I want to know how much energy is at a specific frequency in a signal. I am using FFT to get the spectrum, and the frequency step is determined by the length of my signal.
My spectrum looks, for example, like this :
I want to get the spectrum peak at a specific frequency, -0.08. However, the discretization of the spectrum only give me a peaks at -0.0729 and -0.0833.
Is there a way to shift the spectrum to make sure there is a data point at the frequency I want? Or a way to get the value without necessarily using fft?
Thank you very much!