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% Project 3, Engineering Acoustics

% Question 1

% a) - c)

fs= 44100;

rec= audiorecorder(fs, 16, 1);

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record(rec);

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stop(rec);

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y= getaudiodata(rec);

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wavwrite(real(y), fs, 'voiced name 44100.wav')

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sound(real(y), fs)

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t= linspace(0, length(y) ./ fs, length(y));

subplot 311

plot(t, real(y))

axis tight

xlabel('Time (sec)')

ylabel('Amplitude')

title('"Mark Freeman"')

total_time= length(y) / fs; % sec

az= 0;

el= 90;

toffset= 0;

offset= toffset * fs;

win_time= 0.02;

wtime= win_time/4;

win= round(wtime * fs);

h= hamming(win);

percent_overlap= 0.9;

hop= round(win * (1- percent_overlap));

for i= 0: floor((total_time * fs) / hop) - 10

    s= y((i * hop)+1 + offset : floor((i * hop)+win+offset), 1);

    s= s .* h;

    S= 20.*log10(abs(fft(s)));

    if i == 0

        Z1= S(1:round(length(S)/2));

    else

        Z1= cat(2, Z1, S(1:round(length(S)/2)));

    end

end

subplot 312

t1= linspace(0+toffset, total_time+toffset, floor((total_time * fs) / hop +1) - 10);

f= linspace(0, fs/2, (win + 1)/2);

[X,Y]= meshgrid(t1, f);

surf(X,Y,Z1)

axis tight

ylabel('Freq (Hz)')

xlabel('Time (sec)')

zlabel('Power')

lighting phong

shading interp

view(az,el)

xlabel('Time (sec)')

ylabel('Freq (Hz)')

title('Wideband')

wtime= win_time;

win= round(wtime * fs);

h= hamming(win);

percent_overlap= 0.97;

hop= round(win * (1- percent_overlap));

for i= 0: floor((total_time * fs) / hop) - 34

    s= y((i * hop)+1 + offset : round((i * hop)+win+offset), 1);

    s= s .* h;

    S= 20.*log10(abs(fft(s)));

    if i == 0

        Z2= S(1:round(length(S)/2));

    else

        Z2= cat(2, Z2, S(1:round(length(S)/2)));

    end

end

subplot 313

t1= linspace(0+toffset, total_time+toffset, floor((total_time * fs) / hop +1) - 34);

f= linspace(0, fs/2, (win + 1)/2);

[X,Y]= meshgrid(t1, f);

surf(X,Y,Z2)

axis tight

ylabel('Freq (Hz)')

xlabel('Time (sec)')

zlabel('Power')

lighting phong

shading interp

view(az,el)

xlabel('Time (sec)')

ylabel('Freq (Hz)')

title('Narrowband')

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print 'Voice Utterance 44100, dB' -djpeg100 -r200