Automated compliance test solution for high-speed Ethernet cables

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Testing high-speed cables for data centers or consumer electronics is a highly complex task that requires precision, support for very high frequencies and a multiport setup. Conventional manual testing with a four-port vector network analyzer is a time-consuming task and can be prone to human error. High-speed cables consist of numerous copper wires organized as differential signal paths, commonly referred to as “lanes”. The number of lanes dictates the maximum transfer rate supported by the high-speed cable. For example, the latest IEEE Ethernet PHY specification, IEEE 802.3dj, supports single lane data rates of 200 Gbps. This allows data rates of up to 1600 Gbps in a high-speed QSFP-DD form factor Ethernet cable with 8 lanes.

As the number of lanes in the cable under test increases, the task of testing compliance with the IEEE 802.3 standard becomes more tedious, complex and time-consuming. This is mainly due to the increased number of reconnections when using a four-port vector network analyzer (VNA).

Verifying compliance with the standard requires testing the transmission of each lane (through), as well as the TX to RX crosstalk of all neighboring lanes – near-end crosstalk (NEXT) and far-end crosstalk (FEXT). To measure all the S-parameters, a design or test engineer using a conventional setup with a four-port VNA needs to reconnect the ports to the cable several times to complete the testing of a single cable. Compliance testing can take nearly a week for each cable, as is the case for eight lanes.

Rohde & Schwarz solution

Rohde & Schwarz has introduced a fully automated compliance test solution based on the R&S®ZNrun vector network analyzer automation suite. It allows easy, precise and time-saving standards-compliance testing for high-speed cables.

The compliance test software automatically performs all of the required measurement steps and postprocesses all of the measurement data in accordance with the standard specifications: channel operation margin (COM) and effective return loss (ERL). The software automatically generates a comprehensive test report, including the overall pass/fail verdict. The software suite makes it easy for users to analyze the test results and validate the cable under test, saving a tremendous amount of time while minimizing human error.

The automated Rohde & Schwarz compliance test solution for high-speed Ethernet cable assemblies combines the precision and high performance of Rohde & Schwarz vector network analyzers with the flexible R&S®OSP open switch and control platform and the R&S®ZNrun software suite to make measurement faster, easier and more reliable.

Simple and time-efficient fully automated multiport VNA measurements

R&S®ZNrun with the R&S®ZNRUN‑K4xx compliance test automation options offers a straightforward test procedure with three simple steps: setup, calibration and measurement. Each automated step is designed to minimize calibration and measurement time. Smart cable handling eliminates the need for tedious port reconnections in the test setup. By automating data collection and results processing, the R&S®ZNRUN-K4xx compliance test automation options ensure reproducible results and significant time savings.

Beyond compliance: software features deliver more than just compliance tests

In addition to fully automated compliance tests, R&S®ZNrun offers flexible adaptation to various testing needs. Signal integrity developers and test engineers can use the R&S®ZNrun software suite to validate their cable assemblies. Measurement steps can be deselected for quick initial evaluations of cables. Users can customize measurement parameters such as a frequency range or sweep time in order to perform initial plausibility measurements before starting a full compliance test.

Enhancing testing efficiency with the project generator feature

The project generator feature in the R&S®ZNRUN-K400 signal integrity base option revolutionizes the testing process by automating critical tasks and streamlining workflows. Given the variety of types of connector and cable assembly form factors for IEEE 802.3 Ethernet, this innovative tool allows users to define their DUT topology. This enables tailored setups that meet specific testing requirements, such as asymmetric cable or special connector assembly tests. The project generator can automatically generate comprehensive test plans and cases, which significantly reduces preparation time and minimizes human error.

Additionally, the project generator incorporates optimized calibration algorithms to ensure accurate measurements while enabling seamless file exports for efficient data management. By providing a structured approach to signal integrity testing, the project generator enhances overall efficiency and reliability, making it an invaluable asset for engineers working with high-speed cable serializer/deserializer (SerDes) standards.