Speed requirements of supply modulators used in polar architectures

Abstract

This paper investigates the minimum supply modulator linear processing bandwidth and slew rate (SR) requirements necessary to meet the standard specs of total signal distortion and adjacent signal power ratio in modern polar wireless transmitters. System level simulations, performed under CDMA2000FW and CDMA2000RV excitations, showed that, depending on the filter behavior in the amplitude envelope spectrum main lobe, relaxed bandwidths between 2 and 5 times the original signal are sufficient to guarantee desired specs of 45dB of ACPR and −35dB of NMSE. On what the SR is concerned, we concluded that 1/(2.5) times the maximum AM(t) signal slope is enough to achieve the same desired specs.