MIXED-MODE S-PARAMETER CHARACTERIZATION OF MULTI-PORT BALANCED DUTS

1 Introduction

Balanced transmission lines, like twisted pair cabling systems, are finding extensive adoption in high-speed, short reach data connectivity applications due to the inherent noise immunity and low cost.  The need and importance of characterizing the signal carrying capacity and noise immunity of these channels has significantly increase with the rapid growth in data transmission speeds.  Vector Network Analyzers (VNA) are essential for characterizing RF transmission parameters of communications channels.

Traditional VNAs are best suited for unbalanced (single-ended) transmission systems.  In order to characterizer balanced DUT (Device Under Test), they need either large number of ports, or complex test fixtures.  Also, traditional VNAs are designed for characterizing high bandwidth devices spanning tens of GHz. That proves to be an overkill for balanced DUTs having useful frequency range well below 10 GHz.   In many applications, it is necessary to characterize two ends of a DUT such as a twisted pair cabling channel, while the two ends are far apart (not co-located).  In such case, it is necessary for two VNAs, each connected to one end of the DUT, to synchronize in performing characterization including near-end and far-end parameters from both ends.  Given these factors, VNAs can become prohibitively expensive for large scale characterization of balanced DUTs in the laboratories as well as manufacturing floors.  InspiRain Technologies has developed the new MM-VNA (Mixed-mode Multi-port VNA) to meet the requirements of characterizing balanced DUTs in an accurate, simple, and cost-effective way.

 

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2 MM-VNA 100 Specifications

Table 1  General Specifications

Frequency Range 0.1 – 3,000 MHz
Frequency Resolution 0.01 MHz
RF Measurement parameters – one ended Differential-to-Single ended return loss and cross-talk.  Differential-to-differential return loss and cross-talk.  Refer to the MM-VNA 100 User’s Manual for detailed list of S-parameters
RF Measurement parameters – two ended Differential-to-Single ended return loss and cross-talk.  Differential-to-differential return loss and cross-talk (near-end and far-end).  Differential Insertion loss.  Refer to the MM-VNA 100 User’s Manual for detailed list of S-parameters
Measurement floor – cross-talk 80 dB (fast sweep mode)

110 dB (slow sweep mode)

Measurement floor – Return loss 60 dB
File format Csv file for S-parameter results
size 300 mm X 150 mm X 50 mm
Power consumption 3W

 

3 Main Applications

  • Laboratory characterization and manufacturing test of twisted pair automotive cables (e.g. IEEE 802.3bp 1000BaseT1)
  • Laboratory characterization and manufacturing test of high speed balanced cabling for industrial use
  • Manufacturing test for high speed USB and HDMI cables
  • Laboratory characterization and manufacturing test of high speed data cables for Internet of Things (IoT) applications such as HDBASE-T (TV connectivity), LED connectivity, specialty sensor connections