing/earth-ground/fluke-1630-2-fc

What I wonder is how this instrument works.
Maybe one coil introducing a current in to the conductor under test and another coil is measuring the response?

Anyone here having used such instrument?

[Grandchuck]

Here is a clue:

[AVGresponding]

Yes. The resistance mode uses an AF pulse in the coil. The coil has to be completed when the jaws close, so unlike common current clamps these have fine leaves of metal (not sure what, could be stainless steel or plated copper) which mesh together to make the circuit when the clamp jaws close.

I have an RS Pro 5601 (rebranded Prova) one that I got cheap (£10 + shipping) because the leaves were damaged. They just needed bending (very carefully, they are delicate) back into shape. It can measure loop resistances down into the milliohm range, and leakage currents in the tenths of a milliamp.