The spectrum of a digital radio frequency memory linear range gate stealer electronic attack signal

Abstract

We examine the spectrum of a digital radio frequency memory (DRFM) linear rate gate stealer (RGS) electronic attack (EA) signal. The spectrum has two noticeable characteristics. The first is a small, yet measurable, center frequency shift from the input center frequency. The second is the presence of harmonics (spectral lines) of significant magnitude centered on either side of the shifted center frequency. The primary source of these spectral characteristics is the discrete nature of the DRFM. We develop expressions to predicted the center frequency shift and the locations of the harmonics as function of the radar and DRFM parameters. These spectral characteristics should be of interest to radar and EA engineers since they could potentially affect system performance. Signal intelligence analysts should also find these spectral characteristics of interest since they provide additional clues for assessing EA systems.