Convolution without conv() function

Hi everybody,

I have a issue to plot a convolution without using the conv() function.

I have x1=sin(2*pi*f1*n*T) and x2=cos(2*pi*f2*n*T)

And i have to plot x3[n] = x1[n] conv x2[n]

I tried many different function like sum, int, symsum but i don't succeed to do it. Is there someone that can help me please

Thank you very much

[John D'Errico]

Surely you can write down the convolution on paper as a sum?

So now write it using a loop.

[Geoff Hayes]

jackal's answer moved here

Can i use a function a sum fonction that will make it?

Or do i have to make a loop because i need to plot it after.

Thank you

[John D'Errico]

No. You cannot write it just with a single call to the function sum. You can write it using a loop and a call to sum, or using a nested pair of for loops.

Just take the formula for a convolution. Then see how it would work using a loop.

[Matt J]

jackal's answer moved here

First, thank you a lot for your help.

The teacher gives us as information that for the conv we have to use the formula:

x3[n] = sum for m from -infinity to infinity of x1[n-m]*x2[m]

I don't know how i can represent the infinity sum?

Thank you

[Manolis Michailidis]

First i suppose you could say m=1:INF and shift it in a loop every time, the discrete covolution formoula should be ok i think , as for the sum should be computed in the nested loop , so basically you will calculate a new array .

[Geoff Hayes]

Jackal's answer moved here

So basically i ll have to calculate for n = 0 to for example 10 and put the result in a array?

Or do i misunderstand?

[Geoff Hayes]

@Jackal - if you wish to further the conversation please comment on the above remarks rather than creating answers (which aren't answers to your question).

[jackal dr]

oh!! Ok sorry i didn't know how it works ^^

[Manolis Michailidis]

Yes for example if your signal has lenght n=10 samples you will start for i=1:n+1 (matlab indexing starts from 1) and then yous should calculate in each iteration the sum of your signal with the shifted other , there is a function that does what you are asking take a look http://www.mathworks.com/matlabcentral/fileexchange/23402-convolution-in-matlab-without-using-conv-x-h-

[jackal dr]

Thank you a lot

I will try it and if i have other inquiries i ll ask.

Thank you very much for your time.

Hope i ll suceed ^^

[Image Analyst]

If he won't let you use conv(), then why would he let you use sum()? Seems inconsistent. http://www.mathworks.com/matlabcentral/answers/38787-what-can-be-programmed-without-any-built-in-functions

Answer 1

[Sk Group]

Convolution without Function in MATLAB

Convolution without conv function in MATLAB | Complete CODE | Explanation | Example And Output

For complete detailed post visit: https://www.swebllc.com/convolution-without-function-in-matlab/