Abstract: A modulation system which produces a modulated carrier having a number of central sideband pairs with power closely approximating the carrier power. A signal generator produces a sinusoidal reference voltage which is applied to a plurality of conditioning channels. Amplitude, phase and frequency conditioning means within the channels produce desired modulating signal components. The components are then synthesized in a power combiner and applied as the control voltage to phase/frequency modulation means to produce the desired modulated signal.