A Study on Spectrum Nulling of Barker Code Signal Based on Phase Perturbation

Modern radars operate in very complex electromagnetic environments. The wireless spectrum is divided and used by a large amount of RF users. The signals at the near frequencies may interference with each other, disrupting the operation of radar systems. Radar transmitter忆s interference with other RF users can be reduced by producing nulls in the spectrum of radar signal. These nulls are readily formed at desired frequencies by modifying the phase structure of the given radar waveform. Since the radar waveform keeps constant amplitude, no transmit energy is lost. Phase perturbations are small; so that the signal’s inherent characteristics are maintained. Phase code signal is a kind of pulse compression waveform, and Baker code signal is one of the two-phase code signals. In this paper, based on phase perturbation technique, the spectral nulling of Barker-coded signals was studied. The single and multiple nulling in the main lobe and side lobes of the Barker code spectrum are simulated and discussed. And characteristic of the nulling under error conditions is analyzed.