Impulse noise in the loop plant

In ISDN field trials for basic access, at 144 kb/s, such impulse noise has proved to be one of the major limiting factors in the transceiver´s achievable performance. It is expected to be an even more severe impairment for transceivers operating at data rates substantially larger than ISDN´s basic rate. The author summarizes some of the properties of impulse noise observed in various surveys, such as frequency of occurrence, amplitude probability distribution, and time and frequency characteristics, and discusses in some detail a class of possible impulse events generated in digital subscriber loops by crosstalk coupling with switched voice circuits. A brief discussion of transceiver design issues in an impulse-noise-dominated environment is also provided