Patent ID: 6813319
Filing Date: 2004-11-02
Classification: H03F

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