Communication Harness Ground Line EMC and Power Superposition
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Solution Overview
Problem
In vehicle Ethernet communication, existing technologies face challenges in reducing cable costs while maintaining electromagnetic compatibility (EMC) and incorporating power supply superposition functions, particularly with unshielded twisted pair (UTP) cables which lack noise control and weight reduction demands.
Innovation Solution
A communication harness with a twisted pair cable configuration that includes a ground line for improved EMC resistance and power supply superposition, where the ground line is isolated in the relay connector to prevent noise interference, allowing for efficient power supply superposition using pulse-amplitude modulation (PAM) communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If unshielded twisted pair (UTP) cables are used to reduce cable cost, then manufacturing cost decreases, but electromagnetic compatibility (EMC) resistance deteriorates
Solution Approach 1:
A ground line is introduced as an intermediary element between the signal lines and the external environment. This ground line acts as a mediator that provides a reference potential and shields the differential signal from external electromagnetic interference, thereby improving EMC resistance while still using cost-effective UTP cable structure
Solution Approach 2:
The cable structure is transformed from a simple twisted pair to a composite structure including signal lines, ground lines, and insulation layers. This composite construction combines the cost advantage of UTP with enhanced EMC performance through the integrated ground reference system
2Ease of manufacture
If power supply is superposed on differential transmission signal to reduce cable cost further, then manufacturing cost decreases, but noise interference increases
Solution Approach 1:
The ground line, which could potentially be a source of noise interference when power is superposed, is converted into a beneficial element by using it as a stable reference potential. This reference ground helps filter and stabilize the power supply signal, transforming the potential harm into a benefit for noise reduction
Solution Approach 2:
The electrical parameters of the cable system are changed by introducing a ground reference potential and superposing power supply voltage on the differential signal. This parameter modification enables the system to carry both data and power while maintaining signal integrity through the stabilized reference potential
3Object-affected harmful factors
If ground line is electrically connected between two communication harnesses to improve EMC resistance, then electromagnetic compatibility improves, but weight and cable complexity increase
Solution Approach 1:
The ground line is merged into the existing cable harness structure rather than being implemented as a separate shielding layer or additional external connection. By combining the ground function with the signal transmission function in a single integrated cable assembly, weight is minimized while EMC resistance is maintained
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 solution achieves both EMC resistance and power supply superposition functions, enhancing noise resistance and cable strength, while reducing the number of harnesses and weight, suitable for in-vehicle applications.
Implementation Method 1
differential transmission is used where twisted pair cables are used
Implementation Method 2
improved EMC resistance by arranging a ground line
Implementation Method 3
The ground line of the first communication harness is electrically isolated from the ground line of the second communication harness by the relay connector
Data Source
AI summary
A communication harness is used for mutual data transmission by differential transmission between at least two electronic devices. The communication harness includes a cable, a first signal line, a second signal line, and a first ground line. The first signal line is surrounded by the cable and transmits a first signal for differential transmission. The second signal line is surrounded by the cable and transmits a second signal for differential transmission. The first ground line is surrounded by the cable. A supply voltage is superposed on the first signal line.