. The Bell System technical journal. Telecommunication; Electric engineering; Communication; Electronics; Science; Technology. HIGH-SPEED OCEAN CABLE TELEGRAPHY 247 At the sending end in place of the usual sending condenser there is employed the network Ni shown in the figure. The condenser C« may have a capacity of from 30 to 80 microfarads. It is shunted by a resistance Ri of several thousand ohms. The resistance R^ con- necting the sending end of the cable to earth may be of the order of 100 ohms, and serves approximately to equalize the input impedance of the system over the important rang
. The Bell System technical journal. Telecommunication; Electric engineering; Communication; Electronics; Science; Technology. HIGH-SPEED OCEAN CABLE TELEGRAPHY 247 At the sending end in place of the usual sending condenser there is employed the network Ni shown in the figure. The condenser C« may have a capacity of from 30 to 80 microfarads. It is shunted by a resistance Ri of several thousand ohms. The resistance R^ con- necting the sending end of the cable to earth may be of the order of 100 ohms, and serves approximately to equalize the input impedance of the system over the important range of frequencies. The desira- bility of the resistance i?2 is peculiar to the loaded cable and is occa- sioned by the manner in which its characteristic impedance varies with frequency. N, TO BATTERY TRANS MITTER CABLE CORE. /BALANCING RESISTANCE Fig. 5—Terminal networks for signal shaping and amplification Other sending-end circuit arrangements can, of course, be used and networks combining inductances with capacities and resistances have been effectively employed. The sending-end shaping network may even be dispensed with entirely and all of the shaping done at the receiving end. There are, however, certain conditions under which this leads to the production of distortion due to hysteresis in the magnetic material of the cable and in general it is preferable to reduce the current flowing into the cable by employing sending-end shaping networks which reduce the amplitude of the low-frequency components of the signal. The circuits employed at the receiving end for completing the process of signal shaping and for amplifying the signals may con- veniently be considered in three parts, the receiving shaping network Ni, the shielded transformer T, and the amplifier which includes the interstage shaping networks A^3, ^^4 and N^. The receiving network N2 provides means for correction of a con- siderable part of the distortion introduced by the cable and in so. Please note that the
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
