Hi!

I have a fairly good understanding of FFT. I know what Laplace Transform, Fourier and Z Transform is, and I know how to use it. I made a simple FFT in C once that I used to look at DTMF signals ( like this

) and I also did a vibration sensor (

).

https://github.com/Spekkio/dig_filterBut I want to implement a DFT in an FPGA to boost the speed of the data analysis. I know a little bit VHDL, I have programmed communication to an LCD display to show a temperature value on a CPLD. But nothing more complicated than that.

I have googled around to find some good examples of how people do DFT in FPGA's. But I never found a good example that I can understand. Actually, I don't understand it at all. My biggest question is, how is the exp() calculated?? and the complex numbers

From all the examples I've looked at, exp and complex numbers doesn't seem to be used at all, I cannot understand how that works? Or they just made the example code impossible to understand. I need a much more basic explanation of how people create DFT algoritms in FPGA's, I don't want to get thrown into the complicated stuff immediatly like most tutorials I have found, I have to start from scratch with simple examples.

Do you normally use LUT's for exp() ? Or series expansions ?

Also, how is the clock signal used in a DFT implementation ?

I have this need to understand things, so a pre-made IP for DFT's will not be enough for me

Where do I start?