First PC eigenvalue, λ_ℓ,1 vs. folding period (∆_s = 1 ns) for an acquisition of the Crab pulsar with Iqueye at the NTT, OBS2 (Table 1). For this case, M = 200 was chosen, and the best-fit period found was P_PCA = 33.637 261 ms (with a search of L = 1000 iterations). Second and third eigenvalues,λ_ℓ,2 and λ_ℓ,3, are plotted as well. Their amplitude is significantly lower than λ_ℓ,1, especially near P_PCA.