Quantized Envelope Amplification for Linear RF Power Efficiency
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Solution Overview
Problem
Power amplifiers face a tradeoff between linearity and efficiency, with linear amplifiers being inefficient and non-linear amplifiers producing spectral distortion, especially in modern communication systems with high peak-to-average power ratios, and existing linearization schemes like LINC suffer from efficiency degradation due to power combining issues.
Innovation Solution
A method that decomposes a time-varying envelope signal into quasi or constant envelope in-phase and quadrature components, which are individually amplified and then combined to form a desired quantized version of the signal, allowing for linear amplification using non-linear amplifiers without spectrum spread and power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linear amplification is used to maintain signal quality, then linearity is improved, but power efficiency deteriorates
Solution Approach 1:
The input signal is decomposed into multiple constant-envelope signals that can be processed by efficient non-linear amplifiers. By segmenting the signal processing into decomposition, non-linear amplification, and reconstruction stages, the system achieves both linearity and efficiency.
Solution Approach 2:
A digital signal processor acts as an intermediary to decompose the input signal into constant-envelope components, process them through efficient amplifiers, and reconstruct the output. This intermediary processing enables the use of non-linear amplifiers while maintaining linear output characteristics.
2Use of energy by moving object
If non-linear amplification is used to improve power efficiency, then power efficiency is improved, but spectral distortion increases
Solution Approach 1:
The signal is segmented into constant-envelope components that are suitable for non-linear amplification. Each component can be amplified efficiently without generating spectral distortion, and the components are later recombined to reconstruct the original signal.
Solution Approach 2:
The signal parameters are transformed by converting the time-varying envelope signal into constant-envelope signals through decomposition. This parameter change enables the use of non-linear amplifiers while avoiding spectral distortion in the final reconstructed signal.
3Reliability
If LINC technique is used to achieve linear operation with non-linear components, then linearity is improved, but efficiency degrades due to power combining issues
Solution Approach 1:
The patent extracts and eliminates the power combining stage that causes efficiency degradation in conventional LINC systems. By directly processing constant-envelope signals through non-linear amplifiers without traditional power combining, the system maintains linearity while avoiding power loss.
Solution Approach 2:
The system uses digital signal processing and direct conversion techniques that replace complex analog power combining networks. This substitution with simpler digital processing elements eliminates the inefficiencies associated with analog power combining while maintaining the benefits of non-linear amplification.
Data Source
AI summary
Methods and systems for power amplification of time varying envelope signals are disclosed herein. In one embodiment, a plurality of signals with constant envelope generated from the decomposition of the quantized version of a time varying envelope signal are individually amplified and then summed to form a desired time-varying envelope signal. Amplitude, phase and frequency characteristics of one or more of the constituent signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time varying envelope signal. In another embodiment, a time-varying envelope signal is decomposed into in-phase and quadrature components that are quantized and decomposed into a plurality of quasi constant or constant envelope constituent signals. The constituent signals are amplified, and then summed to construct an amplified version of the original time-varying envelope signal. The signal amplifiers may be Class A, B, AB, C, D, Class F or Class S amplifiers to provide high amplification efficiency.