Bi-Directional Coupler Switching for Test Point Isolation
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Solution Overview
Problem
The use of separate directional couplers for upstream and downstream connections in network testing leads to increased insertion loss and reduced directivity due to imperfect termination of isolating ports, especially when one or both test points are not connected, and the challenge of different power supply voltages between analog and digital SFP modules causing damage.
Innovation Solution
A bi-directional coupler system with switches that terminate ports when test points are not connected and a power supply control system to adjust voltage based on module type, ensuring proper termination and isolation, and preventing damage to digital SFP modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two separate directional couplers are used for upstream and downstream connections, then isolation between upstream and downstream is improved, but insertion loss increases and device complexity increases
Solution Approach 1:
The patent combines two separate directional couplers into a single bi-directional coupler that handles both upstream and downstream connections. This merging reduces the total number of components, decreases insertion loss by eliminating redundant coupling elements, and simplifies the overall system architecture while maintaining isolation through proper port termination
2Reliability
If two separate directional couplers are used for upstream and downstream connections, then isolation between upstream and downstream is improved, but device complexity increases
Solution Approach 1:
The patent merges two separate directional couplers into one bi-directional coupler unit, reducing the component count from two to one. This simplification lowers device complexity, reduces assembly requirements, and decreases insertion loss while maintaining isolation performance through proper termination of isolating ports
Solution Approach 2:
The bi-directional coupler is designed to perform multiple functions: it handles both upstream and downstream signal directions, provides isolation between directions, and includes switchable termination for isolating ports. This multi-functionality eliminates the need for separate couplers for each direction
3Loss of energy
If a single bi-directional coupler is used for both upstream and downstream directions, then insertion loss is reduced, but isolation between upstream and downstream deteriorates when test points are not connected
Solution Approach 1:
The patent implements dynamic termination of isolating ports using switches that respond to the connection status of test points. When test points are connected, the switches connect the isolating ports to termination loads; when test points are disconnected, the switches maintain proper termination. This dynamic adaptation ensures consistent isolation performance regardless of test point status
Solution Approach 2:
The system uses feedback from test point connection status to control the termination state of isolating ports. Detection circuits monitor whether test points are connected and provide feedback signals to switches, which automatically adjust the termination configuration to maintain optimal isolation performance
4Reliability
If analog SFP module uses +5V power supply and digital SFP module uses +3.3V power supply, then each module operates correctly, but incorrect module insertion causes damage
Solution Approach 1:
The system employs self-service through automatic module type detection and adaptive power supply voltage adjustment. When a module is inserted, the system detects whether it is analog or digital type and automatically configures the appropriate power supply voltage, eliminating the need for manual configuration and preventing voltage mismatch damage
Solution Approach 2:
The patent dynamically changes the power supply voltage parameter based on the detected module type. The system can switch between +5V for analog modules and +3.3V for digital modules, ensuring each module receives the correct voltage for proper operation while preventing damage from incorrect voltage application
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
In one embodiment, an apparatus includes a bi-directional coupler for coupling an upstream signal and a downstream signal to a termination load. A test point detection mechanism is configured to detect when a test point device is inserted in a test point connector. The test point device is configured to perform a test of the upstream signal or the downstream signal. A switch is configured to switch from being coupled to the termination load to being coupled to the test point device when the test point device is detected as being inserted in the test point connector. The switch is configured to switch from being coupled to being coupled to the test point device to the termination load when the test point device is detected as being removed from being inserted in the test point connector.