65 lines
1.3 KiB
Matlab
65 lines
1.3 KiB
Matlab
[ x, Fs ] = audioread("0964590.wav");
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Fs
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X = fftshift(fft(x));
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dF = Fs / length(X);
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dOmega = 2*pi / length(X);
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f = -Fs/2 : dF : (Fs-dF)/2; % opd 2.1
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omega = -pi : dOmega : pi-dOmega; % opd 2.2
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%plot(f, 20 * log10(abs(X))); % opd 2.1
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%plot(omega, 20 * log10(abs(X))); % opd 2.2
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%title('Frequentiespectrum |X(f)|');
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%xlabel('f (Hz)');
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%ylabel('|X| (dB)');
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%grid;
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Oc = 0.461983;
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Og = 0.05;
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filterOrde = 1024*1024;
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Oa = Oc - 0.5*Og;
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Ob = Oc + 0.5*Og;
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H = ones(1, length(X));
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for i = round((pi-Oa)/dOmega) : round((pi-Ob)/dOmega)
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H(i) = 0;
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end
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for i = round((pi+Oa)/dOmega) : round((pi+Ob)/dOmega)
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H(i) = 0;
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end
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%plot(omega, H);
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%title('filter ding |H(f)|');
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%xlabel('f (Hz)');
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%ylabel('|X| (dB)');
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%grid;
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h = zeros(1, length(filterOrde));
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j = 1i;
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n = 0 : filterOrde/2;
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%h = 1/(2*pi) * ( exp(i*Ob*n) - exp(i*Oa*n) + exp(i*-Ob*n) - exp(i*-Oa*n) )/exp(j*n);
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%h(n==0) = 1/(2*pi) * Og*2;
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h = ( exp(j*Oa*n) - 1 ...
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+ exp(j*(2*pi)*n) - exp(j*(2*pi-Oa)*n) ...
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+ exp(j*(2*pi-Ob)*n) - exp(j*Ob*n) ...
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)./(j*n*(2*pi));
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h(n==0) = 1/(2*pi) * 2*pi - Og*2;
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%plot(0 : filterOrde/2, h);
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Fa = Oa * Fs/(2*pi)
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Fb = Ob * Fs/(2*pi)
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freqz(h, 1, 0 : Fs/2, Fs);
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y = conv(x, h, 'same');
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Y = fftshift(fft(y));
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dF = Fs / length(Y);
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f = -Fs/2 : dF : (Fs-dF)/2;
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%plot(f, 20 * log10(abs(Y)));
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