Confusion regarding indice vector?

I want to write a MATLAB function to systematically develop the sequence y[?] generated by the convolution of the

two-finite length sequence x[?] and ?[?]. Program should be able to handle causal and non- casual sequences.

Program should call for the input sequences and their indices vector?

Below is my code:

function [ny,y  ] = convolution(nx,x,nh,h )
%UNTITLED7 Summary of this function goes here
%   Detailed explanation goes here
a=nx(1)+nh(1)  %nx is time span of x and nh is time span of h
b=nx(length(x))+nh(length(h))
ny=[a:b]% ny is length of y
y=conv(x,h)
end

What is meant by indices vector in bold? Is it referring to what i have used and wrote nx and nh?

Answer 1

[Deepak]

Hi @ABTJ,

In the context of discrete-time sequences, the "indices vector" typically refers to the vector that specifies the time indices (or positions) corresponding to each element of the sequence. For example, for sequence “x[n]” that starts at index (n = 0), the indices vector “nx” would be [0, 1, 2, ..., N-1], where “N” is the length of the sequence.

In the code,

• nx: The indices vector for the sequence “x[n]”.
• nh: The indices vector for the sequence “h[n]”.

Here is an improved version MATLAB function that handles both causal and non-causal sequences while taking the indices vectors into account:

function [ny, y] = convolution(nx, x, nh, h)
  
    % Calculate the start and end indices for the convolution result
    start_index = nx(1) + nh(1);
    end_index = nx(end) + nh(end);
 
    % Create the indices vector for the output sequence
    ny = start_index:end_index;

    % Perform the convolution
    y = conv(x, h);
end

Please find attached the documentation of functions used for reference:

conv: www.mathworks.com/help/matlab/ref/conv.html

I hope this will help in resolving the issue.