A novel nonlinear technique for sidelobe suppression

Sidelobes can be completely removed if the returns from two pulses based on Golay complementary sequences are combined after pulse compression. However these pulses cannot be sent simultaneously via frequency separation because of a phase term which is dependent on the unknown range. We propose to transmit one of the sequences at two offsets, above and below the carrier frequency. This facilitates recovery of the square of the autocorrelation function independently of signal phase. A modification to the Golay pair results in sequences having com-plementary squares of autocorrelation sequences. This enables complementary behaviour with frequency offset pulse pairs. The nonlinear squaring operation introduces small manageable cross–terms in place of sidelobes.