Test Instrument Common Path Distortion Detection
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Solution Overview
Problem
Existing cable network systems face challenges in detecting common path distortion (CPD) sources located on the downstream side of the network, as conventional test instruments fail to identify these sources when disconnected from the network, leading to false test results and increased labor costs.
Innovation Solution
A computer-implemented method using a test instrument that transmits and measures specific test signals at different frequencies to detect common path distortion, even when the source is on the downstream side, allowing for accurate localization of the distortion without additional hardware or network modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional test instruments are disconnected from the network to test for common path distortion, then false test results are obtained, but the test instrument cannot identify downstream CPD sources
Solution Approach 1:
The test instrument performs preliminary actions by transmitting test signals through the downstream portion of the network before disconnection occurs. This allows the instrument to capture CPD characteristics while still connected, enabling accurate identification of downstream CPD sources without compromising test result validity upon disconnection.
Solution Approach 2:
The patent introduces an intermediary approach where the test instrument uses the network's existing downstream signals as a mediator to detect CPD. By analyzing these intermediate signals rather than directly injecting test signals, the instrument can identify downstream CPD sources while maintaining connection integrity and avoiding false test results.
2Difficulty of detecting and measuring
If additional hardware or network modifications are implemented to detect downstream CPD sources, then detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The test instrument is designed with multi-functionality, enabling it to perform both conventional network testing and downstream CPD detection using the same hardware infrastructure. The instrument can operate in multiple modes: connected mode for downstream CPD detection and disconnected mode for traditional testing, eliminating the need for additional specialized hardware.
Solution Approach 2:
The network's existing downstream signals and infrastructure serve the dual purpose of normal signal transmission and CPD detection. The test instrument leverages these self-existing network resources to perform CPD localization without requiring external additions or modifications, making the system self-sufficient.
3Ease of operation
If conventional testing methods are used with disconnected instruments, then labor costs increase due to false results, but simpler testing procedures are maintained
Solution Approach 1:
The testing procedure dynamically adapts its operation mode based on the detection phase. The instrument transitions between connected and disconnected states as needed, and automatically selects appropriate testing protocols. This dynamic operation maintains procedural simplicity while eliminating the need for manual intervention to correct false results, thereby improving productivity.
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
Enables accurate detection and localization of common path distortion sources, reducing false test results and labor costs by utilizing existing test instruments with software upgrades, improving network performance and diagnostic accuracy.
Implementation Method 1
When the signals pass through this non-linear effect, they mix and produce new signals that are the second and third order intermodulation products
Data Source
AI summary
A method and an apparatus providing common path distortion (CPD) detection from a field instrument, particularly when the source of the common path distortion is at a portion of the network beyond the subscriber's tap.