RF Power Amplifier EVM Prediction Without Transient Post-Processing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for determining error vector magnitude (EVM) in RF devices are time-consuming and sensitive to convergence issues related to power amplifier compression and saturation states.

Innovation Solution

A computer-implemented method for fast EVM prediction using a single-tone harmonic balance AM-AM/PM power sweep simulation, based on the statistics of the modulated IQ waveform, and performed within a simulator without external post-processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If transient simulation (Circuit Envelope approach) is used for EVM determination, then measurement precision is improved, but productivity deteriorates due to time-consuming post-processing

Engineering Contradiction:

ImproveEVM measurement precisionVSAvoiddesign validation speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts only the essential information needed for EVM calculation (amplitude and phase changes) from the simulation data, eliminating the need for time-consuming external post-processing steps while maintaining measurement precision

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the external post-processing mechanical workflow (signal export → external demodulation → EVM calculation) with an integrated simulation-based EVM prediction method that operates within the simulator environment

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If transient simulation with external post-processing is used, then EVM calculation accuracy is improved, but device complexity increases due to multiple external tools

Engineering Contradiction:

ImproveEVM calculation accuracyVSAvoidsimulation system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the EVM prediction functionality directly into the simulation environment, combining signal generation, device simulation, and EVM calculation into a single integrated workflow that reduces system complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal EVM prediction method that works within the simulator itself, making the simulation tool multi-functional by eliminating the need for separate external demodulation and analysis tools

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If traditional transient simulation is used for power amplifier analysis, then reliability is improved through detailed signal analysis, but loss of time increases due to convergence issues

Engineering Contradiction:

Improvesignal analysis reliabilityVSAvoidsimulation convergence time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary characterization of the power amplifier using amplitude and phase change measurements across different input power levels, storing this information for rapid EVM prediction without requiring repeated convergence-heavy transient simulations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses a simplified model that captures the essential non-linear behavior of the power amplifier through amplitude and phase changes, performing only the necessary measurements needed for EVM prediction rather than exhaustive signal analysis

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12231094B2Systems and methods for device specification design and verification by error vector magnitude prediction

Publication Date: 2025.02.18 PSEMI CORP

AI summary

Methods and systems for determining the error vector magnitudes for an RF device by fitting voltage magnitudes to a Rayleigh distribution to produce weighting parameters for an EVM calculation, either in simulation for designing the RF device or as validation measurements from a physical RF device.