Mixed Analog Digital Integrity Test via PRNG Signal Injection

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Solution Overview

Problem

Existing methods are inadequate for efficiently checking the integrity of mixed analog-digital systems, particularly in vehicle systems, where transient errors in digital transmissions can occur unpredictably, impacting safety and are difficult to detect without extensive simulation or real-world testing.

Innovation Solution

A device with a processor that uses a pseudo-random number generator (PRNG) to inject a test signal into the digital transmission, estimating its integrity through an analog output, compensating for the linear transfer function of both digital and analog paths, allowing for non-invasive error detection without direct access to the digital transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If extensive computer simulation and real-world road driving are used to verify integrity, then measurement precision is improved, but loss of time and loss of energy increase significantly

Engineering Contradiction:
Improveintegrity verification accuracyVSAvoidtesting duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing integrity verification through computer simulation before real-world road driving. The system injects test signals into the digital transmission path and analyzes the analog output to detect errors proactively, eliminating the need for extensive post-deployment field testing and reducing overall verification time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by creating a virtual replica of the digital transmission path through computer simulation. Instead of physically testing the entire system for months, the system models the digital path behavior in silo, injecting test signals and analyzing responses to predict real-world performance without requiring actual road driving.

Inventive Principle:
Principle #26Copying

2Measurement precision

If direct access to digital transmission is provided for integrity checking, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveerror detection capabilityVSAvoidtesting system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies the intermediary principle by using the analog output as a mediator between the digital transmission path and the integrity verification system. Instead of directly accessing the digital transmission (which would require complex tap points and signal injection mechanisms), the system injects test signals at the digital path and analyzes their transformed versions at the analog output, simplifying the verification architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces complex mechanical signal injection and tapping mechanisms with a computational approach. Instead of physically accessing the digital transmission line through complex hardware interfaces, the system uses computer-based signal processing to inject test signals and analyze the analog output, substituting mechanical complexity with software-based verification.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If existing integrity check techniques are applied to mixed analog-digital systems, then ease of operation is improved, but measurement precision deteriorates

Engineering Contradiction:
Improveintegrity check simplicityVSAvoiderror detection accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent applies local quality by tailoring the integrity verification method specifically to the mixed analog-digital system architecture. Instead of using generic digital integrity checks that don't account for analog conversion effects, the system adjusts the test signal injection and analysis procedures to match the specific characteristics of the analog output path, improving detection accuracy for this particular system type.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the verification parameters to account for the analog output transformation. The system modifies the test signal characteristics and analysis criteria based on how the digital transmission is converted to analog signals, adjusting parameters such as signal amplitude, frequency response, and noise characteristics to accurately detect errors in the mixed system context.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4228187B1Integrity tests for mixed analog digital systems
Publication Date: 2024.06.19 APTIV TECHNOLOGIES AG
  • EP4228187B1 patent drawingFigure 1
  • EP4228187B1 patent drawingFigure 2
  • EP4228187B1 patent drawingFigure 3

AI summary

Device (120) for checking the integrity of a digital transmission for an analog output (114) of a system (104). The analog output (114) may be checked for transient errors that can be attributed to a digital transmission path embedded somewhere within the vehicle system (104). A test signal is introduced into a digital transmission (112) that can be reassembled from an analog path (118) of the analog output (110), and, if not, allows the test device (120) to pinpoint that errors are appearing due to the digital path, and not because of the analog output. In this way, debugging an installation of a system (104) becomes easier; obtaining confidence in reliability of a mixed analog and digital system becomes less of a challenge and less time consuming.