US2336258A - Carrier current apparatus - Google Patents

Carrier current apparatus Download PDF

Info

Publication number
US2336258A
US2336258A US433824A US43382442A US2336258A US 2336258 A US2336258 A US 2336258A US 433824 A US433824 A US 433824A US 43382442 A US43382442 A US 43382442A US 2336258 A US2336258 A US 2336258A
Authority
US
United States
Prior art keywords
transmission line
condenser
carrier current
impedance
line
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
Application number
US433824A
Other languages
English (en)
Inventor
Edwin W Kenefake
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.)
General Electric Co
Original Assignee
General Electric Co
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
Priority to BE468985D priority Critical patent/BE468985A/xx
Application filed by General Electric Co filed Critical General Electric Co
Priority to US433824A priority patent/US2336258A/en
Application granted granted Critical
Publication of US2336258A publication Critical patent/US2336258A/en
Priority to FR927543D priority patent/FR927543A/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/54—Systems for transmission via power distribution lines
    • H04B3/56—Circuits for coupling, blocking, or by-passing of signals

Definitions

  • My invention relates to carrier current appa- 1 ratus, and more particularly to means for coupresents a purely resistive impedance to the car- I rier current apparatus.
  • Such anarrangement is satisfactory from an operating standpoint where the carrier current apparatus is in close proximity to the power transmission line since tuning means for the coupling capacitor and transmission line may then be in the same enclosure as the carrier current apparatus and is thus readily accessible for easy adjustment without special precautions to protect it from the weather.
  • carrier current apparatus is located at a considerable distance from the power transmission line, making it necessary to use a signal transmission line, such as a coaxialcable, to transmit signals between the carrier current apparatus and the power transmission line.
  • a signal transmission line such as a coaxialcable
  • tuning means and impedance matching means both between the carrier current apparatus and the signal transmission line and between the signal transmission line and the power transmission line.
  • a coupling capacitor is used to insulate the signal transmission line from the power transmission line, and an inductance is provided in series with the coupling capacitor between these two lines to tunethe capacitor and power line to series resonance at the signal frequency.
  • a transformer for matching the characteristic impedance of the signal transmission line to the impedance of the coupling capacitor and power transmission line, so as to provide for the maximum transfer of signals therebetween.
  • tuning means and transformer has been used between the signal transmission line and the carrier current apparatus. These tuning and impedance matching means have reduced attenuation to the low levels.
  • the line II is connected through one winding M of a transformer 55 to ground.
  • One terminal of the other winding 56 of the transformerifi is grounded, and the other terminal is connected through a suitable coupling capacitor ll to the conductor I2 of the power transmissionline it.
  • the windings l4 and it of the transformer 5 have a turn ratio equal to the square root of the ratio of the impedance of the power transmission line H as measured through the condenser H to the characteristic impedance of the signal transmission line. That is, the square of the number of turns in the winding l6 corresponds to the impedance of the power transmission line is, as measured through condenser ii, in the same way as the square or the number of turns of the winding it corresponds to the characteristic impedance of the signal transmission line.
  • Such a relation between impedances and turn ratio of the transformer i5 is desirable because attenuation in a transmission line .is minimum when it is connected at its ends to devices whose impedance, including both resistance and reactance, is equal to the characteristic impedance of the transmission line. While it is true that such attenuation may be further minimized by making the impedance of the connected devices purely resistive, it has been found that the attenuation is satisfactorily low even though reactance be present, if impedances are matched, as stated above.
  • the characteristic impedance of the transmission line need not be matched exactly, as the attenuation does not increase rapidly as the connected impedances vary from a value equal to the characteristic impedance of the line.
  • a coaxial cable of -70 'ohm characteristic impedance is selected as accuses at oneirequency, and a-receiver operative at a difierent frequency.
  • the transmitter in the apparatus it is connected to the adjustable inductthe transmission line, the carrier current appara'tus operates at 100 kilocycles and the coupling condenser H has a capacity oi 0.002 microfarad, the impedance of the-power line is may be assumed to be 400 ohms of pure resistance, and the impedance to which the transmission line must then be matched is 882 ohms.
  • the impedance ratio is then 12.6 and-the turn ratio of transformer 65 is 3.4.
  • the carrier current apparatus ill is connected through the inductance iii, and the transmission line it directly to one terminal of the coupling condenser ll, whose other terminal is connected to the conductor it of the power transmission line it.
  • the inductance it is in this case adjusted so that the whole system including the inductance it, the transmission line H, condenser ii, and the'power transmission line it is resonant at the signal frequency.
  • omitting the impedance matching transformer is oi Fig. 1, there is somewhat more signal refiection' and consequently greater attenuation through the signal transmission line ii. It has been iound;however, that even such greater attenuation is reasonably small over some distances, and, in fact, not lntolerably large.
  • the apparatus illustrated in Figs. 3 and a are modlcations oi the arrangement illustrated in Fig. i.
  • the carrier current apparatus it is arranged for operationat two different frequencies.
  • the carrier current apparatus it may include a transmitter operative ance i3 and transmission line H through two paths, one of which includes an inductance is and condenser 2b in series, and the other of Which includes an inductance 2i and condenser 22 in series.
  • the receiver in the apparatus it is connected through a conductor 23 to a point between the condensers 2t and 22 and the inductance it.
  • the adjustment of these elements is as follows. 'lhe inductance is is adjusted to resonate in series with the condenser 28 at the transmitter frequency, and the inductance it is adjusted to resonate with the condenser H and transmission line 53 are series resonant at the transmitter frequency and present a low impedance to the transmission of carrier current signals from the apparatus it to the transmission line l3.
  • the two series paths one including the transmitter in the apparatus it, the inductance it and condenser 26, and the other including the inductance it and condenser ll, exhibit inductive or capacitive reactance, depending on whether the receiver frequency is higher or lower, respectively, than the transmitter frequency.
  • the inductance it and condenser ll therefore. form one branch of a series tuned circuit, the other branch being formed by the transmitter in the,
  • the apparatus illustrated in Fig. 3 performs in a fashion similar to that illustrated in Fig. 1, and provides emcient transfer of signals with small attenuation over substantial lengths of signal transmission line it between the apparatus it and the power transmission line it.
  • the data presented hereinafter corre lating such attenuation and line lengths for Fig. l is equally applicable forFig. 3.
  • connection shown in Fig. 3 and described in the above mentioned application has been used only where the carrier current apparatus has been so near the power line i 3 that a transmission line has not been needed,
  • connection 23 be made to a point between the coupling condenser IT and the adjacent tuning inductances and condensers I8, I9, 20, 2I and 22.
  • connection 23 may easily be made, thereby resulting in more efllcient operation of the receiver, as well as easier adjustment and maintenance of the apparatusas a whole.
  • the transmission line II, transformer I5 and condenser II are utilized to transfer carrier, current signals between the power transmission lines I3 and two carrier current apparatus, including the apparatus I0 and another apparatus 30.
  • Each such apparatus may include a carrier current transmitter, and a receiver operating at the same frequency, each apparatus as a whole being operative at a different frequency.
  • the apparatus I0 is connected to the adjustable inductance I8 and transmission line II through a condenser 3
  • the apparatus 30 is connected to a point between the inductance I8 and transmission line II through a path serially including an adjustable inductance 33 and a shunt combination of a condenser 34 and an adjustable in-. ductance 35.
  • the adjustment of the apparatus of Fig. 4 is as follows.
  • the parallel tuned circuit including the condenser 3I and inductance 32 is made parallel resonant at the frequency of the apparatus 33.
  • the parallel circuit including condenser 34 and inductance 35 is made parallel resonant at the operating frequency of the apparatus Ill.
  • the inductance I8 is then adjusted so that the apparatus Iii, inductance 32, condenser 3I, inductance I8, transmission line II, transformer I5, coupling condenser I1, and the power line I3 are resonant at the operating frequency of the apparatus Ill.
  • the parallel resonant circuit including condenser 3d and inductance 35 ofiers a high impedance so that signals transferred between apparatus Iii and the power line I3 are not dissipated in the apparatus 30.
  • the inductance 33 is adso that the grounded terminals of the carrier current apparatus may in each case be connected, instead of to ground, to a second conductor of the power transmission line I3.
  • the two terminals of the secondary I6 of transformer I5 may be connected through separate coupling condensers to two different conductors of the power line I3.
  • the apparatus for interphase transmission may be exactly the sameas that illustrated in Figs. 1, 3
  • the apparatus 30 justed so that the apparatus 30, the inductance 35, condenser 34, the inductance 33, the transmission line II, transformer I5, coupling condenser I1, and power line I3, are all resonant at the frequency of operation of the apparatus 30.
  • the circuit including condenser 3I and inductance 32 offers a high impedance so that signals transferred between the power line I3 and apparatus 30 are not dissipated in the apparatus I0.
  • the apparatus I0 and 30 respectively cooperate with the inductances I8 and 33, and with transmission line II, transformer I5, coupling condenser I1 and the power transmission line I3 in the same-way as corresponding elements .in the apparatus of Fig. 1.
  • the relation between attenuation and signal transmission line length is the same as that set forth hereinafter for Fig. 1.
  • FIGs. 1 through 4 has been illustrated as impressing a signal between a single conductor I2 of the power line I3 and ground, it is within the scope of my invention to and 4.
  • One of the conditions termining how a simplified arrangement according to my invention may be utilized is the capacity of the coupling condenser II. This capacity to a substantial extent determines the reactance presented to the end of the transmission line II adjacent the power line I3, and hence is important in considering how much attenuation may be produced through the transmission line II. In all cases hereinafter considered, it is assumed that the impedance between one conductor I2 of the power line I3 and ground is 400 ohms, which value is substantially correct for any,
  • the capacity of the coupling condenser I! is determined primarily by the amount of insulation it must afford between the conductor I2 and ground. That is, the higher the voltage of the power line I3, the more insulation there must be between the capacity elementsof the condenser II, and consequently the less the capacity of the condenser I1. At the present time certain sizes of condensers are available for.
  • the attenuation which is realized when neither the transformer to nor tuning apparatus adjacent the condenser it is utilized is reasonably small even though transmission line it is as much as 1000 it. long.
  • the attenuation realized when the transformer i5 is utilized, as indicated by the curve dd, is even smaller and is well within usable limits for cable lengths greater than 2000 ft, even though no tuning device is used adjacent the condenser ii.
  • Carrier current apparatus as generally utilized at the present time, is capable of producing about 50 decibels gain in a received signal when the automatic volume control voltage is smallest. The total attenuation between carrier current transmitter and receiver must, therefore, never exceed this value, even under the worst conditions of weather and the like.
  • the transmission line H which is to be used approaches a. length equal to one quarter wave length of the carrier current wave at the operating frequency, additional consideration must be accuses given to the possibility of tuning the apparatus by means of the inductances l8 and If the transmission line it, in any particular case, is made slightly greater than one quarter wave length long, the capacityof the power line i3 and condenser ii appearsat the carrier current apparatus iii as inductance, since a quarter wave length line acts as an impedance inversion trans former.
  • the inductance Hi cannot be used to tune the equipment, and if it be desired to use such a transmission line, it is necessary to replace the inductance it with a condenser or with a capacitive combination of a condenser and an inductance.
  • th attenuation is as illustrated in the curves of Figs. 5 through 8, even though the length of transmission line it be exactly one quarter wave length, or a multiple thereof.
  • One form of the transmission line H which is especially suitable iorconnecting the carrier current apparatus 0 to the condenser H is a coaxial cable insulated with a rubber compound.
  • the dielectric constant of one particular rubber compound used in practice is 3.3, so that a quarter wave length of the transmission line I i at 150 kilocycles is 903 ft. at 85 kilocycles is 1,590 ft., and one quarter wave length at 50 kilocycles is 2,710 ft. It should be remembered in making any particular installation that when the length of transmission line H approaches such values an inductance may be incapable of tuning the equipment at the carrier current apparatus i0.
  • the transmission line II I may approach a. quarter wave length or multiple thereof in length, it may be necessary to determine the'actual operating frequency.
  • a. transmission line H may be utilized to connect a carrier current apparatus Hi to a. power line IS without the necessity of providing tuning means at the connection between thetransmission line and the power line, and also that an impedance matching transformenmay be omitted. It is within the scope of tions, the curves 40 and 4
  • An arrangementfor coupling carrier current apparatus to a power line spaced a substantial distance therefrom comprising, means including a transmission line extending between One quarter wave length accepts power line from said transmission line and matching the impedance of said transmission line to the impedance of said condenser and power line, and means for transmitting signals between said carrier current apparatus and said transmission line, the impedance of said power line measured through said condenser, transformer, and transmission line being reactive, said last mentioned means having a reactance equal and opposite in character to the reactive component of the impedance of said power line measured through said condenser and transmission line, whereby attenuation of carrier current signals transmitted between said power line and said-apparatus is minimized.
  • An arrangement for coupling carrier current apparatus to a power line spaced a substantialdistance therefrom comprising, means for transmitting signals between said apparatus and line comprising 'a transmission line, a coupling condenser and transformer connected between' said transmission line and said power line, the impedance of said power line measured through said condenser and transformer being reactive 1 whereby substantial attenuation is produced in pling condenser and transformer connected between said transmission'line and said power line, the impedance of said power line measured through said condenser being reactive, said transformer having an impedance ratio eflective to match said impedance with the characteristic impedance of said transmission line, substantial attenuation being produced in signals transmitted through said transmission line in spite of said transformer because of the reactivecomponent of said impedance, and means coupling said apparatus to said transmission line for tuning the impedance of said power line and coupling condenser through said transmission line and transformer, whereby said attenuation is reduced.
  • An arrangement for coupling carrier current apparatus including a transmitter and a receiver operative at different frequencies to a power line spaced a substantial distance therefrom comprising, a transmission line, a coupling condenser and transformer connected between said lines, said transformer having a turn ratio effective to match the impedance of said transmission line to the impedance of said-power line and condenser, the impedance of said power line measured through said condenser, transformer, and transmissionline being reactive at both the frequencies of said transmitter and receiver, means for connecting said transmitter to said transmission line, said connecting means havingv a reactance at the frequency of said transmitter equal and opposite in character to the reactance of said power line measured through said condenser, transformer, and transmission line, and

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
US433824A 1942-03-07 1942-03-07 Carrier current apparatus Expired - Lifetime US2336258A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE468985D BE468985A (en(2012)) 1942-03-07
US433824A US2336258A (en) 1942-03-07 1942-03-07 Carrier current apparatus
FR927543D FR927543A (fr) 1942-03-07 1946-05-31 Perfectionnements aux systèmes à courant porteur

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US433824A US2336258A (en) 1942-03-07 1942-03-07 Carrier current apparatus

Publications (1)

Publication Number Publication Date
US2336258A true US2336258A (en) 1943-12-07

Family

ID=23721669

Family Applications (1)

Application Number Title Priority Date Filing Date
US433824A Expired - Lifetime US2336258A (en) 1942-03-07 1942-03-07 Carrier current apparatus

Country Status (3)

Country Link
US (1) US2336258A (en(2012))
BE (1) BE468985A (en(2012))
FR (1) FR927543A (en(2012))

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2551696A (en) * 1945-07-06 1951-05-08 Landis & Gyr Ag Transformer
US2611022A (en) * 1949-01-26 1952-09-16 Westinghouse Electric Corp Carrier-current coupler
US2634334A (en) * 1948-02-20 1953-04-07 Harry N Kalb Carrier current communication system
US2743434A (en) * 1952-12-27 1956-04-24 Hugh B Fleming System of carrier current distribution
US2756414A (en) * 1952-03-01 1956-07-24 Motorola Inc Coupling unit
US3846638A (en) * 1972-10-02 1974-11-05 Gen Electric Improved coupling arrangement for power line carrier systems
FR2428354A1 (fr) * 1978-06-08 1980-01-04 Siemens Ag Systeme de telecommandes centralisees avec unite de couplage de faible encombrement
DE102006020029A1 (de) * 2006-04-26 2007-11-08 IAD Gesellschaft für Informatik, Automatisierung und Datenverarbeitung mbH Adaptive, kapazitive Koppelschaltung und Verfahren zur Nachrichtenübertragung über geschirmte Energiekabel eines elektrischen Energieverteilnetzes

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2551696A (en) * 1945-07-06 1951-05-08 Landis & Gyr Ag Transformer
US2634334A (en) * 1948-02-20 1953-04-07 Harry N Kalb Carrier current communication system
US2611022A (en) * 1949-01-26 1952-09-16 Westinghouse Electric Corp Carrier-current coupler
US2756414A (en) * 1952-03-01 1956-07-24 Motorola Inc Coupling unit
US2743434A (en) * 1952-12-27 1956-04-24 Hugh B Fleming System of carrier current distribution
US3846638A (en) * 1972-10-02 1974-11-05 Gen Electric Improved coupling arrangement for power line carrier systems
FR2428354A1 (fr) * 1978-06-08 1980-01-04 Siemens Ag Systeme de telecommandes centralisees avec unite de couplage de faible encombrement
US4383243A (en) * 1978-06-08 1983-05-10 Siemens Aktiengesellschaft Powerline carrier control installation
DE102006020029A1 (de) * 2006-04-26 2007-11-08 IAD Gesellschaft für Informatik, Automatisierung und Datenverarbeitung mbH Adaptive, kapazitive Koppelschaltung und Verfahren zur Nachrichtenübertragung über geschirmte Energiekabel eines elektrischen Energieverteilnetzes
DE102006020029B4 (de) * 2006-04-26 2016-06-30 IAD Gesellschaft für Informatik, Automatisierung und Datenverarbeitung mbH Adaptive, kapazitive Koppelschaltung und Verfahren zur Nachrichtenübertragung über geschirmte Energiekabel eines elektrischen Energieverteilnetzes
EP1850501B1 (de) * 2006-04-26 2017-06-07 iAd Gesellschaft für Informatik, Automatisierung und Datenverarbeitung mbH Adaptive, kapazitive Koppelschaltung und Verfahren zur Nachrichtenübertragung über geschirmte Energiekabel eines elektrischen Energieverteilnetzes

Also Published As

Publication number Publication date
BE468985A (en(2012))
FR927543A (fr) 1947-10-31

Similar Documents

Publication Publication Date Title
US2438367A (en) Transmitter-receiver switching system
US2898590A (en) Multi-frequency antenna
US2336258A (en) Carrier current apparatus
US2184771A (en) Antenna coupling means
US2021734A (en) Transmission line network for radio receiving antennae
US2519524A (en) Multiple-tuned wave-selector system
US2511574A (en) Antenna circuit
US2158875A (en) Antenna system
US2419985A (en) Reactance compensation
US2423083A (en) Loop antenna system
US2202700A (en) Transmission apparatus
US2553734A (en) Power line signal pickup
US3311831A (en) Coaxial combiner-separator for combining or separating different electrical signals
US2777996A (en) Impedance matching device
US2439656A (en) Receiver protective device
US2282968A (en) Coupling apparatus
US2661424A (en) Diplexer arrangement
US1890034A (en) Electrical coupling system
US3162809A (en) Antenna tuner circuit for radio transceiver
US1857055A (en) Coupling system
US2031103A (en) Ultra short wave receiver
US2660710A (en) High-frequency coupling system
US2013154A (en) Translating circuit
US2390839A (en) Radio frequency coupling network
US2373458A (en) Transmission line coupling system