FIELD: physics; communication.
SUBSTANCE: invention relates to a communication system. The quadrature modulator includes four amplitude modulators and a combiner. Each amplitude modulator modulates the corresponding carrier frequency signal with the corresponding input signal to provide the corresponding output signal. The combiner then combines four output signals from four amplitude modulators to provide a modulated signal. Each amplitude modulator can be made with a switching amplifier, for example a class-E amplifier with power modulation. Two input signals are obtained through separate summation of an in-phase (I) modulating signal and the inverted modulating signal I with a shift value. Two other input signals are obtained through separate summation of a quadrature (Q) modulating signal and the inverted modulating signal Q with a shift value. The shift value can be selected based on the estimated value of the modulating signals. These four carrier frequency signals are in quadrature with each other.
EFFECT: obtaining optimum noise characteristics and output power.
21 cl, 6 dwg
