JPH11187378A - Digital broadcast system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital broadcast system allowing a center device to optionally control each terminal devices with reduced power consumption and satisfactory efficiency. SOLUTION: In addition to control information transmitted accompanying digital information to control the operation of a terminal device 200 receiving digital information, a control command for allowing the device 200 to execute prescribed processing different from reception is sent from a center device to the terminal device 200. Thereby, the center device can control the terminal device 200 without limiting to the control of receiving operation and even at the time of not receiving digital information. In addition, when the center device broadcasts digital information through plural channels, the number of commands to be transmitted is reduced compared with the number at the time of transmitting the same control command accompanying the digital information of each channel, therefore efficiency is improved. In addition, as a computer part 252 executed prescribed processing by executing program operation, power consumption is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital broadcasting system, and more particularly, to a digital broadcasting system in which a center device for broadcasting digital information and a plurality of terminal devices for receiving the digital information are provided. The present invention relates to a digital broadcasting system in which a center device controls a receiving operation of each terminal device by transmitting control information accompanying digital information.

[0002]

2. Description of the Related Art In a digital broadcasting system, when pay broadcasting is generally performed, video information is scrambled at a broadcasting center and transmitted to a subscriber side. Then, a conditional access module such as an IC card is provided in the terminal device of each subscriber,
From the broadcasting center to the subscriber side, common information (ECM) common to a plurality of subscribers and individual information (EM
M) is transmitted together with video information, and the subscriber side descrambles using the information, thereby realizing terminal control by the broadcast center such as viewing management.

[0003] The encryption system used there usually has a hierarchical structure. That is, the video information is scrambled using the scramble key Ks which is updated frequently (for example, updated every one second), and the scramble key Ks is used using the work key Kw whose update frequency is relatively low (for example, updated every month). Encrypted. The encrypted scramble key Ks is transmitted while being included in the common information. Further, the work key Kw is encrypted using a master key Kmi prepared for each subscriber, and is transmitted while being included in individual information. The master key Kmi is stored in a conditional access module such as an IC card.

When the broadcasting center gives a subscriber permission to view a pay program, the work information Kw encrypted with the master key Kmi unique to the subscriber is included in the individual information to be sent to the subscriber. Is transmitted. The subscriber,
When the encrypted work key Kw is decrypted with the master key Kmi to obtain the work key Kw, the work key Kw is stored in the conditional access module until it is updated to a new work key. As a result, the subscriber can decrypt the scramble key Ks transmitted as being included in the common information by using the stored work key Kw, and further, the scramble key Ks obtained by decrypting the video information. Can be used for descrambling.

However, since the subscriber does not know at what timing the individual information including the control information for updating the work key Kw is sent, it is necessary to keep the terminal device powered on. I have to. The terminal device consumes as much power as it does when receiving video information even in the standby state of waiting for reception, so that much useless power is consumed. In order to solve such a problem, for example, there is a transmitting device and a receiving device disclosed in Japanese Patent Application Laid-Open No. 7-202888.

FIG. 6 is a block diagram showing a configuration of a main part of a transmitting device and a receiving device (an example of a conventional digital broadcasting system) disclosed in the above publication. Below,
An operation in which the center device controls the terminal device in the system of FIG. 6 will be described. In FIG. 6, a center device 601 is shown.
Transmits the individual information to the terminal device 602, including information indicating an update time indicating when the individual information is updated next. Upon receiving the transmitted individual information, the terminal device 602 extracts update time information from the individual information, stores it in the time information storage unit and the timer 612, and sets the timer. Then, the time information storage unit and the timer 612 output a control signal to the power control unit 613 when the scheduled update time is reached based on the stored update time information.

[0007] The power supply control section 613 turns on the power supply 614 according to a control signal from the time information storage section and the timer 612. Then, after a certain period of time has elapsed since the power supply 614 was turned on, the power supply 614 is turned off. Or,
If the update time information includes information indicating the scheduled update end time, the power supply 614 is turned off based on the information.
In the system of FIG. 6, since the power supply 614 is turned on at the time when the individual information is received by the power supply control unit 613 controlling the power supply 614 in this manner, the individual information can be reliably updated. Therefore, there is no need to always turn on the power supply 614 of the terminal device 602, and wasteful power consumption for waiting for reception can be reduced.

[0008]

However, in the system shown in FIG. 6, once the timer is set and the power is turned off, the power is not turned on until the next scheduled update time unless the subscriber turns on the power. . Therefore, individual information cannot be updated at any time,
Also, it was difficult to provide services such as emergency information provision.

In the system shown in FIG. 6, if the terminal device 602 fails to receive the individual information from the center device 601 and cannot update the individual information, the terminal device 602 uses the new update time information. Since there is no such information, it becomes impossible to know when individual information is sent thereafter. In order to prevent this, the center device 601 must repeatedly transmit the same individual information several times after the scheduled update time. The reason is that the center device 601 is
This is because even if new individual information is transmitted to the terminal device 2, it is not possible to grasp whether the individual information has been updated on the terminal device 602 side. As a result of repeatedly transmitting the same individual information, it is expected that the transmission efficiency of other information is reduced and the control efficiency of the system is correspondingly reduced.

[0010] Therefore, an object of the present invention is to provide a digital broadcasting system in which a center device can arbitrarily control each terminal device efficiently with little power consumption.

[0011]

According to a first aspect of the present invention, there is provided a center device for broadcasting digital information and a plurality of terminal devices for receiving the digital information. A digital broadcasting system in which a center device controls a reception operation of each terminal device by transmitting control information for controlling an operation of receiving digital information by the device in association with the digital information, wherein The apparatus includes a command transmitting unit that periodically or irregularly transmits, to each terminal apparatus, a control command for causing the terminal apparatus to execute a predetermined process different from the receiving operation without accompanying digital information. First terminal means for receiving digital information and control information, and processing the digital information based on the control information; Receiving a control command transmitted from the de-transmitting means, by the operation program in accordance with the control command, and a second circuit means for executing a predetermined process.

[0012] As described above, in the first aspect, the terminal device is different from receiving the digital information in addition to the control information for controlling the operation of receiving the digital information by the terminal device. A control command for executing a predetermined process is transmitted from the center device to the terminal device. Then, since the terminal device performs a predetermined process in response to the control command, the center device not only controls the receiving operation of the digital information, but also controls the terminal device even when the digital information is not being received. Can control. When the center apparatus broadcasts digital information through a plurality of channels, the number of control commands to be transmitted is smaller than when transmitting the same control command accompanying digital information of each channel, similarly to control information. Therefore, the efficiency of the system increases. Furthermore, since the terminal device is provided with the second circuit means and the second circuit means executes a predetermined process by performing a program operation, it consumes less power than executing the same process in terms of hardware. Power is reduced.

According to a second aspect, in the first aspect, the second circuit means of each terminal device is always supplied to the second circuit means of the terminal device regardless of whether power is supplied to the first circuit means of the terminal device. Power is supplied.

As described above, in the second invention, since the power is always supplied to the second circuit means, the center device can transmit the control command irregularly, and therefore, the terminal device can be transmitted at an arbitrary timing. Can control the device.

In a third aspect based on the second aspect, each terminal device further includes a power supply control means for controlling a power supply to the first circuit means of the terminal device, and the command transmission means comprises A control command for starting power supply to the first circuit means of the terminal device, the second circuit means of each terminal device receives the control command transmitted from the command transmission means, By performing a program operation in response to the control command, it is determined whether or not power is supplied to the first circuit means of the terminal device,
When the result of the determination is negative, the power supply control means of the terminal device is instructed to start supplying power to the first circuit means of the terminal device.

As described above, in the third invention, the control command for starting the supply of power to the first circuit means of the terminal device is transmitted from the center device to the terminal device. When the power supply to the first circuit means of the terminal device is stopped, the power supply can be started. As a result, the terminal device can receive the digital information and the control information attached thereto, so that the digital information and the control information attached thereto can be reliably transmitted from the center device to the terminal device. In this manner, the center device can supply power to the first circuit means of each terminal device whenever necessary, so that the center device always supplies power to the first circuit means of each terminal device. Even without this, for example, urgent digital information can be provided or control information can be transmitted irregularly.

In a fourth aspect based on the second aspect, each terminal device is connected to an external storage device for recording digital information received by the terminal device, and each terminal device is connected to the terminal device. External storage device control means for controlling an external storage device connected to the device, wherein the command transmission means transmits a control command for controlling the external storage device connected to the terminal device to each terminal device; The second circuit unit of each terminal device receives the control command transmitted from the command transmission unit, performs a program operation according to the control command, and instructs the external storage device control unit of the terminal device. It is characterized in that an external storage device connected to the terminal device is controlled.

As described above, in the fourth aspect, the terminal device is connected to the external storage device for recording the received digital information. Since the control command for controlling the operation of the external storage device is transmitted from the center device to the terminal device, the center device can control the external storage device connected to the terminal device. Moreover,
The external storage device can be controlled even when power is not supplied to the first circuit means of the terminal device.

In a fifth aspect based on the first aspect, the center device broadcasts digital information on a plurality of channels, and each terminal device selects one of the plurality of channels to receive the digital information. Each terminal device further comprises channel control means for controlling channel selection of the terminal device, and a command transmission means causes each terminal device to execute a control command for causing the terminal device to select a specific channel. And the second circuit unit of each terminal device receives the control command transmitted from the command transmission unit and instructs the channel control unit of the terminal device by performing a program operation according to the control command. And select a specific channel.

As described above, in the fifth invention, the center device broadcasts digital information through a plurality of channels, and the terminal device selects one of the plurality of channels to receive the digital information. Since the control command for controlling the channel selection of the terminal device is transmitted from the center device to the terminal device, the center device can control the channel selection of the terminal device.

In a sixth aspect based on the first aspect, each terminal device transmits a reception response to notify the center device that video information, control information, or a control command has been received from the center device. And a transmission unit for performing the transmission.

As described above, in the sixth aspect, when video information, control information, or a control command is received from the center device, a reception response for notifying the reception is transmitted from the terminal device to the center device. Therefore, the center device can know whether or not the terminal device has received the transmitted video information, control information, or control command. Therefore, the center device does not need to repeatedly transmit the above information and commands in case the terminal device fails to receive, and as a result, the efficiency of the system increases.

In a seventh aspect based on the first aspect, the plurality of terminal devices are previously divided into a plurality of groups, and each terminal device has an individual address unique to the terminal device, And a group address of a group to which the group belongs to, and the command transmitting unit transmits the control command to a terminal device to which a specific individual address or a specific group address has been allocated among the plurality of terminal devices. And

As described above, in the seventh aspect, the plurality of terminal devices are previously divided into a plurality of groups, and each terminal device has an individual address unique to the terminal device and a terminal device. The group address of the group to which the group belongs is given. Of these terminal devices, the control command is transmitted to the terminal device to which a specific individual address or a specific group address is assigned, so that the center device can perform terminal control for each terminal device or for each group. it can.

An eighth invention is characterized in that, in the first invention, the command transmission means transmits the control command using a frequency band different from the digital information and the control information attached thereto.

As described above, in the eighth aspect, since the control command is transmitted using a frequency band different from the digital information and the control information attached thereto, a flexible system configuration can be realized. Become.

According to a ninth aspect, in the first aspect, the command transmission means transmits the control command via a transmission medium different from the digital information and the control information attached thereto.

As described above, in the ninth aspect, the control command is transmitted via a transmission medium different from the digital information and the control information attached thereto, so that a flexible system configuration can be realized. Become.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. In the first to third embodiments, a digital CA which is an example of a digital broadcasting system is used.
The TV system will be described. (First Embodiment) FIG. 1 is a block diagram showing a configuration of a main part of a center device of a digital CATV system according to a first embodiment of the present invention. The center device 100 of FIG.
Are a plurality of video information sources 101, a multiplexing unit 102, a related information control unit 103, a terminal control unit 104, a scrambler 10
5, a modulation unit 106, a modulation unit 107, a demodulation unit 108, and a mixing / distributing unit 109. The center device 100
The transmission path 1 is provided on the broadcasting center side for performing digital broadcasting.
10, a plurality of terminal devices 200 on the subscriber side (FIG. 2)
(See below).

In the center device 100, each of the plurality of video information sources 101 transmits video information for performing a broadcasting service or the like. The related information control unit 103 generates common information (ECM) common to the plurality of terminal devices 200 and individual information (EMM) for each terminal device 200 as first control information, and sends the generated information to the multiplexing unit 102. In addition, a scramble key Ks for scrambling the video information is transmitted to the scrambler 105. The multiplexing unit 102 multiplexes each piece of video information from the plurality of video information sources 101 and common information and individual information from the related information control unit 103, and outputs the multiplexed video stream to the scrambler 105.

The scrambler 105 has a scramble key K
The video stream from multiplexing section 102 is scrambled using s, and the video stream obtained by scrambling is output to modulating section 106. The modulation unit 106 modulates the video stream from the scrambler 105 using a digital modulation method such as 64QAM (64-level quadrature amplitude modulation) and modulates the video stream obtained by the modulation / distribution.
9 is output. The terminal control unit 104 includes a plurality of terminal devices 2
A terminal control command as second control information for controlling 00 is output to the mixer / distributor 109 via the modulator 107, and the uplink data (transmitted from the terminal device 200) from the mixer / distributor 109 is output. The signal is received via the demodulation unit 108.

Modulation section 107 modulates a terminal control command from terminal control section 104 using a modulation scheme such as FSK (frequency shift keying) and outputs the result to mixing / distributing section 109.
Demodulation section 108 demodulates uplink data from mixing / distributing section 109 and outputs the demodulated data to terminal control section 104. Mixer / distributor 10
9 receives the modulated video stream from the modulator 106 and the modulated terminal control command from the modulator 107, allocates them to appropriate frequency bands, and outputs them to the transmission line 110. 110 receives the uplink data (transmitted from the terminal device 200) and demodulates the data
08.

FIG. 2 is a block diagram showing a configuration of a main part of a terminal device of the digital CATV system according to the first embodiment of the present invention. 2 includes a distributor 201, a tuner 202, a demodulator 203, a packet separator 204, a conditional access module 205, a descrambler 206, a decoder 207, a modulator 208, and a demodulator 20.
9, a CPU 210, a RAM 211, a ROM 212, and an I / F 213.

In the terminal device 200, the distributor 201
Outputs the video information received from the transmission line 110 and the video stream including the common information and the individual information as the first control information to the tuner 202 and the terminal control command as the second control information to the demodulation unit 209, respectively. Then, it transmits the uplink data modulated by the modulator 208 to the transmission line 110. The tuner 202 is controlled by the CPU 210, receives a video stream from the distributor 201, extracts a video stream of a specific frequency band therefrom, and outputs the video stream to the demodulation unit 203. The demodulation unit 203 demodulates the video stream from the tuner 202 and outputs the demodulated video stream to the packet separation unit 204.

The packet separating section 204 extracts common information and individual information from the demodulated video stream, outputs them to the conditional access module 205, and outputs video information to the descrambler 206. Conditional reception module 205
Performs a limited reception using the common information and the individual information, and performs a scramble key Ks encrypted from the common information.
Is taken out, decoded, and output to the descrambler 206. The descrambler 206 descrambles the video information from the packet separation unit 204 using the scramble key Ks obtained by decryption, and outputs it to the decoding unit 207. The decoding unit 207 decodes the video information obtained by descrambling and outputs it to a TV or the like.

The modulator 208 modulates the uplink data from the CPU 210 using a modulation scheme such as PSK (phase shift keying) and outputs the modulated data to the distributor 201. The demodulation unit 209 includes:
The terminal control command from the distributor 201 is demodulated and the CPU
Output to 210. The CPU 210 controls the demodulation unit 209 in addition to controlling the tuner 202 and the terminal device 200 as a whole.
Performs a predetermined program operation in response to a terminal control command from the base station, and outputs uplink data to the modulation section 208.
The RAM 211 stores various data for the CPU 210 to perform a predetermined program operation, intermediate data generated in an operation process, and the like. The ROM 212 stores a computer program or the like for causing the CPU 210 to perform a predetermined program operation. I / F (interface)
213 is a command of a subscriber who operates the terminal device 200,
CPU 210 converts the data into a format suitable for computer processing.
Give to.

As can be seen from the above description, the tuner 2
02, one receiving system (hereinafter referred to as a first receiving system) that performs processing related to reception and decoding of a video stream by the demodulation unit 203, the packet separation unit 204, the conditional access module 205, the descrambler 206, and the decoding unit 207.
Are configured, and the TS processing unit 251 collects them.
Call. Further, the CPU 210, the RAM 211, and the RO
M212 is collectively called a computer unit 252.

The computer section 252 and the demodulation section 20
9 forms a control command receiving system (hereinafter, a second receiving system) different from the first receiving system. Also, the computer section 252 and the modulation section 208 constitute a transmission system for an uplink signal. Power is supplied to the second receiving system and the transmitting system independently of the first receiving system. In other words, even when the power of the terminal device 200 (the TS processing unit 251 thereof) is turned off, the second reception system and the transmission system are functioning, and the control command is transmitted from the center device 100 to the terminal device 200, From the device 200 to the center device 10
0 can transmit an upstream signal.

FIG. 3 is a diagram showing an example of a frequency arrangement of the transmission line 110 connecting the center device 100 of FIG. 1 and the terminal device 200 of FIG. In FIG. 3, the transmission line 110
On the top, the video information and the first
A plurality of broadcast frequency bands 301 for transmitting a video stream including control information of the terminal, a terminal control frequency band 302 for transmitting second control information including a terminal control command from the center device 100, and a terminal device Uplink data frequency band 30 for transmitting uplink data from
3 are arranged. For example, a plurality of broadcast frequency bands 301
Are arranged at intervals of 6 MHz in a frequency region of 90 MHz or more, the terminal control frequency band 302 is arranged at a frequency of 75 MHz, and the uplink data frequency band 303 is arranged at a frequency of 40 MHz.

The digital CATV configured as described above
The operation of the system will be described below. The center apparatus 100 multiplexes the video information and the first control information including each piece of information necessary for viewing the video information such as common information and individual information, and multiplexes the broadcast frequency band 3 as a video stream.
01 is transmitted. If the conditional access is required, the scrambler 105 scrambles the video information using the scramble key Ks generated in the related information control unit 103 and transmitted from the related information control unit 103. At this time, the related information control unit 103 uses the work key Kw to
s is encrypted and transmitted in the form of common information. Work key K
w is generated in advance by the related information control unit 103, and further encrypts the work key Kw using the master key Kmi of each subscriber, and transmits the work key Kw included in the individual information.

The common information includes, in addition to the scramble key Ks, information common to each subscriber such as a viewing fee. The update interval of the scramble key Ks is relatively short, for example, updated every second. The center device 100 transmits the common information to the plurality of terminal devices 200 as needed (therefore, at a high frequency) whenever the scramble key Ks is updated. On the other hand, the individual information includes contract information for each subscriber in addition to the work key Kw. The update interval of the work key Kw is relatively long, for example, updated every year. The center device 100 transmits the individual information to each terminal device 200 as appropriate (thus at a low frequency) when the contract information changes, when a message is individually sent, or when the work key Kw is updated.

When each terminal device 200 receives a video stream from the center device 100, it extracts common information and individual information therefrom. The extracted common information and individual information are stored by the conditional access module 205 until they are updated. The conditional access module 205 stores the master key Kmi, checks the contract information included in the individual information, and if it can be viewed, decrypts the work key Kw with the master key Kmi, and further decrypts the work key Kw.
Decrypts the scramble key Ks. Then, the obtained scramble key Ks is sent to the descrambler 206. The descrambler 206 descrambles using the scramble key Ks, and decodes the obtained video information into the decoding unit 20.
Send to 7. Then, the decoding unit 207 decodes the video information and outputs it to a TV or the like.

In addition to the above-mentioned video stream, the center device 100 transmits a terminal control command for causing the terminal device 200 to perform a predetermined program operation by using the terminal control frequency band 302 as second control information. Transmit.
In all the terminal devices 200, the terminal control command transmitted by the second receiving system which is always supplied with power is transmitted regardless of whether or not the power of the terminal device 200 is turned on (that is, the first receiving system). (Even if power is not supplied to the receiving system). Also, the terminal device 20
When the power supply 0 is turned on, it is set so that a command can be received regardless of the reception channel selected at that time (see FIG. 3). Further, if necessary, the transmission system can transmit uplink data from the terminal device 200 to the center device 100 using the uplink data frequency band 303.

When terminal device 200 receives the terminal control command, CPU 210 responds to the terminal control command by
The computer program is read from the ROM 212 to perform predetermined program operations, for example, power control of the TS processing unit 251 and control of an external storage device connected to the terminal device 200 (the specific operations are the second and third operations). Will be clarified in the embodiment).

The terminal device 200 transmits the uplink data to the center device 100 using the uplink data frequency band 303 if necessary. The uplink data is typically a reception response signal for notifying the center device 100 that the terminal device 200 has received a signal from the center device 100. Also, the data indicating the channel that the terminal device 200 is currently receiving is included in the uplink data and the center device 10
By transmitting to 0, the center apparatus 100 can grasp the reception status of each terminal 200 such as whether each terminal apparatus 200 is operating correctly or which channel is selected. Furthermore, it is also possible to conduct a survey of the audience rating and create a viewing history for each terminal device 200.

As described above, a plurality of broadcast frequency bands 30
When transmitting video information by using the center device 100,
Can not grasp which broadcast frequency band 301 each terminal device 200 has selected, so that conventionally, the same terminal control command is transmitted using all broadcast frequency bands 301. However, in the present embodiment, since the terminal control command is transmitted using the terminal control frequency band 302, it is not necessary to transmit the same terminal control command using all the broadcast frequency bands 301, and the transmission efficiency of video information is reduced. System efficiency.

In addition, if an abnormality occurs in any of the broadcast frequency bands 301 and the video stream is no longer transmitted, there has been a risk that terminal control may be hindered in the related art. Broadcast frequency band 301
However, even if an error occurs and the video stream is not transmitted at all, the terminal can be controlled using the terminal control frequency band 302.

For example, in the case of performing an announcement broadcast, in the related art, an announcement broadcast is performed using a specific broadcast frequency band 301.
According to the present embodiment, information to be provided to all subscribers, such as an announcement broadcast, can be transmitted by being included in the terminal control command. Can receive the information without performing the channel operation of the terminal device 200 (note that
The center device 100 may switch the channel of each terminal device 200 to a specific channel by transmitting the terminal control command including a command to change the reception channel of each terminal device 200. This will be described in a second embodiment).

In the case of transmitting common information, individual information, video information, or the like, the center device 1 is conventionally used.
00 did not know whether the terminal device 200 correctly received the information, but according to the present embodiment, the terminal device 200
00 is the frequency band 303 for uplink data to the center device 100
The center device 100 transmits a reception response using
Can recognize that the terminal device 200 has correctly received the information. Therefore, the center device 100 does not need to transmit the same information many times as in the related art, and as a result, the efficiency of the system increases.

In this embodiment, all the frequency bands (broadcasting frequency band 301, terminal control frequency band 302, and uplink data frequency band 303) are assigned to the transmission line 110. For example, the terminal control frequency band 302 and the uplink data frequency band 303 are assigned to a telephone line or a CATV line to a satellite line or a terrestrial wave.
Each frequency band can be assigned to a different transmission medium. This enables a flexible system configuration.

The modulation scheme of the video stream in the modulation section 106 is not limited to 64 QAM, but may be other multi-level QAM, multi-level VSB (residual sideband modulation), 8
Any digital modulation scheme such as PSK may be used. Similarly, the modulation scheme of the terminal control command in modulation section 107 is not limited to FSK, and the modulation scheme of uplink data in modulation section 208 is not limited to PSK. Any other modulation scheme may be used.

The frequency arrangement on the transmission line 110 is not limited to the arrangement shown in FIG. 3, but various arrangements are possible.

The present embodiment is not limited to a digital CATV system, but can be applied to all digital broadcasting systems such as a digital satellite broadcasting system and a digital terrestrial broadcasting system.

Further, in the present embodiment, video information is transmitted using a plurality of broadcast frequency bands 301, but video information may be transmitted using one broadcast frequency band 301. In addition, when bidirectional communication is not performed, the uplink data frequency band 303 is not required, and in that case, the demodulation unit 108 in FIG. 1 and the modulation unit 208 in FIG. 2 are not required.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
It is a block diagram which shows the structure of the principal part of the terminal device of the digital CATV system which concerns on embodiment. The terminal device 400 in FIG. 4 further includes a power control unit 401 in the terminal device 200 in FIG. The power supply control unit 401
The power of the TS processing unit 251 is controlled by the instruction of the PU 210. Other components perform the same operation as that of the terminal device 200. The digital CAT according to the present embodiment
Since the configuration of the main part of the center device of the V system is the same as that of FIG. 1, FIG. 1 is also used in the following description. The frequency arrangement of the transmission line 110 connecting the center device 100 of FIG. 1 and the terminal device 400 of FIG. 4 is the same as that of FIG. 3, and therefore, FIG.

The operation of the digital broadcasting system having the above configuration will be described below. Terminal device 40
0 indicates that the first and second receiving systems and transmitting systems are all functioning as long as the subscriber has turned on a power supply (not shown). That is, it is possible to receive the video stream, the common information and the individual information as the first control information, and output the video information to a TV or the like. It is also possible to receive a terminal control command as the second control information. On the other hand, when the subscriber is in a standby state in which the power of the terminal device 400 is turned off, in the terminal device 400, power supply to the TS processing unit 251 is stopped, and power is supplied to other components. In other words, the function of the first receiving system that receives the video stream and the first control information and outputs the video information stops, but the second receiving system that receives the terminal control command and executes the predetermined program operation And a transmission system for transmitting uplink data is functioning.

When updating the individual information or transmitting urgent video information, the center device 100 generates a terminal control command for turning on the power of the terminal device 400 in advance, before updating the individual information, It is transmitted to the corresponding terminal device 400 as the second control information. The terminal device 400 already powered on ignores the terminal control command, and the terminal device 400 powered off starts up the power supply in response to the command.

More specifically, when a terminal control command is received, in the terminal device 400, the CPU 210 first
The terminal control command is analyzed, a computer program for controlling power-on is read from the ROM 212, and the next operation is performed according to the program. That is, it is determined whether or not the power of the terminal device 400 is currently on. If the result of the determination is that the power is off, the power supply control unit 401 is instructed to perform control for turning on the power. In response, the power supply control unit 401 performs power-on control, and when power supply to the TS processing unit 251 is started, the terminal device 400 receives video information and first control information from the center device 100. It is possible to do.

As described above, when urgent video information is transmitted or when individual information is suddenly updated, power control is conventionally performed using a timer. However, in the present embodiment, the terminal control command can be received even when the power of the terminal device 400 is off, so that the terminal control command includes the power control information. By transmitting, the power of the terminal device 400 can be turned on. As a result, the terminal device 400 can receive the control information for updating the video information and the individual information, so that the terminal device 400 transmits urgent video information or when the individual information needs to be updated suddenly. , They can be done reliably.

The second receiving system (the distributor 201, the modulator 208, the demodulator 209 and the computer 252)
Of the first receiving system (TS processing unit 251) is extremely small (for example, 30 W of the first receiving system).
5W for the second receiving system), so that each terminal device 400
Power consumption in the standby state can be significantly reduced. As a result, the power consumption reduced in the entire system is enormous.

Further, the terminal control unit 104
For forcibly changing the receiving channel of the center device 1 by including the information in the terminal control command.
00 to the terminal device 400, and the terminal device 400
The tuner 202 can be controlled according to the transmitted terminal control command to change the receiving channel. More specifically, when a terminal control command is received, in the terminal device 400, the CPU 210 first analyzes the terminal control command, reads a computer program for performing control for changing channels from the ROM 212, and then reads The following operation is performed according to the program. That is, it is determined whether or not the current channel of the terminal device 400 is the specified channel. If the result of the determination is that the channel is not the specified channel, the tuner 202 is instructed.
Switch channels. When the tuner 202 switches the channel accordingly and the designated channel is selected, the terminal device 400 can receive emergency video information from the center device 100. This makes it possible for each terminal device 400 to reliably receive urgent video information and important video information that all subscribers should view.

When control information for updating individual information is received, or when emergency video information is received,
Uplink data including a reception response for notifying that the terminal device 400 has received the information can also be transmitted to the center device 100 through the uplink data frequency band 303. With this configuration, the center device 100 can recognize that the terminal device 400 has received the information, and can reliably and efficiently update the individual information and provide the video information. .

In the present embodiment, the power control unit 401
Turned on the power of all components of the TS processing unit 251. For example, in the case of updating individual information, only the tuner 202, demodulation unit 203, packet separation unit 204 and conditional access module 205 required When the power is turned on, various power controls can be performed, such as a reduction in power consumption.

In order to turn off the power of the terminal device 400 that has been turned on by the center device 100, a timer is provided in the terminal device 400 or the center device 1
00 transmits the terminal control command to the terminal device 400 including the information of power off.

In the present embodiment, the CPU 210 controls the power control unit 401.
May simply transfer a terminal control command for controlling power to the power control unit 401, and the power control unit 401 may control power in accordance with the terminal control command.

Also, an individual address or a group address is assigned to each terminal device 400, and the center device 100 can transmit a terminal control command in units of the individual address or the group address. More specifically, a plurality of terminal devices 400 belonging to the system are grouped in advance into a plurality of groups (for example, divided into regions, divided into subscription periods, or used for general households, companies, public facilities, etc.). Etc.). Then, for each terminal device 400, an individual address unique to the terminal device 400 and the terminal device 400
And the group address of the group to which the group belongs. The center device 100 transmits a control command to a terminal device 400 to which a specific individual address is assigned, or transmits a control command to each terminal device 400 to which a specific group address is assigned, among a plurality of terminal devices 400 belonging to the system. Send By doing so, the specific terminal device 4
00 or the terminal device 400 belonging to a specific group can be updated with individual information or provided with urgent video information. Note that the group address can be appropriately changed by individual information or a terminal control command.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
It is a block diagram which shows the structure of the principal part of the terminal device of the digital CATV system which concerns on embodiment. The terminal device 500 in FIG. 5 is different from the terminal device 400 in FIG. 4 in further including an external storage device control unit 501. Terminal device 500
Is connected to the external recording device 502. The external recording device 502 records video information obtained by decoding by the decoding unit 207 of the terminal device 500. The external storage device control unit 501 controls the external storage device 502 according to an instruction from the CPU 210. The other components are the terminal device 4 of FIG.
The same operation as in 00 is performed. Note that the configuration of the main part of the center device of the digital CATV system according to the present embodiment is the same as that of FIG. 1, so that FIG. 1 is also used in the following description. Further, since the frequency arrangement of the transmission path 110 connecting the center device 100 of FIG. 1 and the terminal device 500 of FIG. 5 is the same as that of FIG. 3, FIG. 3 will be referred to in the following description.

The operation of the digital broadcasting system having the above configuration will be described below. Now, the external storage device 502 is set to record a certain program. It is assumed that the broadcast time of the program has been changed for some reason. At this time, the center device 100 transmits information indicating that the broadcast time has been changed to the terminal device 500 by including the information in the terminal control command. On the other hand, the external storage device 502
Notifies the terminal device 500 in advance of recording information such as which program is reserved for recording and whether the program is currently being recorded. Upon receiving the terminal control command, the terminal device 500 analyzes the terminal control command and the recording information, and determines whether to change the currently set recording reservation. If it is determined that a change is required, the terminal device 500
Transmits control information for changing the currently set recording reservation to the external storage device control unit 501. The external storage device control unit 501 changes the set recording reservation based on the received control information.

More specifically, the external recording device 502
The subscriber is set to record a certain sports broadcast, and recording is currently being performed according to the setting. At this time, it is assumed that the sports broadcast has been extended.
In such a case, conventionally, the recording operation was stopped even during the program as set. However, the present embodiment deals with a change in the program end time as follows. That is, the information to extend the broadcast time for sports broadcasting is transmitted from the center device 100 to the terminal device 500 by including the information in the terminal control command. In the terminal device 500, the CPU
210 compares the terminal control command with the recording information to determine whether or not the sports broadcast is reserved for recording by the external storage device 502. As a result of the determination, if a recording reservation is made, the CPU 210 instructs the external storage device control unit 501 to transmit control information for changing the reserved recording stop time to the external storage device 502. The external storage device 502 delays the set recording stop time based on the received control information. Thus, the external storage device 502 can record the sports broadcast until the end of the broadcast even if the broadcast time is extended.

When the sports broadcast is extended as described above, the start / end times of the subsequent programs are delayed. In such a case, in the related art, a part of the immediately preceding program was recorded, and a part of the reserved program was not recorded. However, in the present embodiment, a change in the start / end time of a program is dealt with as follows. That is, the center device 100
From the terminal control command to the terminal device 500, including information that the broadcast start time is delayed by a predetermined time. In the terminal device 500, the CPU 210 compares the terminal control command with the recording information to determine whether or not a recording reservation for the program is set in the external storage device 502. As a result of the determination, when the recording reservation is set, the external storage device 502 is instructed to transmit control information for changing the recording start time to the external storage device 502. The external storage device 502 delays the recording start / stop time by a predetermined time based on the received control information. Accordingly, the external storage device 502 can correctly record the program reserved for recording even if the broadcast time is changed.

Here, it should be added here that when a certain program is reserved for recording, in order to cope with a change in the broadcast time due to an extension of a baseball broadcast or the like, conventionally, the subscriber side predicts the extension time, and There was no other choice but to set a longer recording time. Further, when the broadcast time of a program is changed due to unexpected extraordinary news or the like, the subscriber has no way to cope. On the other hand, in the present embodiment, since the broadcast center controls the terminal device 500 on the subscriber side to change the reservation setting of the external storage device 502 connected thereto, the change of the broadcast time can be dealt with without any problem. Recording can be performed reliably and efficiently.

When the terminal device 500 changes the reservation setting of the external storage device 502 as described above, if it is necessary to turn on the power of the TS processing section 251, the recording information from the external storage device 502 is added. Power control unit 401 based on
Can also control the power supply of the TS processing unit 251. When it is necessary to switch the receiving channel of the terminal device 500, the CPU 210
The tuner 202 can be controlled based on the recording information from the receiver 02 to switch the receiving channel.

As described above, according to the present embodiment, the center device 100 transmits information indicating the extension of the broadcast time and the delay of the broadcast start / end time to the terminal device 500 by including the information in the terminal control command. Since the terminal device 500 controls the recording operation of the external storage device 502 by comparing the transmitted terminal control command with the recording information from the external storage device 502, the recording may stop in the middle of the program. ,
Problems such as recording another program are eliminated. As a result, the subscriber can, for example, extend the broadcast time or start broadcasting /
It is not necessary to record for a long time in consideration of the change of the end time, etc., and efficient recording can be performed.

Further, the power of the terminal device 500 can be turned on only when the external storage device 502 performs the recording, and the power of the terminal device 500 can be turned off when the external storage device 502 is not recording, so that the power consumption can be reduced.

In the present embodiment, the terminal device 500 compares the terminal control command containing information indicating the change of the broadcast time with the recording information. When it is detected that information indicating a change in the broadcast time is included in the external storage device 5,
02 is transferred to the external storage device 50.
2 itself can control the recording operation by comparing the recording information with the broadcast change information. In this case, it is not necessary to notify the terminal device 500 of the recording information from the external storage device 502.

In this embodiment, the center device 100
Said that information indicating the extension of the broadcast time and the delay of the broadcast start / end time was included in the terminal control command and transmitted. However, the broadcast time was interrupted due to the effects of special programs, etc. Can also be transmitted. In this case, the terminal device 500 controls the external storage device 502 based on the transmitted information to stop recording or advance the recording start / stop time.

Further, from the center device 100 to the terminal device 50
0, the center device 100 directly controls the recording operation of the external storage device 502 by transmitting the information indicating the start and stop of the recording operation to the external storage device 502 through the terminal control command. It is also possible to perform more flexible recording control.

Also in this embodiment, as in the second embodiment, if a terminal control is performed by assigning an individual address or a group address to each terminal device 500, a specific subscriber, a specific region, a group, or the like can be obtained. It is possible to control only the terminal device 500 of the subscriber belonging to (external storage device 502 connected to), and as a result, for example, only the subscriber who has a predetermined contract is allowed to record the video information. More flexible recording control becomes possible. It is needless to say that also in the present embodiment, the group address can be appropriately changed by the individual information or the terminal control command.

In the present embodiment, the external storage device 502 is connected to the terminal device 500 to record the video information sent from the center device 100. Instead, the center device 100 transmits various data and e-mails. In this case, a personal computer or the like may be connected to the terminal device 500 to record such various data and e-mail. Also,
Various application examples are conceivable, such as realizing an electronic newspaper by transmitting newspaper information from the center device 100.
As described above, the present invention is not particularly limited to video information recording.

Also in this embodiment, similarly to the second embodiment, the terminal device 500
If a reception response notifying that the terminal control command has been received is included in the uplink signal and transmitted, it is possible to perform recording control reliably and efficiently.

Further, from the terminal device 500 to the center device 10
It is possible to transmit not only the above-described reception response but also various data in the uplink data transmitted to 0. For example, if information indicating the operation state of the terminal device 500 is transmitted, it is determined whether the terminal device 500 is operating normally.
It can be confirmed on the center device 100 side. In addition, each terminal device 5
If 00 transmits the currently received channel information,
It can also be applied to audience rating surveys.

FIGS. 1 to 5 are views showing main parts as described above, and elements which are not necessary for explanation of the present invention are omitted.

[Brief description of the drawings]

FIG. 1 is a digital CAT according to a first embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a main part of a center device of the V system.

FIG. 2 is a digital CAT according to the first embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a main part of a terminal device of the V system.

FIG. 3 is a diagram showing an example of a frequency arrangement of a transmission line 110 connecting the center device of FIG. 1 and the terminal device of FIG. 2;

FIG. 4 is a digital CAT according to a second embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a main part of a terminal device of the V system.

FIG. 5 is a digital CAT according to a third embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a main part of a terminal device of the V system.

FIG. 6 is a block diagram illustrating an example of a configuration of a main part of a conventional digital CATV system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 center device 101 video information source 102 multiplexing unit 103 related information control unit 104 terminal control unit 105 scrambler 106, 107, 208 modulation unit 108, 203, 209 demodulation unit 109 mixing / distributing device 200, 400, 500 terminal device 201 distribution Device 202 tuner 204 packet separation unit 205 conditional access module 206 descrambler 207 decoding unit 210 CPU 211 RAM 212 ROM 213 I / F 251 TS processing unit 252 computer unit 301 broadcast frequency band 302 terminal control frequency band 303 uplink data frequency Obi 401 Power control unit 501 External storage device control unit 502 External storage device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasufumi Naito 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (9)

[Claims] A center device for broadcasting digital information and a plurality of terminal devices for receiving the digital information are provided, and control is performed from the center device to each terminal device for controlling the operation of receiving the digital information by the terminal device. A digital broadcasting system in which a center device controls a receiving operation of each terminal device by transmitting information in association with the digital information, wherein the center device transmits to each of the terminal devices, A command transmission unit that transmits a control command for executing a predetermined process different from the reception operation, periodically or irregularly without being attached to the digital information; And first circuit means for receiving the control information and processing the digital information based on the control information; Receiving a control command transmitted from, by the operation program in accordance with the control command, and a second circuit means for executing the predetermined processing, the digital broadcasting system. 2. The second circuit means of each of the terminal devices includes:
2. The digital broadcasting system according to claim 1, wherein power is always supplied regardless of whether or not power is supplied to the first circuit means of the terminal device. 3. The terminal device according to claim 1, wherein:
Power supply control means for controlling power supply to the circuit means, wherein the command transmission means transmits a control command to each terminal device for starting power supply to the first circuit means of the terminal device. Then, the second circuit means of each of the terminal devices receives the control command transmitted from the command transmission means and performs a program operation in accordance with the control command, so that the first circuit means of the terminal device can perform the program operation. Determining whether or not power is being supplied, and, if the determination result is negative, instructing the power supply control means of the terminal device to start supplying power to the first circuit means of the terminal device; The digital broadcast system according to claim 2, wherein: 4. An external storage device for recording digital information received by the terminal device is connected to each of the terminal devices, and each of the terminal devices is connected to an external storage device connected to the terminal device. Further comprising an external storage device control unit that controls the terminal device, wherein the command transmission unit transmits a control command for controlling an external storage device connected to the terminal device to each of the terminal devices, The second circuit means receives the control command transmitted from the command transmission means, performs a program operation in accordance with the control command, instructs the external storage device control means of the terminal device, and instructs the terminal device to The digital broadcasting system according to claim 2, wherein the digital broadcasting system controls an external storage device connected thereto. 5. The center device broadcasts digital information through a plurality of channels, and each of the terminal devices is configured to select one of the plurality of channels to receive the digital information. The terminal device further includes channel control means for controlling channel selection of the terminal device, wherein the command transmission unit transmits a control command for causing the terminal device to select a specific channel to each of the terminal devices, The second circuit unit of each of the terminal devices receives the control command transmitted from the command transmission unit, performs a program operation according to the control command, and instructs the channel control unit of the terminal device to execute the program. The digital broadcasting system according to claim 1, wherein a specific channel is selected. 6. Each of the terminal devices transmits to the center device.
2. The digital broadcasting system according to claim 1, further comprising a transmitting unit that transmits a reception response for notifying that the video information, the control information, or the control command from the center device has been received. 7. The plurality of terminal devices are previously grouped into a plurality of groups, and each terminal device has an individual address unique to the terminal device and a group address of a group to which the terminal device belongs. Wherein the command transmission means is provided among the plurality of terminal devices.
The digital broadcast system according to claim 1, wherein the control command is transmitted to a terminal device to which a specific individual address or a specific group address is assigned. 8. The digital broadcast according to claim 1, wherein the command transmission unit transmits the control command using a frequency band different from the digital information and the control information accompanying the digital information. system. 9. The digital broadcast according to claim 1, wherein the command transmission unit transmits the control command via a transmission medium different from the digital information and the control information attached thereto. system.