Adaptive antenna array communication system is considered that receives phase-manipulated signal in a background of Gaussian interferences and internal noise. Reference signal is formed by nonlinear inertialess transformation of the array output. It is shown that weight coefficients vector that minimizes mean square error between reference and output signals also provides maximum of output signal-to-noise ratio (SNR). Statistical characteristics of adaptive array in stationary regime are investigated for different schemes of reference signal forming. Theoretical results are confirmed by computer simulation.