Speed Signal Converter Edge Selection for Reverse Polarity Correction
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Solution Overview
Problem
Existing speed and timing sensing systems in aircraft face challenges in accurately detecting and correcting reverse wiring faults, which can lead to inaccurate signal conversion and noisy speed/timing signals.
Innovation Solution
A speed signal converter circuit with an analog signal conditioning stage and a digital signal processing stage is employed. This circuit determines the optimal edge (rising or falling) by comparing the slopes of the input speed signal edges and corrects reverse wiring faults by detecting mismatches between the expected and actual edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reverse wiring faults are not detected and corrected, then the system operates with inaccurate speed and timing signals, but adding detection and correction mechanisms increases device complexity
Solution Approach 1:
The system performs preliminary detection of reverse wiring faults by comparing edge slopes before final signal conversion. The digital signal processing stage calculates rising edge slope and falling edge slope, compares them to determine if reverse wiring exists, and corrects the signal edge selection accordingly, preventing inaccurate conversion from occurring in the first place
Solution Approach 2:
The system implements feedback by continuously monitoring the slopes of rising and falling edges, comparing them against expected characteristics, and using this information to dynamically adjust edge selection for signal conversion. This closed-loop approach ensures accurate speed and timing signal conversion even when reverse wiring faults are detected
2Measurement precision
If edge slope comparison is performed to detect reverse wiring, then detection accuracy improves, but processing time increases
Solution Approach 1:
The system performs partial action by comparing only the essential characteristic (edge slope) to detect reverse wiring, rather than analyzing the entire signal waveform. This selective approach maintains high detection precision while minimizing processing time requirements
3Measurement precision
If the system processes both rising and falling edges to determine optimal edge, then signal conversion accuracy improves, but computational load increases
Solution Approach 1:
The system extracts only the critical information needed for reverse wiring detection by comparing rising edge slope and falling edge slope, rather than processing all signal characteristics. This extraction approach enables accurate optimal edge selection while reducing unnecessary computational load
Data Source
AI summary
A speed signal converter circuit including an analog signal conditioning stage and a digital signal processing stage. The analog signal conditioning stage determines a voltage of an input speed signal, combines the voltage with an alternating current (AC) injection voltage signal having a set frequency to generate a combined voltage signal, and outputs a pulsed zero-crossing signal including a rising edge and a falling edge indicating a zero-crossing of the input speed signal based on the combined voltage signal. The digital signal processing stage determines a rising edge slope of the input speed signal and a falling edge slope of the input signal based on a rising edge and a falling edge of the pulsed zero-crossing signal, and determines an optimal edge among one of the rising edges or the falling edges based on a comparison between the rising edge slope and the falling edge slope.