In vibroseis, the sweep is a signal sent into the ground by the vibrator. The fundamental sweep is generated by software on the recorder. The ground force signal is a sweep that includes both the fundamental and its harmonics. The harmonics are generated by the vibrator along with the fundamental sweep. Harmonics are considered noise and should be eliminated from field recordings. As the harmonic noise level increases, the seismic quality decreases. Over the years, various methods using sweep parameters and phases have been proposed to mitigate these effects. The pure phase shift filter (PPSF) is one of these methods. In this study, the pure phase shift filter is used to extract the relationship between eliminated and non-eliminated harmonics and the sweep number. Our approach is tested on synthetic and real data and the results are discussed.