I have a noisy signal (Gaussian Noise) with a known SNR and known Noise variance. This signal contains a number of Frequency components. My ultimate objective is to detect the components of the signal. What is the Threshold formula should I use to detect the peaks of the signal in frequency domain given a certain Pfa (probability of false alarm)?
The following plot is an example of my objective. I want a Threshold that separates my useful components from the noise components (Let's say between 0.6 and 1)