UTP Cable End Suppression for In-Band Emission Mitigation
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Solution Overview
Problem
In-vehicle communication networks face challenges with high levels of in-band radiated emission (RE) due to unshielded twisted pair (UTP) cables, which act as effective antennas and cause problematic common-mode currents, exacerbated by cable resonances and reflections, leading to electromagnetic interference.
Innovation Solution
Implementing a signal suppressing device, such as an electromagnetic signal absorbing material or a filter, proximate to the ends of the cable assembly to attenuate signals in the frequency range corresponding to in-band RE, thereby reducing electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If unshielded twisted pair (UTP) cables are used in automotive Ethernet, then weight of wiring harnesses is reduced and bandwidth is increased, but in-band radiated emission levels increase causing electromagnetic interference
Solution Approach 1:
The patent extracts and removes the harmful common-mode currents from the UTP cable system by introducing signal suppressing devices (filters) that specifically target and eliminate the radiated emission frequencies while preserving the desired differential mode signal transmission
Solution Approach 2:
The patent introduces signal suppressing devices as intermediary components between the communication devices and the UTP cable. These intermediaries (filters) mediate the signal transmission by allowing useful signals to pass while blocking the harmful radiated emissions, thus resolving the contradiction between using unshielded cables and reducing EMI
2Productivity
If UTP cables are used as effective antennas for high data rate transmission, then communication bandwidth is improved, but common-mode currents are generated causing radiated emission problems
Solution Approach 1:
The patent applies local quality by placing signal suppressing devices at specific locations (proximate to ends of the cable assembly) rather than uniformly throughout the system. The filters are strategically positioned where they can most effectively suppress common-mode currents without impeding the high-speed differential mode data transmission
3Ease of operation
If cable resonances are allowed to occur in UTP cables, then natural signal propagation is maintained, but in-band radiated emission is exacerbated
Solution Approach 1:
The patent changes the electrical parameters of the cable system by introducing filters that modify the frequency response characteristics. The signal suppressing devices alter the impedance and resonance characteristics of the cable assembly to suppress radiated emissions while maintaining acceptable signal propagation for data transmission
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
Significantly reduces in-band radiation emission in UTP cables over problematic frequency ranges, improving signal integrity and electromagnetic compatibility in vehicle communication networks.
Implementation Method 1
The first signal suppressing device comprises an electromagnetic signal absorbing material coupled around a portion of the cable assembly proximate to the first end of the cable assembly
Data Source
AI summary
A communication system for use in a vehicle includes a first communication device configured for operation in the vehicle, and a second communication device configured for operation in the vehicle. A cable assembly communicatively couples the first communication device with the second communication device. A signal suppressing device is coupled to the cable assembly at a location proximate to an end of the cable assembly. The signal suppressing device is configured to suppress signals in a frequency range corresponding to in-band radiated emission (RE).