Adaptive Control of Low-Level Radio Frequency Signals Based on In-Phase and Quadrature Components

This research work presents a low-level radio frequency (RF) control method based on the in-phase, <inline-formula> <tex-math notation="LaTeX">$I$ </tex-math></inline-formula>, and quadrature, <inline-formula> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula>, components of the RF signal. The proposed method uses only the main four arithmetic operations, i.e., addition, subtraction, multiplication, and division, which makes this control method suitable for implementation on the field-programmable gate array. The control scheme is adaptive in the sense that it estimates the system response on-the-fly, and therefore, it is robust against changes in the loop phase and/or gain during the operation.