Description

• The circumstances in Part 1 and Part 3 are re-examined with the observer now being a human listening binaurally.

MatLab Code (Part 1)

M-File::::::::: Proj1p4.m

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%User Input

disp('The sound source in this example is a single tone with frequency, F0.');

f0=input('Enter the frequency of the single tone: ');

disp('The tone has an inate loudness or amplitude, a');

a=input('Enter the amplitude of the signal: ');

disp('The sound source is moving at a constant velocity, v.');

v=input('Enter the velocity of the sound source: ');

disp('The sound source begins at a distance, d, from the observer.');

d=input('Enter the initial distance of the sound source: ');

%Constants and Initializations

fs=8000;           %Sampling Rate

c=344;              %Speed of Sound in air

t=0:1/fs:2*(d/v);             %X-Axis, Time, seconds

fo=zeros(1,length(t));      %Initialization vector for perceived frequency

io=zeros(1,length(t));      %Initialization vector for perceived loudness

vo=zeros(1,length(t));      %Initialization vector for relative velocity

%Doppler Calculation Algorithm

for i=1:length(t)

    di=t(i)*v;              %Distance source has traveled since t=0 

    diR=abs(d-di+(.017/2));

    diL=abs(d-di-(.017/2));

    ioR(i)=a/diR;

    ioL(i)=a/diL;

    if i<(d/v)*fs

        fo(i)=f0*(c/(c-v));

        vo(i)=v;

    end

    if i>(d/v)*fs

        fo(i)=f0*(c/(c+v));

        vo(i)=-v;

    end

    if i==(d/v)*fs

        fo(i)=f0;

        vo(i)=v;

        ioR(i)=a;

        ioL(i)=a;

    end

end

soR=[ioR.*sin(2*pi*fo.*t)]';

soL=[ioL.*sin(2*pi*fo.*t)]';

so=[soR, soL];

%Plots

subplot(411); plot(t, fo); title('Observed Frequency');

xlabel('Time, sec'); ylabel('Frequency, Hz');

subplot(412); plot(t, 20*log10(ioL)); title('Oberseved Loudness (Left Ear)');

xlabel('Time, sec'); ylabel('Intensity, dB');

subplot(413); plot(t, 20*log10(ioR)); title('Oberseved Loudness (Right Ear)');

xlabel('Time, sec'); ylabel('Intensity, dB');

subplot(414); plot(t, vo); title('Relative Velocity');

xlabel('Time, sec'); ylabel('Velocity, m/s');

axis([0 2*d/v -v-10 v+10]);

%Wav Write

wavwrite(so, fs, 'P4');

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Sample Execution

The sound source in this example is a single tone with frequency, F0.

Enter the frequency of the single tone: 440

The tone has an inate loudness or amplitude, a

Enter the amplitude of the signal: 1

The sound source is moving at a constant velocity, v.

Enter the velocity of the sound source: 20

The sound source begins at a distance, d, from the observer.

Enter the initial distance of the sound source: 30

Generated Wave File :::::  P4.wav

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LINKS

EEN502 Project 1 Part 1

EEN502 Project 1 Part 2

EEN502 Project 1 Part 3

EEN502 Project 1 Part 4 (A)

EEN502 Project 1 Part 4 (B)