Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: In this thesis the design and testing of the baseband components of a modem
intended for use as a telemetry and control link for a low earth orbit satellite is
presented. This includes parts of the physical layer as well as a basic data-link
layer. Binary phase-shift keying (BPSK) is used as the modulation scheme
and is realised by making use of software defined radio on a standard x86
computer with digital to analogue and analogue to digital converters that use
a universal serial bus (USB) connection. The data-link layer makes use of a
basic framing scheme and provides bit synchronisation, an automatic repeat
request (ARQ) system and Bose Chaudhuri Hocquenghem (BCH) forward error
correction (FEC). The ARQ system ensures that data is delivered reliably and
the FEC improves the system’s performance in noisy conditions. A prototype
system was developed to test the performance of the individual layers as well
as the system as a whole. For testing purposes the Linux Internet Protocol (IP)
stack is used as higher network layers. Radio frequency hardware developed by
Verschaeve
[1]
modulates the signal away from baseband, transmits it over the
air and receives it. / AFRIKAANSE OPSOMMING: In hierdie tesis word die ontwerp en toetsing van die basisband komponente van
‘n modem, bedoel vir gebruik op ‘n satelliet in ‘n lae-aarde wentelbaan, bespreek.
Die ontwerp sluit dele van die fisiese vlak sowel as ‘n verbindingsvlak in. Binêre
faseskuifsleuteling word gebruik as die modulasieskema en word verwesenlik deur
gebruik te maak van sagteware gedefinieerde radio. Dit voer uit op ’n standaard
x86 rekenaar wat deur middel van USB gekoppel is aan ’n digitaal-na-analoog-
en ’n analoog-na-digitaal-omsetter. Die verbindingsvlak het ‘n eenvoudige
ramingskema. Dit voorsien bis sinkronisasie, die hersending van verlore rame
en Bose Chaudhuri Hocquenghem (BCH) voorwaartse foutverbetering. Die
hersending van verlore rame verseker dat data betroubaar oorgedra kan word
en foutverbetering verbeter die stelsel se vermoëns in ruiserige toestande. ‘n
Prototipe stelsel is ontwikkel om die vermoëns van die individuele vlakke, sowel
as die stelsel as ’n geheel, te toets. Tydens toetsing is die Linux Internet
Protokol stapel gebruik vir die hoër netwerk vlakke. Radio komponente wat
deur Verschaeve
[1]
ontwikkel was is gebruik om die sein uit te saai en te
ontvang.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/86580 |
| Date | 04 1900 |
| Creators | Van Wyk, Hendrik Petrus Daniel |
| Contributors | Wolhuter, R., 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 | English |
| Type | Thesis |
| Format | xv, 108 p. : ill. |
| Rights | Stellenbosch University |
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