Parallel Pair Cable Shielding Stability
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Solution Overview
Problem
Parallel pair cables experience unstable shielding effects during differential signal transmission due to fluctuations in the distance between the conductive shield tape and signal lines, leading to increased common mode output.
Innovation Solution
A parallel pair cable configuration featuring a pair of insulated wires arranged parallel and not twisted, wrapped with a first resin tape and a longitudinally folded metal shield tape, optionally including a drain wire and jacket layer, to stabilize the shielding effect and reduce common mode output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional shield tape wrapping method is used, then the cable structure is simple, but the shielding effect becomes unstable and common mode output increases
Solution Approach 1:
The shield tape is divided into multiple segments along its length, with each segment independently positioned relative to the signal lines. This segmentation allows the shield tape to maintain stable shielding effect across different cable sections while accommodating variations in cable geometry, thereby reducing common mode output without requiring a completely complex continuous structure.
Solution Approach 2:
The shield tape segments are pre-positioned at specific locations relative to the signal lines during cable assembly. This preliminary positioning ensures that the shielding effect is established before the cable is put into service, maintaining consistent electrical characteristics and reducing common mode conversion without requiring complex real-time adjustment mechanisms.
2Reliability
If the distance between shield tape and signal lines fluctuates, then manufacturing is easier, but shielding effect becomes unstable
Solution Approach 1:
The shield tape structure is designed to accommodate dynamic variations in distance to signal lines along the cable length. By allowing controlled distance fluctuations through the segmented design and appropriate material selection, the shield tape maintains effective shielding across varying conditions without requiring extremely tight manufacturing tolerances, thus balancing reliability with manufacturability.
3Reliability
If shield tape is placed close to signal lines, then shielding effect improves, but cable structure complexity increases
Solution Approach 1:
The shield tape is positioned close to signal lines only at specific critical locations where shielding is most needed, rather than maintaining uniform close proximity throughout the entire cable length. This local quality approach concentrates shielding effectiveness where it provides maximum benefit while avoiding the complexity of a uniformly tight structure, thereby improving shielding without proportionally increasing overall cable complexity.
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
The configuration effectively reduces common mode output and stabilizes the shielding effect, improving transmission characteristics and maintaining uniformity, even under high-frequency signals.
Implementation Method 1
a shield tape comprising a metal layer longitudinally folded on the outside of the first resin tape... when distance between the conductive shield tape and signal lines fluctuates along the length of the cable, there is a risk that a shielding effect thereof on the signal lines becomes unstable
Data Source
AI summary
A parallel pair cable includes a pair of insulated wires arranged to be in contact with each other, parallel to each other and not twisted, a first resin tape wrapped around the pair of insulated wires, and a shield tape longitudinally folded on the outside of the first resin tape and comprising a metal layer.