% Sharifah Fareena Aljunid % BME 301 Homework 1 % Professor Mimi Boutin
% Part 1 clear clc delta = 0.00005;
% A loop is made to separate Question 1 into 3 parts
for p = 1:3
if p ==2
bpm = 112*2; % indicating the tune will be twice as fast
else
bpm = 112; % normal beats per minute
end
% Calculation to determine the length of the in seconds
H = 0:delta:(2*60/bpm);
Q = 0:delta:(1*60/bpm);
E = 0:delta:(0.5*60/bpm);
DQ = 0:delta:(1.5*60/bpm);
% Part 3, rescaling the frequency of A4
if p == 3
fa = 880; % the frequency is double the original as y(t) = x(2t)
else
fa = 440; % original frequency of A4
end
% Calculation of the frequency of any note related to the frequency of A4
fG = 2^(-2/12)*fa;
fC = 2^(3/12)*fa;
fBf = 2^(1/12)*fa;
fDf = 2^(4/12)*fa;
% Calculation of all note length using a sine wave
GQ = sin(2*pi*fG*Q);
BfQ = sin(2*pi*fBf*Q);
CDQ = sin(2*pi*fC*DQ);
DfE = sin(2*pi*fDf*E);
CH = sin(2*pi*fC*H);
% The tune of the song to be played
z = [GQ, BfQ, CDQ, GQ, BfQ, DfE, CH, GQ, BfQ, CDQ, BfQ, GQ];
sound(z,1/delta);
% Adjust song according to what is asked for in Question 1
if p == 1
wavwrite(z,1/delta,32,'Normal melody')
elseif p == 2
wavwrite(z,1/delta,32,'Faster melody')
else
wavwrite(z,1/delta,32,'Transformation x(2t)')
end
end
Media:Normal melody.wav
Media:Faster melody.wav
Media:Transformation x(2t).wav
% Part 2
clear
clc
% Use wavread to read and store the Beatles song
[song,Fs] = wavread('Beatles.wav');
song_reversed = flipud(song); % this will flip the song and play it in reverse
sound(song_reversed,Fs);
The song played in forward say "Number Nine".
When it is played in reversed the sound that comes out is "Turn me on dead man".
