Differential Signal Cable Oval Insulation Skew Reduction
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Solution Overview
Problem
Conventional parallel two-core shielded wires experience loosening of metal foil tape, leading to increased skew and differential-to-common mode conversion, which affects the transmission of high-speed differential signals due to insufficient pressure applied by the tape during winding.
Innovation Solution
A differential signal transmission cable design featuring an insulation with an oval cross-sectional shape formed by continuous convex arcs, providing varying curvature radii to maintain constant pressure on the metal foil tape, thereby preventing loosening and reducing skew and differential-to-common mode conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a metal foil tape is wound around an insulation with a flat portion in cross section, then manufacturing time is reduced, but the metal foil tape is likely to be loosened due to insufficient pressing pressure
Solution Approach 1:
The patent applies curvature principle by designing the insulation's cross-sectional shape to have no flat portions but instead continuous convex curved surfaces. This curvature ensures that when metal foil tape is wound around the insulation, the tape maintains constant pressing pressure against the surface, preventing loosening while preserving the efficiency of the winding manufacturing process.
2Device complexity
If the metal foil tape is loosened, then manufacturing complexity is reduced, but skew and differential-to-common mode conversion quantity increase
Solution Approach 1:
The continuous convex curved cross-sectional shape of the insulation prevents metal foil tape loosening, thereby maintaining consistent electromagnetic shielding properties and preventing increases in skew and differential-to-common mode conversion quantity without complicating the shield conductor structure.
3Stability of the object's composition
If the insulation has a circular cross section, then the metal foil tape experiences uniform tension, but pressure for pressing the tape is not generated in flat portions
Solution Approach 1:
The patent resolves this contradiction by eliminating flat portions from the cross-sectional shape entirely. The continuous convex curved surface ensures that tension in the metal foil tape is consistently converted into pressing pressure at all points along the circumference, achieving both uniform tension distribution and adequate pressing pressure simultaneously.
Data Source
AI summary
A differential signal transmission cable includes a pair of differential signal lines arranged in parallel to each other, an insulation for bundle-covering the pair of differential signal lines, and a shield conductor wound around an outer periphery of the insulation. The insulation is configured such that an outer circumference thereof in a cross section perpendicular to a longitudinal direction thereof has an oval shape formed with a continuous convex arc-curve. The outer circumference of the insulation includes a first curved portion with a pair of symmetrical elliptical arcs located at both ends in a first direction along the arrangement direction of the pair of differential signal lines and a second curved portion with a pair of symmetrical elliptical arcs located at both ends in a second direction orthogonal to the first direction.