Design of an Adaptive Algorithm to Better Estimate the Loop Gain in Unstable Situation

• Published in: 2022 International Conference on Electrical Engineering and Photonics (EExPolytech) pp. 71 - 74
• Main Authors: Liu, Cen, Feng, Ziyang, Gong, Baitao, Wang, Jun, Zhang, Chao, Pan, Changyong
• Format: Conference Proceeding
• Language: English
• Published: IEEE 20-10-2022
• Subjects: adaptive; Adaptive algorithms; digital pre-distortion; Electrical engineering; Estimation; IQ imbalance; Least Square; loop gain; Photonics; Power amplifiers; Table lookup
• ISSN: 2771-697X
• DOI: 10.1109/EExPolytech56308.2022.9950827

In the full-power entry situation, signal transmitted tends to be wide stationary. Power amplifiers tend to work in a stable condition relatively, where the loop gain is also stationary. However, in a situation of incomplete power input, the transmitted signal becomes unstable, its amplitude increasing and decreasing rapidly. Such violent change in the signal will make the power amplifiers and other analog devices work in unstable conditions. One of the results is that the loop gain will be changed quickly corresponding to the change of the signal amplitude. In this paper, we proposed an adaptive algorithm with changeable learning rate to replace Least Square to get better estimation of loop gain.