DK146915B - SUBSCRIPTION TERMINAL FOR CABLES - Google Patents
SUBSCRIPTION TERMINAL FOR CABLES Download PDFInfo
- Publication number
- DK146915B DK146915B DK586075A DK586075A DK146915B DK 146915 B DK146915 B DK 146915B DK 586075 A DK586075 A DK 586075A DK 586075 A DK586075 A DK 586075A DK 146915 B DK146915 B DK 146915B
- Authority
- DK
- Denmark
- Prior art keywords
- subscriber
- high frequency
- subscriber line
- line
- switch
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
- H04K3/00—Jamming of communication; Counter-measures
- H04K3/80—Jamming or countermeasure characterized by its function
- H04K3/82—Jamming or countermeasure characterized by its function related to preventing surveillance, interception or detection
- H04K3/825—Jamming or countermeasure characterized by its function related to preventing surveillance, interception or detection by jamming
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
- H04K3/00—Jamming of communication; Counter-measures
- H04K3/40—Jamming having variable characteristics
- H04K3/42—Jamming having variable characteristics characterized by the control of the jamming frequency or wavelength
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/16—Analogue secrecy systems; Analogue subscription systems
- H04N7/166—Passage/non-passage of the television signal, e.g. jamming, band suppression
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
- H04K2203/00—Jamming of communication; Countermeasures
- H04K2203/10—Jamming or countermeasure used for a particular application
- H04K2203/14—Jamming or countermeasure used for a particular application for the transfer of light or images, e.g. for video-surveillance, for television or from a computer screen
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- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Multimedia (AREA)
- Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
- Details Of Television Systems (AREA)
Description
i 146915in 146915
Opfindelsen angår en abonnentterminal af den i krav l's indledning angivne art. En sådan kendes f.eks. fra beskrivelserne til DE-AS nr. 2 260 621 og nr. 2 324 816.The invention relates to a subscriber terminal of the kind specified in the preamble of claim 1. Such is known e.g. from the descriptions to DE-AS Nos. 2 260 621 and Nos 2 324 816
I de kendte kabelanlæg er abonnenterne sædvanligvis tilsluttet ved hjælp af abonnentterminaler til en forsyningseller ringledning, som i frekvens-multiplex fordeler et antal fjernsyns- og radioprogrammer til de pågældende abonnenter. Et vist antal abonnenter er i et sådant system forbundet til hver abonnentterminal.In the known cable systems, the subscribers are usually connected by means of subscriber terminals to a supply or ring line, which in frequency multiplex distributes a number of television and radio programs to the subscribers concerned. In such a system a certain number of subscribers is connected to each subscriber terminal.
Det er under installeringen af nævnte kabelfjernsynsanlæg en ulempe, at kun de abonnenter, som i forvejen har angivet, at de ønskede at tilsluttes systemet, kan forbindes til a-bonnentterminalen. Ved et senere abonnement skal en tekniker forbinde den pågældende abonnents bolig med en beslægtet abonnentterminal, hvilket er kostbart og tidsrøvende.During the installation of said cable television system, it is a disadvantage that only those subscribers who have already stated that they wanted to be connected to the system can be connected to the a-subscriber terminal. In the case of a subsequent subscription, a technician must connect the subscriber's residence to a related subscriber terminal, which is expensive and time-consuming.
Både ved et ophør og en manglende betaling skal en tekniker desuden afbryde abonnenten fra abonnentterminalen.In addition, both upon termination and non-payment, a technician must disconnect the subscriber from the subscriber terminal.
Med det indledningsvis angivne system er det ikke altid muligt at udelukke allerede tilsluttede abonnenter for modtagelsen af visse programmer.With the system initially stated, it is not always possible to exclude already subscribed subscribers for the reception of certain programs.
Det er formålet med opfindelsen at tillade iværksættelsen af fjernstyring med en egnet kode, således at visse programmer på visse abonnentledninger kan forstyrres således, at observation og aflytning af det pågældende program gøres umuligt.It is an object of the invention to allow the implementation of remote control with a suitable code so that certain programs on certain subscriber lines can be disturbed so that observation and interception of that program is rendered impossible.
Dette formål opnås ifølge opfindelsen ved det i krav l's kendetegnende del angivne.This object is achieved according to the invention by the characterizing part of claim 1.
2 1469152 146915
Den særlige fordel ved dette system er, at hver abonnent kan tillades eller nægtes modtagelsen af visse programmer uden forstyrrelse af de øvrige abonnenter.The particular advantage of this system is that each subscriber can be allowed or denied the reception of certain programs without disturbing the other subscribers.
Opfindelsen skal i det følgende nærmere beskrives med henvisning til tegningen, hvorpå: fig. 1 er et blokdiagram af en abonnentterminal, som indeholder fire abonnentledninger, hvor der i hver ledning er indsat en højfrekvensomskifter i serie, og hvor respektivt transmissionen og afbrydelsen af programmerne kan fjernomskiftes, fig. 2 er et blokdiagram af en abonnentterminal indeholdende en enkelt abonnentledning, som er forsynet med fire højfrekvensomskiftere, som samvirker i parallel med ledningen til efter ønske at forstyrre visse fjernsynsprogrammer og radioprogrammer, fig. 3a viser en udførelsesform for en højfrekvensomskifter af halvledertype, som benyttes i abonnentterminalen ifølge fig. 2 fig. 3b viser delen vedrørende højfrekvensbetjeningen af højfrekvensomskifteren ifølge fig. 3a, fig. 4 viser forsiden af et hus, hvori abonnentterminalen er anbragt, fig. 5 er et blokdiagram af abonnentterminalen indeholdende en enkelt abonnentledning, som er forsynet med fire højfrekvensomskiftere af en anden type, indsat i serie med ledningen til efter ønske at forstyrre visse fjernsynsprogrammer og radiopro- 3 146915 grammer, fig. 6 viser en udførelsesform for en højfrekvensomskifter af anden type, som benyttes i det i fig. 5 viste abonnentterminal, og fig. 7 viser en anden udførelsesform af højfrekvensomskifteren af nævnte anden type, som enkeltvis kan benyttes for et antal kanaler.The invention will now be described in more detail with reference to the drawing, in which: FIG. 1 is a block diagram of a subscriber terminal containing four subscriber wires, in which each high frequency switch is inserted in series and where respectively the transmission and interruption of the programs can be remotely switched; FIG. Figure 2 is a block diagram of a subscriber terminal containing a single subscriber line provided with four high frequency switches cooperating in parallel with the line to interrupt certain television programs and radio programs as desired; 3a shows an embodiment of a high frequency semiconductor type switch used in the subscriber terminal of FIG. 2 FIG. 3b shows the high frequency operation portion of the high frequency switch of FIG. 3a, fig. 4 shows the front of a housing in which the subscriber terminal is placed; FIG. Figure 5 is a block diagram of the subscriber terminal containing a single subscriber line provided with four high frequency switches of a different type inserted in series with the cord to interrupt certain television programs and radio programs as desired; 6 shows an embodiment of a second type high frequency switch used in the embodiment of FIG. 5, and FIG. 7 shows another embodiment of the high frequency switch of said second type, which can be used individually for a number of channels.
I fig. 1 er vist en forsynings- eller ringledning 1, et antal abonnentledninger 2, en datamodtager 3, en logisk styreenhed 4, højfrekvensomskiftere 5 og et afgreningse-lement 6. Datamodtageren 3 i abonnentterminalen er forbundet til afgrenings- eller koblingsfordelingspunktet. Til nævnte afgreningsfunktion kan man benytte en retningskobler eller en aftapning. Den logiske styreenhed 4, som følger efter datamodtageren 3, dekoder de passende koder, som indføres i højfrekvenssignalet. I afhængighed af informationen i nævnte koder vil styreenheden 4 skifte en eller flere højfrekvensomskiftere 5, således at højfrekvenssignalerne for de pågældende fjernsyns- og radioprogrammer overføres til abonnentledningerne 2 eller afspærres fra transmission.In FIG. 1, a supply or ring line 1, a plurality of subscriber lines 2, a data receiver 3, a logic controller 4, high frequency switches 5 and a branch element 6 are shown. The data receiver 3 in the subscriber terminal is connected to the branch or switching point. For said branching function, a directional coupler or a tapping can be used. The logic controller 4, which follows the data receiver 3, decodes the appropriate codes which are entered into the high frequency signal. Depending on the information in said codes, the controller 4 will switch one or more high frequency switches 5, so that the high frequency signals of the respective television and radio programs are transmitted to the subscriber lines 2 or blocked from transmission.
På fig. 2 er angivet et blokdiagram af abonnentterminalen, hvormed det er muligt at koble støjsignaler ind i abonnent-, ledningerne, hvorved de pågældende abonnenter kan nægtes modtagelsen af enkelte programmer. I fig. 2 er der også anført en forsyningsledning 1, en enkelt abonnentledning 2, en datamodtager 3, som er forbundet til afgreningsele-mentet 6, en logisk styreenhed 4, en enkelt højfrekvensomskifter 5, som er indsat i serie med abonnentledningen 2.In FIG. 2 is a block diagram of the subscriber terminal, whereby it is possible to connect noise signals into the subscriber wires, whereby the subscribers concerned can be denied the reception of individual programs. In FIG. 2, there is also provided a supply line 1, a single subscriber line 2, a data receiver 3 connected to the branch element 6, a logic control unit 4, a single high frequency switch 5 inserted in series with the subscriber line 2.
Der er også vist et antal højfrekvensomskiftere 14, som er anbragt i parallel med abonnentledningen 2, et antal i forvejen tilsluttede oscillatorer 9, og et antal atte-nuatorer eller dæmpningsled 7, som er forbundet derimellem.Also shown are a number of high frequency switches 14 arranged in parallel with the subscriber line 2, a number of pre-connected oscillators 9, and a number of attenuators or attenuating links 7 connected therebetween.
4 1469154 146915
Oscillatorerne 9 har i det væsentlige samme frekvens som de pågældende programmer, således at et stærkt interferenssignal ved en sluttet kontakt 14 indføres i abonnentledningen for derved at forbyde observation og aflytning af programmet. Eftersom signalet er koblet ind i abonnentledningen, kan der for disse forstyrrelsessignaler anvendes lave niveauer, f.eks. omkring 0 dBmV. Disse forstyrrelsesniveauer kan opretholdes f.eks. ved hjælp af et pin-diode dæmpningsled, som er styret af den automatiske forstærkningskontrol i datamodtageren 3. For at forhindre lækage inde i systemet, bliver oscillatorsignalerne indført via en retningskobler 8 i abonnentledningen.The oscillators 9 have substantially the same frequency as the programs concerned, so that a strong interference signal at a closed contact 14 is introduced into the subscriber line thereby prohibiting observation and interception of the program. Since the signal is connected to the subscriber line, low levels of these interference signals may be used, e.g. about 0 dBmV. These levels of disturbance can be maintained e.g. by means of a pin-diode attenuator controlled by the automatic gain control in the data receiver 3. To prevent leakage within the system, the oscillator signals are input via a directional coupler 8 in the subscriber line.
Med henvisning til fig. 3a er der vist en højfrekvensomskifter af halvleder- eller faststoftypen. Dæmpningen i denne omskifter er i 50 - 300 MHz-området bedre end 88 dB.Referring to FIG. 3a a high frequency switch of the semiconductor or solid type is shown. The attenuation of this switch is in the 50 - 300 MHz range better than 88 dB.
Den tilførte effekt er 2 mA for 5 V jævnstrøm. Operationen er som følger:The applied power is 2 mA for 5 V direct current. The operation is as follows:
Hvis punkt A er positivt i forhold til punkt B, vil der fremkomme en jævnstrøm i kredsløbet R^, D^, R2, Rj, D2, R^ ved hvilken serie dioderne Dj, D^ og Dj er forbundet i spærreretning og de parallelle dioder D^ og D2 er forbundet i gennemgangsretning. Med henvisning til fig. 3b er der med hensyn til højfrekvensoperationen angivet, hvorledes systemet danner et dæmpningsled, som består af de store serie-impedanser (Dj, D^ og Dj) og små parallel-impedanser (D^ med og D2 med C2), således at højfrekvenssignalet ikke overføres fra indgangen til udgangen (og ligeledes ikke omvendt).If point A is positive relative to point B, a direct current will appear in the circuit R ^, D ^, R2, Rj, D2, R ^ at which series of diodes Dj, D ^ and Dj are connected in blocking direction and the parallel diodes D 1 and D 2 are connected in through direction. Referring to FIG. 3b, with respect to the high frequency operation, it is indicated how the system forms an attenuator consisting of the large series impedances (Dj, D ^ and Dj) and small parallel impedances (D ^ with and D2 with C2), so that the high frequency signal is transferred from the input to the output (and not the other way around).
Hvis punkt A er negativt i forhold til punkt B, vil der fremkomme en jævnstrøm i kredsløbet R^, Dj, D^, Dj, Rj, ved hvilken serie dioderne Dj, D^ og Dj er forbundet i gennemgangsretning og paralleldioderne D^ og D2 er forbundet i spærreretning. Højfrekvenssignalet bliver nu overført praktisk taltuden dæmpning. Kondensatorerne Cj og Cj tjener 5 146915 til at forhindre, at jævnspændingen, som tilføres til punkterne A og B, føres til højfrekvenskablerne.If point A is negative relative to point B, a direct current will appear in the circuit R ^, Dj, D ^, Dj, Rj, by which the series of diodes Dj, D ^ and Dj are connected in the through direction and the parallel diodes D is connected in a blocking direction. The high frequency signal is now transmitted virtually attenuated attenuation. The capacitors Cj and Cj serve to prevent the DC voltage applied to points A and B from being fed to the high frequency cables.
Kondensatoren benyttes med henblik på at forhindre fremkomsten af en højfrekvenslækage via °9 R-j parallel med D^ (i spærreretning). Alle modstande tjener til at indstille DC forspændingen og de har ikke nogen højfrekvensfunktion.The capacitor is used to prevent the occurrence of a high frequency leakage via ° 9 R-j parallel to D ^ (in blocking direction). All resistors serve to set the DC bias voltage and they have no high frequency function.
For fire abonnenter til et afgreningspunkt kræves som eksempel følgende: - en datamodtager; - en logisk enhed indeholdende til afgreningsadresse: n bit abonnentadresse: 2 bit tilslutning/afbrydelse: 1 bit fire programmer: 4 bit - fire oscillatorer og tilhørende dæmpningsled; - fire abonnentenheder, som hver indeholder fem højfrekvensomskiftere.For example, for four subscribers to a branch point, the following is required: - a data receiver; - a logical unit containing branching address: n bit subscriber address: 2 bit connection / disconnection: 1 bit four programs: 4 bit - four oscillators and associated attenuator; - four subscriber units, each containing five high frequency switches.
I princippet kan et vilkårligt antal abonnenter og antal programmer pr. enhed kombineres.In principle, any number of subscribers and number of programs per unit combined.
I fig. 4 er angivet, hvorledes en sådan kombination kan indsættes i et udformet hus. 1 2 fig. 5 er angivet et blokdiagram af en abonnentterminal, med hvilken det er muligt ligesom med apparatet ifølge fig.In FIG. 4 shows how such a combination can be inserted into a formed housing. 1 2 FIG. 5 is a block diagram of a subscriber terminal with which it is possible as with the apparatus of FIG.
2 respektivt at tillade og nægte abonnenten modtagelsen af respektivt fire eller flere eller færre programmer. De komponenter i fig. 4, som svarer til de i fig. 2 viste, er forsynet med samme henvisningsbetegnelser. I stedet for de fire højfrekvensomskiftere 14 i parallel med abonnentledningen er fire højfrekvensomskiftere 10 af en anden type imidlertid indsat i serie med ledningen.2 respectively, to allow and deny the subscriber the receipt of four or more or fewer programs, respectively. The components of FIG. 4 which corresponds to those of FIG. 2 are provided with the same reference numerals. However, instead of the four high frequency switches 14 in parallel with the subscriber line, four high frequency switches 10 of a different type are inserted in series with the line.
6 146915 I fig. 6 er vist en tegning af højfrekvensomskifteren 10 af den anden type. Før denne omskifter af den anden type kan højfrekvensomskifteren 5 (S^) indsættes i serie til respektiv transmission eller blokering af alle højfrekvens-programsignaler pr. abonnent. I omskifteren 10 er indsat et T-filter i serie med abonnentledningen, og et parallelkredsløb bestående af en selvinduktion 11 og blandt andet en kapacitetsdiode 12 er indsat i T-filterets tværgren. Ued periodisk at styre den variable kondensator 12 med f.eks. et lavfrekvenssignal på 50 eller 1000 Hz, kan kredsløbets afstemning svinges tværs over hele kanalen eller en del deraf, således at en anden, relativt lille del af signalets sidebånd periodisk (ikke synkront) filtreres ud, således at det resulterende signal bliver forstyrret. Afstemningen af denne højfrekvensomskifter eller spærringskredsløb foretages i stillingen "na" (not authorized) for kontakten S£ ved indstilling af selv-induktionen 11 på kanalen, som skal forstyrres. Han bør under denne procedure være opmærksom på, at programmer på nabokanalerne ikke forstyrres på nogen måde. Ved at anbringe kontakten under styring af styreenheden 4 fra stillingen "na" til stillingen "a" (authorized), bliver forstyrrelsen af den pågældende programkanal fjernet. Omskifteren S£ skifter kun lave frekvenser og kan derfor både være af den mekaniske type og af faststoftypen.In FIG. 6 is a drawing of the high frequency switch 10 of the second type. Prior to this second-type switch, the high-frequency switch 5 (S ^) may be inserted in series for respective transmission or blocking of all high-frequency program signals per second. subscriber. In the switch 10, a T-filter is inserted in series with the subscriber line, and a parallel circuit consisting of a self-induction 11 and, inter alia, a capacitance diode 12 is inserted into the transverse branch of the T-filter. Without periodically controlling the variable capacitor 12 with e.g. a low frequency signal of 50 or 1000 Hz, the tuning of the circuit can be pivoted across the entire channel or a portion thereof, so that another, relatively small portion of the signal band is periodically (not synchronously) filtered out so that the resulting signal is disturbed. The tuning of this high frequency switch or blocking circuit is made in the "na" (not authorized) position of the switch S £ by setting the self-induction 11 on the channel to be interrupted. During this procedure, he should be aware that programs on neighboring channels are not disrupted in any way. By placing the switch under control of the control unit 4 from the "na" position to the "a" position (authorized), the disturbance of the respective program channel is removed. The switch S £ switches only low frequencies and can therefore be both of the mechanical type and of the solid type.
Når kapacitetsdioden 12 tilsluttes i lederetningen i stillingen "a", forløber en strøm fra jævnspændingskilden via S2, modstanden R, kapacitetsdioden 12 og selvinduktionen 11 tilbage til kilden 15. Selvinduktionen 11 er kortsluttet og de to kondensatorer C, som har relativt små værdier, fremkommer i parallel med ledningen 2 og har da praktisk taget ingen indflydelse på signaltransmissionen.When the capacitance diode 12 is connected in the conductor direction in the "a" position, a current from the DC source via S2, the resistor R, the capacitance diode 12 and the self-induction 11 extends back to the source 15. The self-induction 11 is shorted and the two capacitors C, which have relatively small values, emerge. in parallel with line 2 and has virtually no influence on signal transmission.
7 1469157 146915
Det er også muligt samtidigt at forstyrre et antal kanaler, som ligger i nærheden af hinanden, ved at vælge kildens 16 lavfrekvenssweep tilstrækkeligt stort. I dette tilfælde er én omskifter 10 tilstrækkelig til et antal kanaler.It is also possible to simultaneously disrupt a number of channels that are adjacent to each other by selecting the low-frequency sweep of the source 16 sufficiently large. In this case, one switch 10 is sufficient for a plurality of channels.
I fig. 7 er angivet, hvorledes omskifteren 10 f.eks. kan afstemmes på fire forskellige kanaler ved periodisk at forbinde denne omskifter via en faststofomskifter (S£ og S^-Sg) til forskellige negative spændinger, hvormed et antal kanaler senere forstyrres. Omskifteren kan periodisk (f.eks. 3 yusek.) forbindes igennem. Af kontakterne S^-S6 for fire programkanaler kan hver af dem under styring fra styreenheden 4 kun indstilles til en positiv jævnspænding (ingen forstyrrelse) eller til lavfrekvensspændingen overlejret på en negativ jævnspænding.In FIG. 7 shows how the switch 10 e.g. can be tuned on four different channels by periodically connecting this switch via a solid state switch (S £ and S ^ -Sg) to various negative voltages, with which a number of channels are later disturbed. The switch can be periodically connected (eg 3 ysec) through. Of the switches S ^ -S6 for four program channels, each of them, under control of the control unit 4, can only be set to a positive DC voltage (no interference) or to the low frequency voltage superimposed on a negative DC voltage.
Afstemningen bliver så bestemt ved jævnspændingen på den variable kondensator, og spærrekredsløbet sweepes med 50 eller 1000 Hz spænding tværs over den pågældende kanal.The tuning is then determined by the DC voltage of the variable capacitor, and the blocking circuit is sweep with 50 or 1000 Hz voltage across that channel.
Ved at forbinde eller afbryde lavfrekvensspændingerne ved hjælp af datamodtageren og styreenheden, kan program efter program respektivt tillades eller nægtes. Hver kanal, som nægtes, kan forstyrres tilstrækkeligt på denne måde ved korrekt valg af gentagelsesfrekvensen.By connecting or disconnecting the low-frequency voltages using the data receiver and the control unit, program after program can be allowed or denied respectively. Each channel that is refused can be sufficiently disturbed in this way by properly selecting the repetition frequency.
For at forstyrre et antal kanaler kan en parallelforbindelse foruden den førstnævnte serieforbindelse og ovennævnte antal forbindelser benyttes, nemlig ved i T-filte-rets længdegren at indsætte et antal spærrekredsløb parallelt med hinanden.In order to interfere with a plurality of channels, a parallel connection, in addition to the former series connection and the above number of connections, can be used, namely by inserting a plurality of blocking circuits in parallel with the longitudinal branch of the T-filter.
Claims (3)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL7416880A NL182689C (en) | 1974-12-24 | 1974-12-24 | SIGNAL DISTRIBUTION DEVICE FOR A HIGH-FREQUENT CABLE NETWORK. |
NL7416880 | 1974-12-24 |
Publications (3)
Publication Number | Publication Date |
---|---|
DK586075A DK586075A (en) | 1976-06-25 |
DK146915B true DK146915B (en) | 1984-02-06 |
DK146915C DK146915C (en) | 1984-07-16 |
Family
ID=19822721
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DK586075A DK146915C (en) | 1974-12-24 | 1975-12-22 | SUBSCRIPTION TERMINAL FOR CABLES |
Country Status (13)
Country | Link |
---|---|
JP (1) | JPS608675B2 (en) |
AT (1) | AT361996B (en) |
BE (1) | BE836589A (en) |
CA (1) | CA1033053A (en) |
DE (1) | DE2558147A1 (en) |
DK (1) | DK146915C (en) |
ES (1) | ES443805A1 (en) |
FI (1) | FI67006C (en) |
FR (1) | FR2296335A1 (en) |
GB (1) | GB1507859A (en) |
IT (1) | IT1052630B (en) |
NL (1) | NL182689C (en) |
SE (1) | SE420036B (en) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1554411A (en) | 1975-08-09 | 1979-10-17 | Communications Patents Ltd | Control systems |
FR2336842B1 (en) * | 1976-08-06 | 1987-02-27 | Stern Joseph | IMPROVEMENTS RELATING TO OR RELATING TO CABLE TELEVISION DEVICES |
DE2725250C3 (en) * | 1977-06-03 | 1982-03-18 | Siemens AG, 1000 Berlin und 8000 München | Cable television system with subscriber connections that can be switched off |
DE3045512C2 (en) * | 1980-12-03 | 1982-10-07 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Electronic switching device for television and audio broadcast programs |
JPS58221577A (en) * | 1982-06-18 | 1983-12-23 | Yagi Antenna Co Ltd | Distributing system of catv signal |
JPS5921187A (en) * | 1982-07-27 | 1984-02-03 | Uro Denshi Kogyo Kk | Branching distributor of common reception of wire broadcasting |
US4521809A (en) * | 1982-12-29 | 1985-06-04 | North American Philips Corporation | Method and apparatus for controlling access to selected television programs |
ATE33327T1 (en) * | 1983-06-10 | 1988-04-15 | Tocom | MAIN/SUB CONVERSION SYSTEM. |
GB2161679B (en) * | 1984-07-06 | 1988-02-24 | Cabletime Ltd | Improvements in or relating to signal jamming apparatuses for frequency division multiplex systems |
FR2615342B1 (en) * | 1987-05-13 | 1991-09-13 | Applic Realisa Electro | TELEVISION SYSTEM INCLUDING AT LEAST ONE TELEVISION CHANNEL |
DE3840254C1 (en) * | 1988-11-29 | 1990-06-07 | Neuberger Nachrichten- Und Antennentechnik Gmbh, 8000 Muenchen, De |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3790700A (en) * | 1971-12-17 | 1974-02-05 | Hughes Aircraft Co | Catv program control system |
US3789131A (en) * | 1972-08-03 | 1974-01-29 | Oak Industries Inc | Selective coding system for subscription television |
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1974
- 1974-12-24 NL NL7416880A patent/NL182689C/en not_active IP Right Cessation
-
1975
- 1975-05-23 CA CA227,709A patent/CA1033053A/en not_active Expired
- 1975-06-09 JP JP50069455A patent/JPS608675B2/en not_active Expired
- 1975-12-12 BE BE162705A patent/BE836589A/en not_active IP Right Cessation
- 1975-12-16 AT AT955075A patent/AT361996B/en not_active IP Right Cessation
- 1975-12-22 SE SE7514561A patent/SE420036B/en not_active IP Right Cessation
- 1975-12-22 DK DK586075A patent/DK146915C/en not_active IP Right Cessation
- 1975-12-23 DE DE19752558147 patent/DE2558147A1/en not_active Withdrawn
- 1975-12-23 IT IT5285775A patent/IT1052630B/en active
- 1975-12-23 ES ES443805A patent/ES443805A1/en not_active Expired
- 1975-12-23 FR FR7539520A patent/FR2296335A1/en active Granted
- 1975-12-23 FI FI753640A patent/FI67006C/en not_active IP Right Cessation
- 1975-12-24 GB GB5283675A patent/GB1507859A/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
ATA955075A (en) | 1980-09-15 |
NL182689B (en) | 1987-11-16 |
JPS608675B2 (en) | 1985-03-05 |
DE2558147A1 (en) | 1976-07-01 |
NL7416880A (en) | 1976-06-28 |
DK146915C (en) | 1984-07-16 |
SE420036B (en) | 1981-09-07 |
GB1507859A (en) | 1978-04-19 |
FR2296335B3 (en) | 1980-06-20 |
NL182689C (en) | 1988-04-18 |
BE836589A (en) | 1976-06-14 |
FI67006C (en) | 1984-12-10 |
FR2296335A1 (en) | 1976-07-23 |
JPS5178621A (en) | 1976-07-08 |
CA1033053A (en) | 1978-06-13 |
FI753640A (en) | 1976-06-25 |
FI67006B (en) | 1984-08-31 |
SE7514561L (en) | 1976-06-25 |
AT361996B (en) | 1981-04-10 |
IT1052630B (en) | 1981-07-20 |
DK586075A (en) | 1976-06-25 |
ES443805A1 (en) | 1977-04-16 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUP | Patent expired |