Enhanced TDR Measurements with the SNA5000A Vector Network Analyzer from Siglent 2

Introduction

Time Domain Reflectometry (TDR) is an important method for measuring cable and connection

quality for high-speed transmissions. Some measurements that broadly fall into this category

include characteristics like distance to fault as TDR makes it easy to visualize impedance

changes over distance. Some of the basic analysis modes can be implemented on cable

analyzers and basic spectrum analyzers, but advanced TDR measurements make it possible to

evaluate much more subtle and elusive transmission quality issues. When TDR capabilities are

built into a powerful multiport, multipath Vector Network Analyzer advanced visualization and

analysis becomes possible. One important methodology is the use of simulated eye diagrams

on high-speed communication channels. These eye diagram can be implemented on a number

of device topologies with de-embedding using a 4-port network analyzer while providing

important data visualizations including mask testing and injected jitter. This application note

discusses the advanced TDR implementation and capabilities of the Siglent SNA5000A vector

network analyzers while comparing the quality of 2 standard USB cables.

Differential Measurements and DUT Topology

As it is with many VNA measurements, configuration and calibration are two of the most

important steps in acquiring quality data to guide design and improvement. Siglent’s Vector

Network Analyzer (figure 1) includes a setup wizard to simplify device configuration and

calibration to de-embed cables and connections.

Figure 1: Siglent SNA5000A VNA with

Enhanced TDR

Opon is used for

all

these images and

measurements.