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Old 2002-10-28, 14:18   #7
wpolly's Avatar
Sep 2002
Vienna, Austria

3·73 Posts

Originally Posted by creative1
how did you create the 'i' matrix to be able to make the transform? everything is was very nice explained but i couldnĀ“t get how you filled that matrix with 1, -1, i, -i values
where did that come from?
|+1 +1 +1 +1| |i^0 i^0 i^0 i^0|
|+1 +i -1 -i|=|i^0 i^1 i^2 i^3|
|+1 -1 +1 -1| |i^0 i^2 i^4 i^6|
|+1 -i -1 +i| |i^0 i^3 i^6 i^9|
For FFT size 2N, just replace the i with cos(pi/N)+i sin(pi/N)(That is, a 2Nth root of 1)and constuct the matrix as above.......

P.S. I am only 14 years old!
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