Asynchronous Reflectometry for Intermittent Fault Detection
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Solution Overview
Problem
Conventional reflectometry methods for detecting faults in transmission lines require long acquisition times, complex data processing, and expensive high-performance converters, making it difficult to detect intermittent faults accurately and efficiently, especially in low-cost systems.
Innovation Solution
A method and device that allow for the direct processing of over-sampled signals from analogue-digital converters without post-processing, enabling asynchronous operation of DAC and ADC converters, and using different frequencies for these converters to eliminate parasitic frequencies and reduce hardware costs, thereby increasing detection precision and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple acquisitions of the signal are made with phase shifting of the sampling clock to increase detection precision, then measurement precision is improved, but acquisition time and device complexity increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-computing the memory address increment value based on the known relationship between DAC and ADC sampling frequencies. This pre-computed increment is then used directly during signal acquisition to determine memory addresses, eliminating the need for real-time phase shifting and multiple acquisitions. The preliminary computation of the address increment enables direct processing of the signal without time-consuming post-processing operations.
2Measurement precision
If high-frequency emission signals are used to coincide wavelength with fault dimensions for high precision detection, then measurement precision is improved, but hardware costs and complexity increase
Solution Approach 1:
The patent applies parameter changes by utilizing the existing sampling frequencies of the DAC and ADC converters rather than introducing new high-frequency emission signals. The method changes the approach from modifying signal frequency parameters to utilizing the temporal relationship between existing sampling operations. By computing the memory address increment based on the ratio of DAC to ADC sampling frequencies, the system achieves high precision fault detection without requiring additional high-frequency hardware components.
3Measurement precision
If over-sampling rules are met with analogue components to generate delays and phase shifts, then measurement precision is improved, but parasitic frequencies are introduced and device complexity increases
Solution Approach 1:
The patent applies the taking out principle by extracting and eliminating the complex analogue delay generation circuitry that introduces parasitic frequencies. Instead of using analogue components to generate phase shifts and delays, the method directly computes the appropriate memory address increments based on the digital sampling frequencies. This extraction of the problematic analogue delay generation stage removes the source of parasitic frequencies while maintaining measurement precision through mathematical computation of the address increment.
4Measurement precision
If very-high-performance analogue-digital converters are used to inject and measure high-frequency sampling signals, then measurement precision is improved, but hardware costs increase significantly
Solution Approach 1:
The patent applies the cheap short-living objects principle by using standard, off-the-shelf DAC and ADC converters with moderate performance specifications rather than investing in very-high-performance converters. The method compensates for the lower performance of these standard converters by using computational methods (pre-computed memory address increments) to achieve the desired measurement precision. This approach reduces hardware costs significantly while maintaining adequate measurement accuracy for fault detection applications.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the detection of intermittent faults with increased precision and reduced costs, allowing for faster synchronization and longer acquisition times without the need for additional hardware, effectively addressing the limitations of existing systems.
Implementation Method 1
Reflectometry methods use a principle similar to that of radar: an electrical signal, the probe signal or reference signal, which is most often of high frequency or wideband, is injected into the cable to be tested in one or more places. The signal propagates through the cable or the network of cables and some of its energy is reflected when it encounters an electrical discontinuity.
Data Source
AI summary
A method and device for detecting faults in a transmission line by reflectometry, include the following steps: injecting into the transmission line a reference signal at an emission frequency fDAC; collecting a reflected signal at a point on the transmission line; sampling the reflected signal at a sampling frequency fADC, the sampling frequency fADC being different from the emission frequency fDAC; storing each point of the sampled signal at a memory address corresponding to an index assigned to the point of the sampled signal and according to a precomputed memory-address increment Δ, the memory-address increment Δ depending on the emission frequency fDAC, on the sampling frequency fADC, on an over-sampling factor Ω and on a preset acquisition time Σ; repeating the storing step during the acquisition time Σ; and generating, from the points stored during the acquisition time, a recomposed signal able to be used to detect faults.