Presentation on theme: "DESIGN CHALLENGES OF AN ADVANCED SPACEWIRE ASSEMBLY FOR HIGH SPEED INTER-UNIT DATA LINK Joachim Mueller, W.L. Gore&Associates email: firstname.lastname@example.org."— Presentation transcript:
1DESIGN CHALLENGES OF AN ADVANCED SPACEWIRE ASSEMBLY FOR HIGH SPEED INTER-UNIT DATA LINK Joachim Mueller, W.L. Gore&AssociatesInternet:
2MotivationSystem design solutions for advanced communications missions are driving up symbol/data rates with:Increasingly demanding skew and delay requirementsCritical design issue for the cable assemblies and for an electrical matched and balanced connector in particular.The cable assemblies are used to transfer various types of signals between units on board the spacecraft, e.g.:Reference/synchronisation clock signalsHigh data rate serial links such as SpaceWireDigitally modulated baseband signals (QPSK, 8PSK, etc)These interfacing functions need a differential mode of transmission capable of maintaining high integrity in the process.
4Connector Performance Issues Micro D-SubTriax ContactCommonly used Connector interfaces show strongimpedance mismatch
5Connector Performance Issues Bulk CableAssemblyConnector performance has a strong impact on the signal transmission at frequencies above 30MHz.Assembly shows non-monotonic attenuation characteristic.Matched Connector interface required.Signal Attenuation vs. Frequency
6Symmetrical Connector Interface 4 and 5-way Twinax ConnectorImpedance vs. Length
7Advanced Interconnect Performance Attenuation of 2m long SpaceWire Cable AssemblyInsertion Loss [dB/20m]f [MHz]AWGAWGAttenuation of 20m long SpaceWire Cable Assembly
11SpaceWire cable not significant contributor to crosstalk Crosstalk ResultsSpaceWire cable not significant contributor to crosstalkCrosstalk due to 9-pin Microminiature D-type connector (and connection)Cross talk between Data and Strobe high (~20dB)Crosstalk between Strobe pairs high (~20dB)
12Shielding Measurements Shielding Effectiveness for 1m Assemblies: 100MHz> 1GHz
15SummaryTechnical issues with a symmetrical cable interconnect using a Triax contact has been discussed.A new design with a light and compact twinax contact has been introduced.The electrical Performance in terms of Impedance, Insertion Loss, Return Loss, Crosstalk, Skew, Eye Pattern and Shielding has been presentedThe performance of the new symmetrical cable interconnect is adequate for frequencies up to 2GHz and higher.