. Bell telephone magazine . transforming currentsof the voice range, the region from about 250 to 3,000 cycles,into currents of higher frequencies. A different frequencyband is allotted to each of the conversations transmitted, justas different frequency bands are allotted to different programsin radio broadcast transmission. Not only does the same cir-cuit serve to transmit a large number of conversations at dif-ferent frequencies, but the same amplifier or repeater canserve for all speech channels, with great resultant economy. With this type of transmission, known as carrier transmis-sion,
. Bell telephone magazine . transforming currentsof the voice range, the region from about 250 to 3,000 cycles,into currents of higher frequencies. A different frequencyband is allotted to each of the conversations transmitted, justas different frequency bands are allotted to different programsin radio broadcast transmission. Not only does the same cir-cuit serve to transmit a large number of conversations at dif-ferent frequencies, but the same amplifier or repeater canserve for all speech channels, with great resultant economy. With this type of transmission, known as carrier transmis-sion, the message carrying capacity of a circuit is determinedby the width of the frequency band that the line and its associ-ated apparatus are capable of transmitting effectively. If theavailable band width of the coaxial line is 1,000,000 cycles, forexample, and if a frequency band 4,000 cycles wide is allottedto each speech channel, 250 independent telephone conversa-tions can be conducted over two of these coaxial pipes. 26. Fig. 1. Ix THE Crystal Wave Filter for Broad-baxd Telephony, ax AusterelySimple Exterior Covers a Most Ixterestixg Combination of Research ProductsOriginating in Diverse Fields.
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Keywords: ., bookauthoramerican, bookcentury1900, bookdecade1920, bookyear1922
