Multi-Resolution Code Sequences for OTDR Fault Localization
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Solution Overview
Problem
Current optical time domain reflectometry (OTDR) systems in long-distance fiber optic communication systems face challenges in achieving multi-resolution monitoring, as existing techniques either fail to detect discrete discontinuities or provide insufficient resolution for fault localization within the fiber optic cables.
Innovation Solution
The system employs a set of multi-resolution code sequences, including complementary and mutually orthogonal sequences, to generate test signals that allow for selective resolution in OTDR systems, enabling the detection of both general signal loss and discrete discontinuities by adjusting the frequency spectra of the test signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional OTDR test signals are used, then the system can detect general signal loss, but it fails to detect discrete discontinuities with sufficient resolution
Solution Approach 1:
The test signal is segmented into multiple frequency components through the use of multi-resolution code sequences. Each code sequence in the set corresponds to a specific frequency spectrum, allowing the system to segment the measurement task into different resolution levels - some sequences optimized for detecting discrete discontinuities while others detect general signal loss
Solution Approach 2:
The invention changes the frequency spectrum parameter of the test signal by selecting different code sequences from the set. Each code sequence has a distinct frequency spectrum characterized by a maximum at a specific frequency, allowing dynamic adjustment of the test signal's frequency characteristics to match different monitoring requirements
2Measurement precision
If high resolution test signals are used to detect discrete discontinuities, then fault localization precision improves, but signal-to-noise ratio deteriorates
Solution Approach 1:
The invention merges multiple test signals with different frequency spectra into a unified monitoring approach. By combining the results from multiple code sequences - each optimized for different frequency ranges - the system achieves both high resolution for discrete discontinuities and maintains good signal-to-noise ratio for general loss detection
Solution Approach 2:
Instead of using a single high-resolution test signal that would degrade signal-to-noise ratio, the invention applies partial action by selecting specific code sequences from the set based on the monitoring needs. This allows the system to apply high resolution only when necessary for detecting discrete discontinuities while using lower resolution sequences for general monitoring, thus avoiding excessive noise
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 system to provide full resolution waveforms by combining low and high resolution data, effectively localizing faults and discontinuities within the fiber optic cables without compromising signal-to-noise ratio, thereby enhancing the monitoring capabilities of the OTDR system.
Implementation Method 1
an optical transmitter transmits a set of test signals, each test signal representing a code sequence from a predefined set of code sequences, on an optical fiber path
Implementation Method 2
The correlator receives reflected portions of the first resolution test signals from the optical communication system as reflected first resolution test signals
Data Source
Figure 1
Figure 2A~2D
Figure 3A~3B
AI summary
A system and method for time domain reflectometry (OTDR) using multi-resolution code sequences. One or more subsets of a set of predefined complementary code sequences may be transmitted as an OTDR signal to provide multi-resolution capability.