ASN11 - Leakage demonstration in Octave: Difference between revisions
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fs=1500 | fs=1500 | ||
t=[1:20]/fs; | 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 | Example octave script with leakage | ||
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fs=1500 | fs=1500 | ||
t=[1:20]/ | t=[1:20]/500; %does not include whole periods | ||
y=sin(2*pi*t); | y=sin(2*pi*t); | ||
x= dft(y); | x= dft(y,t); %function x is not continuous and demonstrates leakage | ||
Latest revision as of 16:21, 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