JP2002320213A - Method for retransmitting digital broadcast signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for digitally retransmitting a satellite digital broadcast signal via a cable television broadcast network, whose transmission capacity is smaller than that of the signal by only replacing an NIT. SOLUTION: The transport streams of satellite bands 1 and 2 of satellite digital broadcast, where the band per transmission channel is 40 Mbps (Fig. 2 (a)) are respectively divided into the streams of two CATV bancs (Fig. 2 (b)), so that a program unit and the band (29 Mbps) per transmission channel of CATV broadcast are satisfied. In this case, the respective divided CATV bands 1-4 are added with EPG 1 and 2 accessory to the signals of the satellite bands 1 and 2, as they are, with merely the necessary NIT information being replaced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for retransmitting a digital broadcast signal, and more particularly, to a method for digitally converting a satellite digital broadcast signal through a cable television broadcast network having a smaller transmission capacity than the signal. How to resubmit,
In addition, the present invention relates to a channel selection method performed by a receiver that receives a signal retransmitted by the method.

[0002]

2. Description of the Related Art As is well known, digital television broadcasting by a broadcasting satellite (BS) is started following a communication satellite (CS), and the field of radio broadcasting is shifting to digital multi-channel. On the other hand, the cable television (CATV) system, which is a cable broadcast, has traditionally been required to collectively receive and retransmit these radio broadcasts from the viewpoint of increasing the number of channels to be provided and securing subscribers, in addition to digitizing the system itself. Have gone more.

As a method of digitally retransmitting a digital broadcast signal by CATV, there is a method using a transmodulation (modulation conversion) method. In this transmodulation method, it is required that the band per transmission channel of digital broadcasting is not more than the band per transmission channel in CATV. Therefore, the maximum bandwidth per transmission channel is 28.259M
29 bps BS digital broadcasting signal and the same band.
A CS digital broadcast signal of 162 Mbps can be retransmitted on a CATV having a bandwidth of 29.162 Mbps per transmission channel. In addition, regarding the transmodulation method of BS digital broadcasting,
“Japan CATV Technical Association Standard JCTEA
STD-002-2.0 "Digital Wired Television Broadcasting Multiplexer", Japan Cable Lab Specifications JCL SP
EC-001, version 1.0, “BS Digital Broadcasting Transmodulation Operation Specification”.

By the way, there is a plan to launch CS at the same 110 ° east longitude as BS so that the newly started BS digital broadcast signal and CS digital broadcast signal can be received by the same equipment. However, CS digital broadcasting (hereinafter, 110 digital broadcasting) performed using this new satellite will be described.
CS digital broadcasting) will be operated in a band of 39.1275 Mbps per transmission channel. For this reason, the C of this 110-degree CS digital broadcast signal is
The above-mentioned transmodulation method cannot be used for digital retransmission by ATV.

Therefore, as a method of digitally retransmitting the 110-degree CS digital broadcast signal by CATV, a method using a remultiplexing (remax) method is considered. FIG. 10 is a diagram illustrating the concept of the remultiplexing method. FIG.
FIG. 1 is a diagram showing an example of the configuration of a remultiplexing system that can be used to perform this remultiplexing method. FIG. 12 shows C in FIG.
FIG. 3 is a diagram illustrating an example of a detailed configuration of an S receiver and a multiplexer. As shown in FIGS. 10 and 11, this re-multiplexing method converts a 110 ° CS digital broadcast signal of a band of 39.1275 Mbps (hereinafter referred to as a satellite band) per transmission channel into a number of broadcast programs (streams). Each program is received by a corresponding plurality of CS receivers and each program is extracted. Then, the extracted programs are remultiplexed so as to be within a band of 29.162 Mbps per transmission channel in CATV (hereinafter, referred to as a CATV band).

[0006]

However, in this remultiplexing method, a plurality of dedicated CS receivers must be prepared according to the number of programs, and the whole system becomes expensive. Further, in order to remultiplex programs in different satellite bands into one CATV band, it becomes necessary to operate an electronic program guide (EPG) provided accompanying the programs for each satellite band. That is, the EPG transmitted in each band needs to include detailed information on programs in the same band (note that programs in other bands may be detailed information or simple information).

There are the following three methods for operating the EPG. First, the first method is a simple EPG
It is a method using. The simplified EPG does not use service information (SI information) attached to a program and uses a network information table (NI
By storing simple program information in T), this can be realized by replacing NIT. The NIT has a small amount of information (about several KB) and a small update frequency (at most several times / day) as compared with the SI information, and does not require a real-time process to generate the NIT because it is static information. . For this reason, NI
The replacement of T can be realized with a simple configuration as compared with the reconstruction of SI information. However, with a simple EPG alone, 110
The functions provided by the receiver provided by the CS digital broadcast EPG, that is, the display of the program schedule table, the guidance of the program contents, and the reservation of the recording cannot be realized. Therefore, in this method, there is a problem that a difference in service occurs between a case where a broadcast is received directly via satellite waves and a case where a broadcast is received via a CATV. This problem is a matter of life and death for the subscriber acquisition for the CATV service provider whose service content is restricted. It should be noted that the simplified EPG is described in the Japan Cable Television Engineers Association standard JCTEA STD-003.
-1.1 "Digital Cable Television Broadcasting: Structure of Program Arrangement Information and Operation Standards for Identifiers"

The second method is disclosed in Japanese Patent Laid-Open No. 2000-35018.
This is a method using a conversion table described in Japanese Patent Application Publication No. 0-205. However, in this method, since SI information that is not consistent with the actual program configuration is transmitted, JCTE
There is a problem that it does not conform to the A standard. Also, EP
Since a completely new process is added to the analysis of G, there is a problem that it is difficult to share a CATV receiver program and a direct wave receiver program corresponding to this method. In addition, in 110 degree CS digital broadcasting, EPG
-It is necessary to support advanced services provided in data broadcasting and the like, and the program of the receiver becomes complicated. Therefore, it is not realistic to develop dedicated software for the CATV receiver.

A third method is a method for reconstructing SI information. If the SI information is reconstructed, the EPG function equivalent to the direct wave reception conforms to the JCTEA standard and the like.
It can be realized by reception. However, reconstruction of SI information of 110-degree CS digital broadcasting is difficult for the following reasons. First, since the number of channels is large and the program schedule can be referenced and reserved up to about two weeks ahead, the data amount is very large. Further, the SI information is frequently updated every time a program starts / ends or every time a future program schedule is changed. In addition, the reservation function of the EPG enables the reservation recording control of the VTR, and enables recording in the changed time frame even when the program time frame is changed due to extension of the program. This is a function that can be realized by the receiver to control the VTR with reference to the SI information as needed. Therefore, in order for the CATV receiver to correctly record, it is necessary to reconfigure and transmit the SI information in real time when the SI information is updated. Further, even if the real-time processing is performed, there is a possibility that the time required for the reconstruction and the timing of the transmission cycle may not be enough. Furthermore, since it is necessary to transmit the SI information at a different cycle according to its importance, the transmission of the reconstructed SI information becomes complicated and large-scale. As described above, it takes too much processing time to extract, in real time, only the SI information relating to the retransmitted program from all the SI information, and reconstruct and transmit it. Further, since a large amount of memory and a complicated processing circuit are required for an apparatus for reconstructing the SI information, the equipment of the CATV center station is large-scale and expensive. Therefore, the method of reconstructing the SI information is not practically feasible.

[0010] Therefore, an object of the present invention is to provide a digital broadcast by simply changing NITs without performing complicated changes of SI information or reconfiguring programs for a normal channel selection operation of a receiver. It is an object of the present invention to provide a digital broadcast signal retransmission method capable of digitally retransmitting this signal via a cable television broadcasting network having a smaller transmission capacity than the signal. A further object of the present invention is to provide an MPE
A digital broadcast signal that conforms to standards such as G / JCTEA, and that realizes a function equivalent to that of a direct wave receiver at a low cost in a CATV receiver, and enables the common use of both receiver programs. Is to provide a retransmission method.

[0011]

A first invention is a method of digitally retransmitting a digital satellite broadcast signal via a cable television (CATV) broadcast network having a smaller transmission capacity than the signal. Receiving a satellite digital broadcast transport stream and demodulating the transport stream using a predetermined method; and dividing the demodulated transport stream into program units for each satellite digital broadcast transmission channel to generate a program. A step of generating a plurality of divided streams to which information (such as SI information) that does not belong within the transmission capacity per transmission channel of the CATV broadcast is included, and each of the divided streams is included in each of the divided streams according to the contents of the program allocated by the division. Replacing information for program selection by using a predetermined method,
Digitally modulating each divided stream into a signal for CATV broadcasting; and mixing at least two digitally modulated divided streams and transmitting the mixed stream to a transmission path.

As described above, according to the first aspect, a satellite digital broadcast signal is divided into TSs for each transmission channel into signals of a CATV broadcast transmission channel band. This makes it possible to digitally retransmit a satellite digital broadcast signal having a large transmission capacity via a cable television broadcasting network having a small transmission capacity only by changing information for selecting a program. Further, since the SI information is not reconstructed, it is possible to realize an apparatus conforming to standards such as MPEG / JCTEA. Further, in the CATV receiver, it is possible to realize the same function as the direct wave receiver at low cost.

A second invention is an invention according to the first invention, wherein the step of replacing is performed by replacing a network information table (NIT) indicating physical information on a transmission line.

As described above, according to the second aspect of the present invention, the NIT having physical information on the transmission path and the like can be easily changed to a 110-degree CS digital broadcast or the like simply by replacing the NIT with the divided program. The retransmission method of the present invention can be applied.

A third invention is an invention according to the first and second inventions, wherein C is one of the generated divided streams.
A plurality of TS streams of two or more divided streams less than the transmission capacity per ATV broadcast transmission channel are multiplexed into a plurality of TSs, and CA
The method further includes generating a stream having a transmission capacity per transmission channel of the TV broadcast.

As described above, according to the third aspect, a plurality of divided streams each having a transmission capacity less than the transmission capacity
By performing S multiplexing, the CATV transmission band can be used effectively.

According to a fourth aspect of the present invention, a plurality of divided streams in which a satellite digital broadcast signal is divided in units of programs, information for program selection is replaced according to the contents of the division, and retransmitted, are transmitted to a cable television (CATV). A) a method for selecting a receiver for receiving via a broadcast network, the method comprising: determining whether a selected program is included in a currently received divided stream; If not included, determining whether the divided stream and another divided stream including the program have been transmitted on the same transmission channel during satellite digital broadcasting; and Moving to the transmission channel of the divided stream.

As described above, according to the fourth aspect, the CA
The TV receiver can realize the same function as the direct wave receiver at a low cost, and can share the programs (software) of both receivers.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a 110 ° CS digital broadcast signal having a band per transmission channel of 39.1275 Mbps is assumed to have a band per transmission channel of 29.1.
A method of retransmitting a digital broadcast signal according to the present invention will be described by taking as an example a case where digital retransmission is performed using a CATV of 62 Mbps. In the present embodiment, the signal of the satellite band 1 including the programs 1 to 3 and the signal of the satellite band 2 including the programs 4 to 6 are used.
The digital broadcast signal (FIG. 2A) composed of
A case where retransmission is performed by a digital CATV signal (FIG. 10B) using one of the CATV bands 1 to 4 is described.

FIG. 1 is a block diagram showing a configuration of an apparatus using a digital broadcast signal retransmission method according to one embodiment of the present invention. In FIG. 1, the retransmission apparatus of the present invention
QPSK demodulation units 11 and 21 and TS division units 12 and 2
2, QAM modulators 13 and 14 and QAM modulator 23,
24 and a system control unit 15. As shown in FIG. 1, the retransmitting apparatus includes a QPSK demodulation unit, a TS division unit, and two QPSK demodulation units for each satellite band of a received digital broadcast signal.
It constitutes an AM modulator. In this example, each TS
Although the configuration including two QAM modulators for dividing one satellite band into two CATV bands in the divider is shown, the number of components is determined by the number of divisions in the TS divider. FIG. 2 is a diagram illustrating the concept of a digital broadcast signal retransmission method according to an embodiment of the present invention.

[0021] Of the digital broadcast signals input via the antenna, the signal of satellite band 1 is input to QPSK demodulation section 11. Then, the QPSK demodulation unit 11
The modulated signal of the satellite band 1 is demodulated to extract a TS (transport stream) including the programs 1 to 3. On the other hand, of the digital broadcast signals input via the antenna, the signal of the satellite band 2 is transmitted to the QPSK demodulator 2.
1 is input. Then, the QPSK demodulation unit 21
By demodulating the signal of the satellite band 2 to which the SK modulation is applied,
A TS including programs 4 to 6 is extracted. Note that QPSK
In the demodulation units 11 and 21, QPSK demodulation is performed corresponding to the 110-degree CS digital broadcast signal, but if the digital broadcast signal is modulated by another system,
Demodulation according to the other method is performed.

The TS division unit 12 extracts the extracted programs 1 to 3
Is divided into two divided streams so as to satisfy the band (29.162 Mbps) per program and per transmission channel (FIG. 2).
(B)). Here, the TS division unit 12 stores the EPG1 attached to the signal of the satellite band 1 in two divided streams as they are. In addition, the TS division unit 22
The TS of the satellite band 2 including the extracted programs 4 to 6 is
Program unit and bandwidth per transmission channel (29.16
(2 Mbps) is divided into two divided streams (FIG. 2B). Here, the TS division unit 22
Stores the EPG2 attached to the signal of the satellite band 2 in two divided streams as they are. In addition,
The method of dividing the TS is not limited to that shown in FIG.

Here, a detailed configuration of the TS division units 12 and 22 will be described. FIG. 3 is a block diagram illustrating an example of a detailed configuration of the TS division units 12 and 22. In FIG. 3, T
The S division units 12 and 22 include a PSI analysis unit 31, a PID filtering unit 32, a NIT replacement unit 33, and a speed conversion unit 34 for each transmission channel.

First, as a premise, in a digital broadcasting TS, streams of information, video and audio, etc. are packetized and multiplexed. Each of the information and the stream can be identified by a packet ID (PID) attached to the packet. The information and the stream multiplexed in one TS include the SI information for transmitting the program information and the program identification information (P) which is information necessary for selecting a desired program.
SI information), and streams of video, audio, additional data, and the like that constitute the program. If the sum of the streams of each information, video, audio, etc. is less than the bandwidth of the transmission channel, N
A packet called a UL packet is used for padding. The PSI information is stored in the network information table (N
IT), Program Association Table (PA)
T) and a program map table (PMT). The NIT indicates physical information about the transmission path and the program identification number. PAT is the PID of NIT
(In 110 degree CS digital broadcasting, PID = 0x001
0) and the PID of the PMT of the program included in the TS. The PMT indicates the PID of a stream such as video, audio, and additional data that constitutes each program.

The PSI analysis unit 31 extracts PSI information from the input TS, and acquires the PMT of each program and the PIDs of streams such as video and audio that make up the program. Then, the PSI analysis unit 31 determines the PID to be passed by each PID filtering unit 32 according to the allocation of the program to each divided stream. In addition, 110 degrees C
In S digital broadcasting, the PID of a stream that does not belong to programs such as SI information, PAT, and NIT is 0x0000 to 0x0000.
Since it is allocated in the range of 0x002F, P in this range
The ID is passed by both PID filtering units 32. The PID filtering unit 32 includes a PSI analysis unit 31
, Packets other than the PID to be passed
Each is replaced with a UL packet. When detecting the packet transmitting the NIT, the NIT replacement unit 33
Each packet is replaced with an ATV NIT packet. The speed conversion unit 34 corrects the PCR (Program Clock Reference) by deleting the NULL packet to adjust the transmission speed of the divided stream to the CATV band. This PCR is time information added to the TS in order to adjust the pace of the system clock used by the receiver to measure the timing of reproducing video and audio. In the speed converter 34, N
Deletion of the UL packet causes delay time jitter in which the arrival time of the PCR packet at the receiver differs for each packet. For this reason, it is necessary to perform PCR correction in order to prevent the step clock of the receiver from being disturbed due to the delay time jitter. As a method of PCR correction, see JP-A-20
The method described in JP-A-00-174813 can be used.

As shown in FIG. 2, by the processing of the TS division units 12 and 22, the T
From S, TSs of four CATV bands 1 to 4 can be created. In the example of FIG. 2, the PMT and the stream of the program 1 are retransmitted to the divided stream of the CATV band 1, and the PMT and the stream of the program 2 and the program 3 are retransmitted to the divided stream of the CATV band 2. Also, PAT1 and SI information 1 are retransmitted to both split streams. The NIT for satellite broadcasting is replaced with the NIT for CATV broadcasting, and is transmitted in both divided streams. In FIG. 3, the NIT replacement unit 33 is provided between the PID filtering unit 32 and the speed conversion unit 34, so that it is necessary for each transmission channel.
If the IT information is the same in the divided transmission channels, P
Only one ID filtering unit 32 may be provided in the preceding stage.

The QAM modulators 13 and 14 are connected to the TS division unit 1
The two split streams output from 2 are converted to 64-value QA
M is digitally modulated. On the other hand, QAM modulator 2
3, 24 digitally modulates the two divided streams output from the TS dividing unit 22 into 64-level QAM. Here, each of the QAM modulators 13, 14, 23
And 24 describe the case where the input signal is digitally modulated to 64-value QAM.
It is determined according to the transmission system of the V system.
Each of the divided streams after digital modulation is mixed by a mixing unit (not shown) and transmitted to a CATV transmission path. Note that the system control unit 15 controls the entire retransmission device.

Next, an apparatus for receiving a digital CATV signal transmitted by the above-described retransmission method will be described with reference to FIGS. FIG. 4 is a block diagram showing an example of a configuration of a receiver to which the retransmission method of the present invention can be applied. FIG. 5 is a flowchart illustrating an example of a basic process of a tuning operation performed by the receiver. 4, the receiver includes a QAM demodulation unit 41, a TS decoder 42, an AV decoder 43, and a control unit 44. QAM demodulation unit 4
1 receives a digital CATV signal transmitted via a CATV transmission line, performs QAM demodulation, and extracts a divided stream. The TS decoder 42 decodes the extracted divided stream to obtain a program signal. The AV decoder 43 decodes video and audio of the decoded program signal. The control unit 44 controls the entire receiver.

As described above, in the present invention, in the retransmitting apparatus, the TS of the input digital broadcast signal is divided into two and retransmitted, whereas the EPG itself is not reconfigured and the NIT Perform only replacement. For this reason, the receiver performs the following characteristic channel selection operation. The tuning operation shown in FIG. 5 starts when the identification number of the program to be tuned is input by the user from the displayed EPG screen or directly by pressing a button on the remote control or the like. When the identification number of the program is input, the receiver first receives the NIT of the currently selected transmission channel (step S5).
1). The NIT may be received in advance and stored in the memory, and the stored NIT may be read. In this case, step S51 can be omitted. next,
The receiver searches for information of the received NIT, and the selected program is divided into the currently selected divided stream (own T
S's own divided stream), another divided stream of the same TS as the currently selected divided stream (another divided stream of the own TS), or a divided stream of a band different from that of the currently selected divided stream (another TS). ) Is determined (steps S52 and S5).
3). Note that information necessary for determining whether the stream is a self-divided stream or another divided stream is written in the NIT in advance at the time of TS division and transmitted to the receiver.

If it is determined in the above steps S52 and S53 that the selected program is in the self-divided stream of the own TS (described above), the receiver receives the PAT and receives the PID of the PMT of the selected program. To obtain the PMT of the program (steps S55 and S56). And the receiver
The PID of a stream such as video and audio constituting a program is obtained from the PMT, and each stream is separated and decoded (step S57). On the other hand, steps S52 and S5
In 3, when it is determined that the selected program is in another divided stream of its own TS (described above) and when it is determined that it is in another TS (described above), the receiver uses the information of the NIT to
The selected channel is moved to the channel on which the divided stream including the program is transmitted (step S5).
4). Then, the receiver sets the P of the moved transmission channel.
The PMT of the program selected by receiving the AT is obtained, and the PMT of the program is received (steps S55 and S55).
56). Then, the receiver obtains the PID of the stream such as video and audio constituting the program from the PMT, and separates and decodes each stream (step S57). As described above, by providing the step of determining whether the stream is the own divided stream or the other divided stream at the time of the channel selection operation, it is not necessary to change the TS identifier, and the software on the receiver side can be changed less.

Finally, a method of configuring the CATV NIT will be described. The physical information of the transmission path given by the NIT is conceptually transmitted in a structure as shown in FIG. FIG. 6A shows a satellite NIT, and shows that a network is configured by two TSs (TS1 and TS2). The network is defined for a group of TSs in the same distribution system. In the case of 110-degree CS digital broadcasting, a network is defined for digital broadcasting by a CS satellite launched at a position of 110 degrees east longitude. . In CATV, there is a case where one TS is configured by all TSs transmitted to a transmission path to which a receiver is connected, and a case where a plurality of networks are defined for each head-end facility.
The frequency information of the band in which each TS is transmitted is described in the NIT as a satellite distribution system descriptor (in the case of CATV, a cable distribution system descriptor), and the identifier of a program included in the TS is described as a service list descriptor. . FIG.
(A) shows that TS1 is transmitted in satellite band 1 and includes program 1, program 2 and program 3. Also, TS2
Include programs 4, 5 and 6 transmitted in the satellite band 2. Each TS is provided with a 16-bit identifier called a transport stream identifier and an original network identifier, and the TS can be uniquely identified in the network by a total of 32 bits. When retransmitting a digital broadcast signal without reorganizing SI information as in the present invention, the value of this identifier must not be changed in order to maintain consistency with SI information.

FIG. 6B is a diagram showing an example of a method of configuring a CATV NIT (first method). In the first method, the NIT is configured with the divided streams as independent TSs. Here, it is necessary to add the same transport stream identifier and original network identifier as before the division to each divided stream. For this reason, in order to be able to uniquely identify a TS, it is not possible to accommodate the divided streams constituting the same TS before the division in the same network. Therefore, C for retransmission
Two networks (CATV-1, CAT) on the ATV side
V-2) is defined, and the divided streams are accommodated in each network so as not to include the divided streams constituting the same TS before the division. In this case, in step S53 of FIG. 5, in which it is determined whether the selected program exists in the own divided stream, the newly selected program is stored in the own network (the network in which the currently selected program exists). (The same network).

FIG. 6C is a diagram showing another example of a method of configuring the CATV NIT (second method). This second
Method extends the cable distribution system descriptor to include
It stores frequency information and the like of one channel. In this case, in step S53 shown in FIG. 5, it is necessary to transmit information on which of the two channels each program is included in, for example, by separately defining a descriptor to be transmitted in the NIT.

As described above, in the digital broadcast signal retransmission method according to one embodiment of the present invention, a TS is divided into signals in a CATV broadcast transmission channel band for each transmission channel in a satellite digital broadcast signal. This makes it possible to digitally retransmit a satellite digital broadcast signal having a large transmission capacity via a cable television broadcasting network having a small transmission capacity only by changing the NIT information. Also, since the SI information is not reconstructed, the MPEG
-It is possible to realize an apparatus conforming to a standard such as JCTEA. In addition, the CATV receiver can realize the same function as the direct wave receiver at low cost, and
It is possible to standardize both receiver programs.

In the above embodiment, the TS division unit 1
2 and 22, the case where the TS in the satellite band is divided into two divided streams so as to satisfy the band per program and per transmission channel has been described. May be divided. However, in this case, since one program is retransmitted over two divided streams, it is necessary to have a configuration in which the receiver separately receives and combines the two divided streams. Therefore, the receiver corresponding to this case has a configuration including two QAM demodulation units and a TS synthesis unit as shown in FIG. 7, for example, and is more expensive than the above-described receiver.

In the above embodiment, the TS dividing unit 1
2 and 22, the TS in the satellite band is divided into two divided streams so as to satisfy the band per program and per transmission channel. Therefore, as shown in FIG. (Parts shown by blanks in the figure). Therefore, a configuration shown in FIG. 8 can be considered as a retransmission device according to another embodiment of the present invention. The multiple TS multiplexing unit 71 of FIG.
At 22, the program of the divided stream including the useless band is multiplexed to generate a new CATV band. Thus, the CATV band can be effectively used as shown in FIG.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a retransmitting apparatus using a digital broadcast signal retransmission method according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating the concept of a digital broadcast signal retransmission method according to an embodiment of the present invention.

FIG. 3 is a block diagram illustrating an example of a detailed configuration of the TS division units 12 and 22 in FIG.

FIG. 4 is a block diagram showing an example of a receiver to which the retransmission method of the present invention can be applied.

FIG. 5 is a flowchart illustrating an example of a basic process of a tuning operation performed by the receiver in FIG. 4;

FIG. 6 is a diagram illustrating the concept of a method of configuring a CATV NIT.

FIG. 7 is a block diagram showing an example of another receiver to which the retransmission method of the present invention can be applied.

FIG. 8 is a block diagram illustrating another configuration of a retransmission device using the digital broadcast signal retransmission method according to an embodiment of the present invention.

FIG. 9 is a diagram illustrating the concept of a digital broadcast signal retransmission method according to an embodiment of the present invention.

FIG. 10 is a diagram illustrating the concept of a conventional remultiplexing method.

11 is a diagram illustrating an example of a configuration of a remultiplexing system that can be used to perform the remultiplexing method of FIG. 10;

12 is a diagram illustrating an example of a detailed configuration of a CS receiver and a multiplexing device in FIG.

[Explanation of symbols]

 11, 21 ... QPSK demodulation unit 12, 22 ... TS division unit 13, 14, 23, 24 ... QAM modulation unit 15 ... system control unit 31 ... PSI analysis unit 32 ... PID filtering unit 33 ... NIT replacement unit 34 ... speed conversion unit 41: QAM demodulation unit 42: TS decoder 43: AV decoder 44: control unit

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Satoshi Takari 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. F term (reference) 5C064 BA01 BB05 BC16 BC23 BC27 BD07 BD09 5K072 AA12 AA19 BB14 BB22 CC15 DD05 DD19 EE00 GG13 GG27

Claims (4)

[Claims] 1. A cable television (CATV) having a smaller transmission capacity than a signal of a satellite digital broadcast.
A method of digitally retransmitting via a broadcast network, comprising: receiving a satellite digital broadcast transport stream and demodulating the transport stream using a predetermined method; and Dividing the transport stream in units of programs and generating a plurality of divided streams to which information (such as SI information) not belonging to the program is added within the transmission capacity per transmission channel of CATV broadcasting; Re-assigning information for program selection included in each of the divided streams according to the contents of the program, and converting each of the divided streams to CA using a predetermined method.
A retransmission method, comprising: digitally modulating a TV broadcast signal; and mixing and transmitting the digitally modulated at least two divided streams to a transmission path. 2. The method according to claim 1, wherein the step of replacing includes a network information table (N) indicating physical information on a transmission path.
2. The retransmission method according to claim 1, wherein (IT) is replaced with an NIT in which information necessary for determining which program is allocated to which divided stream is written. 3. In the generated divided stream, C
A plurality of TS streams of two or more divided streams less than the transmission capacity per ATV broadcast transmission channel are multiplexed into a plurality of TSs, and CA
The method according to claim 1, further comprising generating a stream having a transmission capacity per transmission channel of the TV broadcast.
Retransmission method described in. 4. A plurality of divided streams in which a signal of a satellite digital broadcast is divided in units of a program, information for selecting a program is changed according to the contents of the division, and retransmitted, is transmitted to a cable television (CATV) broadcast network. Determining whether the selected program is included in the currently received divided stream, and including the selected program in the currently received divided stream. If not, determining whether the divided stream and another divided stream containing the program have been transmitted on the same transmission channel during digital satellite broadcasting; and Moving to a transmission channel of the segmented stream.