Author |
Lim, Chee Hok |

Title |
Distortion and designing of signals propagating in a coaxial cable. |

Institute |
Thesis (M.Sc.) National Institute of Education, Nanyang Technological University |

Year |
2003 |

Supervisor |
Foong, See Kit |

Call
no. |
TK5102.9 Lim |

Summary | |

Voltage or current waves
travelling along a transmission line suffer distortion in their waveform,
which may be due to energy dissipation and wave dispersion during the
transmission from one end to the other. The objectives of this project
include the study of the distortions of a square waveform along a coaxial
cable, and the designing of the waveform to be sent such that the waveform
after distortion is the desired square waveform. Only the effects of
dissipation and dispersion on the waveforms were considered in this
project. Two methods were used in the study of waveform distortion and the designing. The first method is based on the waveform of sinusoidal travelling wave having an amplitude which decreases exponentially in the propagating direction, and a phase velocity that varies with the frequency. By the use of Fourier series, the effects of dissipation and dispersion on each component wave were considered and the distorted waveform was computed. Knowing the line parameters and hence the propagation characteristics, the Fourier components of the waveform that should be sent could be constructed from the corresponding components of the desired square waveform at a predetermined point. The second method is based on the path
integral solution of the telegrapher's equation which relates the
distorted waveform to the dissipation-free waveform at the same point
along the line. By this relationship, we obtained the distorted waveform
from the dissipation-free square waveform by considering the effect of
dissipation and dispersion on the Fourier components. On the other hand,
by setting the distorted waveform in this relationship as the desired
square waveform, we determined the dissipation-free waveform which was
then used as the designing waveform to be sent. |