Directional coupler for telecommunications use, includes additional windings in earth lines from transformer in feed lines, forming separate, magnetically-coupled transformer

摘要

In wires to earth (16) from the windings (5, 6), additional windings (8, 9) are arranged on a core (12), forming a transformer (3). Magnetic flux, or part of it, in the core (12), is also coupled to the transformers (1, 2). The fraction of energy induced in transformer 3 has the same polarity as that in windings 5 and 6.