FIELD: radio engineering; digital data transmission at narrow-band or broadband frequency-modulated noise. SUBSTANCE: equipment includes receiver and transmitter. Transmitter is provided with newly introduced switching pulse shaper, inverter, two switches, and fourth multiplier. Composite four-phase signal phase-keyed by same data signal is generated in transmitter by alternate transmission of common-mode and quadrature binary signals. Newly introduced in receiver are two commutators, four mixers, standard generator, adder, two switches, inverter, switching pulse shaper, and data allocation unit which enables nonlinear suppression of high-power noise characterized in elimination of the effect of third-order intermodulation noise produced in the process. To this end oscillation of mixture envelope with signal differential frequency and noise is converted into fixed-frequency oscillation phase-keyed by data signal. EFFECT: enhanced noise immunity of system due to elimination of intermodulation noise effect in receiver. 1 cl, 6 dwg
