Impulse noise on telephone loops.

Abstract

Impulse noise is an ever increasing impediment to successful digital data transmission in the telephone local cable plant. Two major factors have caused this to happen. Firstly, remedies have been found for nearly all the other causes of signal degradation, such as crosstalk and intersymbol interference, leaving impulse noise outstanding. Secondly, the user's demand for higher and higher data rates and the proliferation of repeaterless operation at extended loop ranges, have made the effects of impulse noise more prominent. This thesis covers the subject of impulse noise in the local plant. It begins with experimental data obtained from field studies of the local loop segments of digital transmission systems. The theoretical aspects of impulse noise are next addressed, including the various methodologies for modeling it. Burst errors in the recovered data stream, and their relationship with impulse noise, their principal cause, are described. The methodologies for modeling burst errors are then discussed. Finally, the techniques for minimizing the harmful effects of impulse noise are examined. Included in this is a novel scheme, referred to as "Pulse Sharpening", now being introduced.