. The Bell System technical journal . air condenser is adjusted until aminimum lone is observed in the receiver, this adjustment addingcapacity to one side or the other f)f the bridge. The variable con-denser is calibrated to read the unbalances directlv in micro micro- 36S BELL SYSTEM TECHNICAL JOURNAL farads, the direction of the unbalances being indicated b>- red andblack scales and arbitrarily designated as ( + ) and ( —). Fig. 14 shows the circuit arrangement of the bridge for measuringthe capacity unbalance between the phantom and white oscillator, variable condenser and rece
. The Bell System technical journal . air condenser is adjusted until aminimum lone is observed in the receiver, this adjustment addingcapacity to one side or the other f)f the bridge. The variable con-denser is calibrated to read the unbalances directlv in micro micro- 36S BELL SYSTEM TECHNICAL JOURNAL farads, the direction of the unbalances being indicated b>- red andblack scales and arbitrarily designated as ( + ) and ( —). Fig. 14 shows the circuit arrangement of the bridge for measuringthe capacity unbalance between the phantom and white oscillator, variable condenser and receiver are connected asbefore, the black conductor and its mate however, being strai)pedtogether at one of the remaining bridge terminals and ratio armsRi and i?2 each consisting of 2,000 ohms resistance, being connectedas shown to the fourth bridge terminal. For the condition of minimumtone the variable condenser reading then gives a measure of thecapacity unbalance between the phantom and the white pair, that Black mate --V Conden. is a — b. Tlie capacities a and h take into .ucount in this case thecapacities of the white and white mate conductors to ground inaddition to the direct capacities between wires shown in Fig. unbalance between the phantom and black pair is obtainedin the same manner as shown by interchanging the white andblack conductor connections to the bridge. The test set readsonly half the capacity unbalance as defined in the above formula forphantom to side unbalance. In practice the testing arraiigenieiit just tlescribcd is used to lestunbalances of all quads in a cable in each direction. .\t any splicingpoint where the tests are made the three unbalance measurementsin each direction for each ([uad are carefully recorded and the splicesthen made by combining ( + ) and ( —) values so as to neutralize eachother as mucii as possible thereby reducing the resulting capacityimbalances and the crosstalk in each direction to a miniinum. Boththe bridge and
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
