Impedance Control Device for Network Node Signal Interface
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Solution Overview
Problem
Mismatches in impedance between communication nodes in a wired network cause signal reflections, leading to a multipath signal environment that impairs signal passage and increases data error rates, particularly when power is applied or removed from nodes or during resets, requiring adaptive compensation that can be sub-optimal due to the time needed for adaptation.
Innovation Solution
An Impedance Control Device is used to manage the impedance of Transitioning Nodes by slowly transitioning the impedance presented to the network, allowing other nodes to adapt, and by switching to a stable impedance circuit during power transitions to minimize disruptions, ensuring continuous network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impedance compensation is provided for known reflections, then signal quality is improved, but when reflections change due to node transitions, the compensation becomes sub-optimal causing performance degradation
Solution Approach 1:
The patent applies preliminary action by transitioning the impedance of a node slowly and progressively before fully entering or leaving the network, rather than making abrupt changes. This gradual transition allows other nodes to adapt their compensation in advance, preventing sub-optimal compensation during sudden impedance changes and maintaining signal quality throughout the transition process.
2Speed
If a node transitions impedance quickly when power is applied or removed, then device responsiveness is improved, but signal disruptions and errors increase due to abrupt impedance changes
Solution Approach 1:
The patent applies dynamics by making the impedance transition rate adaptive rather than fixed. During power transitions, the impedance changes quickly initially but then slows down as it approaches the final value, creating a dynamic transition profile that balances speed with signal stability. This dynamic approach allows fast response while minimizing disruptions to ongoing communications.
3Reliability
If impedance transitions are made slowly to allow network adaptation, then signal stability is improved, but the time required for node transitions increases
Solution Approach 1:
The patent applies periodic action by using a multi-phase impedance transition approach. The transition occurs in stages: an initial fast phase for quick response, followed by intermediate phases with decreasing transition rates, and finally a slow phase for precise settling. This periodic variation in transition speed allows the system to achieve both fast overall transition time and high signal stability during critical phases.
Data Source
AI summary
The terminating impedance of a networked device in a wired communication channel is controlled to avoid an impedance discontinuity when power is applied and removed from the node or other event occurs that would change the impedance of the signal interface. When the node transmits or receives signals using the communication channel, the transmit or receive device presents a matched termination to the channel. When power is removed or the device is reset, the transmit and receive circuitry is not operational and the matched impedance is therefore maintained by a separate device. The impedance may be varied slowly from a match to a high impedance to allow other devices in the network to adapt to the change in multipath environment that results from the impedance change. Alternatively, the signal interface can be switched to a passive static impedance that is maintained while power is off or the disrupting event occurs.