RF Signal Linearization with Separate Phase and Amplitude Correction

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Solution Overview

Problem

Conventional methods for linearizing signals in RF communications systems face challenges in maintaining both linear amplitude and phase simultaneously due to non-linear behaviors of transmitter and receiver components, leading to unreliable and slow communication.

Innovation Solution

The technique involves separately adjusting the phase and amplitude of the signal based on estimated distortions within the signal path, using distinct phase and amplitude modification circuits, to generate a linearized signal that compensates for phase and amplitude distortions, thereby improving communication reliability and speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex pre-distortion or feedback schemes are used to shape phase and amplitude, then distortion compensation is achieved, but device complexity and difficulty of maintaining linearity increase

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidcomplexity of pre-distortion or feedback schemes
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the signal processing into separate amplitude shaping and phase shaping operations. Instead of using complex coupled pre-distortion schemes, the invention applies amplitude modulation to correct amplitude distortion and phase modulation to correct phase distortion independently. This segmentation simplifies the overall system complexity while maintaining effective distortion compensation.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If phase and amplitude are adjusted together in coupled schemes, then distortion compensation is attempted, but manufacturing precision and ease of operation deteriorate due to coupling effects

Engineering Contradiction:
Improvelinearity of amplitude and phaseVSAvoiddifficulty in maintaining linear amplitude and phase
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent separates amplitude and phase adjustments into independent operations. The amplitude shaping module modifies only the amplitude characteristics without affecting phase, while the phase shaping module modifies only phase characteristics without affecting amplitude. This decoupling makes it easier to maintain both linear amplitude and linear phase simultaneously, improving ease of operation while preserving manufacturing precision.

Inventive Principle:
Principle #1Segmentation

3Reliability

If non-linear behavior of components is present, then signal distortion occurs, but communication speed and reliability worsen

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidcommunication speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary shaping to the modulated signal before transmission through the non-linear components. By pre-shaping both amplitude and phase characteristics according to predicted distortion patterns, the system compensates for non-linear effects before they occur. This preliminary action ensures that the signal maintains its integrity through the non-linear components, preserving both communication reliability and speed.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3035543B1Techniques for linearizing phase separately from amplitude in a communications system
Publication Date: 2019.06.05 VIASAT INC
  • EP3035543B1 patent drawingFigure 1
  • EP3035543B1 patent drawingFigure 2
  • EP3035543B1 patent drawingFigure 3

AI summary

The present disclosure, for example, relates to one or more techniques for linearizing a signal in a communications system. An input signal may be obtained at a beginning of a signal path of a radio frequency (RF) communication device. The RF communication device may estimate subsequent distortion of the input signal due to the signal path. The estimated distortion may include estimated phase distortion and estimated amplitude distortion of the input signal. The RF communication device may adjust phase and amplitude within the signal path to compensate for the estimated phase distortion and the estimated amplitude distortion to produce an adjusted signal. The phase within the signal path of the input signal may be adjusted separately from the amplitude within the signal path of the input signal. The RF communication device may generate a linearized signal at an end of the signal path based at least in part on the adjusted signal.