MSc Dissertation: Roufurd Julie

Citation:

Adobe-PDF-downloadJulie, Roufurd. Gain Stability, Phase Stability And Dynamic Range Measurements Of Analogue Optical Links Used For Radio Astronomy. MSc Dissertation. Department of Electrical Engineering, University of Cape Town, 2010.

 

Abstract:

This dissertation investigates the gain and phase stability and dynamic range of an RFover-fibre optical link as used in a radio telescope. It attempts, via practical experiments, to quantify the gain and phase stability with temperature of the optical fibre and the optical transmitter and receiver. A thermalmodel based on the KAT-7 environment is then defined and together with the stability coefficients determined, the model is used to qualify the link against the KAT-7 requirements. Measurements of gain and phase stability with temperature (at sunset) and movement of the dish are also performed on the XDM dish (a precursor to the KAT-7) to give an indication of the magnitude of gain and phase change in a real optical fibre link installation. Finally an optical transmitter and receiver set is demonstrated to meet the KAT-7 requirement of dynamic range.

To this end: the KAT-7 requirements for gain and phase stability and dynamic range are motivated and discussed, part of which is apportioned to the optical fibre link; software is developed to to control the VNA (the primary measuring device) and log data and controlled experiments using a thermal chamber and a iButton temperature logger are utilised in the data gathering process.

The results are positive in that an analogue optical fibre link will meet the KAT-7 requirements for gain and phase stability and dynamic range.

 

 

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