VHF communication radio power spectra

The power spectral analysis of very high frequency (VHF) communication radios is important to understanding how they affect each other and how they affect VHF surveillance radios. In this paper, we propose an analytical method for lower-bound radio frequency (RF) power spectrum estimation with the consideration of both power amplifier nonlinearity and broadband noise. We then demonstrate how to apply the proposed spectral estimation method to compute the lower-bound power spectra of VHF digital link mode 2 (VDL-2), plain old ACARS (POA) and double-sideband-amplitude-modulated (DSB-AM) voice signals. Finally we present the estimated lower-bound power spectra and shed light on where the discrete spectral line component comes from and how the nonlinearity of a power amplifier leads to the spectral regrowth.