ALU Testing via Segmented Bit-by-Bit Error Analysis

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Solution Overview

Problem

Modern flight control systems using digital components are complex and costly to fully test and analyze for conformance with Federal Air Regulations, as commercially available digital components are not adequately tested or validated for safety requirements.

Innovation Solution

A method for testing a functional unit within an arithmetic logic unit (ALU) is developed, where the ALU is implemented with a programmable logic device or application-specific integrated circuit, allowing for detailed bit-by-bit error analysis and verification of operation results using targeted test vectors, ensuring full testability and analyzability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If digital components are used in flight control systems, then performance is improved and space/weight are reduced, but testing and analysis complexity increases significantly

Engineering Contradiction:
Improvesystem performanceVSAvoidtesting and analysis complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary testing system that includes a data generator, test controller, and error analyzer. This intermediary system mediates between the ALU under test and the test vectors, enabling systematic testing of digital components without requiring exhaustive manual analysis of the entire system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The testing method segments the complex testing task into distinct functional components: test vector generation, operation execution, result comparison, and error analysis. Each functional unit within the ALU is tested independently using targeted test vectors, breaking down the overall testing complexity into manageable segments.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If commercially available digital components are used, then system implementation is simplified, but validation of conformance with safety requirements becomes infeasible

Engineering Contradiction:
Improvesystem implementationVSAvoidsafety conformance validation
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by implementing a comprehensive testing and analysis framework before the ALU can be certified for safety-critical applications. The system performs preliminary structural analysis, functional testing, and error detection to validate conformance with Federal Air Regulations before deployment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The testing system incorporates feedback mechanisms where operation results are compared against expected values, and errors are analyzed and reported. This feedback loop enables continuous validation of the ALU's conformance with safety requirements, allowing iterative improvement and verification.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If full functional testing of ALU is performed using all possible input test vectors, then testing completeness is improved, but testing time and computational resources increase exponentially

Engineering Contradiction:
Improvetesting completenessVSAvoidtesting time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by generating and executing only the necessary test vectors required to thoroughly test each functional unit, rather than exhaustively testing all possible input combinations. The test controller selectively applies test vectors based on the specific functional unit being tested, reducing overall testing time while maintaining adequate coverage.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The testing system is designed to be dynamic and adaptive, adjusting the test vector generation and execution based on the specific functional unit under test. The system can modify testing parameters, test vector selection, and analysis depth dynamically, allowing efficient allocation of testing resources while maintaining comprehensive coverage of critical functions.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2899636B1A method for testing an Arithmetic logic unit
Publication Date: 2019.09.11 HONEYWELL INTERNATIONAL INC
  • EP2899636B1 patent drawingFigure 1

AI summary

An arithmetic logic unit (ALU) (100) for use within a flight control system is provided. The ALU (100) comprises a first register (110) configured to receive a first operand, a second register (111) configured to receive a second operand, and an adder (130) coupled to the first register (110) and the second register (111). The adder (130) is configured to generate a sum of the first operand and the second operand and to generate intermediate sums that are used to determine a product of the first operand and the second operand.