Spectra for two double-banded events: (a,c) Spectra of n_e, B_⊥ and B_|| (b,d) compressibility ratio ξ_e) for the two events. The yellow and violet shadings show the frequency ranges for the right- (RH) and left-handed (LH) polarization respectively. The red vertical line shows the local proton cyclotron frequency. We note that a sharp peak in the n_e spectrum at ∼1.2 Hz is related to the spacecraft interference.