On Dual-Band Amplifications Using Dual Two-Tones: Clarifications and Discussion

Abstract

A significant development of recent research in nonlinear distortion is the expansion of the conventional two-tone test for power amplifiers to the concurrent dual-band transmitters, by Amin et al. A general framework using dual two-tones is developed, which shows that the output signal is affected not only by intermodulation (IM) products but also by cross-modulation (CM) products. In this paper, we will make a number of clarifications to Amin et al.'s paper. The effects of IM and CM in passband will be discussed, IM represents a reduction for compressive devices, and CM reflects an interference caused by the signal from the other band, and followed by the analysis of out-of-band IM. It was concluded that out-of-band IM needs to be taken into consideration for the design of power amplifiers when two bands are very close.