JPH07307713A - Signal transmission system - Google Patents

Abstract

PURPOSE:To transmit plural information signals different in data transmission speed at high speed, efficiently and simultaneously, with respect to a signal transmission system multiplexing plural kinds of information signals and performing a one-way simultaneous transmission from a transmitter to plural receivers, via a communication satellite. CONSTITUTION:An information signal multiplexing means 1b multiplexes different kinds of information signals with each other to plural different prescribed locations within a small frame, transmits the signals to a transmission means 1a. An authorized information multiplexing means 1c multiplexes authorized information at the prescribed location within the small frame and transmits the information to a transmission means 1a. The transmission means 1a makes the transmitted multiplex signal have a two hierarchical frame constitution and performs one-way transmission to plural receivers 2 and 3 at the same time. In a receiver 2, an information signal separation means 2b multiplexes and separates different kinds of information signals with each other which are multiplexed to t.he plural different prescribed locations of the small frames, based on the transmission signal received by a reception means 2a. An authorized information separation means 2c separates the authorized information multiplexed to the prescribed location of the small frame.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmission system comprising a plurality of receiving devices and a transmitting device for performing one-way simultaneous transmission to them, and more particularly to multiplexing a plurality of types of information signals via communication satellites. The present invention relates to a signal transmission system that performs one-way simultaneous transmission from one transmitter to a plurality of receivers.

In recent years, there has been a demand for providing a signal transmission system for efficiently transmitting different types of information signals such as TV signals, audio signals, low speed and high speed data signals simultaneously through a communication satellite. Such a signal transmission system is applied to, for example, intra-company communication from the head office to each branch office, communication of lesson contents from the main school of a prep school to a branch school, communication for wide-area auction of used cars, and the like.

[0003]

2. Description of the Related Art In order to simultaneously transmit a plurality of information signals having different data transmission rates, it is necessary to multiplex the plurality of information signals. Conventionally, the multiplexing has been performed regardless of the data transmission rate. A method of simply allocating a time slot for each channel (each information signal) and performing time division multiplexing, or
A method of time division multiplexing is used in which the number of time slots in which information signals can be used is increased or decreased according to the data transmission rate.

On the other hand, in the conventional satellite communication, a code error is likely to occur in the wireless transmission line, so that a bidirectional communication system is adopted so that a request for resending data can be made.

[0005]

Generally, in a public line,
There are many kinds of information signals to be transmitted, and the combination of the multiplexed information signals constantly changes. Each of the above-mentioned multiplexing methods is suitable as a multiplexing method in such a public line. However, the scale of a device that implements these multiplexing methods is quite large, and therefore the cost of the device is inevitably high.

On the other hand, depending on the environment in which the signal transmission system is used, the type of data to be transmitted may be fixed. If such a multiplexing device is adopted in such an environment, an unnecessarily expensive device is used. Will be.

Further, if one-way communication is possible in satellite communication, cost reduction of the transmitting / receiving device can be expected, and it is demanded to provide a device capable of accurate transmission even in such one-way communication system.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a signal transmission system capable of simultaneously transmitting a plurality of information signals having different data transmission rates at high speed and efficiently.

Another object of the present invention is to provide a signal transmission system capable of accurate transmission even in a one-way communication system.

[0010]

According to the present invention, the type of data to be transmitted and the amount of information are limited, and an efficient data signal flow is realized by a frame structure adapted to them.

FIG. 1 is a diagram for explaining the principle of the present invention made to achieve the above object. The transmitting apparatus of the present invention includes transmitting means 1a for transmitting a transmission signal formed by a two-layer frame including a small frame and a master frame composed of a predetermined number of small frames to a plurality of receiving apparatuses 2 and 3.
Information signal multiplex means 1b that multiplexes different kinds of information signals into a plurality of different predetermined positions in the small frame and sends them to the transmitting means 1a, and transmitting means 1a that multiplexes authorization information in a predetermined position in the small frame. And the authorization information multiplex means 1c for sending to.

Further, the transmitting apparatus of the present invention includes error correction coding means for performing double error correction coding using a convolutional code and a BCH code. Further, the receiving apparatus of the present invention is formed by a two-layer frame including a small frame and a master frame composed of a predetermined number of small frames, and receiving means 2a for receiving a transmission signal transmitted from the transmitting apparatus 1.
A plurality of small frames included in the transmission signal received by the receiving means 2a are multiplexed at different predetermined positions,
An information signal demultiplexing means 2b for demultiplexing different types of information signals and an authorization information demultiplexing means 2c for demultiplexing the authorization information multiplexed at a predetermined position of a small frame included in the transmission signal received by the receiving means 2a. Prepare

Further, the receiving apparatus of the present invention comprises an output control means 2d for controlling the output of the information signal separated by the information signal separation means 2b based on the reception permission information contained in the authorization information.

[0014]

In the transmitting apparatus 1 configured as described above, the information signal multiplexing means 1b multiplexes different types of information signals at a plurality of different predetermined positions in the small frame and sends them to the transmitting means 1a. Authorization information multiplex means 1c
However, the authorization information is multiplexed at a predetermined position in the small frame and sent to the transmitting means 1a. The transmitting means 1a forms a transmitted multiple signal into a two-layer frame structure and receives a plurality of receiving devices 2,
One-way transmission to 3 simultaneously.

In the receiving device 2, the receiving means 2a receives the transmission signal transmitted from the transmitting device 1 and sends it to the information signal separating means 2b and the authorization information separating means 2c. The information signal separating means 2b demultiplexes different kinds of information signals respectively multiplexed at a plurality of different predetermined positions of the small frame included in the transmission signal, and the authorizing information separating means 2c includes the transmission signal. The authorization information multiplexed at a predetermined position of the small frame to be separated is separated.

In the present invention, the frame structure has two layers,
The type of data that can be transmitted and the amount of information are limited. Thereby, a plurality of information signals having different data transmission rates can be simultaneously transmitted at high speed and efficiently.

The output control means 2d controls the output of the information signal separated by the information signal separation means 2b based on the reception permission information included in the authorization information. As a result, only the predetermined receiving device can receive the predetermined information signal.

Further, since double error correction coding is performed using the convolutional code and the BCH code, accurate transmission is possible even in the one-way communication system.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multimedia broadcasting system which is an embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the basic configuration of the multimedia broadcasting system. That is, the multimedia broadcasting system provides a one-way simultaneous transmission service of various information signals utilizing the wide area broadcasting which is one of the features of satellite communication.
It mainly transmits ps TV signals and transmits 7kHz band audio signals and various digital data.

The system is basically composed of a transmitting station 11 and n receiving stations (up to 16000 stations) 12 and 13.
A multiple signal of about 2 Mbps is sent from the transmitting station 11 to the receiving stations 12 and 13 via the communication satellite 14 using one carrier. In addition, when constructing a system using a plurality of carriers according to the demand of a customer who introduces this system, a plurality of this basic configuration shall be installed.

In the transmitting station 11, a TV signal encoder (FEDIS-T etc.) 11a, an audio encoder 11b,
Each output of the network management device 11c is connected to the transmission terminal station device 11d. The TV signal encoder 11a receives and encodes a video signal, and the audio encoder 11b receives and encodes an audio signal. The network management device 11c is composed of a mini computer and controls the operation of the transmission terminal station device 11d. A data terminal is connected to the transmitting terminal station device 11d instead of the audio encoder 11b. The data terminal outputs a synchronous data signal, an asynchronous data signal, or a file data signal. Hereinafter, the encoded audio signal, the synchronous data signal, the asynchronous data signal, and the file data signal input to the transmitting terminal device 11d are collectively referred to as a "data signal". However, the transmitting terminal device 11
Only one of the encoded audio signal, the synchronous data signal, the asynchronous data signal, and the file data signal is fixedly input to d.

The transmitting terminal device 11d multiplexes and modulates various input information signals and sends them to the RF device 11e. The RF device 11e frequency-converts the modulated signal from IF to RF and sends it to the transmitting antenna 11g. Transmission terminal device 1
1d and the RF device 11e are the earth station monitoring control device 11
f is connected.

The receiving stations 12 and 13 demodulate the transmission signal from the transmitting station 11 and demultiplex the receivers 12a and 13a.
a and terminal devices 12b and 13b, respectively.

The main functions of the transmitting terminal device 11d are shown below. TV signal reception processing (interface termination, information extraction, etc.) Data signal reception processing (interface termination, information extraction, etc.) TV signal and data signal multiplexing Scramble processing for multiplexed signals, error correction coding 4-phase phase Modulation and its IF signal transmission Monitoring control information exchange with the earth station supervisory control unit 11f Transmission state control (transmission start, stop) according to instructions from the network management unit 11c Operator interface processing (status display, control input acceptance, etc.) , TV signal is MPEG-1 (Moving Picture Codi
ng Experts Group-1, CCITT H.221) video, accompanying audio, low-speed data LSD, high-speed data HSD, 1536
Refers to kbps video-related signals. Further, in FIG. 2, the TV signal encoder 11a, the audio encoder 11b, and the network management device 11C are accommodated in the transmitting station 11. However, they are installed in a place different from the transmitting station 11 and are connected to the public network. You may make it connected to the transmission station 11 via such as.

The modulation method performed in the transmitting terminal device 11d is absolute quadrature phase modulation (QPSK), and the modulation speed is 40
It is 96ksymbol / sec (transmission speed 2048kbps). Further, the transmission terminal station device 11d performs double error correction coding of BCH coding and convolutional coding. This double error correction coding improves the effect of error correction.

FIG. 3 is a diagram showing a transmission format (frame structure) in the satellite section. That is, the satellite frame is composed of two layers, a frame (small frame) and a master frame. The master frame is composed of 36 frames (# 1 to # 36), and the master frame serves as a unit for transmitting later-described authorization information, and the same authorization information is transmitted during one master frame. In order that the receiving station can identify the master frame, the head position of the master frame is notified to the receiving station by a bit b ₁₃ (master frame identifier) in the frame control code described later.
That is, the master frame identifier b ₁₃ in the first frame of the master frame is set to "1" and the other frames are set to "0".

A frame consists of 2048 bits (1 ms) and is a basic unit of information transmission. A TV signal, a data signal, etc. are time-division multiplexed in this frame and sent to a satellite line. That is, a frame is a 16-bit frame sync code (unique word UW), a 16-bit frame control code, 32-bit authorization information, a 1536-bit TV signal, and a 224-bit data signal (coded as described above). Audio signal, synchronous data signal, asynchronous data signal, and file data signal) and 224 bits of BCH parity.

The coding is performed by convolutional coding on the part from the frame control code to the BCH parity in FIG. 3, and further, BCH coding is performed on the part from the authorization information to the BCH parity in FIG. Will be implemented. These encodings are performed for any master frame.

A unique word UW is inserted into the frame synchronization code after convolutional coding (32 bits in total, 16 bits for each of I and Q) so that the receiving station can identify the frame. The frame control code is for transmitting DES (Data Encryption Standard) encryption information, a master frame identifier, and the like, and basically notifies the contents of the next master frame.

FIG. 4 shows the bit arrangement of the frame control code. The frame control code is from bit 0 to bit 15
Are sent to the satellite line in this order. In the figure, the DES encryption IV bit is a bit for transmitting a 36-bit IV (Initial Vector) in master frame units, and indicates the content of the next master frame. It is transmitted in 1 bit / 1 frame (36 bits / 1 master frame) and 1 master
The value is incremented by 1 for each frame.

The DES encryption ON / OFF control bit in FIG. 4 is
This bit is used to notify the receiving station whether DES encryption is being executed (ON / OFF). One master frame has the same content and shows the encrypted state of the next master frame. Not executed when the initial system operation is confirmed (OFF
) Is set, so that it is possible to avoid performing encryption when merely confirming the operation.

The master frame identifier bit of FIG.
It is a bit that displays the first frame of the master frame. It is set to "1" in the first frame and "0" in other frames.
And

The authorization information is used to permit reception of information signals (TV signals, data signals) to the receiver of the receiving station and DE.
This is for transmitting the key number for S-cipher, etc. By this, basically the contents of the master frame of the next and next times are notified.

FIG. 5 shows a bit array of the authorization information. Note that the authorization information is bit 0 to bit 31.
Are sent to the satellite line in this order. Receiver number SID in the figure
The designated bit is a bit that designates the receiver number SID, which is an ID number unique to the receiver, and is used to identify the receiver for which output control (reception permission control) described later is to be performed.

The group number GID designation bit in FIG. 5 is a bit for designating the number of a group to which a plurality of receivers belong, and is for identifying a group to which output control is to be performed. Note that one receiver can belong to a maximum of 24 groups, and this group is managed by the network management device 11c. The group number GID designation bit is also used to inform the receiver of the group to which it belongs.

The TV signal output control bit in FIG. 5 indicates whether or not the receiver designated by the receiver number SID designation bit or the receiver belonging to the group designated by the group number GID designation bit is permitted to receive the TV signal. Or (ON /
This is a control bit for instructing OFF). On the receiver side, when the own receiver is designated or even if one group is designated, the TV signal is received.

The data signal output control bit in FIG. 5 instructs the receiver designated by the receiver number SID designating bit or the receiver belonging to the group designated by the group number GID designating bit to permit reception of the data signal. Is a control bit for. Of the data signals, the audio signal and the asynchronous data signal are configured so that they can be transmitted through four channels independent of each other, and reception permission is also performed independently. Data signals other than the audio signal and the asynchronous data signal (synchronous data signal, file data signal) follow the data signal output control bit of bit 25.

The contact output control bit of FIG. 5 instructs the receiver designated by the receiver number SID designation bit or the receiver belonging to the group designated by the group number GID designation bit to open or close the contact output of the receiver. This is a control bit for doing. On the receiver side, when its own receiver is specified or even if the group to which it belongs is specified, the contact output is closed if there is a CLOSE command and the contact output is opened if there is an OPEN command. To do so.

The encryption key number control bit in FIG. 5 is a control bit for notifying all receivers of the DES encryption key to be used in the future. Four types of unique encryption keys for each system and the corresponding key numbers (Nk) are determined in advance and stored in the transmitting station side and the receiving station side. The receiving station can obtain the encryption key when the transmitting station notifies the key number (Nk) after the operation starts.

Next, a basic operation method of the authorization information will be described with reference to FIG. 6 showing the definition of the content of the authorization information as appropriate. First, the system operator determines in advance the group to which each receiver belongs.

Then, after the system is started up, each receiver is notified of the group to which it belongs by an instruction from the network management device 11c (the format shown in). Next, output control notification on the receiver side (TV signal or data signal reception permission notification, contact output open / close control notification)
Is basically done for the group (the format shown in). However, it is also possible to perform individual output control notification to a specific receiver (format shown in).

Since the receiver can belong to a maximum of 24 groups, when the contents of the output control notification for each group are different, the actual control is performed by the logical sum (OR) of the execution (on) control. And For example, a receiver belongs to group G1 and group G2, output control notification for G1 is TV signal = on, contact output = on (CLOSE), output control notification for G2 is TV signal = on, data signal = on. , The receiver actually performs output control based on TV signal = on, data signal = on, contact output = on (CLOSE).

In addition, the system operator appropriately specifies and changes the encryption key.
More instructions (format shown in). However, encryption execution (o
If the encryption key is changed in the state of n), the part where the encryption cannot be decrypted always appears at the change point on the receiver side. In order to avoid that, in the transmitting terminal device 11d,
When the encryption key change notification is received from the network management device 11c, the encryption is automatically stopped (off) once,
The actual encryption key change notification is sent, and then the encryption is executed again (on).

In addition, when adding or deleting a belonging group to a receiver, all the groups already registered in the receiver are once deleted (the format shown in) and then newly set (the format shown in ). Therefore, on the receiver side, when adding or deleting the belonging group,
Output control momentary interruption occurs. To avoid this, even if the notification of addition or deletion of the belonging group is received, the output control is temporarily held in the previous state until the next output control notification is received.

Although it is possible to notify all receivers of the deletion of the belonging group information (the format shown in), this is not used because it is dangerous in actual operation. The output control notification is sent to the receiver every minute by the network management device 11c via the transmitting terminal device 11d regardless of the change. The notification of the change of the group to which the user belongs is sent using the gap of the output control notification.

Next, TV signal extraction processing and multiplexing will be described. The TV signal is input from the TV signal encoder 11a to the transmitting terminal station device 11d through various interfaces, and after the information portion is extracted in the transmitting terminal station device 11d, it is multiplexed according to the satellite frame format. , To the receiving station.

That is, high-speed digital leased line (I431a)
When the interface is used, the line is terminated at the common part in the transmitting terminal device 11d, and the TV information part (1536kbp
s, accompanying voice, low speed data / high speed data, etc.) are extracted, and 1544kHz clock and 8kHz timing are extracted. These clocks and timings are used for multiplexing processing and clock generation. Note that TV information is not extracted when the line is open (when the line is manually set).

Further, when the RS-449 interface or the V.35 interface is used, the TV signal and the clock itself are transmitted, and therefore, the transmitting terminal station device 11d does not particularly perform the extraction work. However, for the purpose of reducing the load (circuit) at the receiving station because 8 kHz timing is required at the time of decoding the TV signal at the receiving station side, the transmitting terminal station device 1
8kHz timing is extracted in 1d and used for multiplexing timing to satellite frame.

The timing extraction is performed by the H.221 compliant sync code (FAS) detection. The TV information extracted by the above method is multiplexed on the satellite frame at various timings created according to the clock and 8 kHz timing.

Next, the processing of the audio signal will be described. The audio signal (maximum 4) coded by the audio encoder 11b is transmitted as a burst of 56 kps per channel at a line speed of 2048 kHz and is transmitted to the transmitting end station device 1
Passed to 1d. Specifically, 12 at a line speed of 2048kHz
7-bit audio signal every 5 μs (up to 4)
Is passed to the transmitting terminal device 11d.

In the transmitting terminal device 11d, a maximum of four audio signals are format-converted into a format suitable for a satellite frame, multiplexed, and output to the satellite line. In addition, in the transmitting terminal device 11d, the transmission signal is interleaved to disperse burst errors. That is, since convolutional coding is performed on the transmitting side and it is decoded on the receiving side by the Viterbi decoding method, random error burst error occurs. In order to deal with this, in the bit string after multiplexing each information signal, one frame (2048
(Bit) is sequentially divided into 32 blocks with one block consisting of 64 bits, BCH encoded and sequentially stored in the memory for each block. Then, interleaving (bit rearrangement) is performed so that the data at the same bit position in each block is read in block order.

Next, the scramble processing performed by the transmitting terminal device 11d will be described. As the scramble processing for the signal sent to the satellite line, the 10th M-sequence PN code for the purpose of preventing the transmission of the non-converted carrier and the DES (Data Encry) for the purpose of concealing information outside the system subscribers
ption Standard) Two types of encryption and encryption are performed. The degree of confidentiality can be increased by this double encryption process.

That is, a PC for satellite broadcasting on the receiving side
Since the M decode LSI (μPD6395 in Fig. 12) is used,
Scrambling is performed using a 10th-order M-sequence PN code that conforms to the satellite broadcasting system. This scrambling shall always be performed regardless of whether DES encryption is executed or not (ON / OFF). The generator polynomial is (X ¹⁰ + X ³ +1), the scrambling method is synchronous scrambling for each frame,
The entire scrambling area except the frame sync code is the scramble range.

In the encryption by the DES method, an encryption pattern is generated by the DES method-OFB mode (Output Feedback Mode), the encryption method is synchronous scramble for each master frame, and the encryption range is frame synchronization. All parts (1984 bits) of the satellite system frame except the code, frame control code and authorization information. Then, under the control of the operator of the network management device 11c or the transmission terminal device 11d, the execution and non-execution (ON / O
FF). When the encryption is not executed (OFF), the output of the exclusive OR of the transmission data and the encryption pattern is stopped (the encryption pattern is continuously generated).

The procedure of encryption by the DES method will be described below with reference to FIG. 7 showing the functions of the network management device 11c and the transmission terminal device 11d. First, the transmitting terminal device 11d periodically starts the system (every 1 minute regardless of the change of the encryption key or the presence of control information in order to eliminate the omission of the encryption key on the receiving station side) after the system is started up. The key number (Nk = K ₁ , K ₂ , see FIG. 5) is received from the management device 11c.

Next, the transmitting terminal device 11d (TXCN described later)
(T-board) has a correspondence table of the key number Nk and the encryption key Ks in advance (the contents of the correspondence table is different for each user), and uses the encryption key Ks corresponding to the key number Nk received from the network management device 11c. To generate. Then, the encryption keys Ks and IV (Initial Val
ue) to operate DES in OFB mode to generate an encryption pattern, and obtain the exclusive OR (EX-OR) of this encryption pattern and the transmission signal to perform encryption.

FIG. 8 is a block diagram showing a detailed functional configuration of the transmitting terminal station device. That is, the transmission terminal station device includes the transmission processing units 21 and 22 of the duplex structure of the working and protection,
The monitor control unit 23, a switching unit 24 for switching between the active and standby, and an IF synthesizing unit 25. The transmission processing unit 21 and the transmission processing unit 22 have the same internal configuration, and details thereof are shown in FIG. This will be described below with reference to FIGS.

The main processing functions of the transmission processing section are the following 13 functions, and the functions are realized by corresponding boards. That is, control information processing function ..... TXCNT board 31 TV signal interface function ..... TVINF board 32 data signal interface function ..... DTINF board 33 Transmission information signal multiplexing function ..... 2MMUX board 34 BCH encoding function ........... 2MMUX board 34 interleaving function ...・ ・ ・ ・ ・ ・ ・ ・ 2MMUX panel 34 10th-order M series scramble function ・ ・ ・ ・ ・ ・ ・ ・ 2MMUX panel 34 DES encryption function ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ SCR panel 35 tatami Coding function ・ ・ ・ ・ ・ ・ ・ ・ COD board 36 Modulation function ・ ・ ・ ・ ・ MOD board 37 Master clock generation function ・ ・ ・・ ・ ・ ・ ・ ・ MCLK board 38 Alarm collection function ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ TXCNT board 31 Self-diagnosis function ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ TVINF, DTINF, TXCNT, CO D board 32, 33, 31, 36 In addition, TVINF-I, TVINF-R, TVINF- is installed on the TVINF board 32 to support the interface. Three types of V, DTINF board 33
There are four types of DTINF-F, DTINF-S, DTINF-A, and DTINF-V, but only one of each is installed in the transmitting terminal device.

Each board will be described below. The TXCNT board 31 has a control information processing function and an alarm collection function, and the control information processing function is performed by the network management device (“N” in the figure).
W)), and sends the authorization information to the 2MMUX board 34 in a format suitable for the satellite system frame, and according to the contents, change the encryption key, execute encryption and not execute (on / off). off) Set the control and operation mode.

That is, the active system takes in the operation mode notified from the network management device into the own system transmission processing section 21 and also notifies the monitoring control section 23. The backup system is
According to the state control notified from the monitoring control unit 23. Also,
The active system takes in the encryption execution and non-execution (on / off) control notified from the network management device to the own system transmission processing unit 21, and notifies the monitoring control unit 23 and the receiving station. However, encryption is executed or not (on /
Off) Control execution and non-execution (on / off) control are performed on the own system transmission processing unit 21 two master frames after the control is notified. The standby system follows the encryption execution and non-execution (on / off) control notified from the monitoring control unit 23. Further, the active system passes the authorization information notified from the network management device to the 2MMUX board 34 in a format which can be multiplexed as it is with the satellite system master frame. However, only the key number change notification information should be imported and
Generate the corresponding encryption key, and the authorization information is 2MMUX
It notifies the SCR board 35 that the encryption key should be changed two master frames after it is delivered to the board 34.

The control information processing function is internally generated.
IV value, master frame timing, and encryption execution / non-execution (on / off) from network management equipment
Frame control code is generated based on the control, and 2MMUX board 34
Pass to.

The alarm collecting function of the TXCNT board 31 collects and collects the alarms in the transmission processing section of the own system to obtain the transmission processing section alarm, the operation mode of the own system, and the control information signal disconnection alarm from the network management device. Then, these are notified to the monitor control unit 23. In addition, from the monitor control unit 23,
The control notification of the operation mode, the automatic / manual control mode, and the working / standby state is received, and the state control in the own system transmission processing unit is performed accordingly.

Next, the TV signal interface function of the TVINF board 32 terminates the interface of the TV signal from the terrestrial network (via the REDSW board of the switching unit 24) and uses it as transmission information.
The 1536kbps TV signal is extracted and passed to the 2MMUX board 34.
At the same time, an 8 kHz clock is also extracted and supplied to the MCLK board 38. In addition, disconnection of TV signal input from the ground network, 2MMUX board 34
Alarms such as a TV signal output interruption to the MCLK board 38 and an extraction clock interruption to the MCLK board 38 are detected and notified to the TXCNT board 31. Furthermore, a diagnostic pattern is generated in the self-diagnosis mode, and 2MMU
It is sent to the X board 34.

The data signal interface function of the DTINF-F board (for file data) of the DTINF board 33 receives the file data and checks it by a parallel interface with the network management device.
The received file data is passed to the 2MMUX board 34.
It also detects the disconnection of the interface on the network management device side and the disconnection of the signal sent to the 2MMUX board 34, and notifies the supervisory controller 23 and the TXCNT board 31 of it. Further, in the self-diagnosis mode, a diagnostic pattern is generated and sent to the 2MMUX board 34.

The data signal interface function of the DTINF-S board (for synchronous data) of the DTINF board 33 interfaces the synchronous data, and extracts the data portion and the clock as the transmission information. The extracted data signal is
2MMUX board 34, the extracted clock is MCLK board 3
Passed to 8 respectively. Also, each alarm of the input interruption of the synchronous data signal from the ground network, the interruption of the output of the synchronous data signal to the 2MMUX board 34, and the interruption of the output of the extracted clock to the MCLK board 38 is detected, and the monitoring controller 23 and the TXCNT board Notify 31. Further, in the self-diagnosis mode, a diagnostic pattern is generated and sent to the 2MMUX board 34.

The data signal interface function of the DTINF-A board (for asynchronous data) of the DTINF board 33 performs the interface of the asynchronous data signal, extracts the data portion as the transmission information, and passes it to the 2MMUX board 34. In addition, disconnection of asynchronous data signals from the terrestrial network, and 2MMUX board 3
Each of the alarms of the output interruption of the asynchronous data signal to 4 is detected and notified to the monitoring controller 23 and the TXCNT board 31. Furthermore, a diagnostic pattern is generated in the self-diagnosis mode, and 2M
It is sent to the MUX board 34.

The data signal interface function of the DTINF-V board (for audio signals) of the DTINF board 33 is 56 kb.
It interfaces the ps audio signal, extracts the data portion as transmission information, and passes it to the 2MMUX board 34. In addition, each alarm of the audio signal input disconnection from the audio encoder 11b and the audio signal output disconnection to the 2MMUX board 34 is detected, and the monitoring control unit 23 and TXCNT are detected.
Notify the board 31. Further, in the self-diagnosis mode, a diagnostic pattern is generated and sent to the 2MMUX board 34.

The 2MMUX board 34 has a multiplexing function for the transmission information signal, which includes the frame control code and the authorization information from the TXCNT board 31, the TV signal from the TVINF board 32, and the DTINF board 3
The data signals from 3 are multiplexed according to the satellite frame format.

The BCH coding function, the interleaving function, and the 10th-order M-sequence scrambling function of the 2MMUX board 34 are sequentially applied to the signals multiplexed by the above-mentioned multiplexing function.
BCH coding, interleaving, 10th-order M-sequence scrambling, and passing to SCR board 35. In addition, SCR board 3
The disconnection of the signal passed to 5 is detected and notified to the TXCNT board 31.

The DES encryption function of the SCR board 35 performs DES encryption on the information signal subjected to the 10th-order M-sequence scramble by using the encryption key and IV notified from the TXCNT board 31. In addition, according to an instruction from the TXCNT board 31, encryption execution / non-execution (ON / OFF) control is performed.

The convolutional coding function of the COD board 36 completes a satellite system frame by performing a convolutional coding on the information signal subjected to the DES encryption processing and then adding a frame synchronization code. And pass it to the MOD board 37.

The RAS function of the COD board 36 comprises a self-diagnosis function, a first 2M signal output function, and a second 2M signal output function. The self-diagnosis function compares the signal sent from the TVINF board 32 or the like and subjected to processing such as multiplexing with the built-in diagnostic pattern according to an instruction from the TXCNT board 31, and performs self-diagnosis. The first 2M signal output function adds the BS unique word UW to the signal before convolutional coding and outputs the signal to the outside. The second 2M signal output function receives the data before the convolutional coding from the outside, performs the convolutional coding on the data, and sends the data to the MOD board 37.

The modulation function of the MOD board 37 performs QPSK modulation on the transmission signal from the COD board 36 and passes it to the IF synthesizing section 25 as a 70 MHz band IF signal. The transmission frequency is determined by the frequency division ratio serially notified from the monitor control unit 23. It should be noted that the IF signal level drop and the synthesizer / unlock alarms are detected and notified to the TXCNT board 31.

The master clock generation function of the MCLK board 38 selects any one of the external clock, the built-in clock, the TV signal extraction clock, and the data signal extraction clock according to the priority order, and selects the master clock (20
48kHz), and distribute to each part in the device.

The in-device timing generation function of the MCLK board 38 has a counter interlocking with the satellite frame and the master frame, and the frame timing (1 ms) generated by counting based on the master clock, the master frame・ Provide timing (36ms) to each part in the device.

Next, the receiver of the receiving station (the receivers 12a and 13a in FIG. 2) will be described. The receiver is connected between the LNB fixed to the receiving antenna and the terminal equipment (TV, VTR, audio amplifier, data terminal) at the receiving station, and the TV signal (video signal, accompanying audio signal, low speed data signal and high speed data signal) Data signal) and a data signal (any one of an audio signal, a synchronous data signal, an asynchronous data signal, and a file data signal), demodulation, demultiplexing, decompression of compressed information, and conversion from a digital signal to an analog signal. It is a device that performs conversion, data interface conversion, and the like.

FIG. 10 is a block diagram showing the main functional structure of the receiver. That is, the demodulation unit 41 receives and demodulates a 1 GHz band signal, the Viterbi decoding unit 42 performs error correction by Viterbi decoding, and the DES decoding unit 43 decodes the DES OFB mode cipher. DES decoding unit 43
An encryption key setting unit 50 is connected to the encryption key setting unit 50, and the encryption key setting unit 50 sets and changes the encryption key according to an instruction from the transmitting side and provides the encryption key to the DES decryption unit 43.

The descrambling unit 44 uses the 10th M-sequence PN.
Descrambling is performed for the scrambling of the coding method, deinterleaving 45 performs deinterleaving (bit rearrangement) for interleaving (bit rearrangement) performed on the transmission side, and BCH decoding unit 46 causes an error due to BCH decoding. Make corrections. The demultiplexing unit 47 is for multiplexing various signals (frame control code, authorization information, TV
Signals and data signals).

The TV signal processing unit 48 expands the TV signal and performs digital / analog conversion, and at the same time, the reception control unit 5
The output control based on the authorization information is performed by the control from 1. The option unit 52 expands the audio signal and performs digital / analog conversion, and performs output control based on the authorization information for the audio signal, asynchronous data, synchronous data, and file data. The channel selection unit 49 manually selects a reception channel (frequency).

Next, the detailed structure of the receiver shown in FIG. 10 will be described with reference to FIGS. 11 to 19 showing the structure of each part of the receiver. In these figures, the same parts as those shown in FIG. 10 are designated by the same reference numerals as those shown in FIG.

FIG. 11 shows the DEM section (demodulation section) of the receiver.
It is a block diagram which shows the internal structure of 41. DEM section 41
Demodulates the 1 GHz band received signal output from the LNB,
It outputs a 2048 kbps digital signal, of which the frequency conversion unit 41a multiplies the reception signal (950MHz to 14500MHz) output from the LNB by the carrier reproduced by the carrier reproduction unit 41b, and a 4-phase absolute phase Modulation signal (4
(096k symbol) is extracted and output to the synchronous detection unit 41c. The synchronous detection unit 41c synchronizes the 4-phase absolute phase modulation signal with the clock reproduced by the clock reproduction unit 41d to perform signal identification, and each of the Ich / Qch capable of soft decision is 3
A total of 6 signals are output. Carrier reproduction unit 41b
On the basis of the reception frequency determined by the channel selection unit 49, the carrier is reproduced in synchronization with the LNB output signal near that frequency. The clock reproduction unit 41d reproduces a clock (CLK) synchronized with the 4-phase absolute phase modulation signal,
Supply to each part.

12 and 13 are block diagrams of the satellite decoder section 53 of the receiver. First, in FIG. 12, the satellite decoder unit 53 establishes frame synchronization for the 2048 kbps digital signal output from the DEM unit 41, performs processing such as error correction, and outputs each information signal (TV signal and data signal). It has a function of separating and outputting to the TV signal processing unit 48 and the option unit 52. It also performs processing such as signal output control from the transmitting station, changing the encryption key, and changing the receiving channel by the user.

That is, the UW detector 53a detects the frame synchronization code. The UW detection unit 53a has IQ, Q
It is also possible to detect patterns of (inversion) -I, Q-I (inversion) and I (inversion) -Q (inversion), and the phase information and the frame synchronization code detection pulse are detected. The frame synchronization protection unit 53b takes forward protection and backward protection of the frame synchronization code detection pulse output from the UW detection unit 53a, and generates frame timing (FT1). The phase uncertainty removing unit 53c removes 0/1 inversion of data based on the phase uncertainty of the received data from the phase information output from the UW detecting unit 53a. The Viterbi decoding unit 42 decodes the convolutionally encoded received signal by the Viterbi algorithm (corrects a random error of data). That is,
Viterbi decoding is performed with a coding rate of 1/2 and a constraint length of 7.

The UW adding section 53d uses a dedicated unique word UW for using a satellite broadcast PCM demodulation LSI (μPD6395) equipped with functions such as descrambling, deinterleaving, and BCH decoding of received signals. (16bit: BS format)
Is also added to the received signal.

The DES decryption unit 43 generates encrypted data (encryption pattern) for decrypting the received signal which is concealed by the DES encryption method. Encrypted data is generated in DES method-OFB mode. The decryption procedure will be described below with reference to FIG. 20 showing the processing contents of the DES decryption.

In advance, the reception control unit 51 of the receiver is the EPROM
Conversion table 5 for encryption key Ks for encryption key numbers (K ₁ , K ₂ )
Has 1d. Also, enter the encryption key number specified by the transmitting station.
Store on EEPROM. When the power is turned on, the receiver first reads the encryption key (K ₁ , K ₂ ) corresponding to the encryption key number on the EEPROM from the conversion table 51d, and the DES
Set in the decoding unit 43. The receiver receives the demodulation IV
Is set in the DES decoding unit 43 after synchronization protection is performed by the master frame boundary. In addition, the received decryption execution / non-execution (ON / OFF) information is also protected and then DES
Set in the decoding unit 43. Then, the DES decryption unit 43
The encryption key Ks and the decryption IV are processed in the DES method-OFB mode to generate encrypted data (2 Mbps). DES decryption is performed by taking the exclusive OR of this encrypted data and the 2Mbps data string. Decoding execution / non-execution (ON / OFF) is performed at the master frame boundary according to the instruction from the transmitting station.

Returning to FIG. 12, the descrambler 44
Is to descramble the received signal by the 10th M-sequence PN code. PCM demodulation LSI for satellite broadcasting (μPD639
Use the function of 5).

The de-interleaving section 45 cancels the rearrangement of bits performed to maximize the error correction capability of convolutional coding and BCH coding. That is, if the random error generated in the transmission / reception section with the satellite cannot be completely corrected by the Viterbi decoding method, the error often spreads to the preceding and subsequent data, resulting in a burst error. Since the BCH code is a code for random error correction, interleaving (bit rearrangement) is performed between convolutional coding and BCH coding on the transmission side so that burst errors become random errors. De-interleaving is a process of rearranging the bits rearranged on the transmitting side on the receiving side. De-interleaving is performed between the Viterbi decoding process and the BCH decoding process, and 32 bits of one frame (2048 bits) are divided into 64 blocks, and data at the same bit position in each block is divided. Are read in block order and output.

The BCH decoding section 46 performs error correction on the received signal encoded by the BCH (63, 56) code.
The frame control code processing unit 53e separates the frame control code from the satellite frame, and the IV synchronization protection unit 53f extracts the DES encryption IV transmitted by the frame control code, and is incremented for each master frame. Provides IV sync protection. Also, the scramble majority decision unit 53g
Is the DES decoding executed by the frame control code /
The majority decision of non-execution (ON / OFF) information is performed.
The result of this majority decision is reflected in the control of the next master frame. Further, the master frame code protection unit 53
h performs forward protection and backward protection of the master frame identifier transmitted by the frame control code, and the master frame generation unit 53i uses the information of the master frame identifier to determine the master frame timing ( MF
T) is generated.

The DMUX section (separation section) 47 receives information signals (authorization information, TV signals, data signals) from the satellite frame at various timings created according to the reception clock.
Is to be separated. FIG. 12 shows a case where the data signal is an audio signal and is separated into four channels. The separated authorization information is received by the reception controller 5
In order to interface with 1, the data for one master frame is written together into one of the two-sided buffer 53j (FIG. 13). The two-sided buffer 53j is switched for each master frame and is used for exchanging data between the DMUX unit 47 and the reception control unit 51.

The monitoring section 53k monitors the internal state of the receiver and the signal input / output state, and the result is monitored by the operating state display section 54k.
The user is notified by a (FIG. 14). The monitoring area includes the DEM unit 41, the TV signal processing unit 48, the option unit 52, the power supply, and the like.

Next, a description will be given with reference to FIG. 13 and FIG. 13 showing the satellite decoder section 53 of the receiver. The reception control unit 51 performs initialization of each unit of the receiver, each reception control, reception channel switching, and the like, and is realized by the firmware. That is, the frequency setting unit 51
a sets the frequency of the DEM unit 41, the system encryption key setting unit (encryption key setting unit) 50 sets the encryption key of the DES decryption unit 43, and the LSI initial setting unit 51b sets the LSI of the satellite decoder unit 53. Perform initial settings.

Based on the authorization information from the two-sided buffer 53j, the authorization data processing unit 51c adds, changes, and deletes the belonging group, outputs permission control of various information signals, contact output control, encryption for DES encryption. Change keys etc. That is, the authorization information is
If the same authorization information is received 5 times in a row in a row and the authorization information includes information indicating its own receiver, reception processing is performed. Control such as output (reception) permission of various information signals is reflected in the master frame next to the master frame in which the reception processing is performed.

TV signal output control is performed in the authorization information.
Based on the control bit b ₂₄ indicating the output permission of the TV signal, one of the controls for the group to which it belongs and its own receiver
If there is an instruction to allow (ON) any of them, output is allowed.

In the audio / data signal output control, output control is independently performed for each of the four channels based on control bits (b _{25 to} b ₂₈ ) indicating output permission of the audio signal (or various data signals). .

[0097] Further, contact output control based on the control bit b ₂₉ indicating the opening and closing control of the contact output, among the control for the Member and the self receiver, an instruction to close (CLOSE) even one for that channel If so, the contact output shall be closed.

[0098] Further, the encryption key number control based on the control bit b ₃₀ ~b ₃₁ representing the number of DES encryption key, but the encryption key number is notified simultaneously for all receivers. 4 types of unique encryption keys and their corresponding key numbers are determined in advance, and the key numbers of the encryption keys to be used initially are determined and set in the receivers of the transmitting station and the receiving station.
Write to M). When changing the encryption key to increase the confidentiality level after the start of operation, use this key number to instruct.

The state of the output permission control based on the above authorization information is displayed on the output control display portion 54b of FIG. FIG. 14 is a block diagram of the operation display unit 54 of the receiver. A reception channel selection unit (channel selection unit) 49 is provided in addition to the operation status display unit 54a and the output control display unit 54b described above. This reception channel selection unit 49
Is for changing the receiving channel when the system is transmitting and receiving using a plurality of carriers. It is composed of a selection switch mounted on the front surface of the receiver and a display LED.

FIG. 15 is a block diagram of the TV signal processing unit 48 of the receiver. The 1536 kbps TV signal separated by the DMUX unit 47 of the satellite decoder unit 53 is a video signal (NTSC), an attached audio signal (analog audio), and low-speed data (LSD:
It is for converting to RS232C) and high speed data (HSD: RS449). That is, TV signal (1536kbps: MPEG format)
Is separated from the satellite frame at various timings created according to the reception clock. The TV signal separated from the satellite frame is separated into four kinds of signals of a video signal, an accompanying audio signal, a low speed data signal and a high speed data signal. The separated video signals are decoded into MPEG1 format digital compressed video signals, converted to analog signals and output to TV monitors, VTRs, etc.

For the accompanying audio signal, a SB-ADPCM digital compressed audio signal is decoded, converted into an analog signal and output to various audio equipments. For low-speed data signals, the speed is converted to the transmission speed used on the terrestrial line and output to terminals.

A high speed data signal is also converted to a transmission speed used on the terrestrial line and output to a terminal or the like. In addition, the output control of the TV signal is performed based on the reception permission instruction from the transmission station, and the output is prohibited when the reception signal disconnection or the device abnormality is detected by the receiver.

FIG. 16 is a block diagram of the option section 52 of the receiver, and shows a case where the option section 52 processes an audio signal. The audio signal is a signal for transmitting music, voice, etc. using a 224 kbps line excluding the header (frame synchronization code, frame control code, authorization information), TV signal and BCH parity. In addition, the audio signal is SB-ADP of 56kbps / 1 channel in order to enable transmission of up to 4 channels in one system.
It is compressed and encoded by CM and transmitted from the transmitting station.

The audio signal separated by the DMUX unit 47 of the satellite decoder unit 53 (56 kbps × 4 ch (max), SB-ADPS
M) is decoded by the SB-ADPCM system. Then, the output control for each channel is performed in accordance with the reception permission instruction from the transmission station, and the process of inhibiting the output is also performed when the reception signal disconnection or the device abnormality is detected by the receiver.

Next, a case where processing other than audio signals is performed by the option section 52 will be described with reference to FIGS. FIG. 17 is another block diagram of the option unit 52 of the receiver, showing a case where the option unit 52 processes the synchronous data. In this case, DMUX in FIG.
The synchronization data is separated by the unit 47, and this synchronization data is input to the option unit 52 as a signal S21.

The information selection unit (SEL) 52a selects the information speed (64 kbps, 192 kbps) to be extracted based on the output permission control. Even if the output is permitted, the synchronous data signal is not output when a device abnormality, an input signal abnormality, or the like is detected. The speed converter 52b converts the transmission speed of the synchronous data signal from the satellite clock (2048 kbps) to the high speed digital leased line clock (1536 kbps). The I431-a transceiver 52c is an interface for multiplexing the speed-converted synchronous data signal in the format of the high-speed digital leased line (I431-a) and outputting it according to the standard.

FIG. 18 is another block diagram of the option unit 52 of the receiver, showing a case where the option unit 52 processes asynchronous data. In this case, DM of FIG.
Asynchronous data is separated by the UX unit 47, and this asynchronous data is input to the option unit 52 as a signal S21.
It should be noted that four lines of asynchronous data signals can be accommodated on the satellite line.

The information selection unit (SEL) 52d selects the line to be extracted based on the output permission control. Even if the output is permitted, the asynchronous data signal is not output when a device abnormality, an input signal abnormality, or the like is detected. The data processing unit 52e converts the asynchronous data signal separated from the satellite frame into a data format and a transmission rate that can be interfaced with a terminal device to be connected. The RS232C transceiver 52f is an RS232C interface that transmits the asynchronous data signal converted by the data processing unit 52e to the terminal device.

FIG. 19 is another block diagram of the option unit 52 of the receiver, showing a case where the option unit 52 processes file data. In this case,
The DMUX unit 47 separates the file data, and this file data is input to the option unit 52 as a signal S21.

The information selecting section (SEL) 52g controls output / non-output of file data based on output permission control. Even if the output is permitted, the file data is not output when a device abnormality, an input signal abnormality, or the like is detected. The data processing unit 52h extracts and combines the file data transmitted in master frame units,
UDP / IP with information such as destination address and source address
It is to be converted to the format. Since the file data signal is not always transmitted, it also has a function of confirming reception of the file data. The DSLINK transceiver 52i is a UDP / IP (10base T) interface that transmits the file data converted by the data processing unit 52h to the terminal device. In addition, the DSLINK transceiver 52i
It has a function to set the address and format for UDP / IP, it is connected to the console by the interface of RS232C start / stop synchronization, and can be set by inputting commands from the console.

[0111]

As described above, according to the present invention, the frame structure has two layers, and the types of data that can be transmitted and the amount of information are limited. Thereby, a plurality of information signals having different data transmission rates can be simultaneously transmitted at high speed and efficiently.

Further, since the double error correction coding is performed using the convolutional code and the BCH code, the effect of error correction is improved and the accurate transmission can be performed even in the one-way communication system. Further, the output control means controls the output of the information signal based on the reception permission information included in the authorization information.
As a result, only the predetermined receiving device can receive the predetermined information signal.

Further, the degree of secrecy can be enhanced by the double encryption process of the 10th M-sequence PN coding and the DES encryption.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a block diagram showing a basic configuration of a multimedia broadcasting system.

[Fig. 3] Transmission format of satellite section (frame configuration)
FIG.

FIG. 4 is a diagram showing a bit arrangement of a frame control code.

FIG. 5 is a diagram showing a bit array of authorization information.

FIG. 6 is a diagram showing a content definition of authorization information.

FIG. 7 is a diagram showing an encryption processing function.

FIG. 8 is a block diagram showing a detailed functional configuration of a transmitting terminal device.

FIG. 9 is a block diagram showing an internal configuration of a transmission processing unit.

FIG. 10 is a block diagram showing a main functional configuration of a receiver.

FIG. 11 is a block diagram showing an internal configuration of a DEM unit of a receiver.

FIG. 12 is a block diagram of a satellite decoder unit of a receiver.

FIG. 13 is a block diagram of a satellite decoder unit of a receiver.

FIG. 14 is a block diagram of an operation display unit of the receiver.

FIG. 15 is a block diagram of a TV signal processing unit of a receiver.

FIG. 16 is a block diagram of an option unit of a receiver, showing a case where the option unit processes an audio signal.

FIG. 17 is another block diagram of the option unit of the receiver, showing a case where the option unit processes synchronous data.

FIG. 18 is another block diagram of the option unit of the receiver, showing a case where the option unit processes asynchronous data.

FIG. 19 is another block diagram of the option unit of the receiver, showing a case where the option unit processes file data.

FIG. 20 is a diagram showing the processing contents of DES decoding.

[Explanation of symbols]

 1 transmitter 1a transmitter 1b information signal multiplexer 1c authorization information multiplexer 2 receiver 2a receiver 2b information signal separator 2c authorized information separator 2d output controller 3 receiver

Claims (14)

[Claims] 1. A transmitter for performing one-way simultaneous transmission to a plurality of receivers, wherein a plurality of receivers transmit a transmission signal formed by a two-layer frame including a small frame and a master frame composed of a predetermined number of small frames. Transmission means (1a) for transmitting to (2, 3)
An information signal multiplex means (1b) that multiplexes different types of information signals at different predetermined positions in the small frame and sends the information signals to the transmission means (1a); and at predetermined positions in the small frame. A transmitter, comprising: an authorization information multiplex means (1c) for multiplexing the authorization information and sending the multiplexed information to the transmission means (1a). 2. The transmission device according to claim 1, wherein the authorization information includes reception permission information indicating that a predetermined reception device permits reception of a predetermined information signal. 3. The transmitting apparatus according to claim 1, wherein the authorization information includes a DES encryption key number to be notified to all receiving apparatuses. 4. The transmitting apparatus according to claim 1, further comprising frame control code multiplexing means for multiplexing a frame control code at a predetermined position in the small frame and sending the multiplexed frame control code to the transmitting means (1a). 5. The transmission device according to claim 4, wherein the frame control code includes a master frame identifier that indicates a head position of the master frame. 6. The frame control code is D for notifying a receiving device whether or not DES encryption is executed.
The transmission device according to claim 4, wherein the transmission device includes ES encryption information. 7. The small frame is composed of 2048 bits, and the transmitting means (1a) sets the small frame to 1 m.
The transmission device according to claim 1, wherein the transmission is performed at a time of s. 8. The transmission means (1a) includes a modulation means for performing four-phase absolute phase modulation and an error correction coding means for performing double error correction coding using a convolutional code and a BCH code. The transmitter according to claim 1, wherein 9. The transmission means (1a) includes scrambling means for performing scrambling according to the 10th-order M-sequence PN code method and encryption means for performing encryption according to the DES method. Transmitter. 10. In each receiving device for receiving a signal transmitted from a transmitting device in one direction simultaneously, the transmitting device (1) is formed by a two-layer frame including a small frame and a master frame composed of a predetermined number of small frames. Receiving means for receiving a transmission signal transmitted from
a) and information signal demultiplexing means (2b) for demultiplexing different types of information signals respectively multiplexed at a plurality of predetermined positions of different small frames included in the transmission signal received by the receiving means (2a). And an authorization information separating means (2c) for separating the authorization information multiplexed at a predetermined position of a small frame included in the transmission signal received by the receiving means (2a). 11. Output control means (2d) for controlling the output of the information signal separated by the information signal separation means (2b) based on the reception permission information included in the authorization information.
The receiving device according to claim 10, further comprising: 12. The receiving means (2a) includes a demodulating means for performing synchronous detection, and an error correcting means for performing double error correction by Viterbi decoding and BCH decoding. Transmitter. 13. A signal transmission system in which a transmitting device (1) performs one-way simultaneous transmission to a plurality of receiving devices (2, 3), the transmitting device (1) being provided with a small frame and a predetermined number A transmission means (1a) for transmitting a transmission signal formed by a two-layered frame including a master frame composed of a plurality of small frames to the plurality of receiving devices (2, 3), and the transmitting device (1), The information signal multiplexing means (1b), which multiplexes different kinds of information signals into different predetermined positions in the small frame, and sends the multiplexed information signals to the transmission means (1a), and the transmission device (1). The authorization information is multiplexed at a predetermined position in the small frame, and the transmitting means (1
authorization information multiplexing means (1c) to be sent to a), and receiving means (2) provided in each of the receiving devices (2, 3) to receive the transmission signal transmitted from the transmitting device (1).
a) and information signal demultiplexing means (demultiplexing means) provided in each of the receiving devices (2, 3) and demultiplexing the information signals respectively multiplexed in the small frames included in the transmission signal received by the receiving means (2a). 2b) and an authorization information separating means (2c) provided in each of the receiving devices (2, 3) for separating the authorization information multiplexed in the small frame included in the transmission signal received by the receiving means (2a). A signal transmission system comprising: 14. The authorization information includes reception permission information indicating that a predetermined reception device permits reception of a predetermined information signal, and the reception device (2, 2).
Output control means (2d) provided in 3) for controlling the output of the information signal separated by the information signal separation means (2b) based on the reception permission information included in the authorization information.
The signal transmission system according to claim 13, further comprising: