Noise Immunity of Digital Data Transmission Systems with Double-Frequency Modulation

A mathematical model of the digital transmission system using the radio channel with both the subcarrier constant-phase frequency modulation and carrier frequency modulation is developed. Quantitative characteristics of the noise immunity, taking into account linear and non-linear channel distortions, are obtained. The loss in the noise immunity of the system is estimated in comparison to systems with bit phase manipulation and coherent processing.