Measuring subscriber line parameters of telephone network - applying pulsed voltages in various connection wire-configurations, cross-correlated to preliminary measurement values

摘要

Measuring communications system subscriber line parameters involves applying a pulsed measurement voltage in various measuremnt configurations of the two wires in the subsriber connection. Before the measurments are performed the voltages between the wires and earth or between the connected wires and earth are measured and stored. Cross-correlation is performed between the preliminary and actual measurement values whilst preserving the different associations of the two measurement sequences and until a definite max. is achieved. The corresp. preliminary values are subtracted from the actual measurement values and the difference used to determine the line parameters. USE/ADVANTAGE - Measuring impedance, capacitance, insulation resistance between subscriber pair and to other lines and/or earth, shunt or arrestor resistance w.r.t. constant value. Eliminates influence of anticipated stray a.c. voltages on results.