Abstracts of Technical Articles by Bell System Authors 



Pulse Echo Measurements on Telephone and Television Facilities} L. (i. 

 Abraham, A. W. Lebert, J. B. Maggio, and J. T. Schott. Pulse echo 

 measurements have been used on telephone and television facilities since 

 194() to locate impedance irregularities and control quality in manufacture 

 and installation. These sets send a pulse into a line and observe on an 

 oscilloscope the echoes returned from irregularities. The shape and width 

 of the pulse, the rate at which it is repeated and the pulse magnitude are 

 important in determining the accuracy of the results and the requirements 

 of the measuring apparatus. The "coaxial pulse echo set" is used for factory 

 and field testing of coaxial cables. The "Lookator" was developed for use 

 on much narrower band systems such as spiral-four field cable and open 

 wire lines. 



Television Neticork Facilities.- L. G. Abraham and H. I. Romxes. This 

 paper describes television network facilities which are needed to connect 

 studios and other pickup points to transmitters in the same and in distant 

 cities, and discusses their transmission characteristics. Short-haul tele- 

 vision circuits may be by microwave radio or over wire circuits. Long- 

 haul television connections may be by radio relay or over coaxial systems 

 of the type originally developed for carrier telephone circuits. Transmission 

 requirements include adequate frequency band, accurate gain and phase 

 equalization, and freedom from interference resulting from excessive noise, 

 crosstalk, or modulation. Radio and wire systems are under development 

 to provide extensive high-quality television networks. 



A Carrier Telephone System for Rural Service.^ J. M. Barstow. The 

 Ml carrier telephone system was designed for the purpose of extending tele- 

 phone service into areas served by rural power lines, but not served by co- 

 existing rural telephone lines. To the local office operator and to a carrier 

 subscriber the service provided is the same, so far as procedures involved 

 in establishing a connection are concerned, as a voice-frequency line. 



At the office end of the system a telephone wire line extends from the 

 office to a point near the power line. Here is located a converter (called 

 common terminal) which converts the voice-frequency signal to be trans- 

 mitted to the subscriber to an amplitude-modulated double-sideband carrier 

 signal. This signal is coupled to the power line through a coupling unit 



1 Trans., A. I.E. E., vol. 66, 1947 (pp. 541-548). 



"^ Transactions, A. I. E. E., vol. 66, 1947 (pp. 459-464). 



' Trans. A. I.E. E., vol. 66, 1947 (pp. 501-507). 



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