DIGITAL POWER AMPLIFICATION USING SIGMA-DELTA MODULATION AND BIT FLIPPING

A data conversion technique suitable for digital power amplifiers (DPA s) is described, based on a modified sigma-delta modulator. The pulse- repetition frequency (PRF) in the bit stream is reduced in order to in crease the efficiency in the power output switching stage. The system offers PRFs comparable to pulse-width-modulation (PWM)-based DPAs, but with higher linearity and more than a thirtyfold reduction in bit-clo ck frequency.