Teradyne, Inc.

Bruce Holmes

Thomas McCartney

Glynn R Ashdown

A two-wired telephone testing system employing a low frequency test signal which is a submultiple of the power line frequency. This test signal is applied between the two-wires or between either wire at a point of potential reference (ground). A measure of the integrated value of the current between the connected points is then made for a period equal to one-half cycle of the applied signal with one polarity and one-half cycle with the polarity of the measured signal reversed. The integration periods are selected to be in phase with the applied signal for determining conductance and 90.degree. out of phase for determining susceptance. Direct current measurement can also be made for the same time periods.

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Twickenman, United Kingdom

Bruce Holmes