Reduction of Distortions in Periodic Signals by Wiener Filtering

Most of the techniques that are used to identify the I/O characteristic of a linear system require that it be stressed at the input through a periodic-type signal. The accuracy of the results is directly related to the degree of harmonic purity of the signal used as excitation. In this paper, a procedure is proposed for generating periodic signals whose degree of spectral purity is increased to extremely high levels using a procedure based on the Wiener filter. The procedure requires that the signal is generated by the usual procedure, and the subsequent filtering has such characteristics as to remove the harmonics that occurred and that decrease its spectral purity. The method does not act on the causes of generation of the additional harmonics, but removes their effects, restoring the signal to a very high degree of spectral purity. The proposed procedure is validated through examples to verify its effectiveness.