2020-12-31 23:11:10 +00:00
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%% Inicialização do ambiente
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clear; close all; clc
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%% >Exercício 8<
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%% Input
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[y, Fs] = audioread("Canto1.mp3"); % Signal and Sampling Frequency
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signal = y(:,1); % Discard second channel
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Fn = Fs/2; % Nyquist Frequency (Hz)
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L = length(signal); % Signal Length
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%% Compute the DFT
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dft = fft(signal)./L;
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magnitude = 10.*log10(abs(dft).^2); % power is squared, thus 10
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Fv = linspace(0, 1, L)*Fn; % Frequency Vector
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%% High-pass Filter
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not_to_cutoff_indices = magnitude > -96;
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dft_filtered = not_to_cutoff_indices.*dft;
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magnitude_filtered = not_to_cutoff_indices.*magnitude;
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signal_filtered = ifft(dft_filtered.*L);
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%% Output
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Fv_half = linspace(0, 1, fix(L/2)+1)*Fn;
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y = abs(dft(1:(L/2+1)));
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y_filtered = abs(dft_filtered(1:(L/2+1)));
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figure(1)
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subplot(2,3,1)
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plot(Fv_half, y)
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grid
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xlabel("Frequência (Hz)"); ylabel("|H_{1}(f)|"); title("DFT do Sinal")
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subplot(2,3,4)
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plot(Fv_half, y_filtered)
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grid
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xlabel("Frequência (Hz)"); ylabel("|H_{1}(f)|"); title("DFT do Sinal Filtrado")
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subplot(2,3,2)
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plot(Fv_half, signal(1:(L/2+1)))
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grid
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xlabel("Frequência (Hz)"); ylabel("Amplitude"); title("Sinal")
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subplot(2,3,5)
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2020-12-31 23:36:15 +00:00
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plot(Fv_half, signal_filtered(1:(L/2+1)))
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2020-12-31 23:11:10 +00:00
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grid
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xlabel("Frequência (Hz)"); ylabel("Amplitude"); title("Sinal Filtrado")
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subplot(2,3,3)
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%plot(Fv, magnitude);
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plot(Fv_half, mag2db(y))
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grid
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xlabel("Frequência (Hz)"); ylabel("Ganho (dB)"); title("Ganho do Sinal")
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subplot(2,3,6)
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plot(Fv_half, mag2db(y_filtered))
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grid
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xlabel("Frequência (Hz)"); ylabel("Ganho (dB)"); title("Ganho do Sinal Filtrado")
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%sound(signal_filtered, Fs);
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%audiowrite('canto1_high_pass.flac', signal_filtered, Fs);
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