Modified Costas signal

A modification to the Costas signal is suggested. It involves an increase of the frequency separation (delta)f beyond the inverse of the subpulse duration t/sub b/ combined with adding linear FM (LFM) with bandwidth B, in each subpulse. Specific relationships between (delta)f and B will prevent autocorrelation grating lobes, that would normally appear when t/sub b/(delta)f>1.