HOW TO REMOVE NOISE FROM A SIGNAL?

i have plotted a figure,here i am inckuding the code and files.Now,i want to smooth my output curve,how can i do it?

[Image Analyst]

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 15;

s = load('matlab.mat')

x0=reshape(b',[1,7001]);
t=linspace(0,1,7001);
Y=fft(b);
Yabs=abs(Y);

plot(Yabs,'b');
hold on

x1=reshape(d',[1,7001]);
t=linspace(0,1,7001);
Y1=fft(x1);
Y1abs=abs(Y1);
plot(Y1abs,'g');

x2=reshape(f',[1,7001]);
t=linspace(0,1,7001);
Y2=fft(x2);
Y2abs=abs(Y2);
plot(Y2abs,'r');

x3=reshape(h',[1,7001]);
t=linspace(0,1,7001);
Y3=fft(x3);
Y3abs=abs(Y3);
plot(Y3abs,'k');

x4=reshape(j',[1,7001]);
t=linspace(0,1,7001);
Y4=fft(x4);
Y4abs=abs(Y4);
plot(Y4abs,'y');

x5=reshape(l',[1,7001]);
t=linspace(0,1,7001);
Y5=fft(x5);
Y5abs=abs(Y5);
plot(Y5abs,'m');
plot([0 ,8000], [.05*10^4,.05*10^4],'k')

%yline(3.3614);
%yticks(unique([yticks(0.5) 3.3614]));

s =

struct with fields:

x3: [1×7001 string]

Unrecognized function or variable 'b'.

Error in test1 (line 11)

x0=reshape(b',[1,7001]);

So, what is b, d, f, and h, etc.? And where do you use x3 that came in from the mat file? You just create a new x3 from h and ignore the one from the mat file.

[shahriar sowad]

i am sorry for the previous file

Answer 1

[Sulaymon Eshkabilov]

You code contains some errs and moreover, your question to smooth the curve is not quite appropriate for FFT. In case, you need to smooth your data before FFT calcs, then it makes sense to apply some sort of low-pass or high-pass filter w.r.t what data component to preserve and diminish. Here is a sample code how to do it:

load matlab.mat
X3 = double(x3);
X=X3;
t=linspace(0,1,7001);
Fs = 1/t(2);          % Sampling frequency                    
L = 7001;             % Length of signal
Xfiltered=lowpass(x,200,Fs);              % Low-pass to preserve the signal under 200 Hz
% Xfiltered=highpass(x,200,Fs);           % High-pass to preserve the signal beyond 200 Hz
N = 2^nextpow2(L);
Y = fft(Xfiltered, N);
P2 = abs(Y/L);
P1 = P2(1:L/2+1);
P1(2:end-1) = 2*P1(2:end-1);
f = Fs*(0:(L/2))/L;
plot(f,P1, 'b'); grid on
title('Single-Sided Amplitude Spectrum of S(t)')
xlabel('f (Hz)')
ylabel('|P1(f)|')