Browsing by Author "Strydom, H. L."
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- ItemHoe spoed koppelvlak vir n nuwe generasie SUNSAT mikrosatelliet(Stellenbosch : Stellenbosch University, 1999-12) Strydom, H. L.; Bakkes, P. J.; Stellenbosch University. Faculty of Engineering. Dept. of Electrical & Electronic Engineering.ENGLISH ABSTRACT: A micro-satellite is a complex system constructed of a number of subsystems. Communication interfaces must exist between these subsystems to exchange data, for example telemetric and telecommand. In order to receive all data, these interfaces must be efficient and reliable. Failure of an interface can result in an unuseable subsystem, which could affect the satellite. The aim of this thesis was to investigate alternative possibilities for the implementation of a high-speed interface between the main camera and mass-memory. On the first generation SUNSAT the interface was realised by sending the analog image-information of the different colours, parallel to the mass-memory, where information is converted to digital data and latched into the main memory. This leads to limitations of the interface, and the disadvantages will be discussed. Various parallel and serial technologies are investigated and discussed. LVDS was chosen as the most suitable technology and was used to design the interface. This technology has the advantage of implementing a serial bus, using low differential voltages for the transmission of data. This minimises the use of power and noise. The high bandwidth of LVDS also allows an errorprotocol to be implemented. As part of the errorprotocol, an EDAC is implemented to correct single biterrors, but it needs a higher bandwidth, which is a disadvantage. A limited-queue can be used to resend data for any other errors, but it is impractical to implement a bigger memory on the sending side. The errorprotocol is implemented and simulated and is discussed in this thesis.