Worst Case Alien-Near-End-Crosstalk Measurements and Analysis for IEEE 802.3bp

Transcription

1 Ethernet-Technology for automotive application Worst Case Alien-Near-End-Crosstalk Measurements and Analysis for data-bus-technology transmission channel UTP camera systems physical layer topology Elektronik GmbH Martin Meurer, Dmitrij Semilovsky, Martin Huber 1

2 Ethernet-Technology for automotive application Worst Case Alien-Near-End-Crosstalk Measurements and Analysis for Supporters: UTP 2

3 Objective Investigation on alien-near-end-crosstalk with different cables Discussion on current limit lines for alien-near-end-crosstalk 3

4 Contents 1. Definition of worst case channel 2. Measurement Setup 2.1 Overview 2.2 Detailed Description 3. Measurement Results PSANEXT BASE-T1 cable 3.1 UTP Data cable 3.1 FlexRay cable 4. Conclusion 4

5 Definition of worst case channel WORST CASE CHANNEL Measurement Setup was slightly modified according to the scenario Camera Module with more Cameras (matheus_3bp_02_0113.pdf) The influence of inline connectors on PSANEXT can be neglected (mueller_01a_0114.pdf) confirms this statement Gorunding effects are insignificant relating to PSANEXT measurements multi-port interfaces cables immediately fixed in a end-to-end bundle PCB1 PCB2 5m The laboratory setup should be as strict as possible to ensure nearly a real-vehicle-simulation 5

6 Measurement Setup /Overview VNA SETTINGS: Calibration: via ECal (sufficient for PSANEXT) VNA: R&S ZVA 8 Frequency Range: 300kHz 1000MHz Meas. Bandwidth: 10kHz Vector Network Analyzer 4-port VNA measurement with 2 differential ports Low loss and phase stable test cables were used and fixed on work plate to avoid phase shift calibration plane 5m adapter board 6

7 Measurement Setup /Detailed Description 50mm styrofoam insulation above floating ground (wiring and adapter boards) Special clips were used to ensure high packing density Matched adapter boards to ensure low influence on measurements Measurements were performed in a laboratory - no anechoic chamber All cables were measured in four-around-one constellation 1.5cm clip adapter board 7

8 Measurement Results /Cable 1 preferred 1000BASE-T1 cable - PSANEXT lay length: 20mm PSANEXT / db PSANEXT_DUT1 PSANEXT_DUT2 PSANEXT_DUT3 PSANEXT_DUT4 PSANEXT_DUT5 5m -80 PSANEXT_Current_Limit PSANEXT_Limit_Proposal f/ MHz 8

9 Measurement Results /Cable 2 established UTP Data cable - PSANEXT lay length: 15mm PSANEXT / db PSANEXT_DUT1 PSANEXT_DUT2 PSANEXT_DUT3-70 PSANEXT_DUT4 PSANEXT_DUT5 5m PSANEXT_Current_Limit PSANEXT_Limit_Proposal f/ MHz 9

10 Measurement Results /Cable 3 established FlexRay cable - PSANEXT lay length: 30 ± 5mm PSANEXT / db PSANEXT_DUT1 PSANEXT_DUT2 PSANEXT_DUT3-70 PSANEXT_DUT4 PSANEXT_DUT5 5m PSANEXT_Current_Limit PSANEXT_Limit_Proposal f/ MHz 10

11 Measurement Results /Cable 2 established UTP Data cable Mode Conversion lay length: 15mm PSANEXT / db PSANEXT_DUT1 PSANEXT_DUT2 PSANEXT_DUT3-70 PSANEXT_DUT4 PSANEXT_DUT5 5m PSANEXT_Current_Limit PSANEXT_Limit_Proposal f/ MHz 11

12 Measurement Setup /Detailed Description 5m Link with 5 cables was placed within a wiring harness 50mm styrofoam insulation above floating ground (wiring and adapter board adapter boards) Matched adapter boards to ensure low influence on measurements Measurements were performed in a laboratory - no anechoic chamber 1

13 Conclusion Alien-near-end-crosstalk investigation shows the need for further discussion on limit lines Tightly packed wiring harness in real vehicles must be taken into account Definition for a reproducible measurement setup for near-end-crosstalk is necessary 12

14 QUESTIONS? THANK YOU FOR YOUR ATTENTION! 13