Unit doublet

In mathematics, the unit doublet is the derivative of the Dirac delta function.

It can be used to differentiate signals in electrical engineering:[1] If u1 is the unit doublet, then where

[2] The function is zero for all values except zero, where its behaviour is interesting.

However, the integral of its absolute value over any region enclosing zero goes to infinity.

The function can be thought of as the limiting case of two rectangles, one in the second quadrant, and the other in the fourth.

Live graphic of a unit doublet of width k as k goes to zero.
Approximation of a unit doublet with two rectangles of width k as k goes to zero.