Patch Cord Plug Contacts for Crosstalk Reduction
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Solution Overview
Problem
High-speed communications systems face significant challenges due to crosstalk and impedance mismatch issues in plug-jack connectors, which degrade signal quality and increase noise interference, especially as frequencies increase.
Innovation Solution
The design of communications plugs with low-profile plug contacts and printed circuit boards that align signal current injection points to minimize crosstalk, combined with offending crosstalk circuits to inject crosstalk close to the plug-jack mating point, ensuring compliance with industry standards while reducing crosstalk and improving return loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional plug contacts with long signal current carrying paths are used, then ease of manufacture is improved, but crosstalk increases and signal integrity deteriorates
Solution Approach 1:
The plug contact is divided into two separate segments: a signal current carrying path segment and a crosstalk injection segment. This segmentation allows the signal current to take a short path while providing a separate structure for controlled crosstalk injection, thereby reducing unwanted electromagnetic interference without complicating the manufacturing process.
Solution Approach 2:
A dedicated crosstalk injection structure acts as an intermediary element between the signal current carrying path and adjacent differential pairs. This intermediary provides a controlled mechanism for crosstalk compensation, separating the harmful crosstalk generation from the signal transmission function.
2Object-affected harmful factors
If signal current carrying path is shortened, then crosstalk is reduced, but manufacturing complexity increases
Solution Approach 1:
The short signal current carrying path and the crosstalk injection structure are merged into a single integrated plug contact design. The contact structure simultaneously performs both functions: transmitting signal current over a short distance and providing controlled crosstalk injection points, thereby reducing overall device complexity while achieving both goals.
Solution Approach 2:
The plug contact structure is designed to perform multiple functions: it serves as both the signal current carrier and the crosstalk injection element. This multi-functionality eliminates the need for separate components, maintaining manufacturing simplicity while achieving reduced crosstalk through the short signal path.
3Object-affected harmful factors
If plug contacts are designed with offset signal current injection points, then crosstalk cancellation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The signal current injection points are deliberately positioned asymmetrically or offset from the physical contact tips. This asymmetric positioning creates specific electromagnetic field patterns that enable crosstalk cancellation with adjacent differential pairs, while the offset distance is designed to be within standard manufacturing tolerances.
Solution Approach 2:
The injection point offset distance is optimized as a specific design parameter to achieve effective crosstalk cancellation. By carefully selecting this parameter within manufacturable ranges, the design achieves superior crosstalk performance without imposing excessive precision requirements on the manufacturing process.
Data Source
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AI summary
A patch cord (100) is provided that includes a communications cable (109) that has at least first through fourth conductors (101, 102, 104, 105) and a plug (116) that is attached to the cable (109). The plug (116) includes a housing (120) that receives the cable (109), a printed circuit board (150), first through fourth plug contacts (141, 142, 144, 145), and first through fourth conductive paths (161, 162, 164, 165) that connect the first through fourth conductors (101, 102, 104, 105) to the respective first through fourth plug contacts (141, 142, 144, 145). The first and second conductors (101, 102), conductive paths (161, 162), and plug contacts (141, 142) form a first differential transmission line, and the third and fourth conductors (104, 105), conductive paths (164, 165), and plug contacts (144, 145) form a second differential transmission line. Each of the first through fourth plug contacts (141, 142, 144, 145) has a first segment that extends longitudinally along a first surface of the printed circuit board (150), and the signal current injection point into the first segment of at least some of the first through fourth plug contacts (141, 142, 144, 145) is into middle portions of their respective first segments.