| 摘要 |
A quadra-polar modulator that is simple to implement and also provides good noise performance. The quadra-polar modulator includes four amplitude modulators and a combiner. Each amplitude modulator modulates a respective carrier signal with a respective input signal to provide a respective output signal. The combiner then combines the four output signals from the four amplitude modulators to provide a modulated signal. Each amplitude modulator may be implemented with a switching amplifier, such as a supply modulated class E amplifier. Two input signals are obtained by summing separately an inphase (I) modulating signal and an inverted I modulating signal with an offset value. The other two input signals arc obtained by summing separately a quadrature (Q) modulating signal and an inverted Q modulating signal with the offset value. The offset value can be selected based on the expected magnitude of the modulating signals. The four carrier signals are in quadrature to each other.
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