Differential Signal Termination Block Impedance Matching
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Solution Overview
Problem
Current test equipment designed for single-ended signal protocols is inadequate for characterizing differential signal protocols, leading to signal degradation and distortion due to mismatched impedance and common-mode voltage issues.
Innovation Solution
A termination block with symmetrical phase-matched connectors and passive circuit elements provides impedance matching and balanced loading for differential signals, while maintaining high signal quality by using coaxial connectors and resistor configurations that support both differential and single-ended signal devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If single-ended connectors with 50 Ohm termination to ground are used in test equipment, then the equipment is well-suited for single-ended signal protocols, but the differential signal impedance matching deteriorates and signal quality degrades
Solution Approach 1:
The patent introduces a termination block as an intermediary device between the single-ended test equipment and differential signal devices. This block contains a transformer that couples the single-ended connector to differential connectors, enabling impedance transformation and proper differential signal termination without modifying the existing single-ended test equipment architecture
Solution Approach 2:
The termination block transforms the impedance parameters from 50 Ohm single-ended termination to 100 Ohm differential termination through the transformer coupling. The transformer changes the electrical parameters to match differential signal requirements while maintaining compatibility with single-ended test equipment
2Reliability
If differential signal protocols consider only the differential portion and suppress the common-mode portion, then the serial link performance is improved under ideal conditions, but the system becomes sensitive to common-mode voltage shifts and external noise
Solution Approach 1:
The termination block separately handles differential and common-mode signal components through the transformer coupling. The differential ports provide 100 Ohm termination for differential signals while the single-ended ports provide 50 Ohm termination for common-mode signals, allowing independent optimization of both signal modes
Solution Approach 2:
The transformer in the termination block acts as an intermediary that properly couples differential and common-mode signal paths, enabling the test equipment to handle both signal modes correctly and reducing sensitivity to common-mode disturbances
3Ease of operation
If a differential signal driver with 100 Ohm termination is connected to test equipment with 50 Ohm single-ended resistance to ground, then the connection is simple, but the driver output signal swing is degraded and signal shape is distorted
Solution Approach 1:
The termination block serves as an intermediary device that maintains connection simplicity while correcting signal integrity issues. The block contains proper 100 Ohm differential termination and transformer coupling to restore correct signal swing and shape without requiring complex modifications to the driver or test equipment
Data Source
AI summary
A termination block for connecting a first signal device and a second signal device. The termination block includes a housing, first and second pair of connectors, and an electrical circuit having passive elements that connect the first and second pair of connectors and provide impedance matching.