%Shishir Biswas %ECE 301: Signals and Systems %Professor Boutin %Assignment 1 %1/18/2011

clc; clear;

%PART 1 bpm = 112;  %Beats per minute bps = 112 / 60;  %Beats per second deltat = 5e-5;  %Time increment

eighth = 0:deltat:(.5 / bps);  %Duration of an eigth note quarter = 0:deltat:(1 / bps);  %Duration of a quarter note d_quarter = 0:deltat:(1.5 / bps);  %Duration of a dotted quarter note half = 0:deltat:(2 / bps);  %Duration of a half note

A = 440;  %Frequency of middle A (given) G = (2 ^ (-2 / 12)) * A;  %Frequency of G B_flat = (2 ^ (1 / 12)) * A;  %Frequency of B flat C = (2 ^ (3 / 12)) * A;  %Frequency of C D_flat = (2 ^ (4 / 12)) * A;  %Frequency of D flat

melody_1 = [sin(2 * pi * G * quarter), sin(2 * pi * B_flat * quarter), sin(2 * pi * C * d_quarter), sin(2 * pi * G * quarter), sin(2 * pi * B_flat * quarter), sin(2 * pi * D_flat * eighth), sin(2 * pi * C * half), sin(2 * pi * G * quarter), sin(2 * pi * B_flat * quarter), sin(2 * pi * C * d_quarter), sin(2 * pi * B_flat * quarter), sin(2 * pi * G * quarter), sin(0 * half)];  %Pieces together the notes with appropriate durations of the melody wavplay(melody_1, 1 / deltat);  %Plays melody wavplay(melody_1, 2 / deltat);  %Plays melody twice as fast

melody_2 = [sin(4 * pi * G * quarter), sin(4 * pi * B_flat * quarter), sin(4 * pi * C * d_quarter), sin(4 * pi * G * quarter), sin(4 * pi * B_flat * quarter), sin(4 * pi * D_flat * eighth), sin(4 * pi * C * half), sin(4 * pi * G * quarter), sin(4 * pi * B_flat * quarter), sin(4 * pi * C * d_quarter), sin(4 * pi * B_flat * quarter), sin(4 * pi * G * quarter), sin(0 * half)];%Pieces together the notes with appropriate durations of the melody with the transformation x(2t) wavplay(melody_2, 1 / deltat);  %Plays melody

wavwrite(melody_1, 1 / deltat, '1A'); wavwrite(melody_1, 2 / deltat, '1B'); wavwrite(melody_2, 1 / deltat, '1C');

%PART 2 [X, f] = wavread('Beatles.wav');  %Reads the sound file Y = flipud(X);  %Reverses the sound file wavwrite(Y, f, 'Beatles_Flipped');  %Writes the reversed sound file into a folder %When played normally, the file sounds like a man repeating the words %"Number Nine." When reversed, the new file sounds like a man saying "turn %me on edmon" or something along those lines.

Media:1A.wav Media:1B.wav Media:1C.wav Media:Beatles_Flipped.wav

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