Radio Chain Loopback Verification for In-Situ Calibration

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Solution Overview

Problem

Existing methods for calibrating and verifying radio components require external measuring devices and modify the radio chain, making them inconvenient and inefficient for in-situ operation and quick calibration.

Innovation Solution

A method utilizing a programmable FPGA to control the radio chain, perform self-calibration, and verify component functionality without external devices, by looping back signals and using iterative methods like the secant method to measure and adjust filter settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If external measuring devices are used for calibration and verification, then measurement precision can be ensured, but device complexity and ease of operation deteriorate due to requiring external equipment and chain modification

Engineering Contradiction:
Improvecalibration accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The radio chain performs self-calibration by using its own internal components (FPGA, DAC, ADC, filters) to generate test signals and measure its own performance parameters. The system loops back signals internally and uses iterative methods like the secant method to automatically adjust filter settings without external intervention, making the system self-sufficient for calibration and verification

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The FPGA serves multiple functions: it controls the DAC and ADC, manages signal routing through switches, executes calibration algorithms, and performs measurements. This multi-functional approach eliminates the need for separate external measuring devices while maintaining measurement capabilities through the existing radio chain components

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If external measuring devices and chain modification are used, then calibration can be performed, but ease of operation and productivity worsen due to requiring equipment changes and external control

Engineering Contradiction:
Improvecalibration capabilityVSAvoidoperational convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system performs self-calibration by internally looping back signals from the DAC through the radio chain components (filters, amplifiers) to the ADC. The FPGA automatically executes calibration algorithms using the secant method to adjust filter center frequencies and bandwidths based on measured power levels, eliminating the need for external equipment and manual intervention

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The calibration process is designed to be performed in advance or at any time during operation without interfering with normal radio chain functionality. The system can quickly execute calibration routines that adjust filter parameters based on temperature compensation and measured power levels, ensuring reliability without requiring operational disruption

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If calibration is performed on external benches, then manufacturing precision can be achieved, but loss of time increases due to inability to perform in-situ calibration

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcalibration time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The radio chain performs self-calibration using its own internal resources, eliminating the need to transport equipment to external benches. The FPGA executes calibration algorithms that measure power levels at different frequencies and iteratively adjust filter parameters using the secant method, achieving accurate calibration in-situ and at any time during operation

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The calibration capability is integrated into the operating system, allowing calibration to be performed continuously or at any time during the radio chain's operational life. The quick calibration routines minimize interference with normal operation while maintaining manufacturing-level precision through iterative measurement and adjustment processes

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3675391B1Method for verifying the operation of a radio channel
Publication Date: 2024.08.07 THALES SA
  • EP3675391B1 patent drawingFigure 1~2
  • EP3675391B1 patent drawingFigure 3A~3B
  • EP3675391B1 patent drawingFigure 4~5

AI summary

The invention relates to a method and a system for verifying the operation of a radio chain comprising at least one signal transmission channel and one signal reception channel characterized in that it comprises at least the following steps: - transmitting from the radio chain a signal configured to verify the correct operation of the radio chain, said signal being transmitted to the reception channel of said radio chain, - determining the value of a parameter representative of the operation of the radio chain at the output of the reception chain and comparing the measured value of the representative parameter to a threshold value in order to verify if the measured power value corresponds to a suitable value for correct operation of the radio chain.