. The Bell System technical journal . nce whichwould result in the maximum steady-state received current with thebridge duplex telegraph circuit shown by Fig. 1, where it is desired tolimit the line current to about .070 ampere. The condition for maxi-mum steady-state received current was sought as the first step towarddetermining the most suitable arrangement of the resistances with theviewpoint that such an arrangement would probably be the most 625 626 BELL SYSTEM TECHNICAL JOURNAL satisfactory from a transmission standpoint If it did not adverselyeffect the important factor of received cur
. The Bell System technical journal . nce whichwould result in the maximum steady-state received current with thebridge duplex telegraph circuit shown by Fig. 1, where it is desired tolimit the line current to about .070 ampere. The condition for maxi-mum steady-state received current was sought as the first step towarddetermining the most suitable arrangement of the resistances with theviewpoint that such an arrangement would probably be the most 625 626 BELL SYSTEM TECHNICAL JOURNAL satisfactory from a transmission standpoint If it did not adverselyeffect the important factor of received current wave shape. An ar-rangement of the resistances was found which results in the maximumsteady-state received current and from oscillographic tests which weresubsequently made, this arrangement fortunately appears to improvethe wave shape of the received current as compared with that resultingfrom other possible arrangements considered. It was also found fromfield trials on a number of practical circuits that this arrangement Jp? ^. Fig. 1—Bridge Duplex Telegraph Circuit results in improved transmission over other arrangements which havebeen considered for the regulating resistances. Three different locations in the bridge duplex circuit are consideredfor the regulating resistances. These locations are designated (1),(2) and (3) in Fig. 1 and may be described respectively as follows: (1) A single resistance in series with the battery branch of the circuit. (2) Equal resistances in series with each of the bridge arms. (3) Equal resistances in series with the line and the artificial line of the duplex set. In considering locations (2) and (3), it is assumed that the resistancesare in the form of a double rheostat with the movable arms mechan-ically connected to facilitate adding equal amounts of resistancesimultaneously. It will be seen from the circuit shown by Fig. 1 that of the threelocations for the regulating resistance, (3) might be expected to reducethe received curren
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