Impedance Matching Circuit for Gigabit Ethernet Over Coaxial Cable
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Solution Overview
Problem
Gigabit Ethernet chips are unable to adapt to coaxial cables, limiting the use of coaxial cables for high-speed data transmission.
Innovation Solution
An impedance conversion device is introduced, comprising impedance loops and resistors to match the impedance of Gigabit Ethernet chips with coaxial cables, enabling signal transmission through coaxial cables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Gigabit Ethernet chips are directly connected to coaxial cables, then the connection is simple, but the impedance mismatch prevents signal transmission
Solution Approach 1:
An impedance conversion device is introduced as an intermediary component between the Gigabit Ethernet chip and the coaxial cable. This device includes a first impedance loop connected to the coaxial cable and a second impedance loop grounded, with specific resistor configurations that transform the 50-ohm Ethernet output impedance to match the 75-ohm coaxial cable impedance, enabling reliable signal transmission
Solution Approach 2:
The impedance conversion device changes the electrical parameter (impedance) from 50 ohms to 75 ohms through a specific circuit configuration. The first impedance loop uses a first chip resistor and first impedance loop with combined impedance equal to the coaxial cable's characteristic impedance, while the second impedance loop provides grounding, collectively transforming the impedance to match the coaxial cable
2Reliability
If impedance conversion device is added to match impedance, then signal transmission becomes possible, but device complexity increases
Solution Approach 1:
The impedance conversion device is segmented into distinct functional loops: a first impedance loop for impedance transformation and a second impedance loop for grounding. Each loop is further divided into specific components (resistors, DC-blocking capacitors) with defined connections, making the complex impedance matching function manageable and implementable through modular circuit design
Solution Approach 2:
The impedance conversion device serves as an intermediary that handles the complexity of impedance transformation, shielding the Gigabit Ethernet chip from the complexity of direct coaxial cable interface design. This mediator approach allows the chip to remain simple while achieving reliable coaxial cable transmission through the intermediate conversion stage
Data Source
AI summary
The invention provides an impedance conversion device for a vehicle-mounted gigabit Ethernet chip adaptive to a coaxial cable transmission, and relates to the technical field of Ethernet communication. The impedance conversion device has a first impedance loop, a cable wiring end of the first impedance loop is connected with the coaxial cable, and a chip wiring end of the first impedance loop is connected with a first signal output end of the vehicle-mounted Ethernet chip; a first chip resistor is connected between a first signal input end and the first signal output end of the vehicle-mounted Ethernet chip, and the sum of an impedance value of the first impedance loop and a resistance value of the first chip resistor is equal to an equivalent resistance value of the coaxial cable.