Twisted-Pair Hearing Device Cable for Crosstalk Isolation
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Solution Overview
Problem
Hearing instruments face significant crosstalk and noise issues due to the combination of multiple transducers sharing a single cable, particularly between microphone and receiver signals, which are exacerbated by varying impedances and current levels.
Innovation Solution
A cable design featuring twisted pairs of conductors around a deformable core wire, with non-conductive filler strands between pairs, and optional shielding, to minimize crosstalk and noise by physically separating signal types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple transducers share a single cable, then device complexity is reduced and integration is improved, but crosstalk and noise between signals increase significantly
Solution Approach 1:
The cable is segmented into multiple twisted pairs, with each pair dedicated to specific signal types (microphone inputs, receiver outputs, power, ground). This segmentation physically separates different signal types within the single cable, reducing crosstalk while maintaining integration.
Solution Approach 2:
Different regions of the cable have different properties: twisted pairs for signal transmission, filler strands for physical separation and structural integrity, and shielding wraps for electromagnetic protection. Each local region is optimized for its specific function to minimize interference.
2Volume of moving object
If receiver drive signals are run in parallel to microphone output signals, then cable space is efficiently utilized, but microphone output signals are significantly polluted
Solution Approach 1:
High-current receiver drive signals and low-level microphone output signals are segregated into different twisted pairs. The segmentation ensures that high-current signals do not directly parallel low-impedance signal paths, preventing signal pollution while maintaining efficient cable space utilization.
Solution Approach 2:
The twisted pair structure acts as an intermediary that allows multiple signals to coexist in close proximity while minimizing direct coupling. The twisting geometry and physical separation through filler strands reduce electromagnetic coupling between high-current and low-level signal pairs.
3Object-affected harmful factors
If conductors are arranged in twisted pairs with filler strands, then crosstalk is reduced, but manufacturing complexity increases
Solution Approach 1:
The cable is manufactured as pre-formed twisted pairs with filler strands integrated during the cable extrusion process. This segmentation approach allows standardization of sub-components, reducing overall manufacturing complexity despite the sophisticated internal structure.
Solution Approach 2:
The use of a plastically deformable core wire allows the cable to be formed into various configurations after manufacturing. This parameter change (from rigid to deformable state) simplifies installation and adaptation to different device geometries without requiring complex custom manufacturing for each application.
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a cable (1) for a hearing device, comprising a plurality of conductors, comprising conductors arranged in twisted pairs (TP1 to TP4) wound around a plastically deformable core wire (FW).