Difference between revisions of "Lectures"

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~~Here is a Matlab script reflecting~~ Lecture 1~~. The script plays various audio signals. Copy and paste the script into an m-file and play:~~

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[[Lecture 1]]

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~~load handel; %Loads 2 variables, y and Fs. y is a signal containing~~

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[http://web.ics.purdue.edu/~huffmalm/301SU09/ComplexNumberOverview.pdf Complex Number Handout]

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~~information~~: ~~a vector of numbers representing an audio clip~~. ~~Fs is the~~

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~~sampling frequency~~.

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~~sound(y,Fs); %play the audio file at the appropriate sampling frequency~~.

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~~input('Press enter to hear the same audio with 1~~/~~4 the samples')~~

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~~downsample = 4; %factor to decrease sampling rate by~~

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~~sound(y(1:downsample:end)*downsample,Fs~~/~~downsample); %Plays the same signal with only~~

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1/~~4 of the original "information~~.~~" Note the degradation in quality~~

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~~input('Press enter to hear the same audio with 1/100 of the original samples')~~

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~~downsample = 100; %factor to decrease sampling rate by~~

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~~sound(y(1:downsample:end)*downsample,Fs/downsample); %Plays the same signal with only~~

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~~1/100 of the original "information." Original audio is nearly unrecognizable.~~

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~~input('Press enter to hear a constant tone note A')~~

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~~delta = 0.00005; %Sampling period~~

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~~t = 1:delta:3; %a vector representing 3 seconds of time~~

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~~x = sin(2*pi*440*t); %a vector representing the sinusoid tone A~~

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~~sound(x,1/delta);~~

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~~input('Press enter to hear a tone note A an octave higher')~~

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~~x = sin(2*pi*880*t); %a vector representing the sinusoid tone A an octave higher~~

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~~sound(x,1/delta);~~

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Difference between revisions of "Lectures" - Rhea

Latest revision as of 05:44, 18 June 2009

Alumni Liaison

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-Here is a Matlab script reflecting Lecture 1.  The script plays various audio signals. Copy and paste the script into an m-file and play:
+[[Lecture 1]]
-load handel; %Loads 2 variables, y and Fs.  y is a signal containing
+[http://web.ics.purdue.edu/~huffmalm/301SU09/ComplexNumberOverview.pdf Complex Number Handout]
-information: a vector of numbers representing an audio clip.  Fs is the
-sampling frequency.
-sound(y,Fs); %play the audio file at the appropriate sampling frequency.
-input('Press enter to hear the same audio with 1/4 the samples')
-downsample = 4; %factor to decrease sampling rate by
-sound(y(1:downsample:end)*downsample,Fs/downsample); %Plays the same signal with only
-/4 of the original "information." Note the degradation in quality
-input('Press enter to hear the same audio with 1/100 of the original samples')
-downsample = 100; %factor to decrease sampling rate by
-sound(y(1:downsample:end)*downsample,Fs/downsample); %Plays the same signal with only
-/100 of the original "information." Original audio is nearly unrecognizable.
-input('Press enter to hear a constant tone note A')
-delta = 0.00005; %Sampling period
-t = 1:delta:3; %a vector representing 3 seconds of time
-x = sin(2*pi*440*t); %a vector representing the sinusoid tone A
-sound(x,1/delta);
-input('Press enter to hear a tone note A an octave higher')
-x = sin(2*pi*880*t); %a vector representing the sinusoid tone A an octave higher
-sound(x,1/delta);