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| − | % Question 1 | + | % Question 1: |
| − | function[] = question1() | + | function[] = question1() |
| − | N1 = sin(2*pi*391.995436*[0:0.0001:1]); %G quarter note | + | N1 = sin(2*pi*391.995436*[0:0.0001:1]); %G quarter note |
| − | N2 = sin(2*pi*466.1637615*[0:0.0001:1]); %Bflat quarter | + | N2 = sin(2*pi*466.1637615*[0:0.0001:1]); %Bflat quarter |
| − | N3 = sin(2*pi*523.2511306*[0:0.0001:1.5]); %C dotted quarter | + | N3 = sin(2*pi*523.2511306*[0:0.0001:1.5]); %C dotted quarter |
| − | N4 = sin(2*pi*391.995436*[0:0.0001:1]); %G quarter | + | N4 = sin(2*pi*391.995436*[0:0.0001:1]); %G quarter |
| − | N5 = sin(2*pi*466.1637615*[0:0.0001:1]); %Bflat quarter | + | N5 = sin(2*pi*466.1637615*[0:0.0001:1]); %Bflat quarter |
| − | N6 = sin(2*pi*554.3652618*[0:0.0001:0.5]); %Csharp eigth | + | N6 = sin(2*pi*554.3652618*[0:0.0001:0.5]); %Csharp eigth |
| − | N7 = sin(2*pi*523.2511306*[0:0.0001:2]); %C half | + | N7 = sin(2*pi*523.2511306*[0:0.0001:2]); %C half |
| − | rest = [0:0.0001:2.5]; %rest half and an eigth | + | rest = [0:0.0001:2.5]; %rest half and an eigth |
| − | %smoke on the water (part a): | + | % smoke on the water (part a): |
| − | tune = [N1 N2 N3 N4 N5 N6 N7 N1 N2 N3 N2 N1 rest]; | + | tune = [N1 N2 N3 N4 N5 N6 N7 N1 N2 N3 N2 N1 rest]; |
| + | wavwrite(0.02*tune, 18667, 'question1a.wav'); | ||
| + | |||
| + | % twice as fast (part b): | ||
| + | wavwrite(0.02*tune, 37333, 'question1b.wav'); | ||
| − | newtune = [1:1:(length(tune)/2)]; | + | % y(t) = x(2t) (part c): |
| − | + | newtune = [1:1:(length(tune)/2)]; | |
| − | for i=1:(length(tune)/2) | + | for i=1:(length(tune)/2) |
| − | + | newtune(1,i) = tune(1,2*i); | |
| − | end | + | end |
| + | wavwrite(0.02*newtune, 18667, 'question1c.wav'); | ||
| + | |||
| − | |||
| − | |||
| + | Sound files: [[Media:question1a.wav]] | ||
| + | [[Media:question1b.wav]] | ||
| + | [[Media:question1c.wav]] | ||
| − | + | ||
| − | 1. | + | |
| − | 2. I | + | % Question 2: |
| + | function[] = question2() | ||
| + | [y, Fs] = wavread('Beatles.wav'); | ||
| + | y = flipud(y); | ||
| + | wavwrite(y, Fs, 'question2.wav'); | ||
| + | |||
| + | |||
| + | |||
| + | Sound file: [[Media:question2.wav]] | ||
| + | |||
| + | 1. The repeated phrase was "number nine". | ||
| + | 2. I couldn't hear any message in the reversed version. | ||
Latest revision as of 19:18, 14 January 2011
% Question 1: function[] = question1() N1 = sin(2*pi*391.995436*[0:0.0001:1]); %G quarter note N2 = sin(2*pi*466.1637615*[0:0.0001:1]); %Bflat quarter N3 = sin(2*pi*523.2511306*[0:0.0001:1.5]); %C dotted quarter N4 = sin(2*pi*391.995436*[0:0.0001:1]); %G quarter N5 = sin(2*pi*466.1637615*[0:0.0001:1]); %Bflat quarter N6 = sin(2*pi*554.3652618*[0:0.0001:0.5]); %Csharp eigth N7 = sin(2*pi*523.2511306*[0:0.0001:2]); %C half
rest = [0:0.0001:2.5]; %rest half and an eigth
% smoke on the water (part a): tune = [N1 N2 N3 N4 N5 N6 N7 N1 N2 N3 N2 N1 rest]; wavwrite(0.02*tune, 18667, 'question1a.wav'); % twice as fast (part b): wavwrite(0.02*tune, 37333, 'question1b.wav');
% y(t) = x(2t) (part c):
newtune = [1:1:(length(tune)/2)];
for i=1:(length(tune)/2)
newtune(1,i) = tune(1,2*i);
end
wavwrite(0.02*newtune, 18667, 'question1c.wav');
Sound files: Media:question1a.wav Media:question1b.wav Media:question1c.wav
% Question 2:
function[] = question2()
[y, Fs] = wavread('Beatles.wav');
y = flipud(y);
wavwrite(y, Fs, 'question2.wav');
Sound file: Media:question2.wav
1. The repeated phrase was "number nine". 2. I couldn't hear any message in the reversed version.
