Measurement of telephone noise and power wave shape

Since the original introduction of devices for measuring or rating the wave shape of power system currents and voltages in terms of their influence on exposed telephone circuits, much additional work on this problem has been done; the results of this work are reported in this paper. In part I, a curve of relative interfering effects based upon recent studies is presented, the characteristics of a meter for measuring telephone circuit noise are described, and the results of a comprehensive series of tests on the adequacy of this meter are presented. In part II, a new telephone influence factor weighting curve is presented, and a comparison is given between results obtained by meters embodying weighting networks based upon the new and old curves.