# What is the difference between pulse response and impulse response?

I would like to know the difference between pulse response and impulse response.

I looked for "pulse" and "impulse" on the internet and found that on some websites they had been used interchangeably. Apart from that I checked out some books and found that they use the term "impulse response" (or unit impulse response) and not "pulse response". Is there really a difference between the two terms?

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The Electrician
Gold Member
"Impulse" usually refers to a ideal mathematical concept. It's the limit of a square topped pulse of finite duration, as the duration is allowed to approach zero, but with the amplitude simultaneously increasing so that the area under this vanishing pulse remains constant.

Whereas, to me, an "ordinary" pulse refers to a square topped pulse of finite duration. If the duration of the pulse is made infinitely long, then you have the "step" response.

Hmm.. I think I get it. From your answer I deduce that impulse is actually a form of a pulse (just that its width approaches zero).

berkeman
Mentor
I would like to know the difference between pulse response and impulse response.

I looked for "pulse" and "impulse" on the internet and found that on some websites they had been used interchangeably. Apart from that I checked out some books and found that they use the term "impulse response" (or unit impulse response) and not "pulse response". Is there really a difference between the two terms?
I don't think I've heard the term "pulse response". I think it's just being used incorrectly, instead of "impulse response".

Quiz Question -- Why is the impulse response so useful in working with LTI systems? We really do use the impulse response for real-world system analysis.