RF Transceiver Linearization via Dynamic Nonlinear Model Extraction
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Solution Overview
Problem
Current RF test systems face challenges in increasing functionality without increasing test times and costs, particularly in characterizing and linearizing transceiver systems, which often require additional circuitry and special calibration steps.
Innovation Solution
A method for dynamic characterization of complex high-order nonlinearities in RF transceiver systems using a loopback connection and existing operating capabilities, allowing for self-characterization and linearization without dedicated hardware, by configuring the RX and TX signal chains to decouple nonlinearities and extract a memory-less model for pre- and post-distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional circuitry and special calibration steps are used to characterize and linearize transceiver systems, then linearity performance is improved, but device complexity and test time increase
Solution Approach 1:
The transceiver system performs self-characterization by using its own RX and TX signal chains to measure and extract nonlinear models of each other. The system configures one signal chain to operate in a linearized mode while the other chain characterizes it, eliminating the need for external characterization equipment and reducing device complexity
Solution Approach 2:
The patent extracts the nonlinear characteristics of the signal chains by separating the characterization process into distinct phases where one chain is configured for high linearity while the other is characterized. This extraction of nonlinear models allows the system to identify and compensate for distortions without adding physical circuitry
2Manufacturing precision
If additional circuitry and special calibration steps are used to characterize and linearize transceiver systems, then linearity performance is improved, but test time increases
Solution Approach 1:
The system uses its own operational capabilities to perform characterization during normal operation or with minimal interruption. By using the existing RX and TX chains to characterize each other, the system avoids time-consuming external calibration procedures while maintaining accurate linearity performance
Solution Approach 2:
The patent performs preliminary extraction of nonlinear models by configuring one signal chain to high linearity mode before actual measurements. This preliminary configuration allows the other chain to be characterized without requiring time-consuming iterative adjustments during the measurement phase
Data Source
AI summary
Dynamic characterization of complex high-order nonlinearity in transmitter (TX) and receiver (RX) signal chains of transceiver systems can be efficiently and accurately performed. A loopback connection may be used to facilitate self-characterization. Appropriate RX and TX configuration settings may be developed to facilitate de-coupling of individual RX and TX nonlinearities from measured cascade nonlinearity. The system's high-order response to a two-tone signal generation may be measured, and complex mathematical analysis may be performed to identify and isolate passband nonlinear components to extract a high-order memory-less model for the system. The extracted system model may be used in the corrective and non-iterative pre-distortion of generated signals and in the post-distortion of received signals to improve linearity performance of the transceiver. The memory-less model and the analytical system are effective in improving performance of class-A-amplifier-based signal chains that are common in test and measurement systems and channel emulation systems.