万博集团仪器设备站 · 专业测试测量仪器授权供应商
介绍 SNA5000A VNA 的增强型 TDR 功能，包括差分测量拓扑设置、去嵌入校准、时域参数选择及眼图高级分析。
中文概述：本文介绍 SIGLENT SNA5000A 矢量网络分析仪的增强型 TDR 功能，通过设置向导完成差分拓扑配置、去嵌入和去偏斜校准，并可进行眼图高级分析。下文为原文。
Time Domain Reflectometry (TDR) is an important method for measuring cable and connection quality for high-speed transmissions, including distance-to-fault and visualizing impedance changes over distance. When TDR is built into a multi-port, multi-path VNA, advanced visualization becomes possible, including simulated eye diagrams with de-embedding on a 4-port network analyzer, mask testing and injected jitter. This note discusses the advanced TDR implementation of the SIGLENT SNA5000A while comparing two standard USB cables.
Configuration and calibration are the most important steps for quality data. The SNA5000A includes a setup wizard to simplify device configuration and calibration to de-embed cables and connections. Enter TDR Mode through the MATH menu, then start the Setup Wizard and select DUT topology. With a 4-port VNA, complete differential measurements are possible — important for high-speed systems using differential signaling.
After the wizard completes, configure traces for desired measurements. Available time-domain parameters include Tdd11, Tdd12, Tdd21, Tdd22, Tdc11, Tdc12, Tcd11, Tcd12, Tcc11, Tcc12 and related ports. The c and d suffixes indicate common-mode or differential measurements; the numbers indicate output/input ports. Traditional S-parameters (e.g. Sdd12) can also be selected by changing the time-domain option, with Smith chart formats available.
The wizard automatically compensates electrical length of cables and fixtures: connect all cables to the VNA, disconnect the DUT, then press Deskew. Since cable loss is not removed, cables should be low-loss and as short as possible. The SNA5000A can create up to 256 traces simultaneously, and time-domain traces fully characterize the DUT before moving to eye diagram view for advanced characterization.
