clear all;close all;clc;warning off;
duration=20;sampling=44100;minf=100;maxf=2000;
starttime=0;
L = sampling*duration;
time = linspace(0, duration, sampling*duration);

x=linspace(0,duration,duration*sampling);

[signal,Fs] = audioread('Voice_002.m4a',[starttime*sampling+1,starttime*sampling+duration*sampling]);
subplot(512)
Fs=sampling;
Y = fft(signal);
P2 = abs(Y/L);
P1 = P2(1:L/2);
P1(2:end-1) = 2*P1(2:end-1);
f = Fs*(0:(L/2)-1)/L;ff=[f,fliplr(f)];
plot(f,P1),xlim([0 5000])


f=100;signal1=0.01*sin(2*pi*f*x)';
f=1200;signal2=0.01*sin(2*pi*f*x)';
f=1400;signal3=0.01*sin(2*pi*f*x)';
signal=signal+signal1+signal2+signal3;


subplot(511)
plot(time, signal, 'b*-');title('Signal in time')
grid on;
subplot(513)
Fs=sampling;
Y = fft(signal);
P2 = abs(Y/L);
P1 = P2(1:L/2);
P1(2:end-1) = 2*P1(2:end-1);
f = Fs*(0:(L/2)-1)/L;ff=[f,fliplr(f)];
plot(f,P1),xlim([0 5000])
% return


%ideal suzgec (Kolay anlaşılması için)
subplot(514)
fN=sampling/2;
dummy=find(ff>=1000 & ff<=3000),
Y(dummy)=0+0i;suzgec=ones(length(Y),1);suzgec(dummy)=0;
% plot(ff,suzgec,'r-'),xlim([0 5000])
% hold on
plot(ff,abs(Y/L)),xlim([0 5000])

subplot(515)
signalsuz = real(ifft(Y));
plot(time, signalsuz, 'b*-');title('Signal in time')

% return
tic
sound(signalsuz,Fs);
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