Backplane Impedance Matching Terminal for Signal Reflection Control
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Solution Overview
Problem
High data rate signals in long backplane signal channels experience significant distortion due to signal reflection, leading to closed 'open eye' patterns and signal energy loss, which complicates signal decoding and is not effectively addressed by current passive or active solutions.
Innovation Solution
The implementation of impedance matching terminals, comprising resistors, capacitors, and inductors, strategically coupled to stubs and grounded within the backplane, to mitigate signal reflection and maintain signal integrity across the channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the data rate of the signal is increased to improve communication speed, then the signal quality deteriorates due to signal reflection and distortion in long stubs
Solution Approach 1:
The patent introduces an impedance matching terminal as an intermediary component between the stub and the signal channel. This terminal includes a resistor, capacitor, and inductor that work together to match the impedance of the stub to the signal channel, thereby reducing signal reflection and improving signal quality at high data rates without requiring changes to the blade or channel design
Solution Approach 2:
The patent changes the electrical parameters (impedance, resistance, capacitance, inductance) of the stub by adding the impedance matching terminal. This modifies the electrical characteristics of the stub to reduce signal reflection and distortion, enabling high data rate transmission while maintaining signal integrity in long stub configurations
2Length of moving object
If the length of the stub is increased to accommodate physical layout requirements, then signal reflection and distortion increase at high data rates
Solution Approach 1:
The impedance matching terminal serves as a mediator that compensates for the negative effects of long stub length. By matching the impedance at the stub endpoint, it prevents signal reflection that would otherwise be exacerbated by the increased stub length, allowing long stubs to be used without sacrificing signal integrity at high data rates
Solution Approach 2:
The impedance matching terminal is placed at the endpoint of the stub to preemptively counteract signal reflection before it can travel back up the stub and cause distortion. This preliminary anti-action prevents the harmful reflection effect from occurring in the first place, rather than attempting to correct it after the fact
3Reliability
If passive impedance matching components are added to reduce signal reflection, then device complexity increases
Solution Approach 1:
The patent extracts the impedance matching function from the blade circuitry and places it as a separate terminal on the backplane. This separation allows the complexity to be localized to the backplane rather than being distributed across multiple blades, and enables the use of standard passive components (resistor, capacitor, inductor) that can be easily integrated into the backplane design
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 use of impedance matching terminals ensures compliance with signal quality standards by maintaining an 'open eye' pattern and minimizing signal energy loss, even at high data rates and long channel lengths, thereby enhancing signal decoding capabilities.
Implementation Method 1
An impedance matching terminal is electrically coupled to one or more of the stubs and to a ground. The impedance matching terminal may include a resistor, a capacitor, and an inductor
Implementation Method 2
The impedance matching terminal may include a resistor, a capacitor, and an inductor
Implementation Method 3
The impedance matching terminal may include a resistor, a capacitor, and an inductor
Data Source
AI summary
An apparatus comprising a printed circuit board having a front side and a back side, and having therein a plurality of conductive layers, each conductive layer including one or more signal channels; a stub extending from the front side to the back side, the stub being electrically coupled to at least one signal channel; and an impedance matching terminal electrically coupled to the stub and to a ground. A process comprising providing a printed circuit board including a front side and a back side, and having therein a plurality of conductive layers, each conductive layer including one or more signal channels, and a stub extending from the front side to the back side, the stub being electrically coupled to at least one signal channel and being designed to receive a signal from a component attached to the printed circuit board; and coupling an impedance matching terminal to the stub and to a ground.