From f4fdd1cb14e96ffbc10e678cb4c6e9bc73b3392e Mon Sep 17 00:00:00 2001 From: Louis GRAZ Date: Mon, 25 Mar 2024 11:41:42 +0100 Subject: [PATCH] Add complete file with complete 4.2.3 Downsampling part --- Code/speech_analysis_complete_sampling_part.m | 182 ++++++++++++++++++ 1 file changed, 182 insertions(+) create mode 100644 Code/speech_analysis_complete_sampling_part.m diff --git a/Code/speech_analysis_complete_sampling_part.m b/Code/speech_analysis_complete_sampling_part.m new file mode 100644 index 0000000..ab9df08 --- /dev/null +++ b/Code/speech_analysis_complete_sampling_part.m @@ -0,0 +1,182 @@ +pkg load signal + +% Load the audio signal +[signal, Fs] = audioread("Sound/modifiedmodulator.wav"); +t = (0:length(signal)-1) / Fs; % Time vector + +% Design low-pass filter +lpf_order = 30; +lpf_cutoff_freq = 1000; % in Hz +lpf_filter = fir1(lpf_order, lpf_cutoff_freq / (Fs/2)); + +% Apply low-pass filter to the original signal +filtered_signal_lpf = filter(lpf_filter, 1, signal); + +% Downsample the filtered signal using downsample() +downsampled_signal1 = downsample(filtered_signal_lpf, round(Fs/4000)); + +% Downsample the filtered signal using decimate() +downsampled_signal2 = decimate(filtered_signal_lpf, round(Fs/4000)); + +% Parameters for measurements +num_measurements = 100; % Number of measurements +durations_dft = zeros(1, num_measurements); +durations_fft = zeros(1, num_measurements); + +for i = 1:num_measurements + % Measure time taken for DFT + tic; + [power_dft, duration_dft] = frequencySpectrum(signal, Fs, false, false); + durations_dft(i) = duration_dft; + + % Measure time taken for FFT with padding + tic; + [power_fft, duration_fft] = frequencySpectrum(signal, Fs, true, false); + durations_fft(i) = duration_fft; +end + +% Calculate average and standard deviation +avg_duration_dft = mean(durations_dft); +std_dev_dft = std(durations_dft); + +avg_duration_fft = mean(durations_fft); +std_dev_fft = std(durations_fft); + +fprintf('Average duration for DFT: %f seconds\n', avg_duration_dft); +fprintf('Standard deviation for DFT: %f seconds\n', std_dev_dft); +fprintf('\n'); +fprintf('Average duration for FFT (with padding): %f seconds\n', avg_duration_fft); +fprintf('Standard deviation for FFT (with padding): %f seconds\n', std_dev_fft); + +% Apply FIR filter +% Design FIR filter +fir_order = 30; +cutoff_freq_fir = 1000; % in Hz +fir_filter = fir1(fir_order, cutoff_freq_fir / (Fs/2)); + +% Apply FIR filter to the original signal +filtered_signal_fir = filter(fir_filter, 1, signal); + +% Check FIR filter stability (FIR filters are always stable) + +% Apply IIR filter +% Design Butterworth IIR filter +iir_order = 8; +cutoff_freq_iir = 1000; % in Hz +[b, a] = butter(iir_order, cutoff_freq_iir / (Fs/2), 'low'); + +% Check IIR filter stability +iir_stable = all(abs(roots(a)) < 1); % Check if all poles are inside the unit circle +fprintf('IIR filter stability: %d\n', iir_stable); + +% Apply IIR filter to the original signal +filtered_signal_iir = filter(b, a, signal); + +% Plot all signals and filtered signals on the same figure +figure; + +% Original Signal +subplot(4, 1, 1); +plot(t, signal); +xlabel('Time (s)'); +ylabel('Amplitude'); +title('Original Signal'); + +% Low-pass Filtered Signal +subplot(4, 1, 2); +plot(t, filtered_signal_lpf); +xlabel('Time (s)'); +ylabel('Amplitude'); +title('Low-pass Filtered Signal'); + +% Downsampled Signal using downsample() +subplot(4, 1, 3); +t_down1 = (0:length(downsampled_signal1)-1) / (Fs/4000); +plot(t_down1, downsampled_signal1); +xlabel('Time (s)'); +ylabel('Amplitude'); +title('Downsampled Signal using downsample()'); + +% Downsampled Signal using decimate() +subplot(4, 1, 4); +t_down2 = (0:length(downsampled_signal2)-1) / (Fs/4000); +plot(t_down2, downsampled_signal2); +xlabel('Time (s)'); +ylabel('Amplitude'); +title('Downsampled Signal using decimate()'); + + +% Plot filtered signals +figure; + +% FIR Filtered Signal +subplot(2, 1, 1); +plot(t, filtered_signal_fir); +xlabel('Time (s)'); +ylabel('Amplitude'); +title('FIR Filtered Signal'); + +% IIR Filtered Signal +subplot(2, 1, 2); +plot(t, filtered_signal_iir); +xlabel('Time (s)'); +ylabel('Amplitude'); +title('IIR Filtered Signal'); + +% Display frequency response of FIR and IIR filters +figure; + +% Frequency response of FIR filter +[h_fir, w_fir] = freqz(fir_filter, 1, 1024, Fs); +subplot(2, 1, 1); +plot(w_fir, 20*log10(abs(h_fir))); +xlabel('Frequency (Hz)'); +ylabel('Magnitude (dB)'); +title('Frequency Response of FIR Filter'); +grid on; + +subplot(2, 1, 2); +plot(w_fir, angle(h_fir)); +xlabel('Frequency (Hz)'); +ylabel('Phase (rad)'); +title('Phase Response of FIR Filter'); +grid on; + +% Frequency response of IIR filter +[h_iir, w_iir] = freqz(b, a, 1024, Fs); +figure; +subplot(2, 1, 1); +plot(w_iir, 20*log10(abs(h_iir))); +xlabel('Frequency (Hz)'); +ylabel('Magnitude (dB)'); +title('Frequency Response of IIR Filter'); +grid on; + +subplot(2, 1, 2); +plot(w_iir, angle(h_iir)); +xlabel('Frequency (Hz)'); +ylabel('Phase (rad)'); +title('Phase Response of IIR Filter'); +grid on; + +% Downsample filtered signals to 4000 Hz +downsampled_filtered_signal_fir = downsample(filtered_signal_fir, round(Fs/4000)); +downsampled_filtered_signal_iir = downsample(filtered_signal_iir, round(Fs/4000)); + +% Compare downsampled filtered signals +figure; + +% FIR Filtered Signal (downsampled) +subplot(2, 1, 1); +plot(t_down1, downsampled_filtered_signal_fir); +xlabel('Time (s)'); +ylabel('Amplitude'); +title('FIR Filtered Signal (Downsampled)'); + +% IIR Filtered Signal (downsampled) +subplot(2, 1, 2); +plot(t_down1, downsampled_filtered_signal_iir); +xlabel('Time (s)'); +ylabel('Amplitude'); +title('IIR Filtered Signal (Downsampled)'); +