Corrections for sinusoidal background and non-orthogonality of signal channels in sinusoidal rapid magnetic field scans

► Rapid scan EPR signals are separated from sinusoidal background in the frequency domain. ► The sinusoidal background signal is fitted and subtracted. ► This background subtraction method does not require recording an off-resonance signal. ► This procedure also corrects for non-orthogonality of the quadrature detection channels. ► Signal to noise is improved by removing half of the noise in the frequency domain.