A novel line-shifting method, which is called mixing-frequency electro
n spin echo envelope modulation (MIF-ESEEM) spectroscopy, is introduce
d and analysed. It is shown that the spectral resolution is enhanced,
and thus the overlapping is removed with this new method. The applicat
ion of this method to systems with S greater than or equal to 1 and I
greater than or equal to 1 is also discussed.