On-Chip TDR Testing for SerDes Transceiver Port Fault Diagnosis
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Solution Overview
Problem
Traditional methods for testing high-speed serializer/deserializer (serdes) transceiver ports in network devices are time-consuming, expensive, and do not scale well for large quantities, requiring disassembly and expert analysis.
Innovation Solution
Implementing an on-chip time domain reflectometry (TDR) diagnostic tool within the network device to test transceiver ports, which identifies and maps port groups, channels, and determines channel status using TDR pulses, eliminating the need for external equipment and expert analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional external TDR equipment and expert analysis are used to test transceiver ports, then measurement precision and reliability are improved, but device complexity and testing time increase significantly
Solution Approach 1:
The patent combines the TDR testing functionality directly into the network device by integrating a TDR engine with the existing serdes transceiver ports. This merging eliminates the need for separate external TDR equipment and expert analysis, reducing system complexity while maintaining testing accuracy through on-chip implementation of TDR circuits and processors
Solution Approach 2:
The network device performs self-diagnosis by incorporating an on-chip TDR engine that can autonomously generate TDR pulses, measure reflections, calculate impedance values, and identify faults without requiring external equipment or expert intervention. The integrated processor automatically analyzes test results and determines pass/fail status, enabling the device to test itself
2Reliability
If traditional external testing methods are used for each transceiver port, then comprehensive diagnostic capability is improved, but productivity and scalability deteriorate
Solution Approach 1:
The on-chip TDR engine is designed to work with multiple transceiver ports simultaneously through the existing serdes infrastructure. The integrated processor can execute TDR tests across different port groups and channels without requiring separate testing setups, enabling comprehensive diagnostic coverage of all transceiver ports while maintaining high testing throughput and scalability
Solution Approach 2:
The TDR testing capability is built into the network device during manufacturing, allowing ports to be tested before deployment. The on-chip engine and integrated processor are pre-configured to perform rapid impedance measurements and fault detection, enabling quick validation of transceiver ports without requiring external equipment setup or expert analysis during deployment
3Reliability
If traditional testing procedures are used, then thorough fault detection is improved, but loss of time and testing cost increase
Solution Approach 1:
The patent replaces mechanical and manual testing procedures with electronic TDR measurement and automated digital analysis. The on-chip TDR engine electronically generates pulses and measures reflections, while the integrated processor automatically calculates impedance values and identifies faults, eliminating the need for physical disassembly, manual measurements, and expert analysis, thereby reducing testing time while maintaining thorough fault detection
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 on-chip TDR tool efficiently detects opens, shorts, and impedance mismatches without disrupting the network device, conserving computing and networking resources and enabling rapid, cost-effective testing of multiple ports.
Implementation Method 1
provide a first time domain reflectometry pulse to a first channel of the transceiver port and receive a first reflected time domain reflectometry pulse via the first channel
Data Source
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AI summary
A network device may identify an integrated circuit, a port group number, port lanes, and port channels associated with a transceiver port of a network device, and may map the integrated circuit, the port group number, the port lanes, and the port channels to the transceiver port. The network device may provide a time domain reflectometry pulse to a channel of the transceiver port at a first time and with a first voltage, and may receive a reflected time domain reflectometry pulse via the channel at a second time and with a second voltage. The network device may calculate a distance and an impedance of the channel based on the first time, the second time, the first voltage, and the second voltage, and may determine a status of the channel based on the distance and the impedance. The network device may output the status of the first channel.