The Fourier Transforms: Difference between revisions

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==== Shifting the function changes the phase of the spectrum ===
==== Shifting the function changes the phase of the spectrum ===


     <math>\mathcal{F}[x(t-a)] = X(t)e^{-j2\pi f a}\</math>
     <math>\mathcal{F}[x(t-a)] = X(t)e^{-j2\pi f a}</math>
 


==== Frequency and amplitude are affected when changing spatial scale inversely ====
==== Frequency and amplitude are affected when changing spatial scale inversely ====

Revision as of 10:55, 12 October 2007

The Fourier transform was named after Joseph Fourier, a French mathematician. A Fourier Transform takes a function to its frequency components.


Properties of a Fourier Transform:

Properties of a Fourier Transform:

Linearity

   [a*x(t)+b*y(t)]=a*X(f)+b*Y(f)


= Shifting the function changes the phase of the spectrum

   [x(ta)]=X(t)ej2πfa

Frequency and amplitude are affected when changing spatial scale inversely

   [x(a*t)]=1aX(fa)


frac{x(t) - x(-t)}{2}</math>