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PRINCIPLES DIGITAL AUDIO AND VIDEO

ASSIGNMENT 2

ADIL SHAH 1600228

Q1 A TRIANGULAR

fs = 44100; [y fs] = wavread('Triangular'); plot(y); sound(y,fs); x = fftshift(abs(fft(y)))/length(y); plot(x);

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Q1 B SAW TOOTH

fs = 44100, 

[y fs] = wavread('Saw Tooth'); plot(y); sound(y,fs); x = fftshift(abs(fft(y)))/length(y); plot(x);

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Q1 C IMPULSE

fs = 44100, [y fs] = wavread('Impulse'); plot(y); sound(y,fs); x = fftshift(abs(fft(y)))/length(y); plot(x); 

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Q1 D WHITE NOISE

fs = 44100, [y fs] = wavread('White Noise'); plot(y); sound(y,fs); x = fftshift(abs(fft(y)))/length(y); plot(x);

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NOISE Q1 E PINK

fs = 44100, [y fs] = wavread('Pink Noise'); plot(y); sound(y,fs); x = fftshift(abs(fft(y)))/length(y); plot(x); 

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Q1 F DIAL TONE

fs = 11025, [y fs] = wavread('Dial_tone'); plot(y); sound(y,fs); x = fftshift(abs(fft(y)))/length(y); plot(x); 

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Q1 G MISSILE

fs = 11025, [y fs] = wavread('Missile'); plot(y); sound(y,fs); x = fftshift(abs(fft(y)))/length(y); plot(x);

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Q1 H MUSIC

fs = 44100, [y fs] = wavread('Music'); plot(y); sound(y,fs); x = fftshift(abs(fft(y)))/length(y); plot(x); 

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Q1 I SINES

fs = 16000, [y fs] = wavread('Sines'); plot(y); sound(y,fs); x = fftshift(abs(fft(y)))/length(y); plot(x);

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Q1 J SQUARE WAVE OF FREQUENCY 1000 HZ

i=1:1000; for n=1:10000 

if(mod(n,10)>=5) y(n)=1; 

else y(n)=0; 

end end fs = 10000; sound(y,fs); x = fftshift(abs(fft(y)))/length(y); plot(x) 

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Q3 SQUARE WAVE OF FREQUENCY 5 HZ AND AMPLITUDE 1

FOURIER SPECTRUM OF THE SQUARE WAVE

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Phase plot for the first three harmonics

Phase plot of first six harmonics

THE OSCILLATIONS IN THE PEAKS OF THE PHASE PLOT CLEARLY INDICATE THE DIFFERENCE BETWEENTHE TWO HARMONICS

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CODEclear all t=0:0.001:10; for n=1:length(t) 

if(mod(t(n),0.2)

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Question # 2

[y fs] = wavread('audio1'); sound(y,fs); x = fftshift(abs(fft(y)))/length(y); plot(x); 

Fourier spectrum of first file.

Listening to audio and plotting the spectrum shows that it contains only one frequency.

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Fourier spectrum of second audio file.

Listening to audio one can slightly guess that it has two frequencies.

Moreover, Zooming into the plot makes it clear that there are two frequencies. The second peak is at

0.0025 with an amplitude of 0.25 which is 0.01 tunes the amplitude of the first peak.

clear all fs = 8000; [y fs] = wavread('audio2');

 sound(y,fs); x = fftshift(abs(fft(y)))/length(y); stem(x);