Generation and Performance of Quadraphase Welti Codes for Radar and Synchronization of Coherent and Differentially Coherent PSK

A class of quadraphase synchronizing sequences, whose lengths may be any power of two, is constructed using codes originally reported by Welti. It is shown that there exist realizations of the codes for both coherent and differentially coherent PSK systems. Like binary maximal length sequences (BMLS) their generation and detection require circuits whose complexity grows as
\log_{2}N
, where
N
is the codelength. Their aperiodic correlation properties, however, are superior to those of any BMLS-their correlation sidelobes are identically zero, giving unambiguous asynchronous detection.