JPH0326599B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a television pay viewing device,
More specifically, the present invention relates to a television pay-to-view device that allows only broadcasts of a specific television channel to be viewed for a fee. Conventional TV pay-viewing devices emit a signal at a specific frequency to interfere with reception to the TV receivers of viewers who have not paid the TV viewing fee, and disturb the image of a specific channel with beats. The mainstream method was to make listening and viewing difficult. However, this method had the drawback that even though the image could not be seen, the sound leaked, and some valuable information was leaked for free. The present invention has been made to eliminate these conventional drawbacks.

Embodiments of the present application will be described below with reference to the drawings.

FIG. 1 is a system diagram of a pay television joint reception system, where 1 indicates a building such as a hotel or inn. 2 is a television antenna for receiving normal television broadcast waves. Reference numeral 3 indicates an amplifier for common television reception, which is provided as necessary. 4 is a VTR that sends out video and audio signals for tape playback. Furthermore, VTR
4, various video/audio playback devices such as a video disk may be used. 5 is a modulator that converts the signal from the VTR 4 into a television signal (hereinafter referred to as an independent broadcast television signal). Furthermore, modulator 5
may be built into the VTR4. Reference numeral 6 denotes a mixer, which mixes the normal TV broadcast signal from the antenna 2 side (hereinafter referred to as normal broadcast TV signal) and the self-broadcast TV signal from the VTR 4 side, and sends the mixture to the subsequent system. 7 is a branch, 8 is a series unit,
9 is a terminating resistor provided at the terminal of the system, 10
indicate television receivers. Reference numeral 11 denotes a television pay-viewing device, which is provided for erasing only the television signal of a specific channel among the television signals of each channel inputted to the input terminal 12, and transmitting the television signal of other channels from the output terminal 13. . The above-mentioned specific channel erasing effect in the television pay-viewing device is canceled by various methods described below only for viewers who have paid the specific channel viewing fee. Further, although the specific channel is often selected from the independent broadcasting channel, it can also be selected from among the regular broadcasting channels. You can also select not only one channel but multiple channels. Reference numeral 14 indicates a transmission line connecting each device.

In the above configuration, the normal broadcast channels are Ch1, Ch3, Ch5, Ch9, and Ch11, and the independent broadcast channel is Ch7, and the operation of the system will be explained when Ch7 is selected as a specific channel. do. The self-broadcast television signal from the VTR 4 and modulator 5 is mixed with the regular broadcast television signal from the antenna 2 and amplifier 3 in a mixer 6, and then passes through a transmission line 14 and a splitter 7 to each television pay-viewing device. 11 input terminal 12. In each TV pay viewing device 11, a specific channel
For viewers who have not paid the viewing fee for Ch7, only the specified channel Ch7 will be deleted as described later, so Ch1, Ch3, Ch5 other than the specified channel,
The television signals of Ch9 and Ch11 are output from the output terminal 13 and reach the television receiver 10 connected at the subsequent stage. On the other hand, for viewers who have paid the viewing fee for specific channel Ch7, as described later, specific channel Ch7 is not deleted, and all the TV signals of each channel are sent out from output terminal 13 and connected to the subsequent stage. It reaches the television receiver 10. In this way, only those viewers who have paid the fee can view the broadcast of the specific channel Ch7 on the television receiver 10.

Next, FIG. 2 is a block diagram showing an example of a television pay-to-view device used in a pay-TV joint reception system. Components corresponding to those in FIG. 15 indicates a transmission line. Reference numeral 16 denotes an extraction unit, which sends out the signal inputted to the input end 17 from the output end 18, and also outputs the signal input to the input end 17 from the extraction end 19.
A well-known branch circuit or distribution circuit with directionality is used, and when a branch circuit is used, its input terminal, output terminal, and branch terminal are input terminal 17, output terminal 18, and extraction terminal, respectively. When a distribution circuit is used, the input terminal, one output terminal, and the other output terminal are respectively connected to the input terminal 19.
7, connected to the output end 18 and extraction end 19. 20
is an injection section which injects the signal input from the injection end 22 into the signal input to the input end 21 and outputs the signal from the output end 23.
A well-known branch circuit or distribution circuit with directionality is used. When a branch circuit is used, its input end, output end, and branch end are connected to the output end 23, input end 21, and injection end, respectively. When a distribution circuit is used, the input end, one output end, and the other output end are connected to the output end 23, the input end 21, and the injection end 22, respectively. 24, 25
passes only the TV signal of a specific channel,
A filter is used to block other television signals, and various filters such as a low-pass filter, high-pass filter, and band-pass filter, or combinations thereof, are used. The filter 24 selects the TV signal of a specific channel from among the TV signals from the extractor 16, and the filter 25 removes distortion components generated in amplifier circuits 26 and 27, which will be described later, and injects only the TV signal of the specific channel. 20. Furthermore, filters 24 and 25
In some cases, only one of them may be provided as needed, and the location is not limited to the one shown in the figure. It may be placed in the position. Amplification circuits 26 and 27 are provided to amplify the television signal of a specific channel.
Note that the total gain of the amplifier circuits 26 and 27 is determined by the extraction unit 16
The level of the signal passing through the input terminal 17, output terminal 18, input terminal 21 and output terminal 23 of the injection section 20 and reaching the output terminal 13, and the input terminal 17 of the extraction section 16, the extraction terminal 19, the filter 24,... is determined so that the level of the signal passing through the injection end 22 and output end 23 of the injection part 20 and reaching the output terminal 13 is the same,
Furthermore, regarding the amount of phase shift, the sum of the phase shift applied to the signal in the amplifier circuit 26 and the phase shift applied to the signal in the amplifier circuit 27 is an integral multiple of 360 degrees (the amplifier circuit 26,
When the signal passes through 27, the phase shift of the signal is made to be the same as the phase of the signal before passing through. For example, the amplifier circuits 26 and 27 each use a two-stage transistor amplifier circuit of a grounded emitter type. Furthermore, only one of the amplifier circuits 26 and 27 may be provided as necessary. 26a and 27a indicate power supply terminals of amplifier circuits 26 and 27, respectively. 2
8 is a phase inversion circuit for rotating the phase by 180 degrees, and various phase inversion transformer circuits are used.
Reference numeral 29 indicates an input end of the phase inversion circuit, and reference numeral 30 indicates an output end. 31 indicates a power supply circuit. Reference numeral 32 designates a switch circuit, and by switching the switch circuit open or close, the power supply circuit 31 is cut off or turned on, and the amplifier circuits 26 and 27 are set in a non-operating state or in an operating state, thereby controlling the TV signal of a specific channel. Provided for transmitting and blocking. 33 is a switch control element which opens the switch circuit 32 if the viewing fee for a specific channel is not paid, and closes it if the fee is not paid. Specifically, various methods are used, such as giving a special key in exchange for the viewing fee and opening the switch circuit 32 by inserting the key into a keyhole and turning it. Alternatively, a coin timer or the like may be used to open the switch circuit 32 for a predetermined time only when a coin is inserted.

In the television pay viewing device 11 having the above configuration, the extraction section 16 and the injection section 20 each have an insertion loss.
A branch circuit with a coupling loss of 10 dB at 1 dB is used, and filters 24 and 25 have insertion loss in a specific channel.
A 2 dB band pass filter is used, a 4 dB insertion loss is used for the phase inversion circuit 28, and the amplifier circuit 2
6 and 27, each with a gain of 13 dB and a phase shift of 360 degrees, will be described. It is assumed that the input terminal 12 is connected to normal broadcast television signals of channels Ch1, Ch3, Ch5, Ch9, and Ch11 and an independent broadcast television signal selected as a specific channel Ch7.

() When the viewing fee for specific channel Ch7 is not paid In this case, the switch circuit 32 is closed and the amplifier circuits 26 and 27 are operating. Each television signal other than the specific channel is input to the input end 17 and output end 18 of the extraction section 16, and the input end 2 of the injection section 20.
1, it passes through the output terminal 23 and is sent out from the output terminal 13. On the other hand, most of the television signal of the specific channel Ch7 is sent out from the output end 18 of the extraction section 16 and input to the input end 21 of the injection section 20, and a part of it is sent out from the output end 18 of the extraction section 16.
9, passes through the filter 24, is amplified in the amplifier circuit 26, and is extracted in the phase inversion circuit 28.
A phase shift of 180 degrees is applied, the signal is amplified in an amplifier circuit 27, passes through a filter 25, and is input to the injection end 22 of the injection section 20. The signal level of Ch7 at the input end 21 of the injection section 20 is lower than the signal level of Ch7 at the injection end 22 by 9 dB (coupling loss minus insertion loss of the branch circuit used in the injection section 20). Furthermore, the phase of the former Ch7 signal and the latter Ch7 signal differ by 180 degrees. Therefore, the signal of Ch7 is
After it becomes 0 and is injected, it does not appear from the output terminal 23. In this case, it goes without saying that both the video signal and the audio signal of Ch7 are canceled. For the above reasons, only the TV signals other than the specific channel Ch7 are sent from the output terminal 13, and the TV receiver connected later
I can't see the image on Ch7, and I can't hear the audio.

() When the viewing fee for specific channel Ch7 has been paid In this case, the switch circuit 32 is opened and the amplifier circuits 26 and 27 do not operate. Each television signal other than the specific channel is sent out from the output terminal 13 in the same manner as in the case () above. On the other hand, the television signal of the specific channel Ch7 is extracted by the extraction unit 16
Most of the water is sent out from the output end 18 of the injector 20 and input to the input end 21 of the injection section 20, and a portion is extracted from the extraction end 19 of the extraction section 16. However, since the amplifier circuits 26 and 27 are not operating, the signal extracted from the extraction section 16 is attenuated, and eventually the signal is attenuated at the input terminal 2 of the injection section 20.
The signal input to the output terminal 23 is not cancelled.
It is sent out from the output terminal 13. For the above reasons, both the signal of the specific channel Ch7 and the other television signals are sent out from the output terminal 13. Therefore, you can enjoy the video and audio of any channel on the television receiver connected later.

Next, FIG. 3 is a diagram for explaining the operation of the television pay viewing device in the above example, in which A, B, C,
The waveforms D, E, F, G, H, and J show the television signal spectrum at each point indicated by the same reference numeral in FIG. 2, respectively. In the figure, P indicates the spectrum of the video signal (video carrier wave), S indicates the spectrum of the audio signal (audio carrier wave), and each waveform indicates the video signal level of the TV signal of each channel at the input terminal 12.
70dB, and the audio signal level was 64dB.

Although the case where the specific channel is only Ch7 has been explained above, the passband of the filters 24 and 25 is set to a bandwidth that includes a plurality of specific channels,
If the amplifier circuits 26 and 27 are also wideband ones, it is possible to provide a plurality of specific channels. For example, in the example above, specifying a specific channel
For example, it could be set to Ch5 and Ch7, or to Ch1, Ch5, and Ch7.

Next, FIG. 4 is a wiring diagram showing an example of a phase inversion circuit used in a television pay-per-view device, and parts corresponding to those in FIG. 2 are given the same reference numerals and redundant explanations will be omitted. 34 is a phase inversion transformer circuit, which has an input terminal 35, a first output terminal 36, and a second output terminal 37.
It is equipped with A signal applied to input 35 appears at first output 36 and second output 37, with a phase difference of approximately 180 degrees between each signal at each output. Reference numeral 38 denotes a phase inversion transformer, which includes a primary winding 39 and a secondary winding 40. still,
The phase inversion transformer 38 is, for example, a ferrite core wound with two polyurethane-coated copper wires as a primary winding 39 and a secondary winding 40 at a turns ratio of 1:1. 41 is a balance circuit for adjusting the phase shift of about 180 degrees created by the phase inversion transformer circuit 34. 42 is a high frequency transformer, which includes a primary winding 43 and a secondary winding 44. The high-frequency transformer 42 has, for example, a ferrite core wound with two polyurethane-coated copper wires as a primary winding 43 and a secondary winding 44 at a turns ratio of n:1 (n is selected from about 1.5 to 2). The rotated one is used. 4
Reference numeral 5 denotes an adjustment variable resistor, which is used for fine adjustment of the phase shift. 46 is a resistor that serves as a load for the phase inversion transformer circuit 34.

If the phase inversion circuit 28 with the above configuration is used, the second
The phase shift error of each part shown in the figure can be corrected by changing the resistance value of the variable resistor 45. That is, when a signal is applied to the input end 17 of the extraction section 16, the phase difference between the signals appearing at the output end 18 and the extraction end 19, the phase shift of the filters 24 and 25, and the phase difference of the amplifiers 26 and 27 (360 the phase difference between the signal applied to the input end 21 and the output end 23 in the injection section 20, and the phase shift that the signal applied to the injection end 22 undergoes before it appears at the output end 23. Therefore, the above-mentioned specific channel cancellation effect in the television pay viewing device 11 can be performed satisfactorily.

Next, Fig. 5 is a system diagram showing different examples of a pay TV joint reception system. Those with the same or equivalent functions as those in Fig. 1 are indicated with the same reference numerals and an alphanumeric letter "e", and redundant explanations will be omitted. . 47 indicates a front desk at a hotel or the like. 48 indicates a switch control element group, and each television pay viewing device 11
This is for opening and closing the switch circuit of e by remote control, and is made up of, for example, a group of changeover switches arranged on a control panel. Reference numeral 49 denotes a transmission line for transmitting control signals from the switch control element group 48. The above configuration has the advantage that viewing of specific channel broadcasts in each room can be centrally controlled from the front desk.

As mentioned above, in the present application, viewers who have paid the viewing fee for a specific channel will be able to watch both the TV broadcast of the specific channel and the TV broadcasts of other channels with beautiful images and noise-free sound. There is an effect that it can be done.

Furthermore, viewers who do not pay a viewing fee for a specific channel can only watch television broadcasts other than the specific channel, thereby preventing valuable information about the specific channel from being leaked for free.

[Brief explanation of the drawing]

Figure 1 is a system diagram of a pay TV joint reception system, Figure 2 is a block diagram showing an example of a TV pay viewing device used in the pay TV joint reception system, and Figure 3 is an operational diagram of the TV pay viewing device. ,
FIG. 4 is a wiring diagram showing an example of a phase inversion circuit used in a pay TV viewing device, and FIG. 5 is a system diagram showing a different example of a pay TV joint reception system. 10...TV receiver, 11...TV pay viewing device, 12...Input terminal, 13...Output terminal,
14...Transmission line, 16...Extraction section, 20...Injection section, 24, 25...Filter, 26, 27...Amplification circuit, 28...Phase inversion circuit, 31...Power supply circuit, 32...Switch Circuit, 33... Switch control element, 34... Phase inversion transformer circuit, 41...
...Balance circuit.

Claims (1)

[Claims] 1 Input terminal 12 to which multiple television broadcast signals are input, and output terminal 13 to which a television receiver is connected
In the television pay viewing device 11, the transmission line 15 connecting the input terminal 12 and the output terminal 13 includes an extraction unit 16 for extracting the television broadcast signal, and an extraction unit 16 for injecting the television signal of a specific channel. The injection part 20 is interposed, and the extraction part 16
and the injection unit 20, so that the phase of only the TV signal of the specific channel can be rotated by 180 degrees.
A filter 24 for selecting a TV signal of a specific channel from among the TV signals from the extraction unit 16
, amplification circuits 26 and 27 for amplifying the television signal of the specific channel, a phase inversion circuit 28 for rotating the phase by 180 degrees, and an amplification circuit 2.
A series circuit with a filter 25 is provided in parallel with the transmission line 15, which removes distortion components generated in the filters 6 and 27 and sends only the television signal of a specific channel to the injection unit 20, and further includes the amplifier circuits 26 and 27. In order to transmit and cut off the television signal of a specific channel, the power supply circuit 31 is connected via a switch circuit 32, and the power supply circuit 31 is cut off and made conductive by opening and closing the switch circuit 32. The switch circuit 32 is switched to be able to switch the amplifier circuits 26 and 27 between a non-operational state and an active state, and also to open the switch circuit 32 when the toll is paid and to close it when the charge is not paid. 32 is connected to a switch control element 33 for controlling a switch circuit.