Pythagorean Idea for Inductance Meter?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jolyon Vater Cox by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>


For the purpose of measuring the inductance of the windings used in TCs , 
is it possible (and economical) to design a meter for true inductance using 
Pythagorean principles -based on fact that the AC voltage across a coil 
with no resistance is proportional to the AC current alone?

I envisage using two opamps (wired as squarers) to register voltages across 
L the test inductor and a reference resistor R connected in series across 
an AC supply

the squares of the two voltages would be subtracted in a difference amp

then square-rooted (by an opamp with a squarer in the feedback loop) to 
give the voltage component due to inductance alone; the latter would be 
displayed on a meter as a measure of the inductance.

Is this method as simple as it sounds or more complicated in practice? Does 
anyone have a schematic for such a circuit?