Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: This thesis describes the design and construction of a two-element digital correlation interferometer
operating at 1.42 GHz. This instrument consists of two 92cm off set-parabolic reflectors
arranged in an east-west baseline, with a maximum length of 24m. The reflectors are out-fi tted with helical beam antennas as primary feeds, and are further equipped with low-noise front-ends. A wideband dual-conversion superheterodyne receiver processes the astronomical
signals before digitisation. The receiver is implemented as far as possible using a ffordable off -the-shelf technologies. The cross-correlation between the two antenna signals is measured using
a 256MHz bandwidth digital FX correlator, and is implemented on a Reconfi gurable Open Architecture
for Computing Hardware (ROACH) board. The preliminary observations made with
this interferometer, suggests that it is possible to detect the sun, and some other much weaker
sources such as Taurus A.
The design of an interferometer in general is presented, from the formulation of the underlying
instrumental requirements, to making meridian drift scan observations. The interferometer
developed may serve as a demonstrator for other engineering students to gain a working knowledge
of radio interferometry, which should prove invaluable when addressing the challenges the
Square Kilometre Array (SKA) is faced with. / AFRIKAANSE OPSOMMING: In hierdie tesis word die ontwerp en konstruksie van 'n twee-element digitale korrelasie interferometer
wat by 1.42 GHz ontvang beskryf. Die instrument bestaan uit twee 92 cm afsetparaboliese
re
ektorantennas met 'n oos-wes basislyn, met maksimum lengte 24 m. Heliese
antennas word gebruik as primêre voer vir die reflektors, en verder maak die voorent gebruik
van laeruis versterkers . Die wyeband superheterodineontvanger verwerk die astronomiese seine
in twee stappe voordat dit digitaliseer word. Bekostigbare kommersiëele komponente word gebruik
in die vervaardiging van die ontvanger. Die kruiskorrelasie tussen die twee antenna seine
word digitaal gemeet deur 'n FX korreleerder met 'n 256MHz bandwydte op 'n ROACH bord.
Die resultate toon aan dat dit moontlik is om die son waar te neem, sowel as sommige ander
swakker bronne, soos Taurus A.
Al die kwessies insluitende die instrumentale vereistes betrokke by die ontwerp van 'n interferometer
word bespreek. Verder word die gebruik van interferometers om meridiaan meetings
te doen bespreek. Die interferometer dien as 'n praktiese demonstrasie van radio interferometrie
vir ingenieurstudente. Hierdie demonstrasie is voordelig vir studente om die uitdagings van die
SKA te bestudeer.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/71803 |
| Date | 12 1900 |
| Creators | Jansen van Rensburg, Juan-Pierre |
| Contributors | Davidson, D. B., Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 195 p. : ill. |
| Rights | Stellenbosch University |
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