Solving difference equation using DFT

How to find output of a difference equation when input is given (and DFT must be used to solve it)?

Say y (n) = x (n) + 2 x (n –1) –4 y (n –1) + y (n –2)

and x (n) = [1, 2, 3, 4, 4, 3, 2, 1]

any MATLAB code reference?

Answer 1

[Priyanshu Mishra]

Hi Vishwajit,

You may use the following code for your reference to solve above difference equation

N = 8;

a = [1 4 -1];

b = [1 2];

x = [1 2 3 4 4 3 2 1]

y = filter(b, a, x)

stem(0:N-1,y);