Improvements in or relating to transformer arrangements particularly adapted for high frequency telephony systems

摘要

204,185. Western Electric Co., Ltd., (Western Electric Co., Inc.). Aug. 12, 1922. Relaying or repeating systems; wired wireless systems.-A double transformer arrangement used in a high-frequency telephony system forconnecting a single circuit carrying signalling currents in both directions to a pair of circuits in which signalling currents flow in one direction along one circuit and in the opposite direction in the other circuit; is characterized by the feature that the transformer arrangement acts also as a wave-filter. The incoming two-way single line L' is connected to the coils 2, 1 and 5, 6. The input side B of the four-wire circuit is joined to the coils 4, 3 and 8, 7, whilst the output side D is bridged by the coils 4, 3 and 8, 7. The main signalling currents flow in the directions indicated' by the full-line arrows. A balancing network N' is connected to coils 6, 5 and 2, 7. Series condensers 20 - - 23 are inserted across the inner ends of the coils contained in each of the circuits, and serve in conjunction with the inductance coils to form either a high-pass or low-pass filter, thus rendering unnecessary the use of excluding filters for undesired frequencies in either the line L1 or the network N'. The impedance of the circuits are so balanced that no undesirable transfer of energy takes place between the input group D and output group B of the four-wire circuit, so that " singing " is prevented in that circuit. The four upper coils shown in the Figure are wound upon one core of the double transformer whilst the four lower coils are wound upon a second core. The induced and balanced potentials are indicated by the dotted-line arrows.