Golay sequences for identification of linear systems with weak nonlinear distortion

Abstract

The design of bipolar excitation sequences for identifying linear time-invariant systems in the presence of weak nonlinear distortion is considered. A Volterra system model is used and system identification is carried out in the time domain by a crosscorrelation analysis. The measured system characteristic is the impulse response. A set of four pairs of Golay complementary sequences is presented which is very suitable for identification of linear systems suffering from weak second and third-order nonlinear distortion. Artefacts in the measured system characteristics caused by this kind of nonlinear distortion are effectively eliminated by averaging the four impulse responses obtained with the proposed four pairs of Golay complementary sequences. The key element in this study is higher-order autocorrelation properties of Golay complementary sequences. Experimental results obtained from a digital magnetic storage system are presented.