. The Bell System technical journal . + 130VOLTS -=r- y VOLTS Fig. 15—Simplified schematic of amplifier. signaling circuit from the two-wire voice circuit. The two circuits areshown in Fig. 4. In each case, the feedback is accomplished by meansof a bridge circuit in the output and a series connection in the can be more readily seen from Fig. 15, which is a simplified circuitrepresenting both amplifiers. There is a considerable saving in circuitelements as compared to the familiar resistance bridge feedback con-nection. The output power loss due to shunt arms of the resistancebridge
. The Bell System technical journal . + 130VOLTS -=r- y VOLTS Fig. 15—Simplified schematic of amplifier. signaling circuit from the two-wire voice circuit. The two circuits areshown in Fig. 4. In each case, the feedback is accomplished by meansof a bridge circuit in the output and a series connection in the can be more readily seen from Fig. 15, which is a simplified circuitrepresenting both amplifiers. There is a considerable saving in circuitelements as compared to the familiar resistance bridge feedback con-nection. The output power loss due to shunt arms of the resistancebridge is eliminated. Furthermore, the impedance of the feedbackcircuit is relatively low, and consequently some wiring difficulties wereavoided. In this application, the bridge is unbalanced, and the im-pedance Zo is a function of KRq. As a result, it was convenient toadjust Zo to the optimum value by choosing the proper value of KRq. 180 BELL SYSTEM TECHNICAL JOURNAL. NEW SINGLE CHANNEL CARRIER TELEPHONE SYSTEM 181 Filters Filters constitute an important part of the Type H carrier represent about 30 per cent of the cost of the terminal andoccupy about 25 per cent of the total space. The various filters required at a terminal are indicated in Fig. transmission characteristic of each filter is given in miniatureabove or below the block representing the filter. The high-pass and low-pass line filters separate the ordinary voicetelephone channel and the added carrier telephone channel madeavailable by this system. The low-pass line filter passes voice fre-quencies and suppresses all other frequencies. The high-pass linefilter passes the carrier frequencies and suppresses the voice filter offers a high impedance to the frequencies passed by theother, and bridges off only a very small part of the energy of thesefrequencies. The remaining filters are associated with the carrier terminal proper,where they serve to separa
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
