lista 8-9

clear all; close all;
fs =1000;
L=32;
N=4096;

w1 = ones(1,L);
w2= hamming (L);
w3 =hanning(L);
w4= blackman(L);

figure(1)
plot(w1,'k');
hold;
plot(w2,'b');
plot(w3,'g');
plot(w4,'r');
hold;
f=linspace(0,fs/2,N/2+1);
wa1=abs(fft(w1,N));
wa2=abs(fft(w2,N));
wa3=abs(fft(w3,N));
wa4=abs(fft(w4,N));

% plot(w2,'b');
% plot(w3,'g');
% plot(w4,'r');

xlabel('próbki'); ylabel('amplituda');
legend('okno prostokątne','okno hamminga','okno hanninga','okno blackmana');
%'okno hamminga','okno hanninga','okno blackmana'
figure(2)
plot(f/fs,20*log10(wa1(1:N/2+1)/max(wa1)),'k');
hold;
plot(f/fs,20*log10(wa2(1:N/2+1)/max(wa2)),'b');
plot(f/fs,20*log10(wa3(1:N/2+1)/max(wa3)),'g');
plot(f/fs,20*log10(wa4(1:N/2+1)/max(wa4)),'r');
xlabel('częstotliwośc unormowana f/f_s []')
ylabel('modul widma [dB]')
legend('okno prostokątne','okno hamminga','okno hanninga','okno blackmana')

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
zad 4

clear all; close all;

fs =1000;
L=32;
N=1000;
t=[0:N-1]/fs;
x=sin(2*pi*50.5*t);


f=linspace(0,fs/2,N/2+1);
widmo =abs(fft(x,N));
okno= blackman (N)';

x_w=x.*okno;
widmo_okienkowe=abs(fft(x_w,N));

figure(1);
subplot(211);
plot(t,x);
hold;
plot(t,x_w,'r');
xlabel('czas');
ylabel('x(t)');

subplot(212);
stem(f,widmo_okienkowe(1:N/2+1),'r');
hold;
stem(f,widmo(1:N/2+1),'b');

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
zad 6
clear all;
close all;

[x,fp]=audioread('czepek.wav');


figure(1)
spectrogram(x,256,128,256,fp,'yaxis')
%xy  syg wej
%256 długośc okna próbek do analizy
%128 ilość próbek nakładowana pomiędzy sąsiednymi ramkami
%256 ilość binów na każdą ramke do wyznaczenia przy pomocy fft
%fp częstotliwość probkowania
%'yaxis' zmiana domyślnego wyświetlenia widmo na osi OY

N=length(x);
t=[0:1:N-1]*1000/fp;

figure (2);
plot(t,x);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
zad 7

clear all;
close all;

load('sig.mat');

fp=4000;
N=length(sig);

t=[0:1:N-1]/fp;

figure(1)
spectrogram(sig,256,128,256,fp,'yaxis')


figure (2);
plot(t,sig);