JPH0983992A - Television broadcasting system - Google Patents

Abstract

(57) Abstract: The present invention provides a television broadcasting system capable of surely improving the hit rate of control information in each receiving terminal and further improved so as to be more practical. ing. SOLUTION: An ordinary television signal, a television signal in which first control information including key information for descrambling and sub information are multiplexed and scrambled, and the television signal is received on a receiving side. Transmitting means for transmitting the second control information for receiving on different channels, first receiving means for always receiving the second control information transmitted by the transmitting means, and this first receiving A second receiving control signal, which is multiplexed with the first control information, on the basis of the second control information received by the means, and obtaining the first control information, which is multiplexed on the television signal;
And a receiving terminal provided with the receiving means of.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
(Cable Television) The present invention relates to improvement of a television broadcasting system that adopts a cable system, such as a broadcasting system.

[0002]

2. Description of the Related Art As is well known, in the television broadcasting system as described above, it is only necessary to transmit a television signal including a video signal and an audio signal from a broadcasting center side to a plurality of receiving terminals. However, it is also necessary to transmit control information for controlling each receiving terminal. In this case, conventionally, control information is multiplexed in the vertical blanking period of the video signal so that the control information is transmitted through a transmission line common to the television signal.

However, this control information is not always multiplexed and transmitted in the television signals of all channels. For example, there is a channel in which control information is multiplexed with a television signal and transmitted, and there is a channel in which control information is not multiplexed at all with a television signal.
Further, even in a channel in which control information is multiplexed with a television signal and transmitted, the control information may be transmitted in a fixed or irregular manner intermittently.

Therefore, in the wired television broadcasting system, it is necessary to ensure that each receiving terminal can receive the control information without omission, that is, the probability that each receiving terminal receives the control information (hit rate). Therefore, it is necessary to control all the receiving terminals based on the latest control information at all times. By the way, in order to increase the hit rate of this control information, various means have been developed from the past, but all of these means are still in the process of development, and the details are sufficiently practical. The current situation is that it cannot be said that the contents have been written.

[0005]

As described above, in the conventional cable television broadcasting system, it is necessary to increase the hit rate of control information in each receiving terminal, but there is still room for improvement in the means for that. There is a lot left behind, and there is a strong demand for detailed development to make it more practical.

Therefore, the present invention has been made in consideration of the above circumstances, and it is possible to surely improve the hit rate of control information in each receiving terminal, and to improve it so that it is more practically applicable. An object is to provide a good television broadcasting system.

[0007]

In a television broadcasting system according to the present invention, an ordinary television signal and first control information including key information for descrambling and sub information are multiplexed and scrambled. The transmitted television signal and the second control information for receiving the television signal on the receiving side are transmitted through different transmission channels, and the second control information transmitted by the transmission means. Based on the first receiving means that always receives and the second control information received by the first receiving means,
Receiving a television signal in which the control information of
And a second receiving means for obtaining the first control information multiplexed with the television signal.

According to the above-mentioned structure, the television set on the transmitting side has the ordinary television signal and the first control information including the descrambling key information and the sub information multiplexed and scrambled. The television signal and the second control information for receiving the television signal on the receiving side are transmitted as separate independent channels, respectively, and the receiving terminal always receives the second control information. Every other time, the channel including the first control information is received by the second control information.
The receiving terminal can surely receive the first control information, the hit rate of the first control information can be improved, and it becomes more practical.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, FIG. 1 shows the configuration of a broadcasting center in the CATV broadcasting system described here. That is, this broadcasting center is equipped with a program source 11 that generates television signals corresponding to a plurality of channels. This program source 1
Among the respective television signals output from No. 1, those not subjected to scramble processing are the plurality of modulation circuits 121, ...
, 12n, respectively, 90MHz ~ 550
After being subjected to modulation processing in the MHz band, it is supplied to the mixing circuit 13.

Of the television signals output from the program source 11, those to be scrambled are a plurality of scramble encoders 141, 142, ...
, 14 m, respectively, and scrambled. In this case, each television signal output from the program source 11 is scrambled in the state where the first control information described later output from the control computer 15 is multiplexed.

Then, the scramble encoder 1
Each of the television signals output from the reference numerals 41, 142, ..., 14m is composed of a plurality of modulation circuits 161, 162 ,.
It is supplied to each 6m, 90MHz ~ 550MHz
After being subjected to the modulation processing in the band, it is supplied to the mixing circuit 13.

Further, the control computer 15 outputs second control information, the details of which will be described later. This second control information is FSK (Frequency Shift Keying).
After being supplied to the modulation circuit 17 and subjected to FSK modulation processing in the band of 70 MHz, it is supplied to the mixing circuit 13.
The mixing circuit 13 includes the modulation circuits 121, ..., 12
, 16m and the outputs of the FSK modulation circuit 17 are frequency-multiplexed and output to a plurality of receiving terminals (not shown) via the output terminal 18.

Here, the first control information is as shown in FIG.
As shown as a data line in (a), it is multiplexed in the vertical blanking period of the video signal. The first control information is composed of a header portion, a control data portion, and a check code portion, and includes key information and sub information for descrambling. Further, as shown in FIG. 2B, the second control information is composed of a header portion, a control data portion and a check code portion, and each modulation circuit 121, ..., 12n, 161, 162. , ……, 1
It is adapted to be transmitted as an independent channel separately from the channel of the television signal output from 6m.

Next, FIG. 3 shows the details of the receiving terminal. That is, in FIG. 3, reference numeral 19 is an input terminal to which the frequency multiplexed signal transmitted from the broadcasting center is supplied. The frequency multiplexed signal supplied to the input terminal 19 is supplied to the demultiplexing circuit 20 and separated into the television signal and the second control information. Of these, the television signal is supplied to the tuner 21 to select a desired channel, and then the audio demodulation circuit 22 and the video demodulation circuit 2 are selected.
3 respectively.

The audio demodulation circuit 22 demodulates the audio signal contained in the input television signal,
The signal is output to the RF (Radio Frequency) modulator circuit 24. Further, the video demodulation circuit 23 demodulates the video signal included in the input television signal and outputs it to the video descramble circuit 25 and the control information separation circuit 26, respectively.

In this case, the control information separation circuit 26 separates the first control information from the input video signal, and outputs the key information in it to the video descramble circuit 25. Therefore, the video descramble circuit 25 descrambles the input video signal based on the key information and outputs it to the RF modulator circuit 24.
In addition, the sub information of the first control signal extracted by the control information separation circuit 26 is supplied to the microcomputer 27 and decoded.

Here, the RF modulator circuit 24 synthesizes the audio signal output from the audio demodulation circuit 22 and the video signal output from the video descramble circuit 25,
It is output to a television receiver (not shown) via the output terminal 28. Further, the second control information separated by the demultiplexing circuit 20 is FS supplied to the FSK demodulation circuit 29.
After being subjected to K demodulation processing, it is supplied to the microcomputer 27. The microcomputer 27 controls the operations of the tuner 21 and the video descrambling circuit 25 based on the input second control information and the sub information, which will be described in detail later.

Further, operation information is input to the microcomputer 27 from an unillustrated keyboard, remote control operation unit or the like via the input circuit 30. Therefore, when the subscriber selects and operates a desired channel, the operation information is analyzed by the microcomputer 27 and supplied to the tuner 21, and the specified channel is selected. Further, a display unit 31 is connected to the microcomputer 27 so as to display the operation information and the operating state of the entire receiving terminal.

Further, in FIG. 3, reference numeral 32 is a power supply circuit. The power supply circuit 32 is provided with the demultiplexing circuit 20, the tuner 21, the voice demodulation circuit 2 via the power supply terminal 33.
2, DC voltage is applied to the video demodulation circuit 23, the RF modulator circuit 24, the video descramble circuit 25, the control information separation circuit 26, the microcomputer 27, the FSK demodulation circuit 29, the input circuit 30, and the display 31, respectively. .

In this case, the demultiplexing circuit 20, the microcomputer 27, the FSK demodulating circuit 29, the input circuit 30 and the display 31 output from the power supply circuit 32 regardless of the on / off state of the power switch (not shown). The applied DC voltage is always applied. Further, the tuner 21, the audio demodulation circuit 22, the video demodulation circuit 2
3. The microcomputer 27 controls the RF modulator circuit 24, the video descramble circuit 25, and the control information separation circuit 26 so that the DC voltage output from the power supply circuit 32 is applied or not applied.

In the television broadcasting system configured as described above, the contents of the first and second control information and an operation example based on them will be described below. First, as shown in FIG. 4, in the control data portion of the second control information from the broadcasting center, an information destination for designating the receiving terminal to which the information is to be sent, and the receiving terminal designated by this information destination The information type for instructing to forcibly select the channel including the control information and the selected channel for specifying the channel including the first control information are transmitted.

Then, the microcomputer 27 of the receiving terminal is operated based on the flowchart shown in FIG. First, the microcomputer 27 determines that its own receiving terminal is designated based on the information destination included in the received second control information, and the operation is started (step S1). Then, when the microcomputer 27 determines in step S2 that the second control information includes the forced tuning instruction, the microcomputer 27 determines in step S2.
At 3, the various processes that have been performed up to that point are interrupted.

Thereafter, the microcomputer 27 determines in step S4 whether or not the power switch is in the off state, and if it is determined that the power switch is in the off state (YES), in step S5, Tuner 21,
The audio demodulation circuit 22, the video demodulation circuit 23, the RF modulator circuit 24, the video descramble circuit 25, and the control information separation circuit 26 are controlled to apply the DC voltage output from the power supply circuit 32.

After step S5, or if it is determined in step S4 that the power switch is not in the off state (NO), the microcomputer 27 includes the second control information in step S6. The tuner 21 is controlled so as to select the channel designated by the selected channel to be displayed, and the process is ended (step S7).

That is, the second control information is transmitted from the broadcasting center separately from the television signal as an independent dedicated channel, and the second control information is constantly transmitted to the receiving terminal regardless of the ON / OFF state of the power switch. The second control information is used to receive the first
Since the channel including the control information is forcedly selected, the receiving terminal can be surely received the first control information and the hit rate of the first control information can be improved.

When the power switch is off, the branching circuit 20, the microcomputer 27, F
Since only the circuit blocks necessary for receiving the second control information, such as the SK demodulation circuit 29, the input circuit 30, and the display unit 31, are supplied with power and are in an operating state,
Power consumption is also reduced and it becomes extremely suitable for practical use.

In the above example, the receiving terminal is forced to select the channel of the television signal in which the first control information is multiplexed, but this is, for example, the second control information. The channel number of the television signal in which the first control information is multiplexed may be displayed on the display 31 and the channel may be selected at the subscriber's discretion.

When the content of the first control information multiplexed in the broadcast television signal is different for each channel, what content is assigned to which channel by the second control information. Of the first control information is displayed on the display 31 so that the subscriber can select a channel in which the first control information having the necessary contents is multiplexed. It's okay.

Next, as shown in FIG. 6A, in the control data portion of the second control information from the broadcasting center, an information destination for designating the receiving terminal to which the information is to be sent and this information destination are designated. The information type indicating that the character message to be given to the receiving terminal is generated, and the transmission channel designating the channel on which the character message is multiplexed and transmitted are transmitted.

Further, as shown in FIG. 6B, an information destination for designating the receiving terminal to which the information is to be transmitted is designated in the control data portion of the first control information from the broadcasting center, and this information destination is designated. The information type indicating that the text message should be given to the receiving terminal and the message content indicating the content of the text message are transmitted.

Then, the microcomputer 27 of the receiving terminal is operated based on the flowchart shown in FIG. First, the microcomputer 27 determines that its own receiving terminal is designated based on the information destination included in the received second control information, and the operation is started (step S8). When the microcomputer 27 determines in step S9 that the second control information includes the text message generation instruction,
After the occurrence of the text message is displayed on the display 31 in step S10, the transmission channel of the text message is stored in step S11, and the process ends (step S1).
2) It is done.

When the transmission channel of the text message is stored in this way, the microcomputer 27 of the receiving terminal is operated based on the flowchart shown in FIG. First, the subscriber confirms that the occurrence of the text message is displayed on the display unit 31, and performs an operation for viewing the message, whereby the operation is started (step S13).

Then, the microcomputer 27 controls the tuner 21 in step S14 so as to select the transmission channel of the stored text message, and in step S15, the first channel multiplexed in the transmission channel. Control information is received, and the first control information is decoded in step S16. Then, the microcomputer 2
In step S17, the device 7 looks at the information type of the decrypted first control information and determines whether the first control information is a text message.

When it is determined that the decrypted first control information is not a text message (NO), the microcomputer 27 executes another process in step S18 and returns to the process of step S15. . When it is determined that the first control information decrypted in step S17 is a text message (YES), the microcomputer 27 displays the content of the text message on the screen of the television receiver in step S19. Let
It is ended (step S20).

That is, the second control information indicates that a text message is being generated, and also indicates the channel on which the text message is transmitted.
The content of the text message is transmitted according to the first control information, and when it is determined that the text message is generated at the receiving terminal, the transmission channel of the text message is tuned in and the text message is taken in. Therefore, it is possible to prevent the subscriber from missing the text message as much as possible, and the hit rate can be improved in this respect as well.

Next, as shown in FIG. 9A, an information destination for designating a receiving terminal to which the information is to be transmitted is designated in the control data portion of the second control information from the broadcasting center, and this information destination is designated. Information type indicating that it is the contract information to be given to the receiving terminal, the update number of the contract information given to the receiving terminal contracted by the contract information, and the updated contract information are multiplexed and transmitted. And the transmission channel that specifies the channel to be transmitted.

Further, as shown in FIG. 9B, an information destination for designating a receiving terminal to which the information is to be transmitted is designated in the control data portion of the first control information from the broadcasting center, and this information destination is designated. The information type indicating the contract information to be given to the receiving terminal and the contract information content indicating the content of the updated contract information are transmitted.

Then, the microcomputer 27 of the receiving terminal is operated based on the flowchart shown in FIG. First, the microcomputer 27 determines that its own receiving terminal is designated based on the information destination included in the received second control information, and the operation is started (step S21). Then, when the microcomputer 27 determines in step S22 that the information is contract information based on the information type in the second control information, the update number is the same as the update number of the previously received contract information in step S23. If it is the same (YES), the process is ended as it is (step S31).

If it is determined that the update number received in step S23 is not the same as the previously received update number (NO), the microcomputer 27 determines in step S23.
At 24, the tuner 21 is controlled so as to select the transmission channel in which the contract information is multiplexed. Then, the microcomputer 27 receives the first control information multiplexed in the transmission channel in step S25, and decodes the first control information in step S26. After that, the microcomputer 27, in step S27,
By looking at the information type of the decrypted first control information, it is determined whether or not the first control information is contract information.

When it is determined that the decrypted first control information is not the contract information (NO), the microcomputer 27 executes other processing in step S28 and returns to the processing of step S25. . When it is determined that the first control information decrypted in step S27 is contract information (YES), the microcomputer 27 takes in and updates the contents of the contract information in step S29, and in step S30. Then, the new update number is stored and the process ends (step S31).

That is, the second control information indicates the update number of the contract information, the channel on which the contract information is transmitted is indicated, and the content of the contract information is transmitted by the first control information. Every time, if the receiving terminal determines that the update number has changed from the previous time, it selects the transmission channel of the contract information and fetches the contract information, so even if the contract information is updated, the subscriber It is possible to prevent missing new contract information as much as possible, and the hit rate can be improved also in this respect.

Next, when the second and first control information shown in FIGS. 9A and 9B are sent from the broadcasting center, the microcomputer 27 of the receiving terminal is
It may be operated based on the flowchart shown in FIG. First, the microcomputer 27
However, the operation is started by determining that its own receiving terminal is designated based on the information destination included in the received second control information (step S32).

Then, in step S33, the microcomputer 27 determines from the information type in the second control information that the contract information is contract information, and in step S34, the update number of the contract information received last time is updated. If it is determined that they are the same (YES), it is ended (step S44).

When it is determined that the update number received in step S34 is not the same as the previous update number (NO), the microcomputer 27 determines in step S35.
The display 31 warns the subscriber to select the transmission channel in which the contract information is multiplexed. After that, the microcomputer 27 waits in step S36 until the subscriber gives permission to select the transmission channel in which the contract information is multiplexed, and when the permission is issued, the contract information is multiplexed in step S37. The tuner 21 is controlled so as to select the converted transmission channel.

Then, the microcomputer 27 receives the first control information multiplexed in the transmission channel in step S38, and decodes the first control information in step S39. After that, in step S40, the microcomputer 27 looks at the information type of the decrypted first control information and determines whether or not the first control information is contract information.

In this case, when it is determined that the decrypted first control information is not the contract information (NO), the microcomputer 27 executes another process in step S41 and returns to the process of step S38. Be done. When it is determined that the first control information decrypted in step S40 is contract information (YES), the microcomputer 27 takes in and updates the contents of the contract information in step S42, and in step S43. Then, the new update number is stored and the process ends (step S44).

That is, when the receiving terminal determines that the update number has changed from the previous one, it does not forcefully switch to the channel on which the contract information is transmitted, but waits for permission from the subscriber before transmitting the contract information. Since it is switched to the channel, it becomes more suitable for practical use.

Next, when the second and first control information shown in FIGS. 9A and 9B are transmitted from the broadcasting center, the microcomputer 27 of the receiving terminal is
It may be operated based on the flowchart shown in FIG. First, the microcomputer 27
However, the operation is started by determining that its own receiving terminal is designated based on the information destination included in the received second control information (step S45).

Then, in step S46, the microcomputer 27 determines from the information type in the second control information that the contract information is contract information, and in step S47, the update number of the contract information received last time is updated. If it is determined that they are the same (YES), it is ended (step S50).

When it is determined that the update number received in step S47 is not the same as the previous update number (NO), the microcomputer 27 determines in step S48.
The transmission channel transmitting the contents of the contract information to be updated is stored, and a new update number is stored in step S49, and the process ends (step S50).

When the transmission channel transmitting the contents of the contract information to be renewed and the renewal number are stored in this way, the microcomputer 27 of the receiving terminal is shown in FIG.
It is operated based on the flowchart shown in FIG. First,
The operation is started when the subscriber switches the power switch from the on state to the off state (step S51).

Then, the microcomputer 27 mutes the video and audio outputs in step S52, and then determines in step S53 whether a new update number is stored before the power switch is turned off. To do. When it is determined that the new update number is stored (YES), the microcomputer 27 controls the tuner 21 so as to select the transmission channel in which the contract information is multiplexed in step S54.

After that, the microcomputer 27 receives the first control information multiplexed in the transmission channel in step S55, and decodes the first control information in step S56. Then, in step S57, the microcomputer 27 looks at the information type of the decrypted first control information and determines whether or not the first control information is contract information.

In this case, when it is determined that the decrypted first control information is not the contract information (NO), the microcomputer 27 executes another process in step S58 and returns to the process of step S55. Be done. Further, when it is determined that the first control information decrypted in step S57 is contract information (YES), the microcomputer 27 fetches and updates the contents of the contract information in step S59.

After this step S59 or when it is determined in step S53 that a new update number is not stored (NO), the microcomputer 27 proceeds to step S60, where the tuner 21 and the voice demodulator are demodulated. The circuit 22, the video demodulation circuit 23, the RF modulator circuit 24, the video descramble circuit 25, and the control information separation circuit 26 are controlled so that the DC voltage output from the power supply circuit 32 is not applied, and the operation ends (step S61). )
Is done.

That is, when the power switch of the receiving terminal is in the ON state, even if it is judged that the update number of the contract information has changed from the last time, the channel for transmitting the contract information is not compulsorily switched, When the subscriber turns off the power switch of the receiving terminal, it switches to the channel transmitting the contract information and fetches the contract information, and then the tuner 21 and the audio demodulation circuit 2
2. Since the power supply to the video demodulation circuit 23, the RF modulator circuit 24, the video descramble circuit 25, the control information separation circuit 26, etc. is cut off, it becomes even more practical.

Next, when the second and first control information shown in FIGS. 9A and 9B are transmitted from the broadcasting center, the microcomputer 27 of the receiving terminal is
4 may be operated based on the flowchart shown in FIG. First, while the subscriber is turning off the power switch, the microcomputer 27 determines that its own receiving terminal is designated based on the information destination included in the received second control information. This starts the operation (step S62).

Then, the microcomputer 27 determines in step S63 that the contract information is the contract information based on the information type in the second control information, and in step S64, the update number of the contract information received last time is updated. If it is determined that the numbers are not the same (NO), the microcomputer 27 determines in step S65.
The DC voltage output from the power supply circuit 32 is supplied to the tuner 21, the audio demodulation circuit 22, the video demodulation circuit 23, the RF modulator circuit 24, the video descramble circuit 25, and the control information separation circuit 26. Control.

Then, in step S66, the microcomputer 27 controls the tuner 21 so as to select the transmission channel in which the contract information is multiplexed. afterwards,
The microcomputer 27 receives the first control information multiplexed in the transmission channel in step S67, and decodes the first control information in step S68. Then, the microcomputer 27 executes step S
At 69, the information type of the decrypted first control information is checked to determine whether the first control information is contract information.

In this case, when it is determined that the decrypted first control information is not the contract information (NO), the microcomputer 27 executes another process in step S70 and returns to the process of step S67. Be done. When it is determined that the first control information decrypted in step S69 is contract information (YES), the microcomputer 27 takes in and updates the contents of the contract information in step S71, and in step S72. , Store a new update number.

After this step S72, or when it is determined in step S64 that the update number is the same as the last time (NO), the microcomputer 27
Is the tuner 21, the audio demodulation circuit 22, the video demodulation circuit 23, and the RF modulator circuit 2 in step S73.
4. The video descramble circuit 25 and the control information separation circuit 26 are controlled so that the DC voltage output from the power supply circuit 32 is not applied, and the process ends (step S74).

That is, when the power switch of the receiving terminal is in the off state, when it is determined that the update number of the contract information has changed from the previous one, power is forcibly supplied to each circuit block and the contract information is transmitted. Since it receives an existing channel, fetches the contract information, and then shuts off the power supply to each circuit block, it becomes even more practical.

Next, as shown in FIG. 15A, an information destination for designating the receiving terminal to which the information is to be sent is designated in the control data portion of the second control information from the broadcasting center, and this information destination is designated. Information type indicating that it is the contract information to be given to the receiving terminal, the update number of the contract information given to the receiving terminal contracted by the contract information, and the updated contract information are multiplexed and transmitted. And the transmission channel that specifies the channel to be transmitted.

As shown in FIG. 15 (b), the information center for designating the receiving terminal to which the information is to be transmitted is designated in the control data portion of the first control information from the broadcasting center, and this information destination is designated. Information type indicating that the contract information should be given to the receiving terminal, the update number of the contract information given to the receiving terminal contracted by the contract information, and the contract information content indicating the content of the updated contract information And send.

Then, the microcomputer 27 of the receiving terminal is operated based on the flowchart shown in FIG. First, the microcomputer 27 determines that its own receiving terminal is designated based on the information destination included in the received second control information, and the operation is started (step S75). When the microcomputer 27 determines in step S76 that the contract information is the information type in the second control information, the update number is the same as the update number of the previously received contract information in step S77. If it is the same (YES), the process is ended as it is (step S86).

If it is determined that the update number received in step S77 is not the same as the previously received update number (NO), the microcomputer 27 determines in step S77.
At 78, the tuner 21 is controlled so as to select the transmission channel in which the contract information is multiplexed. Then, the microcomputer 27 receives the first control information multiplexed in the transmission channel in step S79, and decodes the first control information in step S80. Thereafter, the microcomputer 27, in step S81,
By looking at the information type of the decrypted first control information, it is determined whether or not the first control information is contract information.

When it is determined that the decrypted first control information is not the contract information (NO), the microcomputer 27 executes another process in step S82 and returns to the process of step S79. . When it is determined that the first control information decrypted in step S81 is contract information (YES), the microcomputer 27 determines in step S83 that the update number included in the first control information is second. It is determined whether or not it matches the update number included in the control information of 1., and if it is determined that they do not match (NO), the process ends (step S86).

If it is determined in step S83 that the update number included in the first control information and the update number included in the second control information match (YES), the microcomputer 27 In step S84, the contents of the contract information are fetched and updated, and in step S85, a new update number is stored and the processing is ended (step S86).

That is, when it is determined by the second control information that the update number of the contract information is not the same as the previous one, the first channel is selected after the channel on which the contract information is transmitted.
Whether the update number included in the control information of the second control information matches the update number included in the second control information, and if it is determined that the update number is included, the content of the contract information is taken in. By this, the broadcasting center can reliably provide the necessary contract information to the receiving terminal of the intended subscriber,
The hit rate can be improved.

Next, the second shown in FIGS. 15 (a) and 15 (b).
Also, when the first control information is sent from the broadcasting center, the microcomputer 27 of the receiving terminal may be operated based on the flowchart shown in FIG. First, the microcomputer 2
The operation is started when the terminal 7 determines that its own receiving terminal is designated based on the information destination included in the received second control information (step S87).

When it is determined in step S88 that the microcomputer 27 is contract information based on the information type in the second control information, the microcomputer 27 updates the contract information whose update number was previously received in step S89. Whether or not it is the same as the number is determined, and when it is determined to be the same (YES), the process is ended as it is (step S99).

If it is determined that the update number received in step S89 is not the same as the update number received previously (NO), the microcomputer 27 determines in step S89.
At 90, the tuner 21 is controlled so as to select the transmission channel in which the contract information is multiplexed. Then, the microcomputer 27 receives the first control information multiplexed in the transmission channel in step S91, and decodes the first control information in step S92. After that, the microcomputer 27, in step S93,
By looking at the information type of the decrypted first control information, it is determined whether or not the first control information is contract information.

When it is determined that the decrypted first control information is not the contract information (NO), the microcomputer 27 executes other processing in step S94 and returns to the processing of step S91. . When it is determined that the first control information decrypted in step S93 is contract information (YES), the microcomputer 27 determines in step S95 that the update number included in the first control information is second. It is determined whether or not it matches the update number included in the control information of No. 1, and if it is determined that they do not match (NO), a descramble operation is performed on the video descramble circuit 25 in step S96. The process is stopped and terminated (step S99).

If it is determined in step S95 that the update number included in the first control information and the update number included in the second control information match (YES), microcomputer 27 determines In step S97, the content of the contract information is fetched and updated, and in step S98, a new update number is stored and the processing is ended (step S99).

That is, when it is determined that the update number included in the first control information does not match the update number included in the second control information, the video descramble circuit 25.
By stopping the descrambling operation of, it is possible to prevent the receiving terminal from fetching wrong contract information, that is, the contract information to be given to another receiving terminal, which makes it even more practical. Is. It should be noted that the present invention is not limited to the above-described embodiments, and can be implemented with various modifications without departing from the scope of the present invention.

[0076]

As described above in detail, according to the present invention,
It is possible to surely improve the hit rate of the control information in each receiving terminal, and to provide an extremely good television broadcasting system improved so as to be more suitable for practical use.

[Brief description of drawings]

FIG. 1 is a block diagram showing details of a broadcasting center, showing an embodiment of a television broadcasting system according to the present invention.

FIG. 2 is a diagram shown for explaining first control information and second control information in the same embodiment;

FIG. 3 is a block configuration diagram showing details of a receiving terminal in the embodiment.

FIG. 4 is a diagram shown for explaining an example of second control information in the same embodiment;

FIG. 5 is a flowchart shown to explain the operation of the receiving terminal based on the second control information.

FIG. 6 is a diagram shown for explaining another example of second and first control information in the same embodiment.

FIG. 7 is a flowchart shown for explaining the operation of the receiving terminal based on the second and first control information.

FIG. 8 is a flowchart shown to explain the operation of the receiving terminal based on the second and first control information.

FIG. 9 is a diagram for explaining still another example of the second and first control information in the same embodiment.

FIG. 10 is a flowchart shown to explain the operation of the receiving terminal based on the second and first control information.

FIG. 11 is a flowchart shown to explain the operation of the receiving terminal based on the second and first control information.

FIG. 12 is a flowchart shown to explain the operation of the receiving terminal based on the second and first control information.

FIG. 13 is a flowchart shown to explain the operation of the receiving terminal based on the second and first control information.

FIG. 14 is a flowchart shown to explain the operation of the receiving terminal based on the second and first control information.

FIG. 15 is a diagram shown for explaining still another example of the second and first control information in the same embodiment.

FIG. 16 is a flowchart shown to explain the operation of the receiving terminal based on the second and first control information.

FIG. 17 is a flowchart shown to explain the operation of the receiving terminal based on the second and first control information.

[Explanation of symbols]

 11 ... Program source, 121-12n ... Modulation circuit, 13 ... Mixing circuit, 141-14m ... Scramble encoder, 15 ... Control computer, 161-16m ... Modulation circuit, 17 ... FSK modulation circuit, 18 ... Output terminal, 19 ... Input Terminals, 20 ... Demultiplexing circuit, 21 ... Tuner, 22 ... Audio demodulation circuit, 23 ... Video demodulation circuit, 24 ... RF modulator circuit, 25 ... Video descramble circuit, 26 ... Control information separation circuit, 27 ... Microcomputer, 28 ... output terminal, 29 ... FSK demodulation circuit, 30 ... input circuit, 31 ... indicator, 32 ... power supply circuit, 33 ... power supply terminal.

Claims (9)

[Claims] 1. A normal television signal, a television signal in which first control information including key information for descrambling and sub information is multiplexed and scrambled, and a receiving side of this television signal. Transmitting means for transmitting the second control information for receiving by the respective channels on different channels, a first receiving means for always receiving the second control information transmitted by the transmitting means, and a first receiving means for transmitting the second control information. A television signal in which the first control information is multiplexed is received based on the second control information received by a receiving means, and the first control information multiplexed in the television signal is received. A television broadcasting system comprising: a receiving terminal having a second receiving means for obtaining. 2. The second control information includes channel designation information for designating a channel of a television signal in which the first control information is multiplexed, and the second receiving means designates the channel. 2. The television broadcasting system according to claim 1, wherein a channel designated by the information is automatically selected. 3. The second control information is character message generation information indicating that a character message has occurred in the sub-information included in the first control information, and a television in which the character message is multiplexed. Channel designation information for designating a channel of a signal, and the first receiving means includes display means for displaying that a text message is generated based on the text message generation information,
The television broadcasting system according to claim 1, wherein the channel designated by the channel designation information is automatically selected based on an operation of receiving the text message. 4. The second control information specifies an update number of the sub information included in the first control information and a channel of a television signal in which the sub information corresponding to the update number is multiplexed. Channel designation information, and the second receiving means detects that the update number has changed and automatically selects the channel designated by the channel designation information. Item 1. The television broadcasting system according to Item 1. 5. The first receiving means includes a display means for displaying that the update number has changed, and the channel designated by the channel designation information is automatically generated based on an operation of receiving the sub-information. The television broadcasting system according to claim 4, wherein the television broadcasting system is selected selectively. 6. The first receiving means, when the power switch of the receiving terminal is in an ON state, detects that the update number has changed and stores the channel designated by the channel designation information. Storage means, channel selection means for automatically selecting a channel stored in the storage means in a state in which the power switch of the receiving terminal is switched from an on state to an off state, and this channel selection means Control means for controlling the receiving terminal to a state corresponding to the OFF state of the power switch when the reception of the sub-information included in the television signal of the selected channel is completed. Item 4. The television broadcasting system according to Item 4. 7. The first receiving means always receives the second control information regardless of the ON state and the OFF state of the power switch of the receiving terminal, and the second receiving means is the power switch. Is in an off state, the first control means for detecting that the update number has changed and controlling the receiving terminal to a state corresponding to the on state of the power switch, and the first control means Completed the reception of the channel selection means for automatically selecting the channel specified by the channel specification information in the driven state and the sub information multiplexed with the television signal of the channel selected by this channel selection means. 5. The television broadcasting system according to claim 4, further comprising: second control means for controlling the receiving terminal to a state corresponding to the off state of the power switch in this state. 8. The first control information has an update number of sub-information included in the second control information, and the first receiving means has an update number included in the second control information. Detecting that the channel has been changed and automatically selecting the channel designated by the channel designation information, and the update number included in the television signal of the channel selected by the channel selecting means. 5. The television according to claim 4, further comprising control means for taking in the sub information included in the first control information in a state where the update number included in the second control information matches. Broadcast system. 9. The control means, if the update number contained in the television signal of the channel selected by the channel selecting means and the update number contained in the second control information do not match, the first means. 9. The television broadcasting system according to claim 8, wherein the descramble processing for the television signal in which the control information is multiplexed is stopped.