Linearizer Calibration Using Dual-Tone AM/PM Distortion Measurement
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Solution Overview
Problem
Existing methods for compensating non-linear distortions in electronic components, such as power amplifiers, require direct phase shift measurement and demodulation, which are challenging, especially in environments like satellites where time and phase references are difficult to implement, leading to infrequent and laborious linearizer adjustments.
Innovation Solution
A method that uses a dual-frequency test signal to adjust pre-distortion parameters of a linearizer without direct phase measurement, minimizing dissimilarity in the signal spectrum by measuring relative power levels and calculating the AM/PM conversion coefficient, allowing for continuous calibration and adaptation to environmental changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct phase shift measurement and demodulation methods are used to calibrate the linearizer, then calibration accuracy can be achieved, but the device complexity and difficulty of implementation increase significantly, especially in satellite environments
Solution Approach 1:
The patent extracts and eliminates the need for direct phase shift measurement and demodulation functions from the calibration system. By using an indirect method based on power level measurements of dual-frequency test signals, the complex phase measurement and reference synchronization equipment is removed, while still achieving accurate linearizer calibration through the relationship between input power levels and output spectral components
Solution Approach 2:
The patent introduces an intermediary measurement approach where instead of directly measuring phase shift, the system measures power levels of spectral components (fundamental frequencies and intermodulation products) as intermediate parameters. These power level measurements serve as mediators to infer the linearizer's performance and adjust calibration without requiring direct phase measurement equipment
2Reliability
If linearizer adjustment is performed frequently to adapt to environmental changes, then linearization quality is maintained, but the time required for calibration and system availability decreases
Solution Approach 1:
The patent enables the linearizer calibration system to be self-sufficient by using simple power level measurements that can be performed autonomously without external phase reference equipment. The system can independently determine calibration parameters by measuring the power levels of output spectral components and adjusting the linearizer accordingly, making frequent calibration practical and efficient
Solution Approach 2:
The patent changes the measurement parameter from phase shift to power level of spectral components. This parameter change enables faster, simpler measurements that can be performed frequently with minimal system interruption, while still providing sufficient information to maintain linearization quality through iterative adjustment of the linearizer parameters
3Object-generated harmful factors
If pre-distortion parameters are optimized for maximum linearity, then non-linear distortions are reduced, but the electrical efficiency of the amplifier decreases
Solution Approach 1:
The patent implements dynamic pre-distortion parameters that can be adjusted based on operating conditions. Rather than using fixed aggressive pre-distortion that always prioritizes linearity, the system can adapt the pre-distortion level to balance linearity requirements with efficiency considerations, allowing the amplifier to operate more efficiently when extreme linearity is not critical while still maintaining acceptable performance
Data Source
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AI summary
Method for calibrating a linearizer and a linearized electronic component. The method includes pre-distorting a signal upstream of an electronic component (18, 28) in a pre-distortion linearizer (20, 34) to compensate for non-linear distortion. Determining the pre-distortion adjustment parameters involves applying a dual-frequency test signal to the component and measuring the relative amplitudes of the output lines. An indicative value of the magnitude |Kp| of the AM/PM conversion factor of the component is calculated based on these measurements. The pre-distortion adjustment parameters are then adjusted to minimize |Kp|. The method can be implemented, in particular, in a linearized amplifier device (12) and in an amplifier test bench (24).