US1835080A - Transmission regulation in cable circuits - Google Patents

Transmission regulation in cable circuits Download PDF

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Publication number
US1835080A
US1835080A US386436A US38643629A US1835080A US 1835080 A US1835080 A US 1835080A US 386436 A US386436 A US 386436A US 38643629 A US38643629 A US 38643629A US 1835080 A US1835080 A US 1835080A
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US
United States
Prior art keywords
transmission
potentiometer
steps
circuit
shunt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US386436A
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English (en)
Inventor
Kenneth W Pfleger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AT&T Corp
Original Assignee
American Telephone and Telegraph Co Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by American Telephone and Telegraph Co Inc filed Critical American Telephone and Telegraph Co Inc
Priority to US386436A priority Critical patent/US1835080A/en
Priority to FR698983D priority patent/FR698983A/fr
Application granted granted Critical
Publication of US1835080A publication Critical patent/US1835080A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/04—Control of transmission; Equalising
    • H04B3/14—Control of transmission; Equalising characterised by the equalising network used
    • H04B3/143—Control of transmission; Equalising characterised by the equalising network used using amplitude-frequency equalisers
    • H04B3/145—Control of transmission; Equalising characterised by the equalising network used using amplitude-frequency equalisers variable equalisers

Definitions

  • This invention relates to methods of and means for regulating the transmission over telephone or carrier telegraph circuits, and
  • Cable circuits are affected as to transmission characteristics by changes of temperature, the transmission characteristics being a function of the frequency of the transmitted Current.
  • field measurements show that an increase of temperature, for instance, produces an increase of transmission loss at low and intermediate frequencies and that this change of transmission varies with frequency change, passing through zero at a certain high frequency and becoming a negative increment in loss at the higher frequencies.
  • the principal object of the invention is to provide for transmission regulation which will offset the variations mentioned above and produce a substantially fiat transmission characteristic over the normal range of temperatures and a wide range Vof frequencies.
  • I accomplish the above-stated object by associating resonant shunt circuits with a potentiometer in the transmission line, and providing for impedance adjustments in accordance with the regulation required.
  • Figs. 2, 3 and 4 show diagrammatically'the effective circuits produced by adjustment of the arrangement of Fig. l to meet various transmission conditions; f
  • FIG. 5 shows curves illustrating the effect i of the circut adjustments of Fig. l;
  • Figs. 6, and 8 show the effect on the transmission of temperature and frequency changes and indicate the correction to be introduced
  • Fig. 9 shows diagrammatically a desirable form of apparatus embodying the invention as applied to a vacuum tube repeater.
  • a circuit including a potentiometer controlled by a switch S1, which has three positions, step 0, step -l- 1 and step -1. These steps have relation to changes in temperature of a certain number of degrees, measurements being made on a certain cable circuit of fixed length. Step 0 may correspond to the average temperature affecting the circuit. While certain impedance elements are shown as pure resistances, and the resonant shunts are shown as composed of an inductance and a capacity in series, it will be understood that this specific disclosure is merely for the purpose of illustration of the methods and means of the invention. Furthermore, the values assigned tothe various elements are merely for the purpose of exposition through equations.
  • the potential impressed on the circuit is assumed to be 1 volt, and the values of the resistances in ohms are indicated.
  • the impedances of the shunts are designated as al and z2.
  • Equations (A) and (B) give the curves A and B, respectively, of Fig. 5 of the drawings, transmission being plotted as ordinates and frequency as abscissaa.
  • the receiving impedance may be nearly infinite as in the case of a vacuum tube grid), but that this feature is not essential.
  • Figs. 6 and 7 of the drawings show some of the transmission variations brought about in a cable circuit by change of temperature and change of frequency, and indicate the correction which approximates the ideal result 'of constant transmission.
  • the field measurements are expressed in terms of a cable circuit having a length of 17 8 miles; an average or step-zero temperature of degrees Fahrenheit is taken; and each step corresponds to a change in temperature of about 5.4 degrees Fahrenheit. Only the results for the even steps are shown, and the figures are concerned with the variation with frequency in the range over one thousand cycles per second.
  • a curve is shown corresponding to each of the even plus steps, transmission losses in Z6 being plotted as ordinates and frequencies in cycles per second as abscissae.
  • These curves show the variations of gain or loss with respect to frequency which it is desired that the regulating system should give, the curves being determined by measurements made on existing cable systems. rIlhe dots. crosses and circles indicate the variation in gain which. it has been found from measurements made on a particular regulator, may be introduced to give an approximate compensation for the transmission variation. It is seen that these variations give a very close approximation to the ideal variations indicatedby the curves. It will be noted that at the higher frequencies, the transmission loss becomes negative, and accordingly losses must be introduced at those frequencies to give constant transmission.
  • Fig. 7 shows the transmission loss variation with frequency for the even minus steps and, like Fig. 6, which covers the positive steps, indicates the variation of gain which must be introduced for correction.
  • Fig. 8 four curves are shown, two for the plus steps and two for the minus steps. T hese curves show on a scale different from that of Figs. 6 and 7 the gain which is to be introduced to give a substantially flat transmission characteristic. It Will'be noted that in this figure, the Alower as well as the higher frequencies are covered.
  • a regulator for producing a compensating variation such as that indicated in Figs. 6, 7 and l8.
  • the specific case chosen for illustration is an arrangement including a potentiometer designed to operate .between the stages of a vacuum tube repeater. This arrangement is shownin Fig. 9 of the drawings.
  • the vacuum tubes T1 and T2 are two tubes of a4 repeater. At the right of Fig. 9, in association with the grid of the tube T2, a poten- 'on each side of the series resistance R2.
  • step +10 the potentiometer contacts are adjusted, in any suitable manner, between step +10 and step 10 in accordance with the temperature affecting the transmissioncircuit.
  • the resonant shunts are varied by switches shown on the drawings and designated step 0, steps +1 to +10 ⁇ and steps +1 to -10.
  • a resonant shunt including in series one or more of the upper bank of condensers, shown to the left of the switches, and the inductance indicated at Il, is connected from step 10 of the potentiometer over point Y to ground.
  • the tuning of the shunt is provided for as indicated above, the shunt impedance being made suitable to the given positive step of the potentiometer.
  • a potentiom#V eter In a transmission circuit, a potentiom#V eter, a variable impedance in shunt with said potentiometer, and means for adjusting said.
  • potentiometer and said shunt impedance by definite and corresponding stepsto give a fiat transmissionY characteristic over a Wide range of temperatures and frequencies.
  • a transmission circuit including a .Y potentiometer, the method of transmission Y regulation Which. consists in associating a yvariable impedance in shunt With the potentiometer and adjusting the potentiometer steps vin accordance with temperature changes affecting the circuit, to'givelaflat transmis-- ⁇ sion characteristic over the Vrange of temperatures and a Wide rangeof frequencies. ⁇
  • 2.111 al transmission circuit including a regulation which consists in adjusting the tive at certain other frequenciesfor the same potentiometer setting.
  • fthe ⁇ method of regulating'the transmission y of alternating.currentsover the circuitvvhicli consists in determining the transmission variations YWith changes of temperature and With changes of frequency, including the range from 3,000 to 8,000 cycles per second,'intro ducing an auxiliary impedance'in shunt With thepotentionieter, and adjusting the potentiometer and the shunt impedance by definiteV steps .corresponding to temperaturev changes Y *to produce transmission variations compen- Satine;V forthose caused bythe temperature Vto and frequency changes.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Networks Using Active Elements (AREA)
US386436A 1929-08-16 1929-08-16 Transmission regulation in cable circuits Expired - Lifetime US1835080A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US386436A US1835080A (en) 1929-08-16 1929-08-16 Transmission regulation in cable circuits
FR698983D FR698983A (fr) 1929-08-16 1930-07-10 Perfectionnements aux systèmes électriques de transmission

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US386436A US1835080A (en) 1929-08-16 1929-08-16 Transmission regulation in cable circuits

Publications (1)

Publication Number Publication Date
US1835080A true US1835080A (en) 1931-12-08

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US386436A Expired - Lifetime US1835080A (en) 1929-08-16 1929-08-16 Transmission regulation in cable circuits

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US (1) US1835080A (fr)
FR (1) FR698983A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2676305A (en) * 1950-12-12 1954-04-20 Bell Telephone Labor Inc Isothermal electric cables
US3041555A (en) * 1958-05-29 1962-06-26 Submarine Cables Ltd Attenuation equalization device and method for using same
DE1155820B (de) * 1960-03-01 1963-10-17 Fernseh Gmbh Elektrischer Spannungsteiler, vorzugsweise fuer impulsfoermige Spannungen, in Geraeten der elektrischen Nachrichtentechnik
EP2975414A1 (fr) * 2014-07-18 2016-01-20 Siemens Aktiengesellschaft Solution redondante de sorties sur un diviseur de tension résistif-capacitif

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2676305A (en) * 1950-12-12 1954-04-20 Bell Telephone Labor Inc Isothermal electric cables
US3041555A (en) * 1958-05-29 1962-06-26 Submarine Cables Ltd Attenuation equalization device and method for using same
DE1155820B (de) * 1960-03-01 1963-10-17 Fernseh Gmbh Elektrischer Spannungsteiler, vorzugsweise fuer impulsfoermige Spannungen, in Geraeten der elektrischen Nachrichtentechnik
EP2975414A1 (fr) * 2014-07-18 2016-01-20 Siemens Aktiengesellschaft Solution redondante de sorties sur un diviseur de tension résistif-capacitif
WO2016008795A1 (fr) * 2014-07-18 2016-01-21 Siemens Aktiengesellschaft Solutions redondantes de sorties sur un diviseur de tension rc
CN106537157A (zh) * 2014-07-18 2017-03-22 西门子公司 在rc分压器上的输出的冗余解决方案
CN106537157B (zh) * 2014-07-18 2019-03-26 西门子公司 在rc分压器上的输出的冗余解决方案
US10630074B2 (en) 2014-07-18 2020-04-21 Siemens Aktiengesellschaft Redundant solution of outputs on a RC voltage divider

Also Published As

Publication number Publication date
FR698983A (fr) 1931-02-09

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