ASN11 - Leakage demonstration in Octave: Difference between revisions
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Leakage occurs when the Discrete Fourier Transform (DFT) is applied to a signal whose range is not a multiple of the total period. |
Leakage occurs when the Discrete Fourier Transform (DFT) is applied to a signal whose range is not a multiple of the total period. The DFT function assumes that the signal is periodic it when it repeats the function should be periodic. If the sample range is not a multiple of the period them when the DFT repeat the function will have disctonuity at the restarting point. |
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The DFT function assumes that the signal is periodic. |
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Example octave script no leakage |
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fs=1500 |
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t=[1:20]/fs; %is multiple of the period 1/fs |
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y=sin(2*pi*t); |
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x= dft(y,t); %function x is continous |
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Example octave script with leakage |
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fs=1500 |
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t=[1:20]/500; %does not include whole periods |
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y=sin(2*pi*t); |
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x= dft(y,t); %function x is not continuous and demonstrates leakage |
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Latest revision as of 15:21, 21 December 2009
Leakage occurs when the Discrete Fourier Transform (DFT) is applied to a signal whose range is not a multiple of the total period. The DFT function assumes that the signal is periodic it when it repeats the function should be periodic. If the sample range is not a multiple of the period them when the DFT repeat the function will have disctonuity at the restarting point.
Example octave script no leakage
fs=1500
t=[1:20]/fs; %is multiple of the period 1/fs
y=sin(2*pi*t);
x= dft(y,t); %function x is continous
Example octave script with leakage
fs=1500
t=[1:20]/500; %does not include whole periods
y=sin(2*pi*t);
x= dft(y,t); %function x is not continuous and demonstrates leakage