I'm looking for two signals embedded in very noisy data. I know they are close to periodic and integral with the run, but are rather close (30s and 21s during a 210s measurement), and our sampling rate is low (1.25s). We have multiple observations to work with per sample.
I am wondering how I might deal with the problem of spectral leakage: it is evident in the FFT of our samples. Since our two signals of interest are so close together (10 and 7 cycles per measurement), it may well be that spectral power is leaking from the stronger of the two signals into the weaker one.
Will zero-padding with a window (rectangular or hamming) allow us to define a boundary between the two signal? Would another approach would be to concatenate these observations, driving the periodicities further apart (20 and 14)?
Thanks for your help, joseph