Contributions to a DFT frequency bin So, a frequency bin is centered around an interesting frequency $f_0$. Assume the spectrum is such that there is no spectral leakage from other frequencies to that specific frequency $f_0$. Now. I center a frequency bin around f0. The value (magnitude) of this bin is then the value of EXACTLY this frequency $f_0$ and is not affected by non-zero frequency values (magnitudes) of frequencies that also lie in that bin's range. A frequency bin 'only' covers the value of its center frequency (+ potential spectral leaks to that center frequency). 

Is that correct?
A frequency bin 'only' covers the value of its center frequency (+ potential spectral leaks to that center frequency). Is that correct?Is that correct?


No. All frequencies show up in all frequency bins EXCEPT frequencies that are an integer multiple of $f_{\Delta}=f_s/N_{FFT}$ sample rate divided by FFT length. 

In other words a frequency bin is affected by ALL frequencies except the center frequencies of the other bins. 

You need to take into account that the FFT assumes that the signal is periodic with N. For a periodic signal contains only integer multiples of the fundamental frequency.