JPS622732A - Information service system - Google Patents

Abstract

PURPOSE:To enable only a specific subscriber to receive the specific information service from the station side by using the sync code which functions as a part of the control data part as the deshuffling information of the control data part. CONSTITUTION:The sync code SC underwent no shuffling processing is used as a part of a control data part CD for transmission of the decoded information of a service data part SD. Thus the shuffling of the part CD is different according to the using code SC. Furthermore the high privacy is secured for the part CD and the part CD can not be easily decoded because the shuffling information of the part SD following the part CD is included in the part CD. Then the service data SDA is not easily decoded either because the decoded information of the part SD is put into the shuffled part CD.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A. Field of industrial application B. Overview of the invention C. Prior art D. Problem to be solved by the invention E. Means for solving the problem F. Effect G. Example G, general explanation of the information service system G2. System diagram showing the basic schematic configuration (Figure 1) Format of the transmission signal inserted into the G3 broadcast signal (Figure 2) Format of the service data section SD before G and shuffling (Figure 3) G5 service data Format showing the relationship between part SD and the following service data SDA (Fig. 4) Explanation of G6 baud rate part BR (Fig. 5) Description BA of G7 control data part CD (Fig. 6) Explanation of GS sync code SC ( Figure 7) Explanation of G9 control data CDA (Figure 8) Explanation of Glf + addressing (Figure 9) Format of G11 addressing data AD (Figure 9) G12 Reason for using two types of key codes CI3 Multiple addressing Reason for setting the mode System diagram of G14 receiver 30 (Fig. 11) Circuit explanation of GI5 decoder 50 (Fig. 12) CI6 service data SD
Decoding process G of A, decoding process G in 7 addressing mode G+8 sync code detection section 60 and judgment circuit section 5
Description of No. 9 (Fig. 13) H Effects of the Invention A Field of Industrial Application This invention relates to a new information service system that can conceal information data and provide information services for a fee.

B. Summary of the Invention The present invention relates to an information service system in which information data is concealed and information services are charged.

This information service system receives the service data and key code sent from the database station using a decoder installed on the subscriber side, and the key code sent after decoding these data matches the key code on the receiving side. This system allows users to receive specific information services sent out from database stations only when they do so.

In this invention, the shuffling pattern of the shuffled and transmitted control data section is changed by a sync code inserted as part of the control data section, so that non-subscribers can
This prevents the data contents from being easily decoded.

C. PRIOR TECHNOLOGY As an information service system that allows specific information to be provided only to specific subscribers, systems that utilize a dedicated line have been known for some time.

Specifically, specific information transmitted from the database station using a dedicated line is received by a decoder installed on the subscriber side, and the information provided by the station side can be received. There is.

D. Problems to be Solved by the Invention However, the above-mentioned information service system has a limit because it becomes difficult to secure a dedicated line when the number of subscribers increases significantly.

In addition, if the information provided by the station requires a large amount of money to collect the information and provide information transmission equipment, such as stock information or commodity trading information in multiple markets, non-subscribers may It is necessary to devise a system in which the information cannot be easily decoded. In conventional information service systems, information can be easily obtained by simply installing a decoder on the subscriber side, so even non-subscribers can easily obtain the information.

In such a case, it is necessary to take advanced measures to prevent wiretapping, but conventionally such concealment measures have not been adopted.

Furthermore, conventionally, once a decoder is purchased, information can always be provided as long as the user owns the decoder. However, as mentioned above, when the cost of collecting information and the cost of equipment for station operation are enormous, it is preferable to provide the information for a fee.

Therefore, an information service system that targets a large number of subscribers, ensures confidentiality of information, and charges a fee has not yet been developed.

This invention takes these points into consideration and provides a means for maintaining information confidentiality, which is a problem when configuring an information service system that can realize information confidentiality and paid information services. It is.

E. Means for Solving the Problems In order to solve the above-mentioned problems, the present invention employs the following means.

That is, in this invention, the service data and key code sent from the database station are received by a decoder provided on the subscriber side, and the key code sent after decoding these data matches the key code on the receiving side. The target is an information service system in which a specific information service sent from a database station can be received only when

In this invention, a service data part shuffled for information anonymization and a control data part (which functions as information for decoding this service data part)
Similarly, a sync code (shuffled to maintain confidentiality) is provided, and the sync code functioning as part of the control data section is used as deshuffling information for the control data section.

F Effect: In this configuration, the shuffling pattern of the control data section is changed depending on the type of sync code.

The deshuffling information in the service data section is encoded and inserted into the control data section.

Therefore, the control data part cannot be deshuffled by simple deshuffling, and even if the control data part is deshuffled, the service data part cannot be deshuffled.

For this reason, the confidentiality of the transmitted data is strong, and only specific subscribers can receive specific information services transmitted from the station side, making it possible to easily achieve the above-mentioned purpose.

G. Embodiment FIG. 1 is a schematic configuration diagram showing an example of an information service system that is the premise of this invention.
An outline of the information service system according to the present invention will be explained. 'G1 Overview of the information service system This information service system, as described above, receives service data and key codes sent from the database station using a decoder installed on the subscriber side, and decodes these data. A system in which a specific information service sent from a database station can be received only when the transmitted key code matches the receiving side's key code.

The first feature is that the transmitted data is shuffled to prevent eavesdropping.

This is to make it difficult for non-subscribers to obtain information and to provide specific information only to specified subscribers, as described above.

Second, information services are charged.

In other words, the system is such that only those who have paid the fee can receive information services.

To this end, in this system, a reception contract period, for example, a monthly reception contract period, is determined, and information can be continuously provided by updating the contract period.

Payment of fees for each reception contract period and non-payment are checked on the station side, and if the fees are not paid, the information service is automatically stopped, so the addressing on the decoder side, which will be described later, is the same as data transmission. carried out by means.

Therefore, after addressing, a key code is transmitted at the same time as the data transmission described above, and only when the transmitted key code matches the key code stored in the receiver's decoder (the key code stored by addressing), information is sent. You can receive the offer.

System diagram showing the basic schematic configuration of the G2 information service system Now, FIG. 1 is a configuration diagram showing an example of a new information service system 10 that is the premise of the present invention.

10A is a database station, IOB is a ground relay station, 10C
is a receiving station (subscribing station), and the transmission signal formed by the database station 10A is inserted into a predetermined horizontal line or several horizontal lines in the vertical blanking period of the broadcast signal, and the broadcast signal into which the transmission signal is inserted is (The format is shown in FIG. 2) is transmitted to the broadcasting station 122, and this broadcasting signal is transmitted from the broadcasting satellite 22 to the terrestrial relay station 10B.

The terrestrial relay station 10B has a BS antenna 24, and the SHF band broadcast signal received by this antenna is supplied to a transmitter 26 via a BS converter 25, and the broadcast signal is converted into a UHF or VHF band suitable for retransmission. While being converted into a broadcast signal, this is fed to the antenna 27 and transmitted to a plurality of receiving stations 1.
Sent towards 0C.

The broadcast signal received by the antenna 29 of the receiving station 10C is decoded by the transmission signal inserted into the broadcast signal in the receiver 30, and the service data obtained as a result of the decoding is supplied to the personal computer 31, and the necessary information is Once selected, it is provided to the monitor 32 to monitor its data.

Assuming that a maximum of 8 horizontal lines (8 channels) are used as transmission signals inserted into broadcast signals, it is possible to install multiple database stations IIA to IIH in the database station 10A, and therefore 8 databases IIA to IIH according to the number of channels mentioned above. can.

Each of the databases IIA to IIH includes large host computers 12A to 12H and a pilling computer 13A corresponding to each database.
~13H will be installed. The host computer collects stock information, product transaction information, etc. for each region and provides service information data (hereinafter referred to as service data) to customers.
is formed.

The pilling combination manages the status of the reception contract of the subscriber subscribed to each database, and pilling data, that is, addressing data, corresponding to the reception contract and its cancellation is created for each reception contract period.

Service data and pilling data are supplied to corresponding processors (front end processors, FEPs) 14A to 14H using telephone lines or dedicated lines. One processor can process one channel of data, where one data channel corresponds to one horizontal line inserted into the video signal.

Each of the processors 14A to 14H has eight data input ports, and can multiplex up to eight types of service levels for one channel. Therefore,
As shown in FIG. 1, the service data transmitted from the first database IIA
It is designed so that it can be input to the 4H port. 2nd~
The same applies to the service data from the eighth bases IIB to IIH. Therefore, 8 processors 14
A to 14H can handle up to 64 types of service data.

Each of the processors 14A to 14H is connected to a host computer 15 that generates control data, which will be described later, and a shuffled transmission signal is formed based on this data.

The transmission signal is superimposed on the video signal supplied to the terminal 18 in the data insertion circuit 17 . Which horizontal line in the vertical blanking period the transmission signal is inserted into is determined by a control signal (not shown) supplied thereto.

The broadcast signal into which the transmission signal has been inserted is sent to the transmitter 20 by S
After being converted into an HF band signal, it is transmitted to a broadcasting satellite 22 by a BS antenna 21.

Format of the transmission signal inserted into the G3 broadcast signal Now, Figure 2 shows an example of the format of the transmission signal (one horizontal line) that is superimposed on the broadcast signal. Part SD (21 bytes in this example) ■, Check bit part CB for this service data part SD (10 bytes) ■, Control data part CD inserted at the front of the service data part SD (1 byte) ■, Control data Bit sync (2 bytes) inserted at the front of the CD
It is composed of a synchronous data section (1) consisting of BIS and byte sync BYS (1 byte), and a channel address section CA (1 byte) inserted between the synchronous data section and control data section CD.

The synchronous data section is clock data inserted to decode the transmission signal.

The channel address section CA is data indicating the type of channel used.

The control data portion CD is data indicating shuffling block data and shuffling map data for the shuffled service data portion SD, etc., and this control data portion CD is also transmitted in a shuffled state.

The service data section SD is data provided for customer services such as securities information.

G. Format of service data section SD before shuffling FIG. 3 shows the format of service data section SD before shuffling.

In this example, the service data section SD has 62 fields (
62 lines) as one data block, and each data block further consists of eight service blocks (SB,
~5Be).

The data inserted into the I horizontal line of one data block is 31 bytes, and one service block consists of 31 bits.

The data inserted into the first field before shuffling is the header data portion HD, and the second field and subsequent fields are service data SDA.

The header data portion HD is used as decoding information (service data multiplexing information, etc.) for the service data SDA inserted below the second field.

G5 Format showing the relationship between the service data section SD and the following service data SDA FIG. 4 is a format showing the relationship between the service data section SD and the following service data SDA.

That is, in the first horizontal line corresponding to the first field, a header data section HD having a format as shown in the figure is located for each service block. The header data section HD includes: (1) Service level section SL (3 bits) This indicates data indicating which channel is used to insert service data.

(2) Baud rate section BR (2 bits) This is because the configuration of the service block during transmission differs depending on the baud rate. The details will be described later.

■, Sync/Async (SYNC/ASYNC) section 5A
S (1 bit) Data indicating whether data is transmitted in synchronous mode or asynchronous mode.

■Key code section KC (4 bits) A key code inserted for each service of the month to ensure that only paying subscribers can receive the information service. It is compared with the key code sent to the decoder, and if they match, the data service is executed.

(2) Line data end portion LDE (6 bits) Since the length of the blocks constituting one service block is different for each service block, this data indicates the number of lines constituting the block.

In the case shown in FIG. 4, the service block ends at the 58th line, so in this case, data indicating that the 58th line is the last line is inserted as the line data end part LDE. .

■Bit data end part BDE (5 pinto) Data indicating the number of bits in the last line of the service block.In the example shown in Fig. 4, the 10th bit is the last bit, so this last bit is It is expressed by the data end part BDE.

It is set to a format like .

Even after shuffling, the header data portion HD in such a format is applied to the first horizontal line of each service block.

G6 Description of baud rate section BR The structure of the service block during transmission differs depending on the baud rate section BR.

For example, when the transmission capacity is up to 9600 baud,
When the transmission rate is set to 9600 po, the first to eighth service blocks SB, ~SB
, is only one channel data, and when configured at 4800 baud, two channels of data can be transmitted as shown in FIG. Examples of other baud rates are shown in C and D of the same figure. However, you can also select 2400 baud and 1200 baud, so
It is easy to understand that combinations other than those illustrated may also be used.

The header data section HD, service data SDA, and check bit section CB described above are shuffled within each line and also between 62 lines.

However, even after shuffling, the service data section SD inserted into the first horizontal line of one block data
Processing in which the above-described header data section HD is located is executed by the processors 14A to 14H.

G7 control data section CD tm light Figures 6 to 8
The figures up to the figure are used to explain the contents of the control data section CD.

The control data section CD is also shuffled except for some data, and an example of the structure of the control data section CD corresponding to one block after being deshuffled is shown in FIG.

The control data section CD has a variable length data structure, which is as follows: 1) sync code SC (1 byte) 2) control data CDA (48 bytes fixed length) 2) dummy code DC (4 to 11 bytes variable length) long code).

The sync code SC is used as data information for deshuffling the shuffled control data portion CD and as data information indicating the division of the control data portion CD. When using 64 types of sync codes as the sync code sc, control data section C
D can select from 64 types of shuffling patterns.

Description of CO sync code SC The sync code SC has not been subjected to shuffling processing. A sync code SC is considered to be a sync code SC only when the same code is inserted three times in succession.

That is, as shown in FIG. 7, this sync code SC is inserted from the first line to the third line.

The 48 bytes of data following the sync code SC becomes control data CDA.

The control data CDA includes shuffling block information of the service data section SD transmitted to the decoder 50 (see FIG. 12) and its shuffling map information.

G9 Description of Control Data CDA FIG. 8 shows an example of the format of control data CDA (before shuffling).

The control data CDA is composed of 4 bytes as a basic unit, and the first 2 bytes are shuffling block data S.
In B, the last two bytes are shuffling map data SM.

First, shuffling block data SB is formed of 2 bits of the first byte and 4 bits of the second byte, a total of 6 bits. Check code CC inserted into each byte
is for data checking of the shirt ring block data SB inserted into each byte.

Shuffling map data SM is formed of a total of 6 bits, 2 bits of the third byte and 4 bits of the fourth byte. The check code CC inserted into each byte is for checking the shuffling map data SM inserted into each byte.

The same code as this control data CDA is repeated 5 times (
A total of 20 bytes) are inserted, so the format before shuffling is as shown in FIG.

The reason why the same data is used five times in this way is to avoid malfunctions caused by noise mixed in during transmission. It is used as control data CDA.

The control data section CD has a fixed length of 48 bytes, and the data following the above-mentioned control data CDA is used as optional data. Therefore, data slots after 20 bytes are not used as control data.

The dummy code DC inserted at the rear of the control data CDA has a variable length, so that the code length of the entire control data section CD has a variable length configuration. In this example, the control data section CD is varied over 55 to 62 fields, and therefore the dummy code DC is 4 to 62 fields.
This is any code length between 11 fields. As a result, the control data section cD has 55 to 62 fields in one block configuration.

The dummy code DC uses a code pattern that is not present in the sync code SC. This is the control data part C
This is to accurately separate the sync code SC from D.

If the control data section CD is configured to have a variable length, it becomes difficult to detect the control data section CD inserted into one block, which complicates the data deshuffling process by non-subscribers and reduces the confidentiality of information. will be strengthened.

Also, the control data section CD may contain a sync code SC that has not been shuffled, but even if the sync code SC has not been shuffled, the code length of the control data section CD itself is variable. , the control data section CD cannot be easily decoded.

However, the decoder installed by the subscriber has a map of the deshuffling pattern that detects the sync code SC and deshuffles the control data section CD. Deshuffling processing can be performed accurately.

In this case, since the data length (48 bytes) following the sync code SC is constant, it is relatively easy to detect the sync code SC on the decoder side.

As described above, the control data section CD is shuffled according to the type of sync code SC, and by decoding the shuffling map data SM included in the shuffled control data CDA,
The service data portion SD will be deshuffled.

The service data section SD and control data section CD thus shuffled are inserted into one horizontal line in units of 31 bytes, forming the format of the transmission signal shown in FIG. 2. In this case, the synchronization data (see FIG. 2) inserted into each horizontal line is not shuffled.

Explanation of GIG Addressing Before sending out the transmission signal shown in FIG. 2, addressing is performed on the decoder 50 provided in the receiver 30 as a preliminary step.

Addressing is also performed using broadcast signals as well as transmission signals. In this case, among the transmission signals shown in FIG. 2, one in which addressing data ADA is inserted instead of service data SDA is used as the transmission signal.

First, an overview of addressing will be explained.

The plurality of decoders provided in the plurality of receiving stations 10C include
A non-volatile memory is provided to store the key code.
The key code transmitted during addressing is stored in these memories. Consecutive addresses are attached to the decoder, and when an address that specifies the decoder (an address map may be used) is transmitted, it enters the key code waiting state, and the binary code of the address map becomes '1'. The writing state of the key code is automatically controlled depending on whether the value is "0" or "0".

For example, assuming that writing is enabled when the binary code is "1", when the binary code of the address map is "1", the key code is written to the corresponding decoder. Therefore, in this case, when the binary code is 11 degrees, the reception contract fee has been paid.

When the binary code is "0", the reception contract fee has not been paid, so in that case, the key code is not stored in the corresponding decoder.

Addressing is performed for each reception contract period, and the addressing period is performed using a predetermined period before the reception contract period (which may extend into the next month's reception contract period).

As shown in Figure 2, the current month's key code KC is inserted into the transmission signal, so the information service is only received when this key code KC matches the key code stored in the decoder. be able to.

Therefore, the format shown in FIG. 9 is adopted for the addressing data AD.

GI, Format of Addressing Data AD Addressing data AD is also constructed of 62 fields as one block, and is subjected to shuffling processing to conceal information.

The format shown in FIG. 9 is for one horizontal line before shuffling.

Addressing data AD is configured as follows.

■Key code KC (1 byte) Two types of key codes are sent. The key code consists of 4 bits, one is the key code for the current month, and the remaining one is the key code for the next month.

When the decoder receives the service data SDA, if either of the two key codes is stored in the memory, the decoder enters the service state.

■, address data AD1, AD2 (3 bytes each)
Address data AD is address data for specifying a decoder, and although it differs depending on the mode code at the time of addressing, which will be described later.

With data from AD2 to AD2, decoder addresses can be specified in units of 100 units.

However, this address data cannot specify the addresses of individual decoders.

■, Address map data AM (13 bytes) 1 based on the address of address data ADI (ADD)
Addresses are specified for 04 decoders.

The first bit of the address map is address data A.
The address of each decoder is specified in sequence so that the address is for the same decoder as Ih (A D2 ), and the next 1 bit is the address for the next decoder.

Address data AD1, AD2 and address map data AM have different addressing specifications depending on the mode code MD described below.

(2) Mode code MD (2 bits) This is a code for specifying the mode during addressing.

Since it has a 2-bit configuration, the following four types of addressing modes can be selected.

(a) Mode O This is a batch addressing mode in which data service is not provided to all decoders having addresses specified by address data AD, AD2 and AD2.

In this case, the bits of the address map data AM are all set to "0", and the transmitted key code KC is not stored in the memory of the decoder.

(b), Mode 1 A mode in which data service is provided to the decoder specified by the address of address data AD and the decoder specified by the address of address data AD2 (therefore, only two decoders are specified). be.

(C), Mode 2 For each of the 104 decoders whose address data AD, 5AD2 is the base point of the address, 1'' of the address map AM following the address data AD, , AD2.
, 0'' performs addressing.

In this case, address data A DH, A D 2
Both have the same address data.

When address data AD specifies a decoder in the 100s, the first bit of address map AM is 100.
The bit following this specifies the 101st decoder.

When the bit is 'l', the above-mentioned key codes (two types) are stored in the memory of the corresponding decoder.

On the other hand, when the bit is "0", no key code is stored.

(d+, mode 3, opposite to mode O, addresses all decoders specified by address data AD, , AD2 at once.

Therefore, key codes will be stored in those decoders. In this case, address map data AM is set to all "1"s.

(2) Service level code 5L (6 bits) This is a code indicating which host computer's data was inserted into which channel for transmission. The upper 3 bits are assigned to the data channel, and the lower 3 bits are assigned to the service level.

In the above example, eight host computers and eight horizontal lines (eight channels) are used for transmission, so a total of 64 types of service levels can be specified.

G. Reason for using 22 types of key codes In the addressing format described above, first, two types of key codes KC are used.
The reason for sending out the two at the same time is as follows.

Addressing is performed in units of reception contract periods before the contract period expires. For example, if the contract period is determined on a monthly basis, next month's addressing will be executed in the current month. The key code (in the transmission signal) sent during the contract period uses a key code with a different pattern from the previous key code, so if only the next month's key code (one type) is sent during addressing,
The following inconvenient situations occur.

For example, as shown in Figure 10, the current month is January,
It is assumed that KC, is used as the key code KC for January, and KC2 is used as the key code KC for February.

In this case, addressing using the key code KC2 is executed during period T in the latter half of January. If a particular decoder has been paid the reception contract fee for both January and February, that particular decoder will store the key code KC2 in a predetermined memory during addressing in mode 2.

As a result of this memory operation, the key code KC2 for January is stored in this memory instead of the key code KC.

Therefore, since the key code will be changed to KC2 from the second half of January, there will be inconveniences such as not being able to receive data service even though the reception contract fee has been paid during the second half of the period after addressing. occurs.

On the other hand, if the key codes KC, KO2 for the current month and the next month are simultaneously sent during addressing as described above, and the addressing is executed at the same time, the key codes K CH and KC2 are both stored in memory. , even after addressing, the data service for that month can be received, and the above-mentioned inconvenience is solved.

C'+3 Reason for setting multiple addressing modes The reason why multiple addressing modes can be selected is as follows.
Based on the following reasons.

For example, if the receiving station 10A, which has all decoders for addresses in the 0 to 1000 range, has not yet paid the reception contract fee, batch addressing using mode 0 is preferable to performing addressing individually using mode 2. This can significantly reduce the time required for addressing.

For the same reason, when the reception contract fee for a certain receiving station 10A is paid, if you execute addressing in mode 3, addressing will be done in bulk in this case as well, and the addressing time can be greatly reduced. It is.

However, when the reception contract fee is paid differently depending on the address, by selecting mode 2, addressing can be performed according to the contract status of each receiving station 10A.

In addition, when addressing a specific receiving station among the plurality of receiving stations 10A, it is necessary to perform addressing in mode 2, but if mode 1 can be selected as described above, it is possible to Since only the receiving stations of 1 are addressed immediately, the addressing time can be reduced compared to when mode 2 is selected.

For this reason, by selecting the addressing mode according to the reception contract status, even if there are a large number of subscribers, the addressing time for all subscribers can be shortened.

FIG. 11 shows an example of a receiver 30 installed in the receiving station 10A for receiving a transmission signal having the above format and receiving a specific data service.

G1. The broadcast signal received by the system diagram antenna 29 of the reception tia 30 is supplied to a tuner 40 with an all-channel configuration, where it is converted into a television signal in a predetermined frequency band, and this is supplied to a ghost canceller 41 to perform ghost cancellation processing. are implemented to avoid data extraction malfunctions.

The output is supplied to a data separation circuit 42, where the transmission signal inserted into the broadcast signal is extracted and separated. The extracted transmission signal is supplied to a decoder 50 and service data S
Decoding processing such as DA is executed. The service data SDA is converted into a code format that conforms to the standards of the personal computer 31 and is then supplied to the personal computer 31 via the interface 43 .

44 is a control system, which is a controller 45,
It is comprised of a keyboard 46 for giving commands. 4
7 is a power supply device.

Circuit Description of G15 Decoder 50 FIG. 12 is a system diagram showing an example of the above-mentioned decoder 50. The transmission signal separated by the data separation section 42 is subjected to byte sync BYS extraction in the byte sync section 51.

To detect the byte sync BYS, a gate signal is generated in advance by the gate pulse generator 52 using the horizontal and vertical synchronizing signals HD, VD and the clock signal CK, and the vicinity of the byte sync BYS is gated with this gate signal, and then detected.

When the byte sync BYS is detected, the detection signal is input to the gate pulse generator 52, and the channel address CA is set based on the byte sync BYS.

Gate signals for extracting the control data section CD, service data section CD, addressing data AD, etc. are generated.

The channel address data CA extracted by the channel address gate section 54 is sent to the error correction (hamming) section 5.
5, and the error is corrected.

The error-corrected 4-bit channel address data CA is compared with the 4-bit channel address setting data sent from the controller 45 in the channel address comparison section 56, and if they match, the gate pulse generation section 52
sends a match signal to

The gate pulse generator 52 uses this coincidence signal as a reference to gate the insertion timing of channel address data on the same line in the next field. Similarly, gate pulses are output to the data gate 57 and control data gate 58.

The control data section CD extracted by the control data gate 58 is sent to the sync code detection section 60 to detect the sync code SC included in the control data section CD, and 64 types of sync codes SC are extracted. .

Here, when the same sync code SC is detected over three fields, it is sent as the sync code SC to the determination circuit section 59 as a sync detection signal. When the determination circuit section 59 receives this detection signal, it sends a holding signal to the sync pattern holding section 70 for holding the sync code SC.

Further, a gate signal for detecting the sync code of the next control data section CD is sent to the sync code detection section 59.

This allows the sync code SC to be easily detected. The details will be described later.

When the sync code SC is detected, the judgment circuit unit 59 tells the timing generator 72 to write the control data CDA itself following the sync code SC to the RAM 73, and at the same time to perform deshuffling according to the type of the sync code SC. Sends a sync detection signal to start.

The deshuffling pattern generating section 75 receives a pattern code (6 bits) from the sync pattern holding section 7o, and generates a deshuffling pattern that becomes a write address of the RAM 73. The start signal is output from the timing generator 72.

When the control data CDA is read from the RAM 73, it is deshuffled.

For this reading, the read counter 74 operates in response to a counter start signal from the timing generating section 72, and at the same time, the address switching section 76 is switched to the read side and a read signal is supplied to the RAM 73.

The read control data CDA is error-corrected by an error correction (hamming) section 80, and further, by a holding signal generated by a timing generation section 72, a data block information extraction section 81 converts data block information SB into deshuffling information. The extraction section 82 extracts the deshuffling map information SM and uses it as a key signal for reproducing the data part.

Service data SDA (
Alternatively, addressing data ADA) is stored in a data buffer 85 and sent to a deshuffling circuit 86, which is controlled by a buffer control section 87.

The buffer control section 87 receives a reference signal indicating the position (field) of the sync code in the control data CDA from the determination circuit section 60 and the data block information section 81.
receives data block shift information from , and sets service data SDA (or addressing data ADA) to
The data is stored in the data buffer 85 in units of blocks and then sent out.

The deshuffling circuit 86 is the deshuffling information unit 8
2, the deshuffling pattern information SM is input, and the service data is deshuffled. After that, service data SDA (or atranging data A
DA) is error corrected by an error correction circuit 91.

Note that when a data transmission failure occurs, a data reset signal is sent from the gate pulse Q generation unit 52 to the buffer control unit 87, and the data in one block stored until the data transmission failure occurs is reset. is cleared.

Similarly, this data reset signal is also supplied to the control data processing system to clear the data.

Specifically, the above-mentioned data reset signal is supplied to each of the deshuffling pattern generation section 75, the data block information extraction section 81, and the deshuffling information extraction section 82.

On the other hand, the capacity of RAMI 10 for data storage is selected so that it can store a transmission capacity (9900 baud) that is higher than the normal transmission rate (9600 baud), and even in the event of a transmission failure as described above, Data can be sent to the subsequent interface 43 without interruption. This processing mode is a so-called catch-up mode.

Decoding process of CI6 service data SDA When the addressing mode detection unit 100 detects the service mode, the error-corrected service data part SD (
1 data block) 1st line belly dark part H
Service level code detection $10 to read information on D
1 baud rate detection section 102, sync/async detection section 1
03, data end detection section 104, key code detection section 1
05 respectively operate and detect each piece of information.

The detected service level code SL is compared with the service level code sent from the controller 45 in the service level comparison section 107, and if they match, a match signal is sent to the buffer control section 108 and the key code comparison section 109.

The detected key code is compared with a predetermined key code stored at the time of addressing in key code comparison section 109, and if they match, a match signal is sent to buffer control section 108.

The buffer control unit 108 performs control to buffer necessary data in the RAM 110 based on the service level match signal, key code match signal, baud rate information, and data end information, and output it to the interface 43 at a constant rate.

A boat rate signal and a sync/async signal are also sent to the interface 43.

Decoding processing in G17 addressing mode In the addressing mode, each line of the data block serves as addressing information.

Therefore, for each line, mode signal MC, service level code SL, key code KC, address data A
D I % A D 2 , address data map AM
Detect.

Therefore, in addition to the i-code code detection section 112, the service level code detection section 121, the key code KC detection section 122, the address data AD detection section 123, the address data AD2 detection section 124, and the address data map AM A detection unit 125 is provided respectively.

Mode code M detected by mode code detection unit 112
C is sent to the address data ID comparison section 113. The address data ID comparison section 113 compares the sent address data with the ID (address data) unique to each decoder stored in the nonvolatile memory +7-114. Before this comparison, the mode code is
D, , A D 2 is a code for processing the address data map AM according to the format.

When a match with the output of the decoder ID holding unit 115 is detected, an ID matching signal is sent to the memory control unit 116, and the memory control unit 116 selects the key code (two types) at this time.
is stored in the nonvolatile memory 114. At this time, the address of the non-volatile memory 114 is 6 of the service level code.
This is bit information (3 bits for channel address, 3 bits for service level).

The address selector 120 selects the service level code SL sent in the addressing mode,
In the service mode, the channel address data CA sent from the controller 45 and the service level setting value are selected.

In the service mode, the key code stored in the set channel address and service level is read out from the non-volatile memory 114 and sent to the key code comparison unit 109.
sent to.

Thirteenth explanation of CI8 sync detection section 60 and judgment circuit section 59
The figure is a system diagram showing the relationship between the sync code detection section 60 and the judgment circuit section 59, and the sync code detection section 60 is composed of a sync comparison section 61 and a sync pattern comparison section 62.
Each data in the control data section CD gated by the control data gate section 58 is converted into 8-bit parallel data by the shift register 65, and then supplied to the sync comparison section 61, and the pattern of the sync code SC is 64.
A comparison is made to see which pattern among the types of sync patterns matches.

If the pattern matches any of the 64 types of patterns, the match signal from the sync comparison section 61 is supplied to the sync pattern comparison section 62. The sync code SC itself is also supplied to the sync pattern comparison unit 62, and a comparison is made to see if the same sync pattern and matching signal have been input three times in a row.

When the same sync pattern is supplied over three fields, the sync pattern comparison section 62 outputs a sync detection signal.

The sync detection signal is supplied to the determination circuit section 59.

The determination circuit section 59 is composed of a counter timer, and a vertical synchronization pulse VD is supplied as its clock. The sync detection signal is used as a start signal for the counter timer, and the sync detection signal starts the counting operation.

When the counter timer counts 48 vertical synchronization pulses VD, an "H" gate signal is output. As a result, the final field of the control data CDA of <48 bytes following the sync code SC is detected.

For this reason, the 48-byte fixed-length control data CDA in the control data section CD is 'L', and the variable-length dummy code DC and the following 3-byte sync code 800 are 'L'. A gate signal that becomes "H" is generated by this judgment circuit 59.

The gate signal is supplied to the sync pattern comparison section 62 as a masking signal, and the pattern comparison operation is prohibited during the period when the gate signal is "L", and the pattern comparison operation is executed only during the period when the gate signal is "H".

Since the sync code SC and the coincidence signal are supplied to the sync pattern comparison section 62 at any timing during the period when the gate signal is H'', even if the dummy code DC has a variable length, the dummy code DC The subsequent sync code SC can be detected.

When the sync code detection section 60 and the judgment circuit section 59 are configured in this way, the sync code SC inserted into the control data section CD can be reliably detected even if the control data section CD has a variable length configuration. be able to.

Although the control data CDA may include the same pattern as the sync code SC, the dummy code DC input during the pattern comparison operation does not include the same pattern as the sync code SC. Together with this configuration, the detection accuracy of the sync code SC can be improved.

Note that the holding signal supplied to the sync pattern holding section 70, the sync detection signal supplied to the timing generation section 72, and the reference signal supplied to the buffer control section 87 are all output at the same timing as the sync detection signal. Ru.

〔Effect of the invention〕

As explained above, in the present invention, in a new information service system, a sync code SC that is not subjected to shuffling processing is used as a part of the control data section CD for transmitting the decoding information of the service data ISD. This is what I did.

According to this, the shuffling of the control data section CD differs depending on the sync code SC used, and the shuffling information of the service data section SD is included in the control data section CD following this control data section CD. Therefore, the control data part C
D is highly confidential, and the control data section CD cannot be easily decrypted.

Moreover, since the decoding information of the service data portion SD is inserted into this shuffled control data portion CD, the service data SDA cannot be easily decoded either.

As a result, there is a practical benefit of being able to provide an information service system with extremely high confidentiality. Therefore, the present invention is extremely suitable for application to a paid service system that provides information only to specific subscribers as described above.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing a schematic configuration of an information service system according to the present invention, FIG. 2 is a diagram showing a format of a transmission signal, FIG. 3 is a diagram showing a format of a service data section, and FIG. 4 is a diagram showing a service data section. FIG. 5 is a diagram showing the relationship between the baud rate and the service block, FIG. 6 is a diagram showing an example of the format of the control data section, and FIG. 7 is a diagram showing the relationship between the baud rate and the service block.
FIG. 8 shows the relationship between C and control data CDA.
Figure 9 shows an example of the format of control data CDA, Figure 9 shows an example of the format of addressing data, Figure 10 shows an explanatory diagram for the sync code SC, and Figure 11 shows an example of the receiver. A system diagram of the main parts shown,
FIG. 12 is a system diagram showing an example of a decoder, and FIG. 13 is a system diagram showing a specific example of a sync code detection section and a discrimination circuit section. 10 is an information service system, IOA is a database station, IOB is a ground relay station, IOC is a receiving station, 12A-12
15 is a host computer, 13A to 13H are pilling computers, 50 is a decoder, 59 is a judgment circuit section, 60 is a sync code detection section, and 87 is a buffer control section.

Claims (1)

[Claims] The service data and key code sent from the database station are received by a decoder provided on the subscriber side, and the key code sent after decoding the data becomes the key code on the receiving side. In an information service system in which a specific information service transmitted from the database station can be received only when a match is made, the service data section to be transmitted and the control data for transmitting the decoding information of this service data section. An information service system comprising: a sync code that is not shuffled to extract information from the control data section among the shuffled data sections;