Importance

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Abstract

A transmitter for directly modulating an RF carrier with a complex baseband waveform comprises a programmable device adapted to generate amplitude and phase information collectively corresponding to a complex baseband waveform, a signal generator adapted to generate an RF carrier whose phase is responsive to phase information generated by the programmable device, a plurality of delta modulators, and an amplifier coupled to the signal generator and receiving the RF carrier with phase information. Each delta modulator is operative to sample an error signal at a time period offset from all other delta modulators to thereby generate streams of pulses collectively approximating the amplitude information. The supply voltage of the amplifier is adjusted in accordance with approximated amplitude information represented by the streams of pulses generated by the delta modulators. Specifically, the supply voltage is adjusted such that the output voltage of the amplifier varies substantially linearly with changes in the supply voltage. In this manner, both the amplitude information and the phase information are both impressed upon the RF carrier.

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First Claim