Honored Contributor
Honored ContributorHi Daixiwen,
I'm currently investigation these questions you ask in the matlab and modelsim simulations. I was able to regenerate the hardware results in matlab by putting data with different (extreme) scaling factors into the fft core. Now, I try to find out, where in the hardware my calculations go wrong. It is well possible, that I did some input data scaling errors (or implement them with my hanning window calculation). Right now, I'm pretty confident that I will discover those errors. After some iterations, my modelsim simulation looks quiet good. Sometimes, it is just helpful to ask some questions in the forum to get the thoughts straight, even if you don't get the answer (which I quiet understand by looking at my first post ;-)). The one thing I have to investigate a little deeper is the skipping of the remainder of the sqrt megafunction. I have no idea to what degree this will affect the accuracy of my results. What really impressed me during the matlab simulations is the fact, that the matlab model of the altera fft really behaves like in the hardware once you put the same data in. So the model really seems to be bit-accurate like to manual promises ;-). Regards, Maik
