Left: fractional amplitude of various harmonics (1 – fundamental, 2 – first overtone, and 3 – second overtone) as a function of energy using background corrected data from XMM-Newton EPIC-pn (circles), NICER (squares) and NuSTAR (triangles). The pulsed fraction of the fundamental component increases from ∼10% till ∼17% from 1.5 to 3–4 keV, from where it more or less saturates at a level of ∼17%. Right: phase-angle as function of energy for the three Fourier components. The shift towards lower phases from ∼1.5 keV till ∼10 keV for both the fundamental and first overtone is evident.