# Real impulse response

It will be great if someone can explain me what exactly means "real impulse response". Further more , what is the effect of such a response on ROC (Laplace plane) and in particular if its restrict the possible area of the poles and zeros? Thanks

real impulse response

An impulse response that is real-valued.

effect of such a response on ROC

nothing specific, since realness doesn't imply any kind of stability/convergence, far as I can tell. It does tell you something about poles and zeros always appearing in conjugate pairs, but that's it.

restrict the possible area of the poles and zeros

no

• thank you very much
– idos
Aug 16, 2020 at 14:59
• Well, the possible values of the poles and zeros are subject to only coming in conjugate pairs -- i.e., if you have a pole at $a + jb$, there would need to be a matching one at $a - jb$ for the impulse response to be real. Aug 16, 2020 at 21:42
• @TimWescott I feel like that's the second sentence of my second paragraph? Aug 16, 2020 at 21:48
• Ah, I missed that. Need to go back to 3rd grade and repeat the reading comprehension part of my education, apparently. Aug 16, 2020 at 22:34
• @TimWescott you're doing fine so far; it's probably just a erasure on reading my post, and then your FEC decoder kicked in Aug 17, 2020 at 9:20