Welch's method implementation

Hi Dears;

I want to loop through the data 256 points at a time, and 128 points overlap, However, I beleive that my function missing something to perform that because when I run the code, it returns "Unable to perform assignment because the size of the left side is 512-by-1 and the size of the

right side is 256-by-128."

How can I do loop through the data 256 points at a time and 128 points overlap?

I really appreciate for your help

clc;
close all;
clear;
load('ecg_60Hz_Noise_Fs200Hz.mat');
data = ecgn(1:1024)';
Fs = 200;
w = hamming(256);

psd = zeros(512,7);

for i = 0:6
    temp = data(1+256*i:128+i*256)'.*w;
    temp = fft(temp);
    temp = abs(temp).^2;
    psd(:,i+1) = temp;
end
psd1 = mean(psd,2);

psd1 = psd(1:257);

psd1 = psd1/(Fs*sum(w.^2));

psd1(2:end-1)= psd1(2:end-1)*2;

figure
plot(f,psd1);

Answer 1

[Tala]

Instead of the for loop, I would reshape the array first.

temp0 = reshape(ecgn,[256,4]);
temp1=fft(temp0);
temp2=abs(temp1).^2;

psd=temp2;

then the rest of your calculations...