RF Transmitter Linearizer Feedback for Power Amplifier Distortion

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Solution Overview

Problem

Radio frequency (RF) transmitters face challenges in maintaining signal linearity due to distortion caused by RF power amplifiers, which affects modulation integrity and is often addressed by using high-quality amplifiers that are costly and inefficient.

Innovation Solution

The implementation of a linearizer module that adjusts intermediate frequency signals before amplification, using a feedback loop to minimize distortion in the amplified RF signal, allowing for improved linearization and power yield with lower-cost, lower-performance RF power amplifiers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-quality RF power amplifiers are used to maintain signal linearity, then linearity performance is improved, but cost and power consumption increase

Engineering Contradiction:

Improvesignal linearityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements a feedback loop that samples the amplified RF signal, downconverts it to intermediate frequency, compares it with the original intermediate frequency signal, and uses the error signal to adjust the intermediate frequency signal in real-time, compensating for distortion without requiring high-quality amplifiers

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The linearizer module pre-adjusts the intermediate frequency signal before amplification based on predicted distortion characteristics, reducing the burden on the RF power amplifier and allowing the use of lower-quality, more efficient amplifiers

Inventive Principle:

Principle #10Preliminary action

2Reliability

If high-quality RF power amplifiers are used to maintain signal linearity, then linearity performance is improved, but cost increases

Engineering Contradiction:

Improvesignal linearityVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The feedback mechanism continuously monitors and corrects signal distortion, allowing the system to achieve high linearity performance using lower-cost RF power amplifiers that would otherwise produce unacceptable distortion

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent deliberately uses lower-quality, cheaper RF power amplifiers and compensates for their deficiencies through the linearization system, achieving the same performance at reduced cost

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If RF power amplifiers operate at high power levels to maintain signal integrity, then linearity is improved, but heat dissipation and power consumption increase

Engineering Contradiction:

Improvesignal integrityVSAvoidheat dissipation

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The feedback loop enables the system to maintain signal integrity by dynamically adjusting the intermediate frequency signal to compensate for amplifier non-linearity, allowing operation at lower power levels with reduced heat dissipation

Inventive Principle:

Principle #23Feedback

4Reliability

If ambient temperature decreases to improve RF power amplifier performance, then linearity is improved, but the system becomes sensitive to temperature changes

Engineering Contradiction:

Improvelinearity performanceVSAvoidtemperature sensitivity

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The feedback mechanism continuously compensates for temperature-induced variations in amplifier characteristics by adjusting the intermediate frequency signal in real-time, maintaining consistent linearity performance across varying temperature conditions

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The linearizer module dynamically adapts to changing environmental conditions by continuously monitoring the amplified signal and adjusting compensation parameters, making the system robust to temperature changes

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10476445B2Systems and methods for improved power yield and linearization in radio frequency transmitters

Publication Date: 2019.11.12 AVIAT U S

AI summary

An exemplary system comprises a linearizer module, a first upconverter module, a power amplifier module, a signal sampler module, and a downconverter module. The linearizer module may be configured to receive a first intermediate frequency signal and to adjust the first intermediate frequency signal based on a reference signal and a signal based on a second intermediate frequency signal. The first upconverter module may be configured to receive and up-convert a signal based on the adjusted first intermediate frequency signal to a radio frequency signal. The power amplifier module may be configured to receive and amplify a power of a signal based on the radio frequency signal. The signal sampler module may be configured to sample a signal based on the amplified radio frequency signal. The downconverter module may be configured to receive and down-convert a signal based on the sampled radio frequency signal to the second intermediate frequency signal.