Damping and dispersion of twisted-pair transmission line and a compensation method to improve location of impedance discontinuities.

by Ross, Rebecca W

Abstract (Summary)
In this thesis, a method to compensate for propagation effects in twisted-pair transmission lines is developed, with a goal of improving the location of impedance discontinuities in the line. There are many methods to locate impedance discontinuities, among them are single-ended measurements using frequency domain reflectometry (FDR), which is the focus of this work. With FDR, one transmits a steady-state tone or tones onto the line, then measures the amplitude and phase difference of the tone at the receiver relative to the transmit tone. Propagation effects of the line, especially damping and dispersion, which are generally unknown, can negatively impact the performance of FDR methods, making identification of impedance discontinuities difficult. A method is presented to compensate for the damping without requiring a priori knowledge of the cable type and length. In the absence of impedance mismatches between the source and the line, the compensation method improves impedance discontinuity location. Performance of the method degrades considerably when there is an impedance mismatch, but a procedure to compensation for this effect is presented. This compensation requires an assumption of the initial cable type and impedance of test equipment's connecting path. Results are presented on simulations and field data to quantify the performance of the method and identify benefits and limitations.
Bibliographical Information:

Advisor:Dr. El-Jaroudi; Dr. El Nokali; Dr. Loughlin

School:University of Pittsburgh

School Location:USA - Pennsylvania

Source Type:Master's Thesis

Keywords:electrical engineering


Date of Publication:01/28/2009

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