moving filter average with convolutional function

For question 2i, I am confused that question, I have understanded in 2 ways:

firstly, we take N as a vector and find y[n] by con(1./N,ecg)

secondly, we take each number of N and multiplies to conv(ecg, h) with h is delta function.

Which way is correct?

Thank you so much for your answer

Answer 1

[Image Analyst]

No, N is not a vector it's a number, though you can make a vector from all the Ns:

allN = [2, 4, 8, 16, 32];
plot(ecg, 'b-', 'LineWidth', 3);
grid on;
for k = 1 : length(allN)
    % Get this one N
    N = allN(k);
    % Construct kernel
    h = ones(1, N) / N;
    % Do the convolution, cropping to the same size as the input vector.
    output = conv(ecg, h, 'same');
    % Plot it.
    hold on;
    plot(output, '-');
    % Create the string for the legend since all plots show up in different colors.
    legendStrings{k} = sprintf('N = %2.2d', N);
end
legend(legendStrings);

[Tu Nguyen]

Thank you so much

Answer 2

[Benjamin Thompson]

Are you asking how to define h in MATLAB?

>> h = ones(8,1)/8

h =

0.1250

0.1250

0.1250

0.1250

0.1250

0.1250

0.1250

0.1250

Then if you have an input signal ecf you can call conv(h, ecg)

[Tu Nguyen]

Thank you so much