23. 1. 30.
Discrete time signal
Definition
discrete signal
x = {x[n]}
if there is analog signal x_a, and x[n] are sample of the signal,
then
x[n] = x_a(nT)
unit sample sequence
refering to it as impulse
δ[n] = 0, n != 0 and 1, n = 0
any sequence can be expressed as
x[n] = Σ_k x[k] * δ[n-k]
Power, Energy
power
P=T→∞limT1∫−(T/2)(T/2)∣x(t)∣2dt (Watts)
energy
E=∫−∞∞∣x(t)∣2dt (Joules)
Convolution
(f∗g)(t)=∫−∞∞f(τ)g(t−τ)dτ

Reference. https://towardsdatascience.com/a-comprehensive-introduction-to-different-types-of-convolutions-in-deep-learning-669281e58215