Let's consider any physical quantity depending on the frequency. For example, the impedance of a certain electrical component: $Z(f)$.
Now, imagine to measure it in a continuous interval of frequencies. You get a graph. Now, let's take some samples separated by $∆f$ (uniform sampling).
My questions are:
- If I compute the Fourier Transform of $Z(f)$, what will I get? I think it is a signal like $Z(t)$, but it seems strange to me that from a frequency dependent signal, it will appear a time - dependence only by calculating the Fourier Transform.
- Which is the mathematical condition to apply to $∆f$ to avoid aliasing? I'd say that it should be greater of the maximum frequency of $Z(f)$, which is a graph on frequency. Is this frequency variation of Z with respect to frequency related to time?