Simulation of Digital Modulation Systems with Quasi–Orthogonal Sequences

Abstract

Modulation impulse shaping in conventional communication systems usually is realized by the root-raised-cosine filtering. Recently modulation impulse shaping on the basis of wavelet transform was proposed. The present paper deals with the use of quasiorthogonal sequencies for impulse shaping. The main objective is to design the SIMULINK models of communication systems with modulation impulse shaping on the basis of quasi-orthogonal sequencies, wavelets and root-raised-cosine filters and to evaluate the nonlinear amplification sensitivity and the performance of systems corrupted by noise. The main results are: the systems with quasiorthogonal sequences require more bandwith, the performance of them is is some what less and non-linear amplification sensitivity of them is notibly less comparing with other systems. Ill. 16, bibl. 7 (in Lithuanian; summaries in English, Russian and Lithuanian).