Sideband KPFM is in principle similar to FM KPFM, again using combination of mechanical and electrical oscillation, however the amplitude at frequency which equals to sum of the excitation frequencies (mechanical+electrical) is not evaluated using two step lock-in procedure, but detected directly using the second lock-in. If we use low frequency electrical excitation as in FM KPFM, the amplitude of oscillations is very small and high-speed input bit depth of Gwyscope controller cannot detect it in the large background of the mechanical oscillation. However, if we choose the electrical excitation frequency so, that the sum of the frequencies equals to second resonance frequency of the cantilever, the signal is amplified by resonance and can be detected.