Biphase codes with minimum peak sidelobes

Abstract

Biphase codes of lengths 14 through 34 with the optimum matched filter PSLs (peak sidelobe levels) have been found and enumerated. The minimum achievable sidelobe level seems, generally, to increase with code length but is not monotonic with length. Both ISL (integrated sidelobe level) and the PSL of a given code can be improved by the application of mismatched filtering. For many codes, sidelobe suppression resulting in -30 dB PSL and -25 dB ISL is possible with little loss in SNR (signal-to-noise ratio) as compared with the matched filter implementation. Biphase code compressions seem to exhibit a great deal of uniformity in their response to Doppler shift in the case of both matched and mismatched compression filtering.<>