Abstract
M.Phil.
The advantages offered by power line communications (hereon after called PLC) cannot
be over-emphasized neither can the inherent problems affecting its commercial takeover
be underestimated. This research work creates a background study for experimental
measurement and eventual implementations on power lines. It explains those salient
aspects of commercially available communication modules that are rather not straight
forward to understand from reading the Comblocks user manual. Especially, addressing
those shortcomings of Comblocks that were not indicated in the documentation, we o er
solutions to those we could nd our way around.
M-ary frequency shift keying was implemented. This implementation tested the ro-
bustness of the scheme against noises, attenuation and other power line channel char-
acteristics as encountered practically. Based on our results, we nally recommend an
optimal set of frequencies; we believe to be good for use in most PLC application pur-
poses. Pseudo random bits of information were generated, encoded and modulated; the
signals were transmitted over power line channels. The impact of noise sources, impulse
noise especially was observed at di erent distances along the channel.
Coupling and decoupling circuits used for this research, with associated issues sur-
rounding the use of coupling circuitry are also presented.
The CENELEC norm for PLC communication was adhered to, hence only frequencies
that fall within the CENELEC speci cation for low voltage power distribution network
were considered for MFSK use. Signal-to-noise ratio and other factors that a ect signal
transmission over PLC was also measured.
A complete communication system comprises of the transmitter, the channel and the
receiver. This work however did not cover the receiver part of the system. Future work
can now be done on this aspect which amongst others can take care of synchronization
issues, in which a coding system as well as bit error rates can be determined.