This paper gives the variance of the phase recovered by a conventional quadriphase Costas loop in 16 QAM modulation in the presence of selective fading, represented as a two rays simplified model. The phase error variance is evaluated for different values of the fade depth, the location of the maximum attenuation in the frequency band and the delay of the reflected ray. The influence of an IF amplitud equalizer is discussed. Finally the relation between the performance degradation and phase noise is given, assuming a gaussian p.d.f. of the phase error.

Peer Reviewed