BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information repeater system, and is suitably applied, for example, to an information repeater system for receiving a digital satellite broadcasting wave formed by multiplexing the programs of plural channels, extracting an arbitrary channel, and then distributing it to the. desired channel of a cable broadcasting system.

2. Description of the Related Art

Heretofore, there has been a compression coding method called MPEG2 (moving picture experts group phase 2) as a method for reducing the amount of information such as video and audio or the like. A DVB (digital video broadcasting) system has been provided as a digital broadcasting system for compressively coding video and audio broadcasting data using the above compression coding method and broadcasting programs using terrestrial waves or satellite waves. In this broadcasting system, broadcasting data compressively coded by the MPEG2 system is packetized in each prescribed block, and thus obtained packet train is transmitted (hereinafter, the packet is referred to as TS (transport stream) packet and a data stream formed of a train of the above TS packet is referred to as transport stream). Furthermore, in the digital broadcasting system, thus packetized broadcasting data of plural program channels are multiplexed. Thereby, plural program channels can be broadcasted by a single line.

In this connection, a program channel is one of broadcasting services. One formed by multiplexing plural program channels is referred to as single transmission channel. The above single transmission channel is relayed by the corresponding single transponder of a communication satellite. Plural transponders are provided in the communication satellite to relay and transmit the broadcasting data of plural transmission channels to the earth.

By the way, in a cable television system for distributing information such as television programs or the like by a cable (hereinafter, this is referred to as CATV (cable television)), a repeater system which receives a digital multiplex satellite broadcasting wave distributed via a communication satellite and redistributes this as a cable television program broadcasting is considered.

As one of methods for receiving and distributing a digital multiplex satellite broadcasting wave to a CATV, a method for demodulating a signal relayed by one of the single transponders of a communication satellite to generate a transport stream, and then modulating the above transport stream correspondingly to the CATV, and transmitting this to a single CATV channel is considered. In the case of this method, as shown in

FIG. 1

, all program channels included in the transmission channel relayed by the specified transponder are distributed to the single CATV channel. For example, in the case where a transponder Tr

1

of satellite broadcasting corresponds to a CATV channel Ch

1

of CATV, program channels C

1

, C

2

and C

3

which have been multiplexed in a transmission channel to be distributed by relayed by the transponder Tr

1

are multiplexed into the CATV channel Ch

1

.

In the case where a digital multiplex satellite broadcasting is redistributed to a CATV by the above method, however, since a transmission channel to be relayed to a single CATV channel by a single transponder is distributed, it is difficult to selectively distribute a program channel to be relayed by another transponder to the above CATV channel. Thus, a desired program channel cannot be distributed to a single CATV channel from among plural transmission channels, and it causes a problem in usability.

The present invention has been done considering the above point and is proposing an information repeater system capable of selecting and distributing a desired broadcasting program with a simple construction.

SUMMARY OF THE INVENTION

In view of the foregoing, an object of this invention is to provide an information repeater system for receiving a broadcasting wave formed by multiplexing plural broadcastings and distributing it to the corresponding channel of a specified broadcasting system, in which a data stream relayed by a specified transponder is extracted from the broadcasting wave, an arbitrary packet is specified and extracted from the above data stream, and the above extracted packet is transmitted to the specified channel of the specified broadcasting system. Thereby, a desired channel can be extracted and transmitted to the desired channel of the specified broadcasting system from among the plural broadcastings multiplexed in the broadcasting wave.

The data stream relayed by the specified transponder is extracted from the broadcasting wave, and thus extracted data stream is assigned to a specified packet extracting means. In the above packet extracting means, the arbitrary packet is specified and extracted from the data stream, and thus-extracted packet is transmitted to the specified channel of the specified broadcasting system. Thereby, the desired channel can be extracted from the plural broadcastings multiplexed in the broadcasting wave and can be transmitted to the desired channel of the specified broadcasting system.

Furthermore, since a single packet extracting means is made to correspond to each broadcasting program to be distributed to the specified broadcasting system, the number of the above packet extracting means can be limited to the number of broadcastings to be distributed. Thus, the constitution of the information repeater system can be simplified.

This repeater system has a system information update detecting means for detecting whether or not the contents of system information to make the desired program channel correspond to a packet corresponding to said desired program channel has been updated. Thereby, if it is detected that the contents of said system information has been updated by said update detecting means, the system information is replaced by new system information in a system information memory means.

The nature, principle and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings in which like parts are designated by like reference numerals or characters.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1

is a schematic diagram showing the relationship between transponders and CATV channels;

FIG. 2

is a block diagram showing a satellite broadcasting distribution CATV system according to the present invention;

FIG. 3

is a schematic diagram showing rearrangement of channels;

FIG. 4

is a block diagram showing a receiving distribution device according to the present invention;

FIG. 5

is a block diagram showing a packet selecting part according to the present invention;

FIG. 6

is a perspective view showing the receiving distribution device according to the present invention;

FIG. 7

is a block diagram showing a satellite broadcasting distribution CATV system according to another embodiment of the first and a second embodiments;

FIG. 8

is a block diagram showing a receiving distribution device according the other embodiment of the first and the second embodiments;

FIG. 9

is a block diagram showing a receiving distribution device according to the second embodiment;

FIG. 10

is a block diagram showing a packet selecting part according to the second embodiment;

FIG. 11

is a perspective view showing a receiving distribution device according to the second embodiment; and

FIG. 12

is a block diagram showing a receiving distribution device according to a third embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENT

Preferred embodiments of the present invention will be described with reference to the accompanying drawings:

(1) Satellite Broadcasting Distribution CATV System

Referring to

FIG. 2

,

1

generally shows a satellite broadcasting distribution CATV system according to a first embodiment. A satellite broadcasting signal S

1

relayed by a communication satellite (not shown) is received by an antenna

5

and supplied to a receiving distribution device

10

as an information repeater system. In the receiving distribution device

10

, the satellite broadcasting signal S

1

is supplied to N pieces of tuner parts

25

A to

25

N having the same construction. Here, the number of tuner parts

25

A to

25

N, N is the same as the number of transponders had in the communication satellite.

The tuner parts

25

A to

25

N perform demodulation and error correction synchronizing with each corresponding transponder of the satellite broadcasting signal S

1

, and extract the transport streams D

25

A to D

25

N of the transmission channels relayed by each transponder and supplying them to a multiplexing part

50

. These transport streams D

25

A to D

25

N are formed by multiplexing plural program channels, respectively. The multiplexing part

50

temporary separates the transport streams D

25

A to D

25

N into TS packets forming each of them, and then remultiplexes the TS packets of plural program channels to be assigned to a single CATV channel among the above plural TS packets, and distributing it to the corresponding CATV channel.

In the first embodiment, M pieces of CATV channels are provided. Program channels obtained via N pieces of transponders are arbitrary combined and distributed to each CATV channel. Transport streams D

50

A to D

50

M thus obtained by the remultiplexing in the multiplexing part

50

are distributed to each corresponding CATV channel and supplied to modulation parts

70

A to

70

M provided in each CATV channel.

FIG. 3

shows an example of the rearrangement of channels at the time of remultiplexing in the multiplexing part

50

, that is, when each of the program channels C

1

to C

9

of a satellite broadcasting is redistributed to a CATV. Three program channels C

1

, C

2

and C

3

have multiplexed in a transmission channel to be relayed by a transponder Tr

1

had in a communication satellite. Similarly, three program channels C

4

, C

5

and C

6

have multiplexed in a transmission channel to be relayed by a transponder Tr

2

, and three program channels C

7

, C

8

and C

9

have multiplexed in a transmission channel to be relayed by a transponder Tr

3

.

The receiving distribution device

10

performs remultiplexing by selecting and combining arbitrary channels among the nine program channels C

1

to C

9

. For example, the program channels C

2

, C

5

and C

6

are remultiplexed into a first CATV channel Ch

1

, and the program channels C

3

, C

8

and C

9

are remultiplexed into a second CATV channel Ch

2

. Here, the program channels C

1

, C

4

and C

7

are not remultiplexed into a CATV channel and not distributed. As the above, the multiplexing part

50

selects the arbitrary program channels among the program channels multiplexed in the satellite broadcasting, and performs remultiplexing with arbitrary combinations.

In

FIG. 2

, the demodulation parts

70

A to

70

M of each CATV channel modulates the transport streams D

50

A to D

50

M according to a 64QAM (quadrature amplitude modulation) being one of CATV modulation systems, and supplies transmission signals S

70

A to S

70

M to a head end part

80

. The head end part

80

performs frequency multiplexing on the transmission signals S

70

A to S

70

M, and transmits this to a CATV cable

90

as a transmission signal S

80

. The transmission signal S

80

is subjected to demodulation, channel selection and decoding in a set top box (STB)

100

had by a CATV subscriber. The resultant signal is transmitted to a television receiver (not shown) to be displayed.

(2) Configuration of Receiving Distribution Device of First Embodiment

FIG. 4

in which the same reference numerals are added to corresponding parts of

FIG. 2

generally shows the receiving distribution device

10

. In this device, receiving board parts

20

A to

20

N, a CPU board part

56

and a modulation board-part

60

are connected to an internal multiplex bus BUS. The N pieces of receiving board parts

20

A to

20

N of which the number is equal to the number of transponders have the same configuration respectively, and on each board the tuner parts

25

A,

25

B, . . . ,

25

N and packet selecting parts

30

A to

30

M of which the number is corresponding to the number of the CATV channels (M) are provided respectively. Similarly, also the CPU board part

56

and the modulation board part

60

form individual boards respectively. The modulation parts

70

A to

70

M of which the number is corresponding to the number of the CATV channels are provided in the modulation board part

60

.

The tuner part

25

A of the receiving board part

20

A performs demodulation and error correction on the satellite broadcasting signal S

1

received by the antenna

5

(FIG.

2

), and transmits this to the M pieces of packet selecting parts

30

A to

30

M as the transport stream D

25

A. Here, the number of the packet selecting parts

30

A to

30

M, M is the same as the number of the CATV channels.

FIG. 5

generally shows the packet selecting part

30

A. The transport stream D

25

A is supplied to an NIT (network information table)/PAT (program association table)/PMT (program map table) version monitoring part

31

.

Here, an NIT, a PAT and a PMT are system information in hierarchical structure defined by the MPEG2 system, and each of them is assigned to the predetermined position of a transport stream. The NIT is positioned at the top of the system information having the hierarchical structure, to which the frequency information of each transponder had in the communication satellite, the list of program channels and information on transponders for relaying a program channel for each program channel, or the like are assigned. The PAT is a table to which the value of the packet identifier PID of the PMT (i.e., the position of PMT) is assigned. In this connection, the PMT is provided for each program channel in the transport stream, and it is a table to which the value data of the PID added to the TS packet of each program channel (i.e., the position of the TS packet of a program channel) is assigned.

For example, in a digital multiplex satellite broadcasting receiving system, when a user selects a desired program channel, the above receiving system first refers its NIT to discriminate a transponder for relaying the desired program channel, as well as tuning to the frequency of the above transponder. Thus, the transport stream of a transmission channel in which the program channel desired by the user has multiplexed is received.

Then the above receiving system refers the PAT assigned to the received transport stream to recognize the position of the PMT of the desired program channel (i.e., the PID of the PMT). Thus, the receiving system can refer the PMT of the program channel desired by the user. Therefore, the PID of each TS packet of the above program channel is recognized, and only TS packet forming the desired program channel can be selected from the transport stream in which plural program channels have multiplexed.

In the satellite broadcasting distribution CATV system

1

for redistributing a digital multiplex satellite broadcasting to a CATV, the NIT/PAT/PMT version monitoring part

31

shown in

FIG. 5

extracts an NIT, PAT and PMT assigned to the transport stream D

25

A, and storing them in an NIT/PAT/PMT memory part

35

. Therefore, the position of the TS packet of each program channel can be recognized by referring to the above NIT/PAT/PMT memory part

35

.

A CPU part

55

(

FIG. 4

) presets program channels to be distributed to predetermined CATV channels. For example, with respect to a program channel to be distributed to a first CATV channel, the CPU part

55

reads the position of the TS packet of the program channel to be distributed to the first CATV channel (i.e., the PID of the above TS packet) from the NIT/PAT/PMT memory part

35

of the packet selecting part

30

A shown in

FIG. 5

, that is corresponding to the first CATV channel, and storing this in a specified-PID memory part

37

as PID information D

37

.

A packet filter

32

fetches only a TS packet specified by the PID information D

37

from the incoming transport stream D

25

A, and transmitting this to a following FIFO (first in, first out) buffer

33

. Thus, only the TS packet of the program channel to be distributed to the first CATV channel is supplied to the above FIFO buffer

33

from the transport stream D

25

A relayed via the first transponder of the communication satellite.

In this connection, in the transport stream D

25

A, the same information is always repeatedly assigned as the NIT, PAT and PMT. As the case where the contents of broadcasting of the digital multiplex satellite broadcasting is changed, however, if the combination of a transponder and a program channel is changed, also information on the above NIT, PAT and PMT are updated. Here, since the NIT, PAT and PMT have version information, the version information is simultaneously updated if the contents of broadcasting is changed. That is, by monitoring the version information of the NIT, PAT and PMT, the update of the above NIT, PAT and PMT can be detected.

In the system (

1

) for redistributing a digital multiplex satellite broadcasting to a CATV, the NIT/PAT/PMT version monitoring part

31

shown in

FIG. 5

always monitors the NIT, PAT and PMT assigned to the transport stream D

25

A, detects the NIT, PAT and PMT of the transport stream D

25

A inputted in the initial state, and stores them in the NIT/PAT/PMT memory part

35

as NIT/PAT/PMT data D

31

. At the same time, if the update of the version of the NIT, PAT and PMT is detected after the above initial state, the above NIT, PAT and PMT are stored for update in the NIT/PAT/PMT memory part

35

as the NIT/PAT/PMT data D

31

. Therefore, the latest NIT, PAT and PMT are always stored in the NIT/PAT/PMT memory part

35

.

A CPU interface

36

always monitors the NIT/PAT/PMT memory part

35

. If the update of the version of the NIT, PAT and PMT is detected by the CPU interface

36

, this means that the assignment of the program channel of the digital multiplex satellite broadcasting or the like is changed, so that the above CPU interface

36

transmits version update information D

36

to the CPU part

55

.

If receiving the version update information D

36

, the CPU part

55

reads the latest NIT/PAT/PMT data D

31

from the NIT/PAT/PMT memory part

35

, and generates NIT/PAT/PMT data for CATV D

56

(

FIG. 4

) corresponding to the channel structure of the CATV, based on the above NIT/PAT/PMT data D

31

, and repeatedly transmits this to the internal multiplex bus BUS.

Thus, the NIT/PAT/PMT data for CATV D

56

can be obtained to always distribute a predetermined program channel to a CATV channel even if the program channel structure of the digital multiplex satellite broadcasting is changed.

The FIFO buffer

33

of the packet selecting part

30

A of

FIG. 5

reads a selected TS packet D

32

A written in the above FIFO buffer

33

according to a read command D

66

A that is to be transmitted from the read control part

65

A of the modulation board part

60

shown in

FIG. 4

, and transmitting this to the bus BUS via a PCR (program clock reference) adding part

34

.

A PCR is clock reference information in the MPEG2 system, and is a 42 [Bit] count value representing 24 hour counted by a 27 [MHz] system clock, recorded in the prescribed TS packet in a transport stream. In the MPEG2 system, the PCR is recorded to the above TS packet by a transmission device at a time point when the TS packet is generated. In a receiving device, the system clock of the above receiving device is reset to a value shown by the above PCR at a time point when the above TS packet arrives, so that the system clock of the transmission device and the system clock of the receiving device are synchronized.

In the satellite broadcasting distribution CATV system

1

according to the present invention, the receiving device corresponds to the STB

100

shown in FIG.

2

. In the FIFO buffer

33

, the selected TS packet D

32

A generates a stand-by time from write till read against the above FIFO buffer

33

. The above stand-by time is not constant, however, it fluctuates according to the occupied amount of the TS packets D

32

A to D

32

M in the FIFO buffer

33

of each of the packet selecting parts

30

A to

30

M (FIG.

4

), or the like. Owing to the fluctuation of this stand-by time, the fluctuation of the time from a time when the selected TS packet D

32

A is transmitted from the transmission device until arriving the STB

100

is generated. This time fluctuation is called jitter. If the above jitter is generated, the system clock of the transmission device and the system clock of the receiving device cannot be synchronized with the system clock of the STB

100

. On this account, the PCR had in the selected TS packet data D

32

A is corrected according to the stand-by time of the above selected TS packet D

32

A in the FIFO buffer

33

.

That is, a PCR calculation part

38

shown in

FIG. 5

always monitors the FIFO buffer

33

to obtain the stand-by time from a time when the selected TS packet D

32

A is written in the above FIFO buffer

33

until read as stand-by time information D

33

. Then, the PCR calculation part

38

corrects the PCR value of the selected TS packet D

32

A obtained from the transport stream D

25

A according to the stand-by time information D

33

, and transmitting this to the PCR adding part

34

as a corrected PCR value D

38

. The PCR adding part

34

corrects the PCR of the selected TS packet D

32

A to a value shown by the corrected PCR value D

38

, and transmitting this to the bus BUS.

Thereby, in the first packet selecting part

30

A (

FIGS. 4 and 5

) of the receiving board part

20

A (

FIG. 4

) that receives a transmission channel relayed via the first transponder of the communication satellite (transport stream D

25

A) in the digital multiplex satellite broadcasting, only the TS packet of the program channel to be distributed to the first CATV channel is selected as the selected TS packet D

32

A, and transmitting this to the channel of the internal multiplex bus BUS that is corresponding to the first CATV channel.

The second to the M-th packet selecting parts

30

B to

30

M provided in the above receiving board part

20

A respectively select the TS packets of the program channels to be distributed to the second CATV channel to the M-th CATV channel among the transmission channels relayed by the first transponder of the communication satellite, by the control of the CPU part

55

, and transmitting this to the corresponding channel of the internal multiplex bus BUS.

The first receiving board part

20

A selects the TS packet of the program channel to be distributed to each CATV channel previously specified by the CPU part

55

from among the plural program channels multiplexed in the transmission channel relayed by the first transponder of the communication satellite, respectively, and transmitting this to the corresponding channels of the internal multiplex bus BUS.

Similarly, the second to the N-th receiving board parts

20

B to

20

N respectively select each TS packet of the plural program channels multiplexed in the transmission channel relayed by the second to the N-th transponders of the communication satellite by each corresponding packet selecting part, and transmitting this to the corresponding channel of the internal multiplex bus BUS.

The bus BUS has plural channels corresponding to each CATV channel. For example, the selected TS packets D

32

A selectively and respectively outputted from the packet selecting part

30

A corresponding to the first CATV channel of each of the receiving board parts

20

A to

20

N are supplied to a channel corresponding to the first CATV channel. And selected TS packets D

32

B selectively and respectively outputted from the packet selecting part

30

B corresponding to the second CATV channel of each of the receiving board parts

20

A to

20

N are supplied to a channel corresponding to the second CATV channel.

As the above, each TS packet of the plural program channels to be distributed to each CATV channel separated from each transmission channel (selected TS packet) is assigned to the corresponding CATV channel of the internal multiplex bus BUS.

In

FIG. 4

, the modulation board part

60

has M pieces of read control parts

65

A to

65

M corresponding to the CATV channels. The above read control parts

65

A to

65

M respectively always monitor the FIFO buffer

33

of the corresponding packet selecting parts

30

A to

30

M (

FIG. 5

) via the internal multiplex bus BUS. Then, the read control parts

65

A to

65

M transmit read commands D

66

A to D

66

M to the above FIFO buffer

33

based on the occupied amount of the TS packets D

32

A to D

32

M in the FIFO buffer

33

in a prescribed order, respectively. The selected TS packets D

32

A to D

32

M in the FIFO buffer

33

are sequentially read out to the internal multiplex bus BUS to be multiplexed into each CATV channel.

As the above, in the plural program channels multiplexed in the first transmission channel relayed by the first transponder of the communication satellite, the TS packet of the program channel to be distributed to the first CATV channel is selected by the first packet selecting part

30

A of the first receiving board part

20

A, and distributed to the above first CATV channel by the read control part of the first CATV channel

65

A.

In the plural program channels multiplexed in the second transmission channel that have relayed by the second transponder of the communication satellite, the TS packet of the program channel to be distributed to the first CATV channel is selected by the first packet selecting part

30

A of the second receiving board part

20

B, and distributed to the above first CATV channel by the read control part of the first CATV channel

65

A.

In the plural program channels multiplexed in each transmission channel, the TS packet of the program channel to be distributed to the first CATV channel is selected by the first packet selecting part

30

A that is corresponding to the first CATV channel provided in each of the receiving board parts

20

A to

20

N, read out by the read control part of the first CATV channel

65

A, and multiplexed for CATV distribution.

Also in the second to the M-th CATV channels, similarly, in the plural program channels multiplexed in a transmission channel corresponding to each transponder of the communication satellite respectively, the TS packet of the program channel to be distributed to each CATV channel is read out from a corresponding packet selecting part to be multiplexed.

At this time, the read control part

65

A transmits the read commands D

66

A to D

66

M synchronizing to the NIT/PAT/PMT data D

56

repeatedly supplied from the CPU part

55

, so that the transport streams D

50

A to D

50

M corresponding to each CATV channel are generated. At the same time, the corresponding NIT/PAT/PMT data for CATV D

56

is added to each of the transport streams D

50

A to D

50

M, so that the NIT, PAT and PMT are written in each of the transport streams D

50

A to D

50

M according to the CATV channel structure.

In

FIG. 4

, the selected TS packet D

32

A transmitted from the packet selecting part

30

A to the internal multiplex bus BUS forms the transport stream D

50

A in the above internal multiplex bus BUS, and it is supplied to the modulation part of the first CATV channel

70

A via the read control part

65

A. In the modulation part

70

A, the transport stream D

50

A is subjected to 64QAM modulation, and it is transmitted to the head end part

80

shown in

FIG. 2

as transmission signal S

70

A. Remultiplexing is then completed.

Also in the other CATV channels, similarly, selected TS packets D

32

B to D

32

M transmitted from the corresponding packet selecting parts

30

B to

30

M to the internal multiplex bus BUS form transport streams D

50

B to D

50

M in the above internal multiplex bus BUS, and they are supplied to the modulation parts of the second to the M-th CATV channels

70

B to

70

M via the read control parts

65

B to

65

M, respectively. In the modulation parts

70

B to

70

M, the transport streams D

50

B to D

50

M are subjected to 64QAM modulation respectively, and transmitted to the head end part

80

shown in

FIG. 2

as transmission signals S

70

B to S

70

M. Remultiplexing is then completed.

As shown in

FIG. 6

, the housing

15

of the receiving distribution device

10

houses the following plural boards, the modulation board part

60

, the CPU board part

56

and the N pieces of receiving board parts

20

A to

20

N in the same number of the transponders of the satellite. A personal computer (PC)

90

is connected to the CPU board part

56

. The combination of channels in remultiplexing is changed by controlling the CPU part

55

by means of the above PC

90

.

According to the above structure, the receiving distribution device

10

has the N pieces of receiving board parts

20

A to

20

N corresponding to the transponders of the communication satellite. Each of the receiving board parts

20

A to

20

N receives a digital multiplex satellite broadcasting wave from each corresponding transponder.

The digital multiplex satellite broadcasting wave fetched in each of the receiving board parts

20

A to

20

N is a transmission channel obtained by multiplexing plural different program channels. In the packet selecting parts

30

A to

30

M for M channels provided corresponding to the number of CATV channels, only the TS packet of the program channel to be distributed to each CATV channel is selected.

As the above, since a processing for passing only the TS packet to be distributed to the corresponding CATV channel is performed in each of the packet selecting parts

30

A to

30

M, the number of the above packet selecting parts

30

A to

30

M is limited to the number agree with the number of the CATV channels.

The selected TS packets selected in the packet selecting parts

30

A to

30

M of each of the receiving board parts

20

A to

20

N are transmitted to the corresponding internal multiplex bus BUS for each CATV channel. Thus, the selected TS packet of the program channel to be distributed to each CATV channel is extracted from each of the receiving board parts

20

A to

20

N, and collected for each CATV channel to be multiplexed.

According to the above structure, since the plural program channels multiplexed in each transmission channel relayed by the different transponders are collected for each CATV channel to be distributed respectively, the plural program channels relayed via the different transponders can be distributed to a single CATV channel.

Furthermore, since the number of the packet selecting parts

30

A to

30

M provided in each of the receiving board parts

20

A to

20

N may be prepared by the number of the CATV channels, the configuration can be simplified comparing with the case where a necessary program channel is selected after all program channels are temporary extracted.

The above embodiment has dealt with the case of having the N pieces of receiving board parts

20

A to

20

N, and the number is the same as the number of the transponders of a satellite. The present invention, however, is not only limited to this but more many receiving boards than the transponders of the satellite, for example, N+1 pieces of that may be provided. In this case, normally, N pieces of receiving board parts are used for active system, and remaining one receiving board part is not used in normal but as reserve system. If a failure is caused in the receiving board for active system, the CPU part

55

is controlled by the PC

90

shown in

FIG. 6

to make the reserve system substitute a receiving processing to be performed by the receiving board having the above failure. Thereby, the redundancy of the receiving distribution device

10

is improved and a stop of CATV service accompanied with the failure of the receiving board part can be prevented.

Furthermore, in the above embodiment, only the satellite signal S

1

is supplied to the receiving distribution device

10

. The present invention, however, is not only limited to this but also a video signal peculiar to CATV may be supplied to the receiving distribution device. Referring to

FIG. 7

in which the same reference numerals are added to the same parts of

FIG. 2

,

2

generally shows a satellite broadcasting distribution CATV system. Video signals peculiar to CATV S

6

A to S

6

N which are supplied from program supplying parts

6

A to

6

N are compressively coded according to the MPEG2 system in encoding parts

7

A to

7

N. The coded signals are transmitted to a multiplexing part as peculiar program transport streams D

7

A to D

7

N.

Referring to

FIG. 8

in which the same reference numerals are added to the same parts of

FIG. 4

,

11

generally shows a partly detail of a receiving distribution device. N pieces of receiving boards

21

A to

21

N having the same configuration, the CPU part

55

and the modulation board

60

are connected to the bus BUS. The configuration of the receiving distribution device

11

is the same as the receiving distribution device

10

shown in

FIG. 4

except for the configuration of the receiving boards

21

A to

21

N.

The peculiar program transport stream D

7

A transmitted to the multiplexing part is supplied to the input selecting part

26

of the receiving board

21

A. Here, the transport stream D

25

A obtained by performing demodulation and error correction on the satellite signal S

1

is simultaneously supplied from the tuner part

25

A. The CPU part

55

transmits a selection signal D

55

to the input selecting part

26

to select either of the peculiar program transport stream D

7

A by self-broadcasting of CATV or the transport stream D

25

A, and supplying this to the packet selecting parts

30

A to

30

M as a transport stream D

26

A. Thus, the receiving distribution device

11

can select between a satellite signal and a video signal peculiar to CATV before distribution.

Note that, here it has dealt with the case where all the N pieces of receiving boards had in the receiving distribution device

11

have the input selecting part

26

. The present invention, however, is not only limited to this but only a part of the N pieces of receiving boards may have the input selecting part

26

.

Furthermore, the above embodiment has dealt with the case of redistributing the digital multiplex broadcasting wave S

1

to a CATV. The present invention, however, is not only limited to this but various broadcasting systems are applicable to the object of redistribution such as the case of redistibuting the digital multiplex broadcasting wave S

1

to other broadcasting systems as a terrestrial wave, or the like.

Moreover, the above embodiment has dealt with the case of broadcasting a program formed of video and audio. The present invention, however, is not only limited to this but various objects to be relayed, e.g., data communication, etc., can be applied.

(3) Configuration of Receiving Distribution Device of Second Embodiment

FIG. 9

in which the same reference numerals are added to corresponding parts of

FIGS. 2 and 4

,

1

generally shows a partial detail of the receiving distribution device

10

. In this device, a receiving board part

20

having the N pieces of tuner parts

25

A to

25

N of which the number is equal to the number of the transponders of a communication satellite, and plural packet selecting board parts

35

A to

35

K respectively having plural (three in the second embodiment) packet selecting parts

30

A to

30

C are connected by an internal multiplex bus BUS

1

. The number of the channels of the input multiplex bus BUS

1

is equal to the number of the tuners

25

A to

25

N.

Each of the packet selecting board parts

35

A to

35

K is connected to the modulation board part

60

via an output multiplex bus BUS

2

. The number of the channels of the output multiplex bus BUS

2

is equal to the number of the channels of a CATV (M pieces). The (M pieces of) read control parts

65

A to

65

M and the modulation parts

70

A to

70

M, by the number of the channels of the CATV, are provided in the modulation board part

60

.

The corresponding channel of the input multiplex bus BUS

1

receiving the transport stream D

25

A from the first tuner

25

A of the receiving board part

20

supplies this to all the packet selecting parts

30

A to

30

C of all the packet selecting board parts

35

A to

35

K.

The corresponding channel of the input multiplex bus BUS

1

receiving the transport stream D

25

B from the second tuner part

25

B of the receiving board part

20

supplies this to all the packet selecting parts

30

A to

30

C of all the packet selecting board parts

35

A to

35

K.

In this manner, the transport streams D

25

A to D

25

N extracted in each of the N pieces of tuners

25

A to

25

N are supplied to all the packet selecting parts

30

A to

30

C of all the packet selecting board parts

35

A to

35

K via the corresponding channel of the input multiplex bus BUS

1

, respectively.

The total of the packet selecting parts

30

A to

30

C provided in each of the packet selecting board parts

35

A to

35

K has preset to be coincide with the number of program channels to be distributed to a CATV channel among the plural program channels multiplexed in each transmission channel of the digital multiplex satellite broadcasting wave (satellite broadcasting signal S

1

).

In this second embodiment, as described referring to

FIG. 3

, the six program channels C

2

, C

3

, C

5

, C

6

, C

8

and C

9

are selected from among the nine program channels C

1

to C

9

, and these are distributed by sharing between the two CATV channels Ch

1

and Ch

2

. Therefore, the total of the packet selecting parts

30

A to

30

C has been set to six corresponding to the number of the six program channels to be distributed to the CATV channels.

FIG. 10

shows the first packet selecting part

30

A provided in the first packet selecting board part

35

A. The transport streams D

25

A to D

25

N supplied from each of the tuners

25

A to

25

N (

FIG. 9

) are inputted to an input selecting part

40

. This input selecting part

40

selects the transport stream D

25

A that includes the program channel to be selected in the above packet selecting part

30

A among the plural program channels to be distributed to the CATV channel.

In this case, the program channel to be selected in the above packet selecting part

30

A has preset in the CPU part

55

(FIG.

9

). The CPU part

55

selects the transport stream D

25

A of the transmission channel in which the above program channel to be selected in the packet selecting part

30

A has multiplexed by selection information D

55

A, and supplies thus selected transport stream D

25

A to the subsequent NIT (network information table)/PAT (program association table)/PMT (program map table) version monitoring part

31

.

The CPU part

55

(

FIG. 9

) presets the correspondence between program channels to be distributed to each CATV channel and a packet selecting part for selecting the above program channels. For example, with respect to the first program channel C

2

to be distributed to the first CATV channel (FIG.

3

), the CPU part

55

reads the position of the TS packet of the program channel to be distributed to the first CATV channel (i.e., the PID of the above TS packet) from the NIT/PAT/PMT memory part

35

of the packet selecting part

30

A shown in

FIG. 10

, that is corresponding to the first program channel C

2

, and storing this in the specified-PID memory part

37

as the PID information D

37

.

The packet filter

32

fetches only the TS packet specified by the PID information D

37

from the incoming transport stream D

25

A, and transmitting this to a following FIFO (first in, first out) buffer

33

. Thus, only the TS packet of the program channel to be distributed to the first CATV channel is supplied to the above FIFO buffer

33

from the transport stream D

25

A selected in the input selecting part

40

.

In this connection, also in the second embodiment, in the transport stream D

25

A, the same information is always repeatedly assigned as the NIT, PAT and PMT. As the case where the contents of broadcasting of the digital multiplex satellite broadcasting is changed, however, if the combination of a transponder and a program channel is changed, also information on the above NIT, PAT and PMT are updated. Here, since the NIT, PAT and PMT have version information, the version information is simultaneously updated if the contents of broadcasting is changed. Thus, the CPU interface

36

can detect the update of the above NIT, PAT and PMT by monitoring the version information of the NIT, PAT and PMT.

In the satellite broadcasting distribution CATV system

1

for redistributing a digital multiplex satellite broadcasting to a CATV, the NIT/PAT/PMT version monitoring part

31

shown in

FIG. 10

always monitors the NIT, PAT and PMT assigned to the transport stream D

25

A. And if the update of the version of the NIT, PAT and PMT is detected, the above new NIT, PAT and PMT are sequentially stored for update in the NIT/PAT/PMT memory part

35

as the NIT/PAT/PMT data D

31

. Therefore, the latest NIT, PAT and PMT are always stored in the NIT/PAT/PMT memory part

35

.

The CPU interface

36

always monitors the NIT/PAT/PMT memory part

35

. If the update of the version of the NIT, PAT and PMT is detected, this means that the assignment of the program channels of the digital multiplex satellite broadcasting or the like is changed, so that the above CPU interface

36