DE2558147A1 - SIGNAL DISTRIBUTION DEVICE FOR CABLE TV - Google Patents

Description

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D-8023 Munchen-Pullach. Wit, -nt, - Sir i> ■. · ■ ..) ö9) 7 ".: ->■" relex W 2 X 7 tiros J. Cables .Patentibus »Munich

2558H7

.hr sign Ta ₉ December 22nd, 1975

Your ref Date Vl / Pz - 5251

OAK HOLLAND BV, Kapt. Nemostraat 2, Emmen, Netherlands

Signal distribution device for cable television.

The invention relates to a signal distribution device for a cable television network with a supply line, over which several television programs and radio programs in frequency multiplex manner to several subscriber introductory lines be transmitted. Such a signal distribution device is well known in practice.

In the known cable television networks, subscribers are usually provided with the aid of signal distribution devices connected to a supply or ring line, which several television programs and radio programs distributed to the respective participants in the frequency multiprex procedure. A certain number of participants is connected to each distribution device in this system.

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The disadvantage inherent in this system is that during the installation of the television cable network, only those subscribers can be connected to the distribution devices who previously indicated that they want to be connected to the system. In the case of a later participant, a specialist must Connect the subscriber's home to a relevant distribution device, which is associated with costs and time. In the event of termination or deregistration and non-payment, a specialist must inform the participant disconnect from the distributor device.

With the system explained at the beginning, it is therefore not always possible to deny reception of certain programs to the subscribers already connected.

It is therefore an object of the present invention to provide a signal distribution device to create, through which each residential section or apartment during the installation of the television network can be connected to the distribution device in such a way that that by installing a remote control unit with the help of a suitable code each participant from a central Place can be connected to the cable television network or disconnected from the network at any time you want can be.

The present invention should also be able to provide a remote control unit with a suitable code, so that certain programs on certain subscriber lead-in lines can be blocked or disturbed and thereby the Watching or listening to the programs in question is made impossible.

The signal distribution apparatus of the present invention is characterized by eineh or more high frequency switches (switched through which the programs from a location remote location '., And / or can be disturbed, and of these

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Switches for each subscriber line one in series and / or several combined to work with this management sindj welter is also a data receiver and a logical one Control unit is provided, which after decoding the appropriate code, the series switch or the switch for a transmission the high-frequency program signals and / or the switch or switches that work together with the line or lines, switch for the disturbance of certain high-frequency signals.

The particular advantage of this system is that each subscriber connected to the distribution device has one central point can be separated or connected to this and that each participant receive certain programs or not receive it without affecting the other participants be disturbed.

An additional advantage is that a subscriber does not have the opportunity to connect himself.

The invention is explained in more detail below using an exemplary embodiment with reference to the drawings. It shows:

Fig. 1 is a block diagram of a signal distribution device with four subscriber import lines, in each Line a high-frequency switch is looped in series and with the transmission and disconnection of the Programs can be switched from a remote location;

Fig. 2 is a block diagram of a signal distribution device with a single subscriber lead-in line equipped with four high-frequency switches running in parallel Work with management to view certain television and radio programs as you wish disturb; · __

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Pig. 3a shows an exemplary embodiment of a high-frequency switch in Kalbleiteraus design that is used in the device according to FIG Figure 2 is used;

3b shows the high-frequency operation of the high-frequency switch according to Figure 3a relevant section;

Fig. 4 is a front view of a housing in which the distribution device is included;

5 shows a block diagram of a distribution device a single participant induction line that is equipped with four high-frequency switches of a different type, which are connected in series with a cable are to interfere with certain television and radio programs at will;

Fig. 6 shows an embodiment of a high frequency switch of the mentioned other type used in the device is used according to Figure 5; 'and

7 shows a further embodiment of a high-frequency switch the other type that can be used alone for multiple channels.

Figure 1 shows a supply or ring line 1, several subscriber entry lines 2, a data receiver 3, a logic control unit 4, high-frequency switch 5 and a branching element 6. The data receiver 3 in the distribution device

^: is connected to the branching or coupling distribution point. A directional coupler can be used for the distribution function

. or a tap can be used. The logical control unit,

'' which follows on the data receiver decodes the appropriate codes, which are contained in the high frequency signal. Dependent on the control unit switches from the information of the codes

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one or more high-frequency switches 5 such that the high-frequency signals the respective television programs and radio programs are transmitted to the subscriber lines 2 or blocked will.

Figure 2 shows a block diagram of a single distribution device, by which it is easier to couple interfering signals into the subscriber lead-in lines, so that the concerned Participants either received or denied permission to receive television and radio programs. According to Figure 2, a supply line 1, a single subscriber lead-in line 2, a data receiver 3, which is connected to a branch distribution point, a logic control unit 4, a single high frequency switch, which is designed in series with the subscriber line 2, available. The arrangement also contains several high-frequency switches 5, which are combined in parallel with the subscriber line 2, as well several upstream oscillators 9 and several attenuators 71 which are connected in between.

The oscillators 9 have essentially the same frequency as the programs concerned, so that after closing one Switch 5 a strong interference signal of the subscriber line is pressed and thereby the observation and hearing of the Program is prevented. If the signal is coupled to the subscriber line, then one needs for the interfering signals low levels, for example approx. 0 dBmV. The interference signal level can be measured with the aid of, for example, a pin diode attenuator (pin-diode attenuator), this attenuator through the automatic gain control of the data receiver is controlled. The oscillator signals are sent via a Directional coupler 8 pressed on the subscriber line.

Figure 3a shows a high-frequency switch in the form of a half

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letters or solid-state component. The attenuation of this switch in the 50-300 MHz range is better than 88 dB. The connected DC power supply corresponds to 2 mA at 5 V. The mode of operation is then as follows:

If the point A is positive with respect to the point Bist, _{a direct current flows in the circle FL, D., R 3} , R ,, D ₂ , R ^, through which the series diodes D ,, Dj. and D, - are reverse biased and the parallel diodes D. and D "are forward biased. According to FIG. 3b, with regard to high-frequency operation, it is shown how the arrangement or the attenuator is constructed, which has large series impedances (D- ,, Dj. And D ₁ -) and small parallel impedances (D ^ with C ^ and Dp with C ₃ ) so that the high-frequency signal is not transmitted from the input to the output (and also not vice versa).

When point A is negative with respect to point B, a direct current flows in circuit Rg, D ₅ , O ^ , D ,, R ₁ -, through which the series diodes D ^, D ₂₁ and D, - are forward-biased and the parallel diodes D ₁ and D _{2 are} reverse biased. The high-frequency signal is now transmitted with practically no attenuation. The capacitances C, and C, - serve as DC voltage blocking capacitors, which is fed to the points A and B and that opposite the high-frequency cables.

The capacitance C. is used to prevent high frequency leakage from occurring across R ₂ and R, parallel to D ₁ ^ (in the reverse direction). All resistors are used to set the DC voltage bias and they have no high frequency function.

The high frequency switch can also be of a mechanical switch type exist.

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For example, for four participants at a branch point the following is required:

a data collector;

a logical unit that is responsible for the

Branch address: η bits

the participant address: 2 bits

Connection / disconnection: 1 bit

and four programs: 4 bits required, four oscillators and corresponding attenuators; four subscriber units, each of which contains five high frequency switches.

In principle, any number of participants and any number of programs can be combined per unit.

Figure 4 shows how such a combination in one created house can be realized.

Figure 5 shows a block diagram of a single distribution device, with which it is possible, as with the device according to FIG. 2, the relevant subscriber to receive four or to allow or not to allow more or fewer programs. The same appearing in Figures 4 and 2 Components have been given the same reference numbers. Instead of four high-frequency switches 5 in parallel with the subscriber line however, four high-frequency switches 10 of a different type can also be connected in series with the line.

Figure 6 shows a high frequency switch 10 of the other type mentioned. In front of this switch, the high-frequency switch 5 (p.) in series for the transmission or blocking of all of them High-frequency program signals are looped in per participant. In switch 10, a T-filter is in series with the subscriber line switched on and also a parallel circle in the form of a

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Inductance 11 and, among other things, is also a capacitance diode; 12 contained in the branch of the T-filter. By periodically controlling the varactor diode 12 with, for example, a low; frequency signal of 50 or 1000 Hz ₁ , the tuning of the circuit can be run over the entire channel or part of it, so that periodically (not synchronously) another relatively small part of the signal's sidebands is filtered out, so that the resulting signal is disturbed. The tuning of this high-frequency switch or interception circuit is obtained 'in the "na" (unauthorized) position of the switch Sp by ■ setting the inductance .11 to the channel to be disturbed. During this process, care should be taken to ensure that neighboring program channels are not disturbed. By 'placing the switch S ₂ under the control of the control unit H , from position "na" to position "a"(authorized)'. the malfunction of the relevant program channel is eliminated. The switch Sp only needs to switch a low frequency and can therefore consist of a mechanical switch or a solid-state switch. :

When the capacitance diode in the forward direction is in position "a" is switched, then flows from the direct current source from a current through Sp, the resistor R, the capacitance diode 12 and the Inductance 11 back to the power source. The inductance is short-circuited and the two capacitances C have relative small values and are parallel to the line, so that they have practically no influence on the signal transmission. ;

It is also conceivable to have several channels that ^! near by- ^; to disturb each other by using the spring frequency sampling

(sweep) selects sufficiently strong. In this case a switch is

10 is sufficient for several channels. :

> i

FIG. 7 now shows the manner in which the switch 10, for example I, can be tuned to four different channels by '■

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this switch is connected to different negative voltages via a solid-state switch (S ₂ and S-Sg), which subsequently disrupts several channels. The switch S1 can be switched through periodically (for example 3 microseconds). The switches S -, - Sg for four program channels, which are under the control of the control unit 4, can each be set to a positive DC voltage (no interference) or to the low-frequency voltage which is superimposed on a negative DC voltage.

The tuning is then done by the DC voltage on the capacitance diode determined and the capture circuit is then swept with the 50 or 1000 Hz voltage over the relevant channel. By It is possible to connect or disconnect the low-frequency voltages with the aid of the data receiver and the control unit "Allow" or prevent program on program. Each blocked channel can be activated in this way by correct selection of the Repetition frequency are sufficiently disturbed.

In order to interfere with several channels, a parallel connection can be used in addition to the series connection mentioned first and the aforementioned Multiple connections can also be used by placing several trap circles parallel to one another in the series branch of the T-filter grinds in.

All technical details that can be recognized in the description and shown in the drawings are essential for the invention significant.

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Claims (10)

PATENT CLAIMS Signal distribution device for a cable television network having a supply line through which a plurality of television programs and Radio programs in frequency division multiplexing to several subscriber introductory lines are transmitted, characterized by one or more high-frequency switches through which the Programs can be switched and / or disturbed from a remote location and from which for each subscriber line one in series and / or one or more in collaboration with are looped into this line; through a data receiver and a logic control unit that, after decoding the suitable. Codes the series switch or the series switch for the transmission of the high-frequency program signals and / or the Switches or switches that work together with the line or lines to interfere with certain high-frequency signals switch. 2. Apparatus according to claim 1, characterized in that the high-frequency switch connected to the subscriber line for coupling of interfering signals in this line work together, are combined with this in parallel; that any high frequency switch a disturbance oscillator is connected upstream, either with or without the interposition of an attenuator, which through the automatic gain control of the data receiver (Fig 2) is controlled. 3. Apparatus according to claim 1 or 2, characterized in that the high-frequency switch (5) consists of a semiconductor component and has a diode-resistance-capacitance network which, for high-frequency operation, is a series connection of three diodes (D ,, D ^, D ₁₅ ) contains that the connection points on both sides of the middle diode (Dn) via a series of a diode and a 609827/0732 2558H7 Capacitance (D ₁ , C ^ and D ₂ , C ₃ ) are connected to earth or ground, and that the cathode of one diode (D.) with the cathode of the other diode and that the anode of the other diode (D _? ) is connected to the anode of the middle diode (D ₁ J, Figure 3b). 4. Apparatus according to claim 3 »characterized in that the input and output high-frequency lines of the high-frequency switch (5) via a capacitance (Cj ,, C ₁ -) with the cathode of the first diode (D,) and the anode of the third diode (Df -) are each connected; that the middle diode (D ^) is shunted by a series circuit of two resistors (R ₂ , R,), the connection point of which is connected to ground or earth via a capacitance (C,); and that the series circuit of the diodes (D ,, D.) and the diodes (D ₁ -, D_) is shunted by a series circuit of two resistors (Rc >> R ₁ and Rg, R ₁ J.), the connection points (A, B) are connected to a DC voltage (Figure 3a). 5. Apparatus according to claim 1 or 2, characterized in that the high-frequency switch consists of a mechanical switch. 6. The device according to claim 1, characterized in that the • High-frequency switches (10) that work together with a subscriber line to filter out certain high-frequency program channels, connected in series with the subscriber line (Figure 5); are tet. 7. Apparatus according to claim 6, characterized in that the high-frequency switch (10) is designed in the form of a T-filter . whose shunt branch consists of a parallel circuit of an inductance! (11) and, among other things, a capacitance diode (12) which is > periodically controlled via a switch (S ₃ ) by a low-frequency signal superimposed on a negative direct voltage or is connected to a positive DC voltage. 609 8 27/0 732 2558U7 8. Apparatus according to claim 7, characterized in that the capacitance diode (12) in the shunt arm of the high-frequency switch (10) is periodically controllable with such a large low frequency signal that a plurality of mutually adjacent signals; are disturbed at the same time and a single high-frequency switch is sufficient for the number of program channels. 9. Apparatus according to claim 7, characterized in that the Capacitance diode (12) in the cross arm of the high-frequency switch (10) with a certain number of further switches (S ,, Sg) is connected via the switch (S ") which has the same number of Has positions and which can be switched through periodically that · the selected positions or switch positions of the further switches (S-r-S / -) can be connected to the positive DC voltage and with the low-frequency signal can be connected to a further negative voltage each time it is superimposed, so that the the same number of program channels or a part of them can be interfered with. 10. The device according to one or more of claims 6 to 9, characterized in that the switch (S ₂ ) in the high-frequency switch (10) consists of either a mechanical switch or a solid-state switch. Blank page