I am experimenting a bit with FFT's. From what I have read the first bin of an FFT is called the DC bin -- that is it is the mean of the other components in the FFT. I have also read that it should be close to 0.
When I actually perform the FFT and take the absolute value, what I find is that the first element of this is always 0. This makes sense mathematically if you consider the definition of the DFT itself.
Is there a best practice to reconstructing this first DC bin?
So it seems that because I was making my test FFT with a sine wave as the transient signal, this is what caused the 0 valued first FFT bin. I changed it to a cosine and got a non-zero first element...And the same with any random data. I should have thought a bit first.