Duty-Cycle Bit Interface for Multi-Test Selection Without Extra I/O
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Solution Overview
Problem
Conventional binary-based bit interface systems in aircraft systems require an exponential increase in components, data lines, weight, and cost as the number of diagnostic tests increases, due to the need for additional dedicated I/O lines to generate binary codes for each test.
Innovation Solution
A duty cycle-based bit interface system that varies the pulse width modulation of an input signal to select diagnostic tests, using pre-defined duty cycle thresholds to determine which test is commanded, eliminating the need for additional I/O lines by employing a duty cycle-based system instead of binary coding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If binary-based bit interface system uses additional dedicated I/O lines to generate binary codes for each diagnostic test, then the number of diagnostic tests can be identified, but the number of components, data lines, weight, and cost increase exponentially
Solution Approach 1:
The patent changes the parameter used for test selection from binary code values (requiring multiple I/O lines) to duty cycle percentages of a single square wave signal. By varying the duty cycle parameter of one signal, the system can select among multiple diagnostic tests without adding I/O lines, thus resolving the contradiction between test versatility and device complexity
Solution Approach 2:
A single I/O line carrying a square wave signal with variable duty cycle replaces multiple dedicated I/O lines that would be needed for binary coding. This single signal performs multiple functions by encoding different test selections through different duty cycle values, reducing the number of components while maintaining adaptability
2Adaptability or versatility
If binary-based bit interface system increases the number of I/O lines to support more diagnostic tests, then more tests can be commanded, but the weight and cost increase
Solution Approach 1:
The system uses parameter variation (duty cycle percentage) of a single signal to encode multiple test selections, eliminating the need for additional physical I/O lines. This reduces the weight of the interface system while maintaining the ability to command multiple diagnostic tests
3Adaptability or versatility
If binary-based bit interface system adds more I/O lines for additional diagnostic tests, then test coverage increases, but the overall costs increase exponentially
Solution Approach 1:
By changing from a binary coding scheme (requiring multiple I/O lines) to a duty cycle-based selection scheme (using one I/O line), the patent reduces the number of components needed. This reduces manufacturing costs and assembly complexity while maintaining the ability to provide comprehensive diagnostic test coverage
Data Source
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AI summary
A duty cycle-based bit interface system includes a first stage voltage converter (104) and second stage voltage converter (106) in signal communication with the first stage voltage converter. The first stage voltage converter converts a digital voltage signal into an analog voltage signal. The second stage voltage converters convert the digital voltage signal into a scaled version of the same. A sampling unit (108) is in signal communication with at least one of the second stage voltage converters, and is configured to sample a portion of the first stage analog output voltage signal during a sampling time period. The sampled portion has a duty cycle based-analog voltage signal during the sampling time period. A bit selector unit (110) is in signal communication with the sampling unit, and outputs a bit enable signal that initiates a specific diagnostic test among a plurality of diagnostic tests based on the duty cycle of the sampled portion.