Implementing orthogonal binary overlay on a pulse train using frequency modulation

As reported recently, overlaying orthogonal phase coding on any coherent train of identical radar pulses, removes most of the autocorrelation near sidelobes and lowers the recurrent lobes. The present work shows that both properties are maintained when a binary orthogonal overlay is replaced by its "derivative phase" (DP) frequency modulation (FM) equivalent. Frequency modulated overlay is more spectrum efficient and would be easier to implement when the original pulses are already frequency modulated.