Network Fault Detection via Interferometric Phase Modulation
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Solution Overview
Problem
In networks with a main line and multiple branch lines, identifying faults or losses along the branch lines is challenging, especially as the number of branch lines increases, as existing methods struggle to distinguish which branch line is responsible for a detected fault.
Innovation Solution
The method involves introducing test signals into the main line, modulating them for a designated branch line, and detecting the phase modulation interferometrically to distinguish signals from that branch line from others, allowing for the identification of faults or losses associated with specific branch lines through temporal characteristics of returned signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If test signals are introduced into the main line and return signals are monitored to detect faults along branch lines, then fault detection capability is improved, but the ability to identify which specific branch line has a fault deteriorates as the number of branch lines increases
Solution Approach 1:
The patent applies segmentation by dividing the return signal into separate components corresponding to each branch line. This is achieved by introducing distinct modulation frequencies to each branch line's test signal, allowing the return signals to be segmented and identified by their respective modulation frequencies through frequency-selective filtering at the monitoring device.
Solution Approach 2:
The patent applies local quality by assigning different modulation characteristics (different frequencies or codes) to different branch lines. This creates a unique local signature for each branch line's return signal, enabling the monitoring device to distinguish which specific branch line a fault occurs on by analyzing the modulation characteristics of the detected return signal.
2Measurement precision
If modulation is imposed on test signals for a designated branch line and phase modulation is detected interferometrically, then the ability to distinguish signals from the designated branch line from other branch lines is improved, but device complexity increases
Solution Approach 1:
The patent applies periodic action by using periodic modulation signals (such as sinusoidal modulation at specific frequencies) imposed on the test signals for each branch line. This periodic modulation creates distinct frequency signatures in the return signals, which can be easily distinguished using frequency-selective filtering and interferometric detection, improving signal distinction while keeping the implementation relatively simple.
Solution Approach 2:
The patent applies the intermediary principle by using modulation frequencies and interferometric detection as intermediaries to distinguish between signals from different branch lines. The modulation frequency acts as an intermediary identifier that carries branch line information through the signal, while the interferometric detection serves as an intermediary measurement technique that extracts this information without requiring complex direct identification methods.
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 effective detection and association of faults with designated branch lines, facilitating further investigation and improving the ability to locate faults or irregularities within the network by distinguishing signals from different branch lines based on modulation and phase characteristics.
Implementation Method 1
the imposed phase modulation being detected interferometrically such that the test signals from the designated branch line can be distinguished with respect to the signals returned from other branch lines
Implementation Method 2
The test signals will preferably be returned by a process of distributed backscattering along the branch line lines
Data Source
AI summary
A network is assessed, in particular, a network having a main line and a plurality of branch lines. The method includes the steps of: (i) introducing test signals into the main line, the main line being coupled to the branch lines; (ii) imposing a modulation on test signals which propagate along the branch line, and (iii) monitoring test signals returned along the main line. The imposed phase modulation is detected interferometrically such that the test signals from the designated branch line can be distinguished with respect to the signals returned from other branch lines.