US1920041A - Electrical network - Google Patents

Electrical network Download PDF

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Publication number
US1920041A
US1920041A US495746A US49574630A US1920041A US 1920041 A US1920041 A US 1920041A US 495746 A US495746 A US 495746A US 49574630 A US49574630 A US 49574630A US 1920041 A US1920041 A US 1920041A
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Prior art keywords
filter
network
terminals
impedance
line
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Expired - Lifetime
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US495746A
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English (en)
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Vos Mauritz
Laurent Torben
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Telefonaktiebolaget LM Ericsson AB
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Telefonaktiebolaget LM Ericsson AB
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/17—Structural details of sub-circuits of frequency selective networks
    • H03H7/1708—Comprising bridging elements, i.e. elements in a series path without own reference to ground and spanning branching nodes of another series path
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/0115—Frequency selective two-port networks comprising only inductors and capacitors
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/46—Networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/36—Repeater circuits
    • H04B3/38—Repeater circuits for signals in two different frequency ranges transmitted in opposite directions over the same transmission path
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/40—Artificial lines; Networks simulating a line of certain length

Definitions

  • the present invention relatesjto an impedance network. ⁇ More particularly the invention relates to such vnetworks yused in telephone lines and in.linesfforfniultiple traiiic with high frequency currents,.the network having then for its purpose to separatecun rents oi 'diiierent frequencies or of different directions of propagation. ln lines having:
  • the network may be used inA ⁇ connection withy differentialtransformers and balancing networks to eliminate reflection disturbances.
  • the networkaccordmg to tlie'invention is arranged iii/"so called bridgedl '" ⁇ connection, ⁇
  • The' inventionf relates also to special embodi ments et the ilter chains includedin the -letvf'ork and certain arrangements and coinbinations of several similar networks-to yobtain the best possible" utilization of the incoming energy. l U
  • Figurev ll shows: diagram-l inatically an embodiment oi the network in iinsym'nietrical4 bridged lm-connection.
  • Figures 2 andi show the two iilter chains included in the network according to Figurerl Vand separated from each ctlier.
  • Figure a shows a' connection corresponding to thev one in Figure l but symmetrically formed.
  • Fig-v ure 5 shows two' filter cnains oi which Vthe net has to be built.
  • y Figure 6 shows two inipedances corresponding to each other Iin the two ilter chains f in' Figure 5.
  • Figure 7 shows a special embodiment 'of the inipedances in ⁇ Figure 6.
  • Figure S showsaii embodiment of the inventionin which a 'di'i fereiitial transformer is included.
  • Figure 9 fsh'ows diagraminatically the connection offa two-wayr amplifier which lis provided with networks according tothe invention.
  • V Figure l0 shows Va part oi a two-way amplifier as carried out in practice.
  • Figure l1 shows a network according to the invention.
  • Figures 12 to l5 show other embodiments of the network and
  • Figure 16 is a circuit diagram of a sending and receiving setv for highfrequency and ⁇ lowifrequericy signals.
  • FIG. l7 shows anenibodiment oi a connection between a two-wire line and a loaded or .pupinized quad wire connection, the two4 talking paths in thefquadv wire connection vbeing used for mutually opposite talking di- 1 60 independently of the number of part networks coiinected in cascade, beadjusted toV ment of such a connection the two'lines in the quad wire connection being parallel connected and forming together a single talking path.
  • tion comprises the shunt inductance 17, the
  • the filter chain 7 e l s a n a A comprises, inV addition yto said series impedances, the shunt impedancev lrlandv the filter chain B comprises, besides the series impedances 11, 12, thebridge impedance 18 connected in shunt thereto.
  • the network is provided with input and output terminals l, 2 and 3, 4 andthe connections between said two'terminal couples may be considered as forming two through-going lines @,b.
  • the terminals 7, 8 oi' the filter ⁇ chainfA are 'disposed onfthe 'shunt impedance 17, and the terminals 5, Gofi the filter chain B are disposed on the bridge impedance 18.
  • the two 35: terininal'couples o, Zand e, fof the two/filter chains maybe considered as junction points.
  • Theoiie 0 of the internal terminals of the filter chain Ag is an imaginary Junction point necting together the external ends of the parallel connected Seriesimpedances 11,l 12.
  • the other Z of the internal terminals ofthe filter chain A is formed by the middle point of the'line Z).-
  • the internal terminals of the filter chain-B may be considered as coincidj ing with th-e terminals 1, 3 of the network.
  • the input impedance between the terminals 3and4 may beexpressed as follows:
  • the input inn pedance of the network is independent of the frequency also in the neighborhood of the limiting frequency of the two filter chains.
  • FIG. 5 shows an embodiment of the filter chains of the network.
  • the filter chain B is provided on its output side with a terminal impedance R2 vand includes a series impedance y1 connected thereto whereupon, counted in the direction towards the input side, shunt impedances y2, y., alternate with series impedances g/3 rlie input terminals of the filter chain B are designated e, f.
  • the lilterchain A is terminated in similar manner with an impedance B1 and comprises, counted in the direction towards thek terminals c, d, Vshunt impedances mi, m3 alternating with series impedances 031 a,
  • rlh'e terminal impedances R1, R2 are so dimensioned that 'VRVR2ZC n where 7c designates a constant.
  • the impedances acl, x2 and y1, y2 respectively included in the twofilter chains are Y so selected that the geometrical mean value If one imagines the building upof the two networks by gradually adding the different impedances a?, y to the terminal impedances R1, R2, the mutually corresponding impedances being then each time added to both lilter chains, we rind that the geometrical mean value of the input impedances in the two gradually growing filter chains will all the time maintain the value la. If one thus first adds the series impedance :r1 to Rl and the shunt impedance to y1 to R2 the geometrical'mean Value of the two impedances thus formed isequal to comply with the abovementioned condition.
  • Fieure G shows diafrrarnmaticall how the impedances m and g/ may be composed -in ⁇ order to comply dition, ⁇
  • Each shunt connectien of two impedances in vway of example@l and a2 corresponds to a series connection of two Correspendinginipedances 1 and b2 in g/ and vice versa.
  • lf now the part impedances @il a2, a3, etc.
  • the error caused by the loss resistance may, however,
  • tie assumption is made that theinput impedances X2 between the terminals c, Z and e, ,t respectively in the filter chains in Figure 5 coincide with the characteristics Z1, Z2 between the same terminals, i.e. that the filter fchains terminate relectionless in terminal impedances dimensioned inV corresponding manner.
  • the input characteristic of the two filter chains A, B in Figure 5 may', accordingto the Equation 3', A', be expressed in the following manner:
  • g2 the reflection lineiangle kofthe lter chain B. Y itl-fthe number of filter sections of the filter chain A.
  • n is an even or an oddnumber
  • the quantity Z acts thus, as in the previous Case, as an ohmic resistance.
  • the re- -sult involves that the refiectionswhich are representedby p1, and gl, g2 compensate eachother 1n the geometrical mean..
  • the filter chain I comprises both Winding L5 in the differential transformer and also the ⁇ bridge impedance f8 connected to the lterminals of the secondary windings.
  • the filter chain I is connected over the differential transformer in the same manner to the two lines a, of the network whereby the symmetry of the connection is obtained.
  • Said network may be advantageouslyv used in two-way amplifiers or the like, a line or a line section being connected tov the fter minals 4 and a nco'rrespending line bal ance to the terminals l, 2.
  • To the external terminal couples 5,. 6 and 7, 8 of the two filter chains I, H may, if desired, 'onesende ing circuit and one receiving circuit, or the amplifier circuits each corresponding-to yone talkingdirection of a repeater, be connected.
  • FIG. 9 shows diagrammatically an embodiment of a two way amplifier according to the invention.
  • the lines or line sections may l be connected.
  • the filter chains K1, I Y i n c i n c K2 on the:. sides facing the ⁇ differential transformer T1 have" T-characteristic and vr-characteristic respectively and, on the opposit'ev sides. ⁇ also 'VT-,characteristic and 1r- ⁇ for one talking direction ⁇ yare connected over dnferential.transformers characteristic respectively.
  • the two filter chains have also the samenumber of half filter se"- tions which number may be even as well as odd. c
  • Figure l() shows a practical embodiment for the applicationof the invention in a twoeway amplifier. Inthe figure only such parts are shown which are necessary for the understanding of the circuit arrangement.
  • rlhe'arrangement comprises two amplifier valves V1, V2, one for each talking direction. .The talking directions are indicated by arrows.
  • the anode side of the valve V1 and the grid side of the valve V2 are connected over corresponding filter chains to the differential transformer T.
  • rlhe filter chain connected to the valve V1 comprises, besides Vthe differential transformer, on the one .hand a coil L.. connected in series with the secondary winding of the differential transformer and, on the other, a condenser Ca bridging the primary winding of the transformer.
  • the condition (6) mayl in this case be expressed as follows
  • the impedance of the line balance N must f obtain the following value in order to suit the line, of which the characteristic is related to Ra, Rp as indicated in Equation (8)
  • the three first conditions may immediately he complied with.
  • the fourth condition may immediately be complied with for free overhead lines and weekly loaded cable lines and may in other cases be met by a suitable line extension.
  • Figure l1 shows an embodiment of .the network according to Figure l.
  • rlhe filter chain B includes, counted from the enter? nal terminals 5, 6, a series capacity composed of two series connected capacities CB1 the secondary windingv LB of a transier T, of which the primary winding Lm ded into two equalparts forms the common part of both filter chains, and finally a capacity'sliunted to the primary winding ylim and consisting ,of two series connected condensers- (lf2.
  • the filter cha-in A includes, counted from the output terminals 7, 8, a shunt condenser ⁇ UA1 a transformer TA and a condenser CA2 connected in series with the primary winding of the transformer, and finally the two winding halves of the primary winding Lm of the transformer T in parallel connection.
  • the parallel connection of capacity and inductance in the one network corresponds to a series connection of inductance and capacity in the other network.
  • the network is so dimensioned that the impuef dance ofthe network at each one of the terminal couples l, 2 and 8, el is equal to lo, between tlie external terminals 5, 6 of the lter chain B equal to 27;, and between the external terminals 7, 8 of the filter chain A equal c to rlhe inipedances of the apparatus connectedoto the terminals 5, 6 and 7, S mustV also be equalto 21a andlC respectively.
  • oscillation energy having frequencies within the range of frequencies-of the filter chains and introducedat the input terminals l, 2 of the network, distributes itself according 'to lc the terminal iinpedances 2k 5 respectivel, 2 is V, the voltage between the terminals 5, 6 will be equal to V and between the terminals 7 8 equal to Strictly speaking this 110 is, however, correct only for the middle frequency of thefrequency range and at ratios of l l of the two transformers TA, T.
  • the impedance of the-network between the terminals 5, 6 is in this case
  • the impedance-,lc between the input terininals l, 2 of the vnetwork according to Figures 12, 13 is constant at all frequencies as in a network, by way of example according 'j to F igure 11, in which there is no joining of the external terminals ofV the twoV filter sliifted the conditions are reversed, i. e. the impedance between thel terminals 3,741 ⁇ will be constant at all frequencies whereas the impedance beweeii the terminals 1, 2 will be constant only at the frequencies outside the range of .frequencies of the filter chains.
  • the oscillation energy is supplied to the input terminals '1,2 of the network l, it will be transferred under equal distribution to the two terminal couples 5, G and 7, 8 to the other filter chain whereas, on the other hand, the voltage between the output terminals 3,
  • the windingr directions in the transformers TA and T are assumed to be so selected that the oscillations incoming, ⁇ to the filter chain Il from two sides and having mutually equal energ (ompensate the mutual effects in relation to the input terminals 1, 2 of the network ll whereby the voltage between the latter will be Zero whereas the oscillation amplitudes areadded as regards the output terminals 3', 4C', of the filter chain H.
  • the impedance between Vthe terminals of said two terminal couples will be constant at all frequencies.
  • a connecting ⁇ together of the different filter chains without energy losses tlieratio of the transformer TA, .l, TA, T, counted in the direction towards the external terminals of the filter chains must be so selected that eigen #A MB where MA, ,aA and im, an designate the ratios of the filter chains A, A', B, B respectively.
  • ZA, A ZB, ZB' denote the impedances at the internal terminals of the filter chaii'is A, A', B, B at
  • the network acts 'as a ⁇ band suppression filter' forsaid range of frequenciesof the 'lter chains.
  • the network' impedance both between the terminals 1, 2 and between the terminals 3, 4 is independent of the frequencies, several similar network'compositions may be seriesl connected without having any mutual disturbing influence.
  • FIG 15 there is'shown' another em- ⁇ bodiment and combination offt-he arrangements described with reference to Figures 12 and 14.
  • the two filter chains A and B are substantially built in a mannersimilar to that Vdescribed in conjunction with ythe above networks. By ytaking certain measures it is attained with only one'network is required to attain the sameresult as in the arrangements according to Figure 14.
  • the secondary ⁇ winding of the transformer T1 is divided. into equal parts and the middle point a 'is connectedto the terminals 6 of the ,filter chainy BjfSaid compensating arrangement may also be.
  • the condenser C5 is divided intotwo equal series connected condensers the middlel point a being branched off' betweeny 'the two condensers.
  • the network is further provided with two terminal couples 1', 2'and 3", 4', of which 1' is connected to the terminals 7, 2' and 4 to the terminal 5, and 3' .tothe lterminal 8. d If and the volt-age between'the terminals 3', 4" ⁇
  • a lowfrequeney line LF is 'connected@V 'l
  • the terminals 3H",s4i1v", andw', 41V' 'of the networksvII' and'IV are each connected to a sender SH and Swrespectively for high frequent signals and the terminals 3m', 4m' and 3V', 4v' of the networks III and V are' each connected to one receiver MmL and y Mv for'high frequencysignals.
  • V network V, IV, III, II are rec'eivedjby the network I, from the'terminals y 31', '4f' ofA which they are forwarded to the line
  • High frequent signals vwithin drf- Y ferent frequencyqranges are lreceived by the Y networks V, IIIVthe Signals designatedkfol the, lat'ter ,networkA passing throughV and IV with only a negligible attenuation and vwithout disturbing thereceiver Mv;
  • Signals from ⁇ the line LFto thenetwork I are so directed thereby that they pass only to the right Vthrough the remaining networks II,
  • the impedance network is preferably formed ,inv conjunc- ⁇ tion with av differential transformer, fof
  • connection One embodiment of such a connection is shown in Figure 17,'the two talking paths in the quad wire connection being used for mutually opposite talking directions, whereas in the connection shown in Figure 1S the two lines in the two-wire connection are parallel connected ⁇ and vform together a single talking path.
  • the differential transformer connecting element between the lines is connected by Aits mutually symmetrical terminal couples l, 2 and 8, 4f respectively'on the one side to the free overhead line .L and on theother side, to la line balancefB having thev same impedance as the overhead line L.
  • the one loaded line L1 is connected whereas theother'loaded line L2 is connected to the undivided winding lof the differential transformer.
  • the one loaded line Ll is, ladjacent to the differential transformer, terminated by an undivided line section,'i. ⁇ e.
  • line portion having a length .equal to'an entire coil distance s, and a load coil ⁇ p connected thereto, the inductance of which is half as jhigh as the inductance of the ⁇ load coils P out on the line.
  • line represents thus a T-filter i. e. a iilter having a falling characteristic.
  • ⁇ V The other loaded line L2 is adjacent to the differential transformer ⁇ terminated by aY half loaded wir@ and represents a i-ltei, i. e. a filter having rising characteristics. Ifthe two lines other- 1 wiseA are similar and loaded with equal load coilsfP and geometrical means oftheir characteristics, counted from the differential transformer, will be constant.
  • Said geometi'ical means should, according to the invention, be or, by suitably disposed line eXtensions, he made equal to the impedance of the line balanceI
  • The, input characteristic of the f network consisting of the differential 'I serving as Said loaded i' transformer together with the loaded line L1 and L2V between the terminals l, 2 is under i said condition constant and equal to the characteristic of the line balance.
  • the line ⁇ L2 is connected to the differential transformer T in the samemanueras in Fig ure 17, i. e. it is terminated adjacent 'to the differential transformer by ahalf line section
  • the v'line L1 is also terminatediwith half a line section which, however, is provided with a line extension" F.
  • Said line extension consists of a shunt condenser C', connected into circuit next to the line and havinga capacity corresponding to the line capacity of half a line section, and a series inductance 2J the size of which is equal to half .the inductance of the load coils P on the line.
  • the line extension may also enclose series resistances R, corresponding together to half the ohmic resistance pro line'section. Bvtheaddition of the line extension 'F the line L1 functions, counted form the differential transformer, inexactly the same manner as ythecorresponding line in Figure 1.7, i. e. asa .T-filter.
  • the quad wire connection is by itsop-vl posite 4end connected in similar lmanner. to-
  • Theslsecond term ⁇ on the right hand side in the ⁇ formula may be neglected because G is very small, only about 106, and the term in question may, evenfin the worst case, ⁇ Y
  • a line made according to V Figure 18 is .particularly suitable to beused in long distance telephonyV or for the transmission'of music.
  • one*,outputlterininal of the network and including an impedance l1, 12 shunted between said terminals, aquadripole 17 having one of the terminals on the one-sidel connected to a middle-tapping on said impedance and the-other terminal of combination a filter including an impedance shunted between its terminals on one side, said impedance being provided with a middle tapping' and forming auseries impedanceY ofthe ,network, an artificial line connected between the symmetry points of,.:the Atwo branches of the network, said impedance of the said filter, forming two y branches of a Y characteristics ofy said two filters on the sides at which they lare associated with one another being independent ⁇ of the' frequency.
  • An electrical network comprising vin combination an-iinpedance having a middle tapping andforming a; series impedance of the network, a first artificial line connected with one pair ofv terminals tothe4 ends of said impedance, a-sec'ond artificialfline connected with one terinfinalto the iiiiddle tapping of'said impedance and with theother terminalV of the saineside to one input ter-f minal and one output terminal of the network, saidlimpedance forming together with thefirst artificial line a first ⁇ filter while the l two halves of said impedance-form paralistic and ⁇ T-characteristic respectively, on,
  • said filters accordingly havingv Tr-characten the sides atwhich they are associated with one another, the mean squares of said chai-1 acteristics being independent oftheV ⁇ frenected betweenone input terminal and one output terminal of the network, airst filter connected to the one side of said differential transformer, a second filter connected with one terminal to the middle point of the transformer and with the other-"terminal of l tl'i'esame side to one input terminal and one output terminal of the network, the mean square values of the characteristics of said filters on the sides associated together being substantially independent of thefrequency.
  • An electrical network comprising in combination a filter having its terminals of the onefside connected Awith one input terminaland one output terminal ofthe network and including an impedance shunted between said terminals, a quadripole having oneof the terminals on the one side connectedvto a middle tapping on said impedance and the othei ⁇ terminal of the saine side halves of thesaid impedance forming two parallel branches of a series impedance of line is connected to the network on the one vside and a corresponding line balance is conconnected withone inputterminal and one ⁇ output terminal Y ofthe network,;the two Y lle a second filter including the said quadripole, the mean squares of the characteristics of lsaid two filters on the sides at which they are associated with one another being independent of the frequency, and transformers being included in the lters, said transformers having their ratio of transformation so chosen as to transmit an incoming ⁇ oscillation with equal voltages to the end impedances of the filters.
  • a circuit arrangement composed of two networks, as claimed in claim 11, said networks being connected in such a manner that the external terminals of mutually corresponding ilter chains are connected to each other.
  • An electrical network as claimed in claim l characterized in that the two ilters associated therein are composed of equal numbers of impedances, each shunt impedance in the one filter corresponding to a series impedance in the other lter in such a manner that the mean square of two corresponding impedances is equal for all pairs of corresponding impedances.
  • a circuit arrangement composed of a number of cascade coupled networks according to claim 1, said networks being dimensioned for different frequency ranges.
  • a circuit arrangement composed of a number of cascade coupled networks according to claim 1, said networks being connected at one end to a transmission line and at the other end to a corresponding line balance, and sending and receiving apparatuses being connected to the two filters associated in each of the networks.
  • An electrical network comprising in combination a filter having its terminals of the one side Connected with one input terminal and one output terminal of the network, a quadripole having one of the terminals on the one side connected to a symmetry point of said ilter and the other terminal of the same side connected with one input terminal and one output terminal of the network, the mean square of the impedance between said terminals of the filter on the one hand and on the other hand the impedance between said terminals in parallel connection and the opposite terminal of the quadripole on the side associated with the filter is independent of the frequency.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Filters And Equalizers (AREA)
  • Details Of Connecting Devices For Male And Female Coupling (AREA)
US495746A 1929-11-18 1930-11-14 Electrical network Expired - Lifetime US1920041A (en)

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US (1) US1920041A (enrdf_load_stackoverflow)
DE (1) DE636091C (enrdf_load_stackoverflow)
NL (1) NL36261C (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2886654A (en) * 1955-12-15 1959-05-12 Bell Telephone Labor Inc Equivalent four-wire repeaters
US3117185A (en) * 1956-12-13 1964-01-07 Int Standard Electric Corp Transient repeater
US3621480A (en) * 1969-02-14 1971-11-16 Post Office Electrical networks

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1116277A (fr) * 1956-01-06 1956-05-07 Cie Ind Des Telephones Perfectionnements aux correcteurs réglables

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2886654A (en) * 1955-12-15 1959-05-12 Bell Telephone Labor Inc Equivalent four-wire repeaters
US3117185A (en) * 1956-12-13 1964-01-07 Int Standard Electric Corp Transient repeater
US3621480A (en) * 1969-02-14 1971-11-16 Post Office Electrical networks

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Publication number Publication date
DE636091C (de) 1936-10-14
NL36261C (enrdf_load_stackoverflow)

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