V.N. Bondarenko

In paper optimal algorithm of time discriminator synthesis for code synchronization system of periodic spread-spectrum signal with minimum frequency shift keying (MSK) receiver by using criterion of maximum likelihood and analysis of quasioptimal algorithms noise stability are carried out. Optimal and quasioptimal algorithms structure of time discriminator spread-spectrum signal with MSK at coherent (synchronous) and incoherent signal detection are shown. The analysis of proposed time discriminator algorithms noise stability by using index characterizing equivalent time fluctuations increasing dispersion in comparison with optimal time discriminator dispersion is carried out. Discriminator and fluctuation characteristics of proposed algorithms, equivalent time fluctuations standard deviation characteristics and noise stability loss versus signal noise ratio by using statistical modeling method are presented. Analysis of results shows exact coincidence modeling and analytical dependences by using proposed equations. It is shown, that algorithm with sign decision function is most perspective at additional digital modulation spread-spectrum signal with minimum frequency shift keying (MSK) receiving: noise stability loss in comparison with optimal algorithm is nearby 0.15dB at a threshold signal noise ratio equal 5dB. Proposed time discriminator algorithms can be used in code synchronization systems of spread-spectrum signal with minimum frequency shift keying receivers