Uebung5_1

close all;
% a)
load Signal.mat x


% b)
Fs = 1000;                      % samples per second
dt = 1/Fs;                     % seconds per sample
StopTime = 1;                  % seconds
t = (0:dt:StopTime-dt)';       %Zeitvektor
N = size(t,1);

figure;
plot(t, x);
title('Zeitsignal x');
xlabel('Zeit in s -->');
ylabel('Amplitude -->');
% C)
%Fourier Transform:
X = fft(x);


%Frequenz
dF = Fs/N;
f = -Fs/2:dF:Fs/2-dF;


%Spektrum:
figure;
plot(f,abs(X)/N);
title('Spektrum');
xlabel('Frequenz in Hz -->');
ylabel('Magnitude -->');

 % d)


   for i = 1:1000
    if mod(i, 20) == 0
        ds(i) = 0;
    else
        ds(i) = x(i);
    end
   end


 ds(ds == 0) = [];


 Fs2 = 949;                      % samples per second
 dt2 = 1/Fs2;                     % seconds per sample
 StopTime2 = 1;                  % seconds
 t2 = (0:dt2:StopTime2-dt2)';
 N2 = size(t2,1);

 figure;
 plot(t(1:949),ds);              %Zeitsignal -49Hz
 title('Zeitsignal ds');
 xlabel('Zeit in s -->');
 ylabel('Amplitude -->');

 % f)

 X2 = fft(ds);
 X2 = abs(X2);

   %Frequenz:
   dF2 = Fs2/N2;
   f2 = -Fs2/2:dF2:Fs2/2-dF2;

   %Spektrum
 figure;
 plot(f2,abs(X2)/N2);
 title('Spektrum');
 xlabel('Frequenz in Hz -->');
 ylabel('Magnitude -->');

 figure;
 num_bins = length(X2);
 plot([0:1/(num_bins/2-1):1], X2(1:num_bins/2)/N);
 title('Spektrum');
 xlabel('Normalized Frequency (\times\pi rad/sample)')
 ylabel('Magnitude -->');

% g)

p = Filter(949,1,150,ds);
figure;
plot(t(1:949),p);

X3 = abs(fft(p));

figure;
plot([0:1/(num_bins/2-1):1], X3(1:num_bins/2));




%figure;
%plot(t(1:949), p);



%Fs3 = 1000;
%Ts = 1/1000;
%ds2=0:Ts:1-Ts;

%nfft=length(ds);
%nfft2=2.^nextpow2(nfft);

%fy = fft(ds,nfft2);
%fy=fy(1:nfft2/2);

%xfft=Fs.*(0:nfft2/2-1)/nfft2;

%plot(xfft, abs(fy));

%cut_off = 5/Fs/2;
%order = 32;

%h = fir1(order, cut_off);
%fh = fft(h,nfft2);
%fh = fh(1:nfft2/2);
%mul=fh.*fy;
%figure;
%plot(abs(mul));

%figure;


%p = Filter(949,1,50,fy);
%plot(f(1:512),p);