Read the reference I supplied again, http://www.dsprelated.com/showarticle/63.php! It shows how to use smaller FFT sizes to calculate a 24-point FFT. You can take this same approach to calculate your 20-point FFT.

.chris Start a New Thread

well well......don't understand how to decomposed 20 points as 8 points,8points and 4 points.???? I think we need a special algorithm here????
please help me as I said decomposition of 20 points = 4*5 or 20points= 2*2*5 and i need an impletation of this processor in vhdl .......thanks a lot
//REGARDS Start a New Thread

>** where I have decomposed N=2*2*5. I have already written radix-2 processor in vhdl but now I'm facing the problem when it is about N=5 in vhdl. I have searched a lot on google but not satisfied. Please help me how to write code in vhdl for N=5. Thanks
>

You would be better off computing 8point, 8point, and a 4point. See the following for more information, http://www.dsprelated.com/showarticle/63.php.

.chris Start a New Thread

Hello,
I'm new in the dsp world. I am doing a project that is about an implememtation of 20-points fft in vhdl.
** where I have decomposed N=2*2*5. I have already written radix-2 processor in vhdl but now I'm facing the problem when it is about N=5 in vhdl. I have searched a lot on google but not satisfied. Please help me how to write code in vhdl for N=5. Thanks Start a New Thread