Chirped excitation for >-100 dB time sidelobe echo sounding

Abstract

A doubly apodized linear chirp signal having a <-100 dB autocorrelation sidelobe is introduced. It has an extra gaussian apodization over the well known cosine-square apodized linear chirp. It allows a range/time sidelobe free echo sounding system virtually equivalent to time shared Golay or other complementary code phase encoding system, yet having essential inter-pulse Doppler tolerance. The signal is best for imaging and Doppler observation in the cardiovascular system, where targets are essentially moving and the Golay code can't maintain its perfect sidelobe cancellation mechanism.