Question

What is a doublet function?

(a) Branch of an impulse function

(b) The output of an impulse function

(c) The first derivative of an impulse function

(d) Any continuous time impulse function has another name that is doublet function

The question was posed to me in an interview.

The origin of the question is The Impulse Function topic in section Signals and Systems Basics of Signals and Systems

Answer 1

Correct choice is (c) The first derivative of an impulse function

To elaborate: The first derivative of d∂(t)/∂(t)=∂’(t) is referred to as a doublet function.  The derivatives of all orders of the impulse functions are also singularity functions. It is defined as d∂(t)/dt=∂’(t)=0.