Modulator with low sensitivity to amplitude and phase errors of the carrier signal

摘要

A modulator includes two modulation units and a summer (412c). Each of the first and second modulation units receives and modulates a set of carrier signals (ILO, QLO) with a set of information signals (IIN, QIN) in accordance with a particular modulation scheme to generate a respective modulated component, with the second modulated component (b) including a signal inversion relative to the first modulation component (a). The summer combines the first (a) and second (b) modulated components to generate a modulated signal. Each modulation unit can include a pair of mixers (410a, 410b; 410c, 410d) and a summer (412a; 412b). The first mixer (410a) receives and modulates an inphase carrier signal (ILO) with a first information signal (IIN). The second mixer (410b) receives and modulates a quadrature carrier signal with a second information signal (QIN). The summer (412a) receives and combines the outputs from the first and second mixers to provide the modulated component. The information signals provided to the first and second modulation units are swapped and may be inverted.