DK162673B

DK162673B - FILTER CLUTCH WITH MULTIPLE RESONANCE CIRCUIT

Info

Publication number: DK162673B
Application number: DK349283A
Authority: DK
Inventors: Wolfgang Wendel
Original assignee: Hirschmann Richard Gmbh Co
Priority date: 1982-07-30
Filing date: 1983-07-29
Publication date: 1991-11-25
Also published as: FI79767B; DK349283D0; FI832528L; DK162673C; ATE38749T1; ES8402481A1; DE3378511D1; DK349283A; ES522248A0; FI79767C; NO831888L; FI832528A0; EP0101789B1; EP0101789A3; EP0101789A2; DE3228449A1

Abstract

1. Filter circuit for blocking partial frequency ranges or allowing partial frequency ranges to pass, with at least two resonant circuit for each partial frequency range, characterized in that the resonant circuits are constructed and dimensioned in such a way that each component of each resonnant circuit at the same part of at least one further resonant circuit for another partial frequency range.

Description

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Den foreliggende opfindelse angår en filterkobling med flere resonanskredse og af den i krav l's indledning angivne art.The present invention relates to a filter coupling having multiple resonant circuits and of the kind specified in the preamble of claim 1.

Ved sådanne filtre er der i praksis ofte behov for en 5 stor spærredæmpning med så stejle filterflanker som muligt, ringe gennemgangsdæmpning og stor returdæmpning. Dette er eksempelvis tilfældet når signalniveauet et sted i et fællesantenneanlæg er så lavt, at en tilfredsstillende signalforsyning til den pågældende abonnent kun kan opnås ved hjælp af en for-10 stærker eller en antennestikdåse med lav tilslutningsdæmning, eksempelvis 5 dB.In practice, such filters often require a large barrier attenuation with as steep filter flanks as possible, low throughput attenuation and high return attenuation. This is the case, for example, when the signal level somewhere in a common antenna system is so low that a satisfactory signal supply to the subscriber concerned can only be obtained by means of an amplifier or an antenna socket with low connection attenuation, for example 5 dB.

Ved sådanne antennestikdåser, som opdeler HF-energien, eksempelvis via en tilpasnings- og en differentialtransformer mellem stamledningsudgang og filterindgang, er det mellem disse 15 tilslutninger kun muligt at opnå en koblingsdæmpning på omkring 2o dB. På den anden side stiller tyske myndigheder krav om en afkobling mellem radio- og TV-tilslutningerne i antennestikdåser på mindst 5o dB for at sikre abonnenterne en støjfri modtagelse. Filterets herfor nødvendige spærredæmpning er således, eksempel-20 vis ved en tilslutningsdæmpning på 5 dB, mindst 25 dB, hvilket kun er opnåeligt ved filterkoblinger med mindst to indbyrdes uafhængige resonanskredse for hvert delfrekvensområde, hvilke filterkoblingers elektriske egenskaber derved opfylder de anførte betingelser. Sådanne filtre kræver imidlertid et stort 25 antal komponenter og kommer derfor ikke i betragtning, når der er tale om de fleste praktiske anvendelser, eksempelvis i antennestikdåser, såvel på grund af fremstillingsprisen soin også på grund af de store pladskrav.In such antenna sockets which divide the HF energy, for example via an adaptation and a differential transformer between mains output and filter input, between these 15 connections it is only possible to achieve a coupling attenuation of about 2o dB. On the other hand, German authorities require a disconnect between the radio and TV connections in antenna sockets of at least 5o dB to ensure subscribers a noise-free reception. Thus, for example, at the filter attenuation of 5 dB, the required blocking attenuation of the filter is at least 25 dB, which is only attainable by filter couplings with at least two mutually independent resonant circuits for each sub-frequency range, the electrical properties of the filter couplings thereby meeting the conditions stated. However, such filters require a large number of components and are therefore not considered in the case of most practical applications, for example in antenna sockets, because of the manufacturing cost, also because of the large space requirements.

Formålet med opfindelsen er at anvise en filterkobling af 30 den indledningsvis nævnte art, som omfatter færrest muligt antal komponenter og har bedst mulige dæmpningsværdier, især en høj spærredæmpning.The object of the invention is to provide a filter coupling of the type mentioned initially, which comprises the fewest possible number of components and has the best possible damping values, in particular a high barrier damping.

Dette opnås ifølge opfindelsen ved den i krav 1 anviste udformning.This is achieved according to the invention in the embodiment of claim 1.

35 Det er ganske vist ved af enkeltkredse opbyggede filterkob linger kendt (se eksempelvis Meinke/Gundlack,Taschenbuch der Hochfrequenztechnik, Springer-Verlag, 1962, side 188-189) at - 2 -35 It is admittedly known by filter circuits constructed by single circuits (see, for example, Meinke / Gundlack, Taschenbuch der Hochfrequenztechnik, Springer-Verlag, 1962, pages 188-189) that - 2 -

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udnytte enkelte blindmodstande som delreaktanser i to enkeltresonanskredse for hver sit delfrekvensområde. En konsekvent anvendelse af dette princip i filtre med flere kredse for hvert delfrekvensområde synes imidlertid ikke at være nærliggende for fag-5 manden i flere årtier, selv om princippet er særdeles virkningsfuldt i forbindelse med eksempelvis antennestikdåser, hvor det for konstruktøren er en basal opgave at spare komponenter.Ved denne dobbelte udnyttelse af alle komponenter opnås med færrest tænkelige komponenter, svarende omtrent til det, der anvendes i de XO kendte enkeltkredsfiltre, en filterkobling, hvor der for hvert delfrekvensområde findes et særligt tokredsfilter. Spærredæmpningen i denne filterkobling er så stor, at eksempelvis den forlangte afkobling på mindst 5o dB mellem radio- og TV-tilslutningerne i to naboantennestikdåser sikres i alle nyttefrekvensområder selv X5 i ekstreme tilfælde, hvor den ene stikdåse (gennemgangsdåse) har en tilslutningsdæmpning på 3 dB og den anden (endedåse uden fordeler) en tilslutningsdæmpning på 1 dB. Desuden er ved den an-. viste filterkobling opnået en gennemgangsdæmpning på højst 1 dB, en høj returdæmpning, samt en meget regelmæssig frekvensgang for 20 overføringsfunktionen i alle delfrekvensområder. Filterkoblingen er således velegnet til brug i eksempelvis efter hinanden koblede antennestikdåser med ringe tilslutningsdæmpning.utilize single blind resistors as sub-reactances in two single resonant circuits for each part frequency range. However, consistent application of this principle in multi-circuit filters for each sub-frequency range does not appear to be obvious to those skilled in the art for several decades, although the principle is particularly effective in, for example, antenna sockets, where it is a basic task for the designer to saving components.This dual utilization of all components is achieved with the fewest conceivable components, similar to what is used in the XO known single-circuit filters, a filter coupling, where for each sub-frequency range there is a special two-circuit filter. The barrier attenuation in this filter coupling is so great that, for example, the required disconnection of at least 5o dB between the radio and TV connections in two neighboring antenna sockets is ensured in all utility frequency ranges even X5 in extreme cases, where one socket (throughput socket) has a connection attenuation of 3 dB. and the other (terminal box without distributor) a connection attenuation of 1 dB. In addition, by the other. The filter coupling shown achieved a throughput attenuation of not more than 1 dB, a high return attenuation, and a very regular frequency response for the transmission function in all sub-frequency ranges. The filter coupling is thus suitable for use in, for example, interconnected antenna sockets with low connection attenuation.

Ved den anviste filterkobling er endvidere de anvendte spolers induktans af en sådan størrelse, at spolerne kan udlægges som 25 trykte kredsløb selv på en så lille kredsløbsplade, at denne kan placeres i en sædvanlig 55 mm vægdåse.Furthermore, at the filter connection shown, the inductance of the coils used is such that the coils can be laid out as 25 printed circuits even on such a small circuit board that it can be placed in a conventional 55 mm wall box.

På denne måde er muliggjort en meget simpel, billig og nøjagtig opbygning af filterkoblingen med ringe pladskrav. Koblingen er således særdeles egnet for seriefabrikation.In this way, a very simple, inexpensive and accurate construction of the filter coupling with low space requirements is made possible. Thus, the coupling is very suitable for series production.

20 Denne fordel forstærkes yderligere ved den i krav 2 anviste udformning, som uden meromkostninger giver en yderligere nedsættelse af pladskravet.This advantage is further enhanced by the design according to claim 2 which, without additional costs, gives a further reduction of the space requirement.

Ved at udlægge flere spoler som en sammenhængende spole, kan den herved forøgede induktans og den trange plads medføre, at 22 spolens egenresonans falder i et nyttefrekvensområde. Dette kan ifølge opfindelsen imødegås på enkel måde ved den i krav 3 anviste udformning.By laying out multiple coils as a continuous coil, the increased inductance and the narrow space can thereby cause the 22 coil's own resonance to fall in a utility frequency range. This according to the invention can be countered in a simple manner by the design according to claim 3.

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Krav 4 anviser en særlig hensigtsmæssig konfiguration af filterkoblingen til adskilt udkobling af radio- og fjernsynsområder.Claim 4 discloses a particularly convenient configuration of the filter coupling for separate switching off of radio and television areas.

Opfindelsen skal i det følgende forklares nærmere i forbindelse med tegningen, hvor 5 fig.l viser en kendt filterkobling, fig.2 en filterkobling ifølge opfindelsen, fig.3 en trykt kredsløbsplade for det i fig.2 viste filter set fra den ene side, og fig.4 de på kredsløbspladens anden side monterede diskrete komponenter.The invention will be explained in greater detail in the following with reference to the drawing, in which: FIG. 1 shows a known filter coupling; FIG. 2 is a filter coupling according to the invention; FIG. 3 is a printed circuit board for the filter shown in FIG. and Fig. 4 the discrete components mounted on the other side of the circuit board.

HF-energi fra en indgangstilslutning E opdeles i fig.2 mellem en stamledningsudgang A og indgangen III til en filterkobling F ved hjælp af en i princippet, eksempelvis fra DE-B 28 o7 327, kendt fordeler, som af hensyn til den bedre mulighed 15 for kaskadekobling af antennestikdåser er asymmetriske. Fordeleren består af en tilpasningstransformer U^, en differentialtrans-former t^, en afkoblingsmodstand , en forbindelse AL i form af en udligningsledning til tvangsmæssig ligelig opdeling af energien, en kondensator C^, til forbedring af tilpasningsværdien ved 20 lave frekvenser, og en kondensator C^, anbragt mellem udligningsledningen AL og stel til forøgelse af den øvre grænsefrekvens og i form af kamlignende ind i hinanden gribende lederplader(fig.3) på den trykte kredsløbsplade, som bærer fordeler og filterkobling. Den asymmetriske udformning af differentialtransformeren er 25 således valgt, at fordelerens gennemgangsdæmpning i hele frekvensområdet udgør omkring 2 dB, medens tilslutningsdæmpningen mellem antennestikdåsens indgang E og filterkoblingens F indgang III udgør ca.5 dB. Under hensyntagen til eksempelvis af skrueklemmer ved tilslutningerne frembragte støjkapaciteter udgør den opnåede 30 koblingsdæmpning mellem udgangen A og filterkoblingens indgang III herved omkring 2o dB i UHF-området. I LM-området fremtræder fordeleren derimod som en 3 dB-fordeler uden afkobling.HF energy from an input terminal E is divided in FIG. 2 between a mains output A and the input III of a filter coupling F by means of a principle known in principle, for example from DE-B 28 o7 327, which for the better option 15 for cascade coupling of antenna sockets are asymmetric. The distributor consists of an adaptation transformer U ^, a differential transformer t ^, a decoupling resistor, a connection AL in the form of an equalizing conduit for compulsory equal distribution of the energy, a capacitor C ^, to improve the adaptation value at 20 low frequencies, and a capacitor C1, located between the equalization line AL and frame for increasing the upper limit frequency and in the form of cam-like interlocking conductor plates (Fig. 3) on the printed circuit board carrying distributors and filter coupling. The asymmetric design of the differential transformer is selected so that the distributor throughput attenuates throughout the frequency range is about 2 dB, while the connection attenuation between the input E of the antenna socket and the input of the filter coupling F is about 5 dB. Taking into account, for example, the noise capacities produced at the connections, the obtained coupling attenuation between the output A and the input coupling III of the filter coupling hereby amounts to about 20 dB in the UHF region. In the LM range, on the other hand, the distributor appears as a 3 dB distributor without decoupling.

Filterkoblingen F består af to grene for henholdsvis radio og fjernsyn med-tilhørende tilslutninger RF og TV. I fjernsyns-35 grenen udgør spoler Lg og en spærring (i praksis kortslutning) for LMK-området, to LC-kredse L^, Cg og Lg, C^q en båndspærre for FM-området, to LC-kredse L,., Cg og L^, et båndfilter for TV- - 4 -The filter coupling F consists of two branches for radio and television respectively with associated RF and TV connections. In the television branch branch, coils Lg and a barrier (in practice short-circuiting) for the LMK region, two LC circuits L ^, Cg and Lg, C ^ q constitute a band barrier for the FM region, two LC circuits L,. Cg and L ^, a band filter for TV - 4 -

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bånd I, medens kondensatorerne C„ og CQ sammen med spolerne L, O 7 0 og udgør et højpasfilter for TV-bånd I.band I, while capacitors C "and CQ together with coils L, O 7 0 and constitute a high pass filter for TV band I.

I radiogrenen udgør spoler Lg, Lg og kondensatorer C12, et lavpasfilter for LMK-området, LC-kredse LQ, C.. og L.n/ C,0 y li iu 12 5 en båndspærre for TV-bånd I, og LC-kredse Lg, og L^Q, C^g et båndfilter for FM-området.In the radio branch, coils Lg, Lg and capacitors C12, a low-pass filter for the LMK region, LC circuits LQ, C .. and Ln / C, 0 y li iu 12 5 constitute a band block for TV band I, and LC circuits Lg , and L ^ Q, C ^ g a band filter for the FM range.

Ved denne eksempelvise udførelsesform for en filterkobling ifølge opfindelsen tjener således alle komponenter i enhver for et delfrekvensområde dimensioneret resonanskreds også som kompo-10 nent i en anden resonanskreds for et andet delfrekvensområde. Spolerne Lg og Ly indgår endda i tre resonanskredse for tre delfrekvensområder .Thus, in this exemplary embodiment of a filter coupling according to the invention, all components in any part frequency range dimensioned resonant circuit also serve as component of another resonant circuit for another sub frequency range. The coils Lg and Ly are even included in three resonant circuits for three sub-frequency ranges.

Ved denne flerfoldige anvendelse af komponenter er, ved en ringe gennemgangsdæmpning på højst 1 dB og en tilsvarende høj 15 returdæmpning, opnået en spærredæmpning på mindst 29 dB i alle delfrekvensområder, der skal spærres, under anvendelse af få komponenter, hvormed de tidligere nævnte tyske myndighedskrav tilfredsstilles også ved de højeste driftsfrekvenser og ved den ringe tilslutningsdæmpning på her 5 dB. Ved lavere frekvenser 20 mere end tilfredsstilles disse krav (eksempelvis3 70 dB i LM-området).With this multiple use of components, with a low throughput attenuation of not more than 1 dB and a correspondingly high return attenuation, a barrier attenuation of at least 29 dB has been achieved in all sub-frequency ranges to be blocked, using a few components with which the aforementioned German regulatory requirements is also satisfied at the highest operating frequencies and at the low connection attenuation of here 5 dB. At lower frequencies 20 more than these requirements are satisfied (for example, 3 70 dB in the LM range).

De i filterkoblinhgen ifølge opfindelsen indgående spoler har alle induktanser, som er mindre end o,25i|H og kan derfor fremstilles som trykte kredse på selv en forholdsvis lille kreds-25 løbsplade (fig. 3), der kan indbygges i en sædvanlig 55 mm vægdåse for en antennestikdåse. Herved er de tre spoler L^, Lg og Ly udlagt som en enkelt spole med to udtag V og VI og udgør derved en rumligt meget lille enhed. Spolerne Lg og Lg er derimod ved den viste udførelsesform adskilt. Herved opnås, at den trykte 30 kredsløbsplade også kan anvendes til antennestikdåser med høj tilslutningsdæmpning, hvor de to spoler ikke er forbundne direkte galvanisk, men via en RC-kreds til forøgelse af tilslutningsdæmpningen i LMK-området. Desuden opnås, ved at spolerne Lg og Lg er adskilt, muligheden for på fordelagtig måde af indføje en på 35 pladen trykt spole L^ til forbedring af afkoblingen ved høje frekvenser mellem de på hver side af kredsløbspladens symmetri- « - 5 -The coils included in the filter coupling according to the invention have all inductances less than 0, 25i | H and can therefore be manufactured as printed circuits on even a relatively small circuit board (Fig. 3) which can be built into a conventional 55 mm wall socket for an antenna socket. Hereby the three coils L1, Lg and Ly are interpreted as a single coil with two outlets V and VI, thus forming a spatially very small unit. In contrast, the coils Lg and Lg are separated in the illustrated embodiment. This provides that the printed circuit board can also be used for antenna sockets with high connection attenuation, where the two coils are not directly connected galvanically, but via an RC circuit to increase the connection attenuation in the LMK region. Furthermore, by separating coils Lg and Lg, the possibility of inserting a coil L L printed on the plate plate to advantageously improve the decoupling at high frequencies between the symmetry of the circuit board on each side is obtained.

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plan liggende stelflader. Naturligvis kan spolerne Lg, L^, og L^q også udlægges som en sammenhængende spole, hvorved en symmetrisk opbygning af hele koblingen opnås. Filterkoblingens antal af blindmodstande er da endog mindre end i den i fig.l viste kendte 5 kobling.plan lying ground surfaces. Of course, the coils Lg, L ^, and L ^ q can also be construed as a continuous coil, whereby a symmetrical structure of the entire coupling is obtained. The number of blind resistances of the filter coupling is then even smaller than in the known coupling shown in Fig. 1.

Ved den beskrevne antennestikdåse er således anvist en filterkobling, som med et minimum af elektriske komponenter har optimale højfrekvensegenskaber, som er egnet for kaskadekobling, som også ved lille tilslutningsdæmpning har høj spærredæmpning, 10 og som har en simpel, for seriefremstilling ved trykt kredsløbsteknik særdeles egnet konstruktion, der ydermere kræver meget lille plads og er billig.Thus, in the described antenna socket, there is disclosed a filter coupling which, with a minimum of electrical components, has optimum high frequency properties suitable for cascade coupling, which also with low connection attenuation has high barrier attenuation, 10 and which has a simple, for series production by printed circuit technology construction that also requires very little space and is cheap.

15 20 25 30 115 20 25 30 1

Claims

1. Filter coupling for blocking and review of sub-frequency ranges and with at least two resonant circuits for each sub-frequency range, characterized in that the resonant circuits are designed and dimensioned so that all components of each 5 resonant circuit are simultaneously included as a component of at least one other resonant circuit for another sub-frequency range.

Filter coupling according to claim 1, characterized in that all coils (1, Lg, L 1) in at least one transmission area (radio and / or TV) are designed as a continuous coil with corresponding outputs (V, VI).

Filter coupling according to claim 2, characterized in that the outer winding (L ^) of the continuous coil (L ^, Lg), at a distance corresponding to the winding distance, is followed at least along part of its length by an adjustment surface whose ends are not .5 conductively connected to each other.

Filter coupling according to claims 1-3 with frequency dividers for separate connection of radio and TV areas, characterized in that the frequency divider for connection of TV areas has a longitudinal branch consisting of a capacitor Cg in series with a> 0 parallel resonant circuit L , -, Cg, the output of which is connected partly to the TV socket and partly to a transverse, grounded branch consisting of a coil Lg in series with a parallel resonant circuit L ^, C- ^ o wherein the coils Lg, L ^ form a barrier for LMK the region, L ^, Cg with Lg, C ^ o forms a band-stop filter for UHF, L ^, Cg, with L ^, C ^ Q forms a bandpass filter for TV area I, and Cg, Cg with Lg, L7 forms a high pass filter for TV area N / V, and 'in that the frequency divider for connecting the radio area has a longitudinal branch consisting of coil Lg in series with a parallel resonant circuit Lg, the output of which is connected partly to the radio socket and partly to 30 transverse, grounded branch consisting of a capacitor C ^ m with a series resonant circuit C ^ Q, C ^ / wherein the coils Lg, Lg with ^ 12 '^ 13 ^ form a low pass filter for the CMK area, Lg, C ^ with L ^ q, C ^ 2 form a band stop filter for TV area I , and Lg, C ^ with L ^ q, C ^ g form a bandpass filter for the VHF region. 35 '