. The Bell System technical journal. Telecommunication; Electric engineering; Communication; Electronics; Science; Technology. 480 BELL SYSTEM TECHNICAL JOURNAL It was desired to equalize the attenuation over a frequency range from zero to 4500 cycles per second and improve the time-of-phase- transmission at the lower frequencies. Computations for this 50-mile cable circuit gave values of attenuation (a in ) and time-of-phase- transmission (b/lTf) as shown in Fig. 15. These circuit characteristics suggested the use of two different networks in tandem shown separately in Fig. 14, one equali
. The Bell System technical journal. Telecommunication; Electric engineering; Communication; Electronics; Science; Technology. 480 BELL SYSTEM TECHNICAL JOURNAL It was desired to equalize the attenuation over a frequency range from zero to 4500 cycles per second and improve the time-of-phase- transmission at the lower frequencies. Computations for this 50-mile cable circuit gave values of attenuation (a in ) and time-of-phase- transmission (b/lTf) as shown in Fig. 15. These circuit characteristics suggested the use of two different networks in tandem shown separately in Fig. 14, one equalizing principally at the lower frequencies, the other at the higher frequencies of the required range. Low-Trequency Disiortiorv Correcting Neitvork n, -o^VVWo—'-0 Hz' :n/i L, lU I High-Freguency ditenuaUon Equalizer n, O-J—oAWW. Fig. 14—Distortion correcting networks for program transmission circuit. The low-frequency correcting network, shown as the upper section in Fig. 14, is of the symmetrical unbalanced bridged-T (la) type and was transformed from Network 7, Appendix IV. In the design of the latter the attenuation data corresponding to (8) were /i = 40-, A, = .536 napier; h = 200-, A2 = .291 napier; /3 = 800~, A, = .176 napier; U = 2000 ~, A, = .100 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
