Tuned-circuit, parallel-resistance substitution apparatus for measurements on balanced-pair cables at frequencies up to 10 Mc/s

Apparatus has been developed which enables the characteristics of balanced-pair cables and feeders to be determined at frequencies at least as high as 10 Mc/s. It operates on the tuned-circuit parallel-resistance substitution principle, the necessary variable resistance being provided by means of diodes with variable cathode resistance loads, and it may be used for measurements on any balanced impedance.