SpaceWire Cable and Connector Characterisation

Authors: 
Martin Suess, Steve Parkes, Paul Crawford
Conference/Journal Name: 
International SpaceWire Conference Dundee 2007
Date Published: 
September 2007
Page References: 
pp.221-228
ISBN of Journal Issue/Conference Proceedings: 
978-0-9557196-0-8

The SpaceWire physical layer comprising twisted pair cables and micro-miniature D-type connectors is specified in detail in the SpaceWire standard ECSS-E-50-12A. In some cases the physical layer defined in the standard is not fulfilling all requirements of a specific application. The cables as defined in the standard are quite rigid and not handy for use in the laboratory and for SpaceWire connections over very long distances (>10 m) cables with lower loss are required. For this purpose cables with stronger gauge as well as different types of connectors have been proposed. In order to be able to assess the consequences of these modifications a test setup for SpaceWire cable and connector characterisation has been developed and a set of performance parameters to be measured have been defined.The testing uses a Vector Network Analyser (VNA) and a set of specially developed interface boards to measure S-parameters. From these S-parameters the performance figures for return loss, insertion loss, near- and far-end crosstalk can be derived. The paper describes the different test setups and how the performance figures are obtained from the measurements.