How can I convert from voltage TDR into impedance TDR
For dynamic signals such as Solar Panels and microwave, we sometimes find Ohm's law is useful for incremental resistance as well as the max power theorem and for the mean impedance.
\$Z(t)=\dfrac{V(t)}{I(t)} = \dfrac{δV(t)}{δI(t)}\$
Similarily yet different for a Solar Panel's MPPT operating point.
\$Z_{mpt}=\dfrac{δV(t)}{δI(t)}\$ where V*I is max and \$Z_{mpt}\dfrac{V_{mpt}}{I_{mpt}}= \dfrac{V_{oc}}{I_{sc}}\$
Another distant relative of this is Load Regulation, where if we know a power supply as 1% load regulation voltage error at some load R , we can imply that the source impedance must be 1% of R.