# What is tha derivative of an unit impulse function?

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#### abdurahman saeed

Joined Apr 5, 2010
4
i want solution for my Q.
What is tha derivative of an unit impulse function?

#### tubelite

Joined Jul 20, 2010
6
from what i understand the derivative only works for continuous or piece wise continuous functions. the impulse is neither and therefore doesn't have a derivative. Remember also that impulse func helps us mathematically but has no real world application. So again you could say that the derivative for the impluse func is zero for x =/=0 and not defined for x=0. I hope that helps

Joined Jul 7, 2009
1,583
Look up the Dirac delta function on wikipedia and it will give you what you want. The informal answer is a positive delta function immediately followed by a negative-going delta function -- i.e., pretty much the same conceptually if you differentiated a narrow, tall pulse.

#### Papabravo

Joined Feb 24, 2006
21,258
@abdurahman saeed -- I'm not sure it is useful to assign the delta function a specific value at the origin. The only statement you can make is that the integral from minus infinity to plus infinity is equal to 1. Thinking of it as having an infinite value there is not a particularly helpful concept. In signal processing, the ability of a time shifted delta function to pick out or sample another function is a more useful concept.

@tubelite - your response is incorrect

The derivative of a delta function is called the unit doublet.

http://en.wikipedia.org/wiki/Unit_doublet

It is zero everywhere except the origin where it has some interesting behavior. Like other functions of this type it is differentiable.

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#### tubelite

Joined Jul 20, 2010
6
oh thank you very much for correcting me.

#### abdurahman saeed

Joined Apr 5, 2010
4
thank you very much

#### Papabravo

Joined Feb 24, 2006
21,258
Glad to help. Sorting through vast quantities if information on the web can be a daunting task. Like a good journalist ask questions and try to find corroboration for anything you find: especially on wikipedia

#### kongweitao

Joined Jan 3, 2010
1

#### bertus

Joined Apr 5, 2008
22,289
Hello,

Only heard the impact function (unit impulse function) at (-8, +8) points seems to be a right? Forgotten
Bertus

#### sophia9rev

Joined Sep 6, 2010
1

#### Ganesh karri

Joined Oct 24, 2014
1
the derivative of impulse function is doublet

#### Papabravo

Joined Feb 24, 2006
21,258
If that was a statement, it is redundant.
Congratulations on resurrecting a zombie thread that died 4 years ago.

#### Wendy

Joined Mar 24, 2008
23,457
Welcome to AAC.

Congratulations, you have practiced the arcane art of necromancy, the revival of a long dead thread. Likely the OP (Original Poster) has solved his problem in the years that has passed, or thrown it away, or something.

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