how to code a discrete signal

hi im new to matlab and just been doing some coding

but i was wondering if anyone could help me cause i really cant find how the code the delayed diescrete signal

so im trying to code the next signal

y[nT]=y[(n-1)T]+3x[nT]

and i tried coding it like

y = @(n,T) y(n-1,T)+3*x(n,T)

but i just cant plot the y[nT] using stem()

it just comes out as a blank so i thought there be an error in the code for the delayed part of y

could anybody help?

[Dyuman Joshi]

You need to initialise the sequence with some values. Looking at the documentation of stem() might help you understand better.

Answer 1

[KSSV]

You need to have array x and initial value of y in hand first.

Example:

x = rand(100,1) ; 
y0 = rand ; 
n = length(x) ; 
y = zeros(n,1) ; 
y(1) = y0 ; 
for i = 2:n
    y(i)=y(i-1)+3*x(i) ;    
end
stem(1:n,y)