103 lines
2.7 KiB
Matlab
103 lines
2.7 KiB
Matlab
pkg load signal
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clear all
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close all
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[y,fs]=audioread('./data/modulator22.wav');
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t=0:1/fs:length(y)/fs-1/fs;
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##figure;
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##set(gcf, 'name','Signal of origin');
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##plot(t,y);
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##xlabel('time(s)');
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##ylabel('amplitude(n.u.');
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audiowrite('./data/modulator22_speedown.wav', y , fs/2);
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[y_speedown,fs_speedown]=audioread('./data/modulator22_speedown.wav');
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t_speedown=0:1/fs_speedown:length(y_speedown)/fs_speedown-1/fs_speedown;
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##figure;
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##set(gcf, 'name','Speed down of the signal of origin');
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##plot(t_speedown,y_speedown);
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##xlabel('time(s)');
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##ylabel('amplitude(n.u.');
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%frequencySpectrum(y_speedown, fs_speedown, false);
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%frequencySpectrum(y_speedown, fs_speedown, true);
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%spectrogram(y_speedown, fs_speedown, 5, 30);
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%spectrogram(y_speedown, fs_speedown, 5, 5);
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##y_downsampled = downsample(y, 2);
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##fs_downsample = fs/2;
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##audiowrite('./data/modulator22_downsample.wav', y_downsampled , fs_downsample);
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##t_downsample=0:1/fs_downsample:length(y_downsampled)/fs_downsample-1/fs_downsample;
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##y_decimated = decimate(y, 2);
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##fs_decimate = fs/2;
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##audiowrite('./data/modulator22_decimate.wav', y_decimated , fs_decimate);
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##t_decimate=0:1/fs_decimate:length(y_decimated)/fs_decimate-1/fs_decimate;
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##
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##figure;
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##set(gcf, 'name','Decimate vs Downsample');
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##title('Decimate vs Downsample');
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##plot(t_downsample,y_downsampled,'b');
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##hold on;
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##plot(t_decimate,y_decimated,'g');
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##xlabel('time(s)');
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##ylabel('amplitude(n.u)');
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##legend('downsample()','decimate()',"location","southeastoutside");
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##
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##frequencySpectrum(y_decimated, fs_decimate, true);
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##frequencySpectrum(y_downsampled, fs_downsample, true);
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%%%FILTER IMPLEMENTATION %%%%
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%creating a low pass filter FIR
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N=30;
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fc=1000;
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bfir=fir1(N,fc/(fs/2));
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freqz(bfir,1);
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%filter the signal
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y_FIR_filter=filter(bfir,1,y);
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%plot of the signal FIR
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##figure;
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##plot(y_FIR_filter,'g');
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%creating a low pass filter IIR
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N=8;
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fc=1000;
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[biir,a]=butter(N,fc/(fs/2));
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freqz(biir,a);
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Z=roots(biir); %zeros of the transfer fct
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P=roots(a); %poles fo the transfer fct
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%representation of zeros/poles in complex plan
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##figure;
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##zplane(Z,P);
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##title('Zeros and poles of the transfer function of the IIR filter');
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##legend('zeros','poles');
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##grid on;
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%filter the signal
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y_IIR_filter=filter(biir,a,y);
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%plot of the signal IIR
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##figure;
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##plot(y_IIR_filter,'b');
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%downsample of the IIR signal
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y_IIR_downsample = downsample(y_downsampled, 2);
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fs_IIR_downsample = fs/2;
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t_IIR_downsample=0:1/fs_IIR_downsample:length(y_IIR_downsample)/fs_IIR_downsample-1/fs_IIR_downsample;
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figure;
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set(gcf, 'name','Downsample of IIR');
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plot(t_IIR_downsample,y_IIR_downsample,'b');
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xlabel('time(s)');
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ylabel('amplitude(n.u)');
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legend('downsample()',"location","southeastoutside");
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