. The Bell System technical journal. Telecommunication; Electric engineering; Communication; Electronics; Science; Technology. 618 BELL SYSTEM TECHNICAL JOURNAL circuit should, of course, be a minimum at carrier and sideband frequencies. At the output a low-pass filter structure F provides for the suppression of the unwanted products of demodulation. A front view of the demodulator unit is shown in Figure 37. The. Figure 37âAssembly of demodulator panel. (Front view) panel layout and general appearance is similar to that of the modu- lator. The two dials shown control the demodulator input and
. The Bell System technical journal. Telecommunication; Electric engineering; Communication; Electronics; Science; Technology. 618 BELL SYSTEM TECHNICAL JOURNAL circuit should, of course, be a minimum at carrier and sideband frequencies. At the output a low-pass filter structure F provides for the suppression of the unwanted products of demodulation. A front view of the demodulator unit is shown in Figure 37. The. Figure 37âAssembly of demodulator panel. (Front view) panel layout and general appearance is similar to that of the modu- lator. The two dials shown control the demodulator input and the oscillator frequency, respectively, as indicated in these figures. Filters. The general function of a band filter is the selection of a band of frequencies, and the protection of this band from interfering frequencies located on either side. The filters determine what band width is transmitted, and thus to that extent they control the quality of speech which may be obtained through the carrier circuit. The type "C" system transmits a band corresponding to approximately 200 to 2,700 cycles per second in the voice range. In considering the requirements imposed upon the band filters it is necessary to keep in mind 'â ' the fact that the modulator produces not only the particular sideband which is to be transmitted but also an unwanted sideband of the same volume as the wanted sideband and ^ R. V. L. Hartley, "Relation of Carrier and Side Bands in Radio Transmission," Bell System Tech. Jl., V. 2, April 1923, pp. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original American Telephone and Telegraph Company. [Short Hills, N. J. , etc. , American Telephone and Telegraph Co. ]
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
