Systems for Wide-Band Transmission Over Coaxial Lines

Espenschied, Lloyd; Strieby, M. E.

doi:10.1002/j.1538-7305.1934.tb04442.x

Cited by 20 publications

(2 citation statements)

References 14 publications

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“…In a similar manner we can derive the following expression for the near-end crosstalk from circuit (2) into circuit (1) via the intermediate circui t (3):…”

Section: Crosstalk Via An Intermediate Circuitmentioning

confidence: 97%

Crosstalk Between Coaxial Transmission Lines

Schelkunoff¹,

Odarenko²

1937

Bell System Technical Journal

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The general theory of coaxial pairs was dealt with in an article on "The Electromagnetic Theory of Coaxial Transmission Lines and Cylindrical Shields" by S. A. Schelkunoff (B. S. T. J., Oct., 1934). The present paper considers a specific aspect of the general theory, namely, crosstalk.Formulae for the crosstalk are developed in terms of the distributed mutual impedance, the constants of the transmission lines and the terminal impedances. Some limiting cases are given special consideration. The theory is then applied to a few special types of coaxial structures studied experimentally and a close agreement is shown between the results of calculations and of laboratory measurements.If the outer members of coaxial pairs are complicated structures rather than solid cylindrical shells, the crosstalk formulae still apply· but the mutual impedances and the transmission constants which are involved in these formulae must be determined experimental1y since these quantities cannot always be calculated with sufficient accuracy.The crosstalk between coaxial pairs with solid outer conductors rapidly decreases with increasing frequency while the crosstalk between unshielded balanced pairs increases. In the low frequency range there is less crosstalk between such balanced pairs than between coaxial pairs but at high frequencies the reverse is true. The diminution of crosstalk between coaxial pairs with increasing frequency is caused by an ever increasing shielding action furnished by the outer conductors of the pairs.Finally, crosstalk in long lines using coaxial conductors is discussed and the conclusion is reached that, unlike the case of the balanced structure, the far-end crosstalk imposes a more severe condition than the near-end crosstalk in two-way systems which involve more than two coaxial conductors.

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“…In a similar manner we can derive the following expression for the near-end crosstalk from circuit (2) into circuit (1) via the intermediate circui t (3):…”

Section: Crosstalk Via An Intermediate Circuitmentioning

confidence: 97%

Crosstalk Between Coaxial Transmission Lines

Schelkunoff¹,

Odarenko²

1937

Bell System Technical Journal

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“…In the one type, originally developed for radio purposes, flexibility is provided by an articulated structure of the outer conductor. % In the other type of coaxial cable the outer tube is formed oi ribbons of See Bibliography, (21).…”

Section: Wide-band Systemsmentioning

confidence: 99%

Modern systems of multi-channel telephony on cables

Angwin¹,

Mack²

1937

Journal of the Institution of Electrical Engineers

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Following a brief reference to progress in the application of carrier telephony to circuits in cables in this and other countries, an account is given of the carrier system operating between Bristol and Plymouth. This system affords 12 telephone channels per pair in the range 12 to 60 kc. Separate cables are provided for the two directions of transmission, and negative-feedback repeaters are provided at intervals of approximately 20 miles. When fully equipped the system will provide 228 circuits. The account of this system is followed by a description of the 4-tube underground coaxial cable which has been installed between London and Birmingham and of the modulating and repeater equipment that has been developed to operate 320 carrier telephone channels in the range 0 • 5-2 • 1 Me. Repeaters are provided at intervals of approximately 7 miles, separate tubes being used for the two directions of transmission.Applications to television and the probable line of development of multi-channel and wide-band systems are discussed. CONTENTS(1) Introduction and General Survey.(2) Bristol-Plymouth 12-Channel Carrier System. (a) General design considerations. (6) Cable system. (c) Terminal carrier and repeater equipment. (d) Field tests and overall system results. (e) Present programme of 12-channel carrier systems. (3) The London-Birmingham High-Frequency Carrier System. (a) General design considerations. (b) Coaxial cable. (c) Equipment (introductory). (i) Repeaters and equalizers, (ii) Terminal equipment, (iii) Carrier-frequency generating equipment. (4) Conclusions.Acknowledgments. Bibliography.

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The Proportioning of Shielded Circuits for Minimum High-Frequency Attenuation

Green¹,

Leibe²,

Curtis³

1936

Bell System Technical Journal

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For given conditions of design there exists an optimum proportioning or configuration which makes the high‐frequency attenuation of a given type of individually shielded circuit a minimum. Determination is made of such optimum proportioning for a wide variety of types of individually shielded circuits including several novel types designed to make the high‐frequency attenuation low in comparison with the cross‐sectional area occupied by the circuit, and the attenuation of different types is compared. The following topics and specific circuit structures are considered: Coaxial Circuits—Basic Coaxial Circuit; Effect of Dielectric; Effect of Frequency on Optimum Ratio; Thin Walls; Stranded Conductors; Optimum Proportioning as a Function of Conductor Resistance. Balanced Shielded Circuits—Shielded Pair (Cylindrical Conductors and Shield)—Condition for Minimum Attenuation, Condition for Maximum Characteristic Impedance, Effect of Dielectric, Effect of Frequency; Pair in Space; Shielded Stranded Pair; Pair with Shield Return; Double Coaxial Circuit; Shielded Pair (Round Conductors and Oval Shield); Shielded Pair (Quasi‐Elliptical Conductors); Shielded Quad.

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Systems for Wide-Band Transmission Over Coaxial Lines

Cited by 20 publications

References 14 publications

Crosstalk Between Coaxial Transmission Lines

Crosstalk Between Coaxial Transmission Lines

Modern systems of multi-channel telephony on cables

The Proportioning of Shielded Circuits for Minimum High-Frequency Attenuation

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