Double Pluse Generator & PEM current transducer

Why do we need a double pulse generator?
Whenever we need to do
1)IGBT short circuit tes
2)In IGBT parallel application,measure output current balance.

Rogowski current transducer
1)Can measure large currents without saturateing
2)Are easy to use
3)Are non-intrusive
4)Have a very wide bandwidth extending from 0.1HZ up to 17MHZ
5)Provide an isolated measurementatground potential
6)Can measure AC signals superimposed on DC
7)Can measure changes of current as fast as 40, 000/us