KR100730464B1 - Receiving device for receiving a digital signal and the method of therefor - Google Patents

Abstract

In the digital broadcast signal, even if the PAT and / or the EIT and the NIT technology are different, the service that can be received is correctly displayed.

The services described in the EIT are sequentially searched (step S101). It is determined whether or not the retrieved service exists in the NIT (step S102). If it is determined that the searched service exists in the NIT, the service is added to the list (step S103). Otherwise, the subsequent service is searched (step S101). After step S103, it is determined whether or not the service is the last in the service described in the EIT (step S104). If it is determined that the service is the last service in the EIT, list creation is terminated, and in the other cases, the subsequent service is searched for (step S101). The EPG is displayed based on the list created.

Digital broadcasting signal, service search, list, information table

Description

Receiving device for receiving a digital signal and the method of therefor}

1 is a schematic diagram showing an example of a digital signal transmission system receiving digital CS broadcast and retransmitted through digital cable broadcast;

2 is a schematic diagram for explaining a multimedia multiplexing scheme by TS of MPEG2.

FIG. 3 is a schematic diagram for explaining a TS packet of MPEG2 in FIG. 2; FIG.

4 is a schematic diagram for explaining a frame configuration of a DVB system.

5 is a schematic diagram for explaining a PAT.

6 is a schematic diagram for explaining a PMT.

7 is a schematic diagram for explaining the NIT.

8 is a schematic diagram for explaining a satellite delivery system descriptor.

9 is a schematic diagram for explaining a service list descriptor.

1O is a schematic diagram for explaining a cable delivery system descriptor.

FIG. 11 is a schematic diagram showing an example where there is a service described in the NIT and not described in the PAT and / or the EIT. FIG.

FIG. 12 is a schematic diagram illustrating an example of an EPG displayed in the case of FIG. 11. FIG.

13 is a block diagram showing an example of a configuration of a modulation conversion unit.

Fig. 14 is a schematic diagram for explaining a modulation method in digital cable broadcasting.

Fig. 15 is a block diagram showing an example of the overall configuration of one embodiment of the present invention.

Fig. 16 is a flowchart for explaining the processing in one embodiment of the present invention.

FIG. 17 is a schematic diagram showing an example in the case where a service described in the PAT and / or the EIT and not described in the NIT exists. FIG.

FIG. 18 is a schematic diagram showing an example of an EPG displayed based on the result of the process shown in FIG. 17; FIG.

Fig. 19 is a flowchart for explaining the tuning process of the present invention.

20 is a flowchart for explaining another channel selection process of the present invention.

<Description of the symbols for the main parts of the drawings>

101: input terminal 102: front end

103. Transport section 104: MPEG decode section

105: host processor 106: non-volatile memory

107: operation input unit 109, 110: output terminal

121: Tuner 122: QAM demodulation circuit

123: error correction circuit 131: descrambler

132: demultiplexer 141: video decoder

142: audio decoder 143: NTSC encoder

144: D / A Converter

The present invention relates to a digital signal receiving apparatus and a receiving method used for receiving digital satellite broadcasting and retransmitting through digital cable broadcasting, for example.

In CS (Communication Sate 11ite) digital broadcast signals and the like that provide services such as video, audio, or text data, the description of the service in the NIT (Network Information Table) only relates to the service actually being broadcasted. In addition, a service described in the NIT and not described in the PAT and / or the EIT is treated as a broadcast pause in a receiver such as a set top box (STB).

In the case of receiving digital CS broadcasting and retransmitting it through digital cable broadcasting, there may be a service described in the PAT and / or the EIT and not described in the NIT. Since such a condition cannot exist in digital CS broadcasting, if the same processing as that of the digital cable broadcasting STB is performed in the digital cable broadcasting STB or the like, there is a risk of malfunction or operation delay.

Accordingly, an object of the present invention is to provide a digital signal receiving apparatus and a receiving method capable of performing normal operation even when there is a service described in the PAT and / or EIT and not described in the NIT.

The invention of claim 1 comprises a first information table describing the relationship between physical information about the transmission path and the data that can be provided, and a digital having a second information table that describes the data that can be provided. In the receiving device for receiving a broadcast signal,

Search sequentially the services described in the second information table,

Create a list of only those described in the first information table in the service to be searched,

A digital signal receiving device characterized in that a predetermined process is performed on the basis of the created list.

The invention of claim 5 comprises a first information table describing the relationship between physical information about the transmission path and the data that can be provided and a second information table that describes the data that can be provided. In the receiving method for receiving a broadcast signal,

A search step of sequentially searching for a service described in the second information table;

Has a list making step of creating a list described only in the first information table in the service searched by said searching step,

A digital signal receiving method characterized in that predetermined processing is performed on the basis of the created list.

According to the above invention, in the service described in the information table such as PAT and / or EIT, which describes the data that can be viewed, the relationship between the physical information about the transmission path and the data to be viewed is described. A list describing only what is described in the information table such as the NIT is generated, and it is possible to perform processing such as display of the EPG in accordance with this list.

<Embodiment of the invention>

FIG. 1 shows an example of a digital signal transmission system that receives digital satellite broadcasting and retransmits it through digital cable broadcasting. The satellite 1 is provided with a plurality of transponders (satellite repeaters). The antenna 2 receives digital broadcast signals transmitted from these transponders, respectively. The modulation conversion unit 3 is supplied with the digital broadcast signal received by the antenna 2, changes the transmission frequency or modulation method of the supplied digital broadcast signal to be suitable for digital cable broadcasting, etc., and sends it to the transmission path 4. . STBs 51, 52, ..., 5 m are connected to the transmission path 4 as a receiver. Monitors 61, 62, ..., 6m are connected to STBs 51, 52, ..., 5m, respectively, and an image of the program number tuned in each STB is displayed on each monitor.

The digital broadcast signal will be described. As an example, a digital broadcast signal corresponding to the DVB (Digital Video Broadcasting) system as the European digital broadcasting standard will be described. FIG. 2 shows an example of a signal format in the multimedia multiplexing method by TS (Transpot Stream) corresponding to the specification of Moving Picture Experts Group (MPEG) 2. Data of each media (video, audio, etc.) constitutes variable length packets called PES (Packetized Elementary Streams) packets. The PES packet is further divided into several transport stream packets (hereinafter referred to as TS packets). The TS packet consists of a header and a payload area.

The detailed structure of the TS packet corresponding to the regulation of MPEG2 is demonstrated with reference to FIG. One packet consists of 188 bytes, of which the first four bytes, i.e., 32 bits, are used as packet headers. In the packet header, one byte, i.e., eight bits, becomes a synchronization byte, and the decoder detects the head of the TS packet based on this synchronization byte. As the pattern of sync bytes, for example, '47H' (H means hexadecimal) is used. In addition, one bit is used as a transport error indicator indicating the presence or absence of an error in the TS packet. In addition, one bit is used as a payload unit start indicator indicating that a new PES packet starts from this TS packet.

In addition, one bit is used as a transport priority bit indicating the importance of the corresponding TS packet. In addition, 13 bits are used as a PID (Packet Identifier) which is an identifier of a TS packet. The identification number of the TS packet stored in the PID indicates the attribute of the individual stream of the packet. In the STBs 51 to 5m and the like, data of each media is identified with reference to the PID. In addition, two bits are used as transport scramble control information indicating whether or not the payload of the TS packet is scrambled and the type thereof.

In addition, two bits are used as adaptation field control information indicating the presence or absence of the adaptation field and the payload in the TS packet. In addition, four bits are used as the continuity index information for detecting whether a packet having the same PID is partially rejected. The presence or absence of such a packet is detected based on the continuity of the 4-bit circulating count information.

On the other hand, 184 bytes other than the packet header are used as the payload area. The payload area is used for accommodating data viewed by a user such as video data and audio data for each TS packet, or program specific information (PSI), service information (SI), and the like described later.

Next, a frame structure of digital broadcast data in the DVB system is shown in FIG. 4A shows a TS packet of MPEG2. FIG. 4B shows a form in which eight TS packets of MPEG2 shown in FIG. 4A are collected to form one frame. Here, the error correction code of Reed-Solomon is added to the data in each TS packet, and one packet is 204 bytes. In addition, the frame is synchronized by inverting the sync byte once every 8 packets. For example, when '47H' is used as the sync byte, the sync byte is 'B8H' once every 8 packets. Digital broadcast data as shown in Fig. 4B is modulated with Quadrature Phase Shift Keying (QPSK).

Next, the PSI will be described. Examples of the PSI include a program association table (PAT), a program map table (PMT), a network information table (NIT), and the like. First, the PAT is an information table in which unique contents are multiplied for each carrier. That is, the PAT describes channel information in each carrier and a PID of PMT (which will be described later) indicating the contents of each channel. An example of the data structure of a PAT is shown in FIG. The table ID (8 bits) indicates the type of table, and is fixedly '0x0000' ('0x' indicates hexadecimal notation) for the PAT. A section syntax indicator (1 bit) indicates whether the header of the section is a long form or a short form. The reserve (2 bits) represents a flag that will be meaningful in the future.

The section length (12 bits) indicates the section length in bytes from immediately after this end to the end of the section (including the cyclic redandancy code (CRC) code). TSID (16 bits) identifies a transport stream (multiplexed encoded data), which corresponds to a transponder in the case of satellites. The version number (5 bits) represents the PAT version, and whenever the contents of the PAT are updated, the version number is also updated. The current next indicator (1 bit) indicates which version is used when simultaneously transmitting the old and new versions of the PAT. The section number (8 bits) indicates the section number, and becomes '0xOO' for the first section, and then increases one by one. The last section number (8 bits) indicates the section number of the last section of the same subtable.

In addition, a portion enclosed by double lines, that is, a program number (16 bits), a reserve (3 bits), a network PID (13 bits) and a program map (13 bits) are repeatedly recorded. The program number is a number for identifying individual channels. The network PID indicates the PID of the subsequent NIT when the program number is '0x0000'. The program map PID indicates a PID corresponding to the PMT (to be described later). The CRC is also an error detection code for the entire section.

The PMT is an information table in which the contents of each channel are multiplexed. That is, the PID of the packet and the PID of the Encryption Control Message (ECM) packet required for the descrambling are described. The PID of the PMT is specified by the PAT as described above. 6 shows an example of the data configuration of the PMT. The description of the same data parts included in the data configuration of the PAT described above with reference to FIG. 5 will be omitted. Table ID (8 bits) indicates the type of table, and table ID = 'OxO2' for PMT itself. PCR (Program Clock Reference) A PID (13 bits) indicates the PID of a packet including a clock which is a reference for decoding. The program information length (12 bits) is a loop immediately after describing information common to this service. The descriptor is repeatedly recorded to describe the information for each section in order to supplement the information of the section.

In addition, a portion enclosed by double lines, that is, a stream type (8 bits), a reserve (3 bits), an elementary PID (13 bits) reserve (4 bits), an ES information length (12 bits), and a descriptor are repeated. Is recorded. Among these, the descriptor is repeated at each time of the repetition. The program number is a number for identifying individual channels. The stream type indicates the type of signal transmitted by the stream, such as video, audio, and data. The elementary PID represents the PID of the elementary stream. The ES information length is the immediately following loop that describes the information of the elementary stream.

In addition, the NIT is an information table in which information related to a transmission path and information related to a broadcast service is described. That is, in the NIT, a list of channels multiplexed on each carrier is described, along with physical information for each carrier, for example, satellite orbits, polarizations and carrier frequencies for each transponder, overlapping rate, and the like. PID of NIT becomes '0x0010'. Further, while the details of the data structure are specified in the MPEG2 system for the above-described PAT and PMT, only the necessity is specified for the NIT, and the data structure is a private.

An example of the data structure of NIT is shown in FIG. Description of the same data portion as the data portion in the data configuration of the PAT and PMT described above with reference to FIGS. 5 and 6 will be omitted. The table ID (8 bits) indicates the type of table, where the network is 'Ox40' and the other network is 'Ox41'. The network ID (16 bits) identifies the network and, in the case of satellite broadcasting, corresponds to an individual satellite. The network descriptor length (13 bits) is a loop immediately after describing common information of the network. The TS loop length is an immediate loop that opens a transport stream belonging to the network. In addition, the TS descriptor length (12 bits) is recorded in the repeated portion enclosed by the double lines. The TS descriptor length describes the information of the transport stream as a immediately following loop.

Next, the satellite delivery system descriptor will be described with reference to FIG. The satellite delivery system descriptor is used as the first of the repeated descriptors according to the TS descriptor length (see Fig. 7), and is paired with the TSID. Descriptor tags (8 bits) are defined in DVB and indicate the type of descriptor. For the satellite delivery system descriptor, the descriptor tag = 'ox43'. The descriptor length (8 bits) represents the data length of the descriptor. The digital frequency (32 bits) represents the transmission frequency for each stream (transponder here). Orbit (16 bits) represents the longitude of the satellite's orbital position.

The west longitude and longitude flag (1 bit) indicate the longitude and longitude of the satellite's orbit position. Polarization (2 bits) represents the polarization of the transmitted signal. For example, '00', '01', '10', and '11' may correspond to a horizontal straight line, a vertical straight line, a left circle, and a priority circle, respectively. In addition, modulation (5 bits) represents a modulation system. For example, '00001' corresponds to QPSK. The symbol rate (23 bits) represents the symbol rate. Forward Error Correction (FEC) (4 bits) represents the convolution rate.

Next, the service list descriptor will be described with reference to FIG. The service list descriptor is used as the second or later of the repeating descriptor according to the TS descriptor length (see Fig. 7), and represents the ID of the service (channel) multiplexed to the stream (transponder here). That is, a service list descriptor is attached to one TSID. A descriptor tag (8 bits) is defined in DVB and shows the type of descriptor. The descriptor tag for the service list descriptor is 'Ox41'.

The service ID (16 bits) identifies the service. Usually, the service matches the channel that the viewer tunes into. The service type represents the contents of a service such as video, audio, and data. In other words, '0x01' corresponds to a digital TV service, 'OxO2' refers to a digital voice service, 'Ox03' refers to a teletext service, and '0x04' corresponds to an NVOD basic service. Also included.

Next, the cable delivery system descriptor will be described with reference to FIG. The description of the same data portion as the data portion of the data structure of the satellite delivery system descriptor described above with reference to FIG. 8 will be omitted. The descriptor tag is defined in DVB and indicates the type of the descriptor. The descriptor tag for the cable delivery system descriptor is '0x44'. The frequency (32 bits) represents the transmission frequency for each stream in the digital cable broadcasting (here, each channel in the digital cable broadcasting).

FEC (Forward Error Correction) The outer code (4 bits) is an error correction code as an outer code, for example, when '0010' indicates that the Reed Solomon code is used as the outer code. . Modulation (8 bits) indicates a modulation scheme and, for example, corresponds to 64QAM when it becomes '0x03'. The symbol rate (28 bits) represents the symbol rate. The FEC inner code (4 bits) represents the convolution rate.

Next, SI will be described. The SI is a section type table that stores information related to channels, services, and the like. Examples of SI include a service description table (SDT) and an event information table (EIT). The SDT stores channel information such as channel number, channel name, channel content description, channel logo mark, and the like. The EIT also stores information related to services such as channel number, service number, start time, duration time, service name, summary, service genre, and parental control age.

EPG (Electronic Program Guide) is created based on the information of this SI. By displaying the EPG on the monitors 61, 62, 6m of the STBs 51, 52, 5m, it is possible to easily find a service that the user wants to watch.

Normally, the service described in NIT and the service described in PAT, EIT, etc. match, but in CS digital broadcasting already broadcasted, there may exist services described in NIT only and not described in PAT and / or EIT. have. An example of such a case is shown in FIG. If the service described in the NIT is as shown in Fig. 11A, and the service described in the PAT and / or EIT is as shown in Fig. 11B / 11C, the service related to 444ch is assigned to the NIT. Although described, it is understood that it is not described in PAT and / or EIT. In this case, the STBs 51 to 5m judge that 444ch is in the broadcast pause state, and the effect is displayed on the EPG (see Fig. 12).

On the other hand, in digital cable broadcasting, when retransmitting digital CS broadcasting, it may not be possible to receive all services in digital CS broadcasting. For example, when the satellite 1 has L transponders and the number of digital broadcast signals in digital cable broadcasting is M (M <L), M digital broadcasting signals are selectively selected in digital cable broadcasting. It may be used as. In such a case, the NIT is updated to delete information related to the service that is not retransmitted.

An example of the structure of the modulation conversion part 3 which has the function to update NIT as mentioned above is shown in FIG. Digital broadcast signals of the SHF (Super High Frequency) band transmitted from the satellite 1 and supplied through the antenna 2 are supplied to the signal processing units 301, 302, ..., 30m. The signal processing units 301 to 30m convert the supplied signals into digital cable broadcasting signals BS1 to BSm of VHF (Very High Frequency) band or UHF (Ultra High Frequency) band. The control unit 31 controls the operation of the entire apparatus by supplying a predetermined signal to the signal processing units 301-30m. The operation unit 32 is a configuration related to setting of a reception frequency of a tuner built in the signal processing units 301 to 30m, for example, a parameter related to control by the control unit 31. The display unit 33 displays the state of the device. In addition, the mixer 34 mixes the digital cable broadcast signals BS1 to BSm, which are outputs of the signal processing units 301 to 30m, and sends them to the transmission path 4.

The configuration of the signal processing unit 301 will be described in more detail. The signal supplied from the antenna 2 is supplied to the tuner 40. The tuner 40 selects the digital broadcast signal transmitted from the first transponder from the supplied signal, performs frequency conversion on the selected signal, generates a QPSK signal, and supplies the QPSK signal to the demodulator 41. do. The demodulator 41 demodulates the QPSK signal supplied from the output tuner 40 of the tuner 40 and converts it into a signal having a frame structure of the DVB. The output of the demodulator 41 is supplied to an ECC (Error Correction Code) decoder 42.

The ECC decoder 42 generates an TS2 packet of MPEG2 as digital broadcast data by performing error correction processing on the output of the demodulator 41, and converts the TS packet of the generated MPEG2 into the NIT replacement circuit 43 and the NIT detection circuit ( 47). The NIT detection circuit 47 detects NIT (hereinafter referred to as NIT0) in the digital broadcast data output from the satellite 1 from the TS packet of MPEG2 supplied from the ECC decoder 42. The detected NITO is supplied to and stored in the memory 48.

The control unit 31 reads the NITO from the memory 48 through the interface 50 as necessary, updates the information related to the service in the NITO to be suitable for digital cable broadcasting, and sets NIT1. That is, the control unit 31 generates an updated NIT (hereinafter referred to as NIT1) by converting the satellite delivery system descriptor (see FIG. 8) in the NITO into the cable delivery system descriptor (see FIG. 10). The generated NIT1 is supplied to and stored in the memory 49 via the interface 50. In addition, the controller 31 controls the reception frequency of the tuner 40 through the interface 50.

As described above, when the transponder number L of the satellite 1 is larger than the channel number M of the digital cable broadcasting, and the M digital broadcasting signals are selectively used for the digital cable broadcasting, the control section 31 ) Works as follows: That is, information related to the TSID corresponding to the digital broadcast signal not used in the digital cable broadcasting, for example, the TSID, the contents of the descriptor, etc. of FIG. 7 are deleted, and NT0 is changed to NT1.

The NIT replacement circuit 43 performs a process of replacing the NITO in the TS packet supplied from the ECC decoder 42 with NIT1 read out from the memory 49, and replaces the TS packet of MPEG2 generated by this process with the ECC encoder 44. Supplies). Here, the NIT replacement circuit 43 performs a process such as inserting a dummy bit at a location where information related to the TSID is deleted.

The ECC encoder 44 adds an error correction code of Reed Solomon to the output of the NIT replacement circuit 43, and converts it into a frame structure of DVB. The output of the ECC encoder 44 is supplied to a modulator 45. The modulator 45 modulates the supplied signal by Quadrature Amplitude Modulation (QAM). The output of the modulator 45 is supplied to the frequency converter 46. The frequency converter 46 generates the signal BS1 by converting the output of the modulator 45 into a transmission output of a predetermined frequency in the VHF band or the UHF band. Signal BS1 is supplied to mixer 34.

As the configuration of the signal processing units 302 to 30m, the NIT detection circuit 47, the memory 48, and the memory 49 may be removed from the configuration of the signal processing unit 301 described above. The signal processing units 302 to 30m respectively select digital broadcast signals corresponding to the second to mth transponders from the output of the antenna 2, and read NIT1 from the memory 49 as necessary to read the NIT. Substitution is performed, and BS2 to BSm of different transmission frequencies are supplied to the mixer 34.

As described above, in digital CS broadcasting, the QPSK (four-phase phase modulation) method is adopted as the digital modulation method. For example, in some digital CS broadcasts, the transmission rate is 27 MHz, and the entire data transmission rate including an error correcting code called Viterbi code is 42.192 Mbps, and the rate excluding the Viterbi code is 31.644 Mbps. In the digital cable broadcasting that retransmits such digital CS broadcasting, the transmission band is 6 MHz and the C / N of the cable is very good compared to the C / N of the CS broadcasting. Therefore, it does not include the Viterbi code as described above. 64 value QAM is used as a modulation scheme.

QAM is one of the digital modulation methods called orthogonal amplitude modulation. The QAM modulates each of two orthogonal carriers (I and Q) to multiple values and adds I and Q. It is a transmission method. In addition, since the 64 value QAM is digitally amplitude-modulated with 8 values of I and Q, and 64 data are expanded on the IQ plane, it is called in this way. By modulating the data of 31.644 Mbps using this 64 value QAM modulation method, it becomes possible to transmit in 6 MHz of transmission bandwidth of a cable.

However, in digital CS broadcasting, increasing the data transmission rate by reducing the Viterbi code rate with the increase in the transmission power of the CS has been considered. In such a case, the following problems exist when retransmitting on a cable. That is, in this case, since 64QAM is used, a band of 6 MHz is exceeded. In such a case, it is necessary to modulate using another multivalued 128QAM or 256QAM in the modulator 45 of FIG. 14A, 14B and 14C show the data arrangement on the QI plane of the digital signal modulated by 64QAM, 128QAM and 256QAM, respectively.

In addition, when digital services other than digital CS broadcasting, such as digital BS broadcasting and terrestrial digital broadcasting, are started, there is a possibility that a modulation scheme other than 64QAM needs to be used for digital cable broadcasting retransmitting their digital services.

Next, Fig. 15 shows an example of the entire configuration of a receiver for digital cable broadcasting which is one embodiment of the present invention. The digital cable broadcast signal is input to the front end portion 102 through the input terminal 101 to which the coaxial cable of the digital cable broadcast network is connected. The front end section 102 selects a predetermined carrier based on control information from the host processor 105 among the received signals.

In addition, the front end section 102 performs demodulation processing corresponding to the modulation processing (64QAM, 128QAM, 256QAM, etc.) performed at the transmission side, and performs error correction processing corresponding to the encoding processing performed at the transmission side. The transport stream obtained by this process is supplied to the transport section 103. The transport unit 103 includes a descrambler 131, a demultiplexer 132, and the like. The descrambler 131 performs descrambling processing when the separated signal component is subjected to scrambling processing on the transmitting side based on the control information from the host processor 105. By this descrambling process, MPEG compression encoding is performed on the video data and / or audio data to be viewed, and the MPEG compression encoding signal is restored.

The output of the descrambler 131 is supplied to the demultiplexer 132. The demultiplexer 132 separates and extracts packets necessary for video data and / or audio from the output of the descrambler 131 based on control information from the host processor 105. This process separates individual packets of a type called Packetized Elementary Stream (PES) related to the desired channel from each channel multiplexed in the transport stream.

The MPEG compressed video data and / or audio data of the separated channel, which are obtained as a result of the above-described processing by the transport unit 3, are supplied to the MPEG decoder 104. On the basis of the control information from the host processor 105, the MPEG decoder 104 performs decoding processing or the like corresponding to the processing performed on the transmission side to form an analog video output and to form an audio output. The MPEG decoder 104 includes a video decoder 141, an audio decoder 142, an NTSC encoder 143, a D / A converter 144, and the like. Separate packets of the PES format separated by the demultiplexer 132 are supplied to the video decoder 141 and / or the audio data decoder 142.

In the video decoder 141, decoding processing is performed on the MPEG compressed signal, and the decoded output is formed through the NTSC encoder 143 to reproduce the reproduced video signal. This reproduced video signal is taken out through the output terminal 109. On the other hand, in the audio decoder 142, a digital audio signal is formed, and this digital audio signal becomes a reproduced audio signal of analog left and right channels through the D / A converter 144. This reproduced audio signal is taken out through the output terminal 110.

Also, the reproduced video signal and the reproduced audio signal extracted through the output terminals 109 and 110 are supplied to, for example, an RF modulator (not shown), and the reproduced video signal and the reproduced audio signal are RF modulated in the RF modulator. The reproduction television signal is formed, and the reproduction television signal is supplied to the antenna terminal of the television receiver.

In addition, the host processor 105, the front end section 102, the transport section 103, and the MPEG decode section 4, which control the respective sections as described above, are connected by a bus. Passing of data becomes possible. The host processor 105 is also connected with an operation input unit 107 having various setting switches, turn keys, and the like, and the setting information from the operation input unit 107 is supplied. Accordingly, the host processor 105 stores the setting information corresponding to the operation state of the operation input unit 107 in the nonvolatile memory 106 and stores the data stored in the nonvolatile memory 106 in response to the need. The control information is read out to form control information, and the control information is supplied to each part to centrally manage each part.

Next, the front end section 102 will be described in more detail. The front end portion 102 includes a tuner 121, a QAM demodulation circuit 122, an error correction circuit 123, and the like. The tuner 121 receives the digital cable broadcast signal supplied through the input terminal 101, selects a desired carrier from the received signal, and converts the selected carrier into an intermediate frequency signal. The intermediate frequency signal that is the output of the tuner 121 is supplied to the QAM demodulation circuit 122. The QAM demodulation circuit 122 forms the baseband digital data by performing QAM demodulation processing corresponding to the modulation processing performed at the transmitting side with respect to the supplied intermediate frequency signal. The digital data of the baseband that is the output of the QAM demodulation circuit 122 is supplied to the error correction circuit 123. The error correction circuit 123 performs an error correction process corresponding to the encoding process performed at the transmitting side with respect to the supplied digital data. As an output of the error correction circuit 123, a transport stream output is formed.

Specifically, the transport stream output from the front end section 102 is composed of a set of 188-byte fixed length packets in a bit string defined by the MPEG system. Each packet consists of a header, an adaptation field for inserting additional information into a particular individual packet, and a payload indicating the content of the packet (video / audio, etc.). The header consists of 4 bytes, and a sync byte must be placed at the beginning. Then, control information such as PID (Packet ID) which is identification information of the packet, scramble existence, subsequent adaptation field or payload existence, and the like are stored.

In the descrambler 131 based on these control information, descramble is performed on a packet basis. In the demultiplexer, necessary packets such as video / audio / data are separated and extracted. Each packet separated and extracted by the demultiplexer 132 is supplied to the MPEG decode unit 104. The output of the descrambler 131 is taken out through the terminal 108 as a high speed data output.

Next, the display processing of the EPG in the receiving apparatus will be described. As described above, the NIT is recorded again in response to a retransmission condition or the like, but the PAT / PIT in the TS packet received from the satellite 1 is used as it is for the PAT / PIT. For this reason, there exists a service which is not described in the NIT but described only in the PAT and / or the EIT. If the handling of such a service is not made clear, there is a possibility that an unreasonable occurrence may occur in the operation of the STBs 51 to 5m. For example, there exists a possibility that a process speed may fall. In addition, as described above with reference to FIG. 11, since only the service searched within the service described in the NIT can be provided to the viewer, the service not described in the NIT cannot be provided to the viewer. Therefore, if the EPG is displayed based on the EIT, there is a fear that a display relating to a service that cannot be provided to the viewer may occur, which may cause confusion.

Therefore, in the present invention, when there is a service described only in the PAT and / or the EIT, which is not described in the NIT, the processing of the EPG display is performed by using the technology of the NIT preferentially in the STBs 51 to 5m. This prevents the display related to the service described only in the PAT and / or the EIT from being generated and from being tuned into.

The operation of one embodiment of the present invention for implementing the above-described processing will be described with reference to the flowchart of FIG. In addition, the process shown in FIG. 16 is performed by the host processor 105, for example. In step S101, the services described in the EIT are sequentially searched. The flow then advances to step S102, and it is determined whether or not the service exists in the NIT for the service retrieved in step S101. If it is determined that the service exists in the NIT, the process proceeds to step S103. Otherwise, the process proceeds to step S101 to search for the service described in subsequent EIT1. In step S103, the service is added to the list. The process then returns to Step S104 to determine whether the service is the last in the service described in the EIT. If it is determined that the service is the last service in the EIT, list creation is terminated. Otherwise, the flow advances to step S101 to search for the service described in subsequent EIT1.

In the list generated as described above, only the service described in the NIT is described. By displaying the EPG based on this list, it is possible to prevent the service described only in the PAT and / or the EIT from being displayed on the EPG. Such EPG display will be described with reference to FIGS. 17 and 18. Comparing the services in the NIT shown in Fig. 17A with the services in the PAT and / or EIT shown in Figs. 17B / 17C, it can be seen that? And?

① The service related to 444ch is described in NIT, but not in PAT and / or EIT.

(2) Services relating to 222ch and 555ch are described in the PAT and / or EIT, but not in the NIT.

In this case, the EPG created and displayed by the method described above with reference to FIG. 16 and the like is the same as that in FIG. So, reflecting the situation of ②, 222ch and 555ch are not displayed on the EPG. That is, a channel not described in the NIT and described only in the PAT and / or the EIT is configured so that it is not displayed on the EPG.

In addition, it is determined that 444ch is in the pause state in consideration of the situation 1), and the effect thereof is displayed on the EPG as in the example described above with reference to FIGS. 11 and 12.

Next, as described above, the channel selection processing in the reception apparatus in the case where there is the possibility of broadcasting by a plurality of modulation methods will be described below. In the tuning process, an information table called NIT (Network Information Table), particularly in information necessary for tuning, called PSI (Program Specific Information) in the transport stream, must be obtained. In the NIT, transmission specifications (carrier frequency, overlap rate, modulation scheme, etc.) for each carrier and a list of all digital transmission channels multiplexed thereto are described. However, the channel to which this NIT is transmitted and the modulation scheme employed in the channel are considered different for each cable television provider and are not uniquely determined. Therefore, when a receiver was first purchased and a contract was signed with a cable television provider, information such as the channel number (or frequency) transmitting the NIT and the modulation method used in the channel was obtained from the cable television provider. Is inputted in the flowchart shown in FIG.

19 is a flowchart showing an example of a tuning procedure. In addition, the process shown in FIG. 19 is performed by the host processor 105, for example. Through the operation input unit 107 or the like, the reception parameters (channel number or frequency and modulation method, etc.) obtained from the cable television operator as described above are input as default values (step S1). Channel tuning is performed in accordance with the reception parameter input in step S1 (step S2). The NIT is separated and extracted from the transport stream related to the channel selected in step S2, and the NIT is stored in the nonvolatile memory 6, thereby obtaining the NIT (step S3). Thus, a chord display relating to the selected channel is performed (step S4).

Subsequently, when the operation input unit 7 is operated by the user and an instruction to change the channel is made, the NIT stored in the nonvolatile memory 6 is referred to to confirm the reception parameter of the new channel related to the channel change. This is done (step S6). Then, it is determined whether or not the change of the reception parameter is necessary (step S7). If it is determined that the reception parameters need to be changed, the process proceeds to Step S8. Otherwise, the process proceeds to Step S9. In step S8, for example, a setting change of a register in the host processor 5 related to the control of the front end unit 2 is made, and the flow proceeds to step S9 again. In step S9, the tuning operation is performed based on the control information of the register whose setting is changed or held in correspondence with the determination result of step S7, and then the process proceeds to step S3.

Through the above processing, the reception parameters for the front end section 2 are set with the channel change. This enables accurate reception of digital cable broadcast signals in response to channel changes. Therefore, the user can change the channel without interruption without being aware of the change of the reception parameter. Further, unless the transmitting side changes reception parameters such as frequency, the NIT held in the nonvolatile memory 6 is repeatedly referred to, so that accurate reception as described above is always possible. Therefore, unless the transmitting side changes the receiving parameters such as the frequency, etc., all channels can be correctly received by inputting the default value of step S1 only once when the receiving apparatus is purchased. That is, step S1 and step S2 enclosed by a dotted line in FIG. 3 need to be performed only once unless a reception parameter such as a frequency is changed on the transmitting side.

In addition, in the nonvolatile memory 6, data of the state of the chord display of the predetermined channel of step S4 is stored in the nonvolatile memory 6 together with the NIT obtained in step S3 when the power is cut off. The selection processing can be performed by reading the stored data of the data.

In addition, when the transmitting side changes the reception parameter such as frequency for some reason, the user is notified of the change and input of a new default value corresponding to the change, that is, steps S1 and S2 are performed under the new default value. By this, the inability to receive is avoided.

In addition, since the unused channel varies depending on the cable broadcaster, it is considered that the channel to be transmitted becomes unified by the service provider. However, even in such a case, when the above-described processing is performed with reference to FIG. You can also respond to operators.

In addition, although FIG. 19 showed the case where it moved to step S3 after performing step S9 and NIT is obtained again, you may make it transfer to step S4 after step S9. In this case, like step S1 and step S2, step S3 may be performed only once unless the receiving parameter such as frequency is changed on the transmitting side. Therefore, there is an advantage that the processing sequence is simplified. However, when the reception parameters related to some channels are changed during viewing, a new NIT cannot be obtained, and as a result, the default value input of step S1 is performed. There is also a problem that the number of times may increase.

Next, another embodiment of the present invention will be described. 20 shows an example of another channel selection procedure operation. The same code | symbol is attached | subjected to the step which performs the same process as each step in FIG. In step S11, step S12, step S13, and step S14, the process for obtaining an NIT is performed like the procedure shown in FIG. These steps enclosed in a dotted line need to be performed only once, as in the case of Fig. 19, unless a change in a reception parameter such as a frequency is performed at the transmitting side.

In other words, the reception parameters such as the frequency are initialized in step S11. Channel tuning is performed in step S12. In addition, the flow advances to step S13 to determine whether or not channel selection has been performed correctly. If channel tuning is performed correctly, the flow advances to step S3. Otherwise, the flow advances to step S14 to change the parameter.

That is, the reception parameters stored at the time of shipment, for example, in predetermined memories, such as the nonvolatile memory 6, are sequentially set in step S14. Subsequently, the process proceeds to step S12 and channel selection is performed under the reception parameter set in step S14. Here, in a predetermined memory such as the nonvolatile memory 6, reception parameters as a combination of all frequencies, modulation schemes, etc. that are considered to be used in digital cable broadcasting are previously stored in a predetermined memory such as the nonvolatile memory 6 or the like. I remember. By this process, the search for the appropriate reception parameters is automatically performed until it is determined that channel tuning has been performed correctly.

Each step after step S3 is the same as each step in one embodiment of the present invention shown in FIG. 19. That is, the processing after determining that channel selection has been performed correctly is performed such that an NIT is obtained, and automatically follows the operation such as changing the channel based on the obtained NIT as in the embodiment of the present invention.

Compared with the above-mentioned example, the said other embodiment has the advantage that the effort which a user inputs a default value (step S1) is abbreviate | omitted.

In addition, in the above-described examples and other examples, the case where a signal modulated by the 64-value QAM, the 128-value QAM, and the 256-value QAM is supplied as another modulation method has been described. However, other modulation methods can also be applied. .

Although one embodiment of the present invention described above applies the present invention to a digital cable broadcast for retransmitting a digital CS broadcast signal, the present invention also applies to a digital BS broadcast signal or a digital cable broadcast for retransmitting a digital terrestrial broadcast signal. The present invention can be applied.

This invention is not limited to embodiment mentioned above, A various deformation | transformation and an application are possible within the range which does not deviate from the summary of this invention.

According to the present invention, in a service described in an information table such as a PAT and / or an EIT in which a description of viewable data is made, an information table such as an NIT describing a relationship between physical information about a transmission path and data to be viewed The list described only in the above is generated, and processing such as display of the EPG is performed based on this list.

For this reason, the handling of services described in PAT and / or EIT and the like but not described in NIT and the like can be clarified.

Therefore, it is possible to prevent the occurrence of irrationality caused by the existence of a service described in the PAT and / or the EIT, but not described in the NIT. For example, it is not described in the NIT or the like, and therefore, it is possible to prevent the occurrence of malfunction such as displaying a service that cannot be provided in reality, or unreasonableness such as an operation delay of the STB.

Claims (8)

delete A reception for receiving a digital broadcast signal having a first information table describing the relationship between the physical information about the transmission path and the first deliverable service and a second information table describing the second deliverable service In the apparatus, Means for retrieving the second information table for determining the second deliverable service also described in the first information table; Means for generating a list describing the first deliverable service described only in the first information table and the second deliverable service also described in the first information table; And means for displaying the information on the deliverable service to a user corresponding to the generated list. The method of claim 2, The digital broadcast signal is a digital satellite broadcast signal, And the first information table is an NIT. The method of claim 2, The digital broadcast signal is a digital satellite broadcast signal, And the second information table is a PAT and / or an EIT. delete A reception for receiving a digital broadcast signal having a first information table describing the relationship between the physical information about the transmission path and the first deliverable service and a second information table describing the second deliverable service In the apparatus, (A) retrieving the second information table to determine the second deliverable service also described in the first information table; Generating a list describing said first deliverable service described only in said first information table and said second deliverable service determined in said step (a); And (c) displaying information on the deliverable service to a user in response to the generated list. The method of claim 6, The digital broadcast signal is a digital satellite broadcast signal, And the first information table is NIT. The method of claim 6, The digital broadcast signal is a digital satellite broadcast signal, And the second information table is a PAT and / or an EIT.

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