. The Bell System technical journal . ameter) quads of the usual construction. These quads served aspartial shields between the carrier circuits and would in a commercialinstallation have been suitable for regular voice-frequency use. Thusa considerable reduction in the crosstalk between the carrier pairs waseffected. When the problem of keeping crosstalk between circuits trans-mitting in the same direction within proper bounds is examined itbecomes evident that no matter how high the line amplifier gains maybe, these gains do not augment this crosstalk since if all of the circuitsare alike tr
. The Bell System technical journal . ameter) quads of the usual construction. These quads served aspartial shields between the carrier circuits and would in a commercialinstallation have been suitable for regular voice-frequency use. Thusa considerable reduction in the crosstalk between the carrier pairs waseffected. When the problem of keeping crosstalk between circuits trans-mitting in the same direction within proper bounds is examined itbecomes evident that no matter how high the line amplifier gains maybe, these gains do not augment this crosstalk since if all of the circuitsare alike transmission remains at the same level on all circuits. Notso evident perhaps is another fact that crosstalk currents due to un-balances at different points tend to arrive at the distant end of thedisturbed circuit at the same time. This makes it possible to neutralizea good part of the crosstalk over a wide range of frequency by intro-ducing compensating unbalances at only a comparatively few points. 256 BELL SYSTEAI TECHNICAL JOURNAL. Fig. 4—Terminal equipment for 9 telephone circuits. X CARRIER IN CABLE 257 In practice, balancing at only one point in a repeater section (whichmay be an intermediate point or either extremity) serves to makepossible considerable reduction of the crosstalk. In the Morristovvnsetup balancing arrangements were applied at an intermediate pointin the cable and found to be entirely adequate for the frequency rangeinvolved; in fact, transmission of considerably higher frequencies wouldhave been possible without undue crosstalk. Other tests have indi-cated that, thanks to these balancing means, the 19-gauge quads usedin the Morristown cable for separating the 16-gauge pairs from eachother can probably be dispensed with, even for frequencies considerablyabove those used in the trial. The photograph of Fig. 5 shows the experimental panel on whichthe circuits were brought together for balancing. This panel was
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