fft help

I guess this question is not vhdl related but I will be coding this problem in VHDL. I have done some research on fft's and have found a lot of info. My question is: While performing my research I found some info on 4k fft's and 1k fft's. Does anyone know what the 4k and 1k are referring to? I do realize that this will effect my code.

Thanks

rgurrola

I also was wondering what radix2 radix4 means in VHDL terms not wikipedia. By the way if anyone does know the answer and is thinking why doesn't this guy read a dsp book. I have and it still is not making sense to me.

rgurrola