PCM equipment has been used by British and other telecommunication administrations in the 30-channel format since the early 1970's and before that in the 24-channel format. By the late 1970's it was considered...
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PCM equipment has been used by British and other telecommunication administrations in the 30-channel format since the early 1970's and before that in the 24-channel format. By the late 1970's it was considered necessary to develop new equipment which would take advantage of new ideas and techniques to produce a design which was versatile, easy to manufacture, cost competitive, low in power consumption, and of minimal size. This paper describes that equipment. The development objectives have been achieved by the use of custom designed IC and a new British equipment practice Tep-1(E).
Advances in digital communications and the growing need to make efficient use ofthe existing telephone network has led many PTT administrations to install PCM equipment on routes handling heavy traffic. In line with t...
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Advances in digital communications and the growing need to make efficient use ofthe existing telephone network has led many PTT administrations to install PCM equipment on routes handling heavy traffic. In line with these developments, the use of higher order PCM is becoming wider on trucks as well as on junction networks. In conjunction with the Turkish PTT administration, a second-order PCM multiplex utilizing positive-zero-negative justification has been realized to investigate its behavior in synchronous and plesiochronous operation. The system and some preliminary results are described.
The codec is the main component of a PCM system which has been developed by the telephone industry to maximise the number of individual channels which can be routed through a single conductor. The codec test adaptor p...
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The codec is the main component of a PCM system which has been developed by the telephone industry to maximise the number of individual channels which can be routed through a single conductor. The codec test adaptor presented here, in combination with the general purpose LSI test system, has been successfully employed in codec characterization and production testing.
It is argued that optical bus systems will in the long run displace conventional electric bus systems. This imposes special demands on receiver circuits. The latter must have a wide dynamic range because the incoming ...
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It is argued that optical bus systems will in the long run displace conventional electric bus systems. This imposes special demands on receiver circuits. The latter must have a wide dynamic range because the incoming signals may present varying levels in extended networks. An additional problem of synchronization and clock recovery prevails in PCM systems. A circuit is described which satisfies these demands.
This article discusses the techniques examined and the results obtained in research work and study programs undertaken in the field of differential PCM coding processes. Variable parameter systems yielding better resu...
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This article discusses the techniques examined and the results obtained in research work and study programs undertaken in the field of differential PCM coding processes. Variable parameter systems yielding better results than those obtained with fixed parameter systems for speech and data transmission applications are considered in greater detail.
Telecom Australia is presently installing primary level PCM systems in its inter-exchange cable network. Repeaters are located between exchanges according to rules designed to ensure that the final cost of the PCM net...
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Telecom Australia is presently installing primary level PCM systems in its inter-exchange cable network. Repeaters are located between exchanges according to rules designed to ensure that the final cost of the PCM network is as low as possible without compromising its transmission performance. The development of the rules dealing with crosstalk noise is outlined and the benefits to be obtained from their application demonstrated.
COMMONLY USED TRANSMISSION codeS ARE REVIEWED AND A COMPARISON IS MADE OF VARIOUS GIVEN codeS. ACCOUNT IS MADE OF SUCH DISTURBANCES AS CROSSTALK AS WELL AS THERMAL NOISE. THE 5B 6B code IS SELECTED FOR THE TRANSMISSIO...
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COMMONLY USED TRANSMISSION codeS ARE REVIEWED AND A COMPARISON IS MADE OF VARIOUS GIVEN codeS. ACCOUNT IS MADE OF SUCH DISTURBANCES AS CROSSTALK AS WELL AS THERMAL NOISE. THE 5B 6B code IS SELECTED FOR THE TRANSMISSION ON SYMMETRIC CABLES WITH DOMINANT FAR-END CROSSTALK, PROVIDED THAT USE IS MADE OF THE GAUSSIAN LF NETWORK FOR THE GENERAL TRANSFER FUNCTION IN ADDITION TO QUANTIZED FEEDBACK IN THE REGENERATOR. THE SELECTED code CONVERSION METHOD IS DESCRIBED AND THE BLOCK DIAGRAMS OF THE codeR AND DEcodeR ARE INCLUDED. IN GERMAN.
The paper describes the factors leading to the invention of p.c.m., and the form first devised by A.H. Reeves. It outlines the development of early p.c.m. telephone systems up to about 1960, with emphasis on developme...
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The paper describes the factors leading to the invention of p.c.m., and the form first devised by A.H. Reeves. It outlines the development of early p.c.m. telephone systems up to about 1960, with emphasis on developments of which the author has personal experience. It surveys the life and work of the inventor, including his later ideas on encoding. Finally, it brings to light a little-known precursor of p.c.m., a form of picture telegraph invented by P.M. Rainey in 1921.
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