A Harmonically Superior Switching Modulator with Wide Baseband and Real-Time Tunability

The paper proposes a class of switching modulators with reduced harmonics to allow a wide base band. In an ordinary switching modulator, the harmonics are rich and the operating bandwidth is rather limited. Here we are advancing a harmonic elimination technique to place the unwanted harmonics at a frequency farther away from the fundamental. It is a novel PWM method where a reference sinusoid with the desired modulating frequency is compared against a complex periodic signal with the same time period as the reference. The modulator can be designed to function as a single frequency converter if the comparing waveform has frequency contents much higher than the reference. Simulation and experimental studies verify the proposed approach.