JPH11275546A - Signal processing unit, signal processing method and served medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a reception terminal to discriminate which network digital broadcast data come in the case that the digital broadcast data are supplied from pluralities of networks. SOLUTION: A control section 31 reads a network information table NIT 1 stored in a memory 48 via an interface 50 as required, changes it in matching with a CATV and an NIT 2 obtained by the result is written in a memory 49, where it is stored. The control section 31 uses a received network ID of a satellite without changing a network ID to identify the network.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing apparatus, a signal processing method, and a providing medium, and more particularly to a signal processing apparatus, a signal processing method, and a medium suitable for use when a digital broadcast program broadcasted on a predetermined network is distributed over another network. The present invention relates to a signal processing device, a signal processing method, and a providing medium.

[0002]

2. Description of the Related Art In recent years, cable television (CATV) operators have been receiving digital multi-channel programs supplied via satellites and distributing them to homes using their own networks (cables). It is becoming.

As described above, the first network (satellite)
When a digital broadcast program being broadcast on the Internet is distributed over a second network (CATV), the digital broadcast data is transmitted through NIT (Net
work information table), it is not possible to provide a distribution service only by converting the modulation method with a modulation conversion device.

Therefore, the NIT of the digital broadcast data in the first network is detected, the detected NIT is changed to conform to the second network, and the NIT of the digital broadcast data in the first network is changed.
To obtain digital broadcast data in the second network. At this time, the network ID, which is the network identification code, in the NIT of the digital broadcast data in the first network is also replaced with the one indicating the second network.

[0005]

However, even from digital broadcast data from a third network different from the first network, it is attempted to obtain digital broadcast data in the second network by using a modulation conversion device. In this case, the network ID in the NIT is changed to the one corresponding to the second network, so that the digital broadcast data received at the receiving terminal of the second network is from the first network. Or from the third network.

[0006] Further, the receiving terminal of the network provided with the distribution service transmits the transmitted digital broadcast data to the receiving terminal.
Since it is determined whether to receive using the network ID in the NIT, a fourth network different from the second network is used.
When the distribution service is provided to the second network, a receiving terminal for the fourth network having a different configuration from the receiving terminal for the second network is required.

[0007] The present invention has been made in view of such a situation, and digital broadcast data supplied to a modulation and conversion device is transmitted from a first network and a third network. NIT when there is more than one
Is changed to be compatible with the second network,
The receiving terminal in the second network can determine whether the digital broadcast data is from the first network or the third network.

[0008] Further, even when a plurality of networks to be distributed are provided with a second network and a fourth network, a receiving terminal having the same configuration can be used as it is.

[0009]

According to a first aspect of the present invention, there is provided a signal processing apparatus for converting a first digital broadcast signal having a predetermined transmission frequency on a first network into a predetermined transmission frequency on a second network. In the signal processing apparatus for converting into a second digital broadcast signal, a first frequency conversion means for performing a predetermined frequency conversion process on the first digital broadcast signal, and a second frequency conversion signal supplied from the first frequency conversion means. 1
Demodulating means for demodulating the digitally modulated signal, table detecting means for detecting a network information table having physical information on a transmission path from digital broadcast data supplied from the demodulating means, and supplied from the table detecting means. A table changing means for changing the network ID in the network information table so that the network ID of the first network is used as it is without changing to the second network, and the others are changed to conform to the second network. , A network information table of digital broadcast data supplied from the demodulating means, and a network information table supplied from the table changing means.
Table replacing means for replacing with a table, modulating means for modulating digital broadcast data supplied from the table replacing means, and second frequency conversion for converting a second digital modulation signal supplied from the modulating means to a predetermined transmission frequency Means.

According to a second aspect of the present invention, a first digital broadcast signal having a predetermined transmission frequency on a first network is converted to a second digital broadcast signal having a predetermined transmission frequency on a second network. A signal processing method for converting a signal into a signal; a first frequency conversion step of performing a predetermined frequency conversion process on the first digital broadcast signal;
A demodulation step of demodulating the first digital modulation signal supplied from the first frequency conversion step; and detecting a network information table having physical information on a transmission path from the digital broadcast data supplied from the demodulation step. In the table detection step and the network information table supplied from the table detection step, the network ID uses the network ID of the first network without changing to the second network, and otherwise uses the second network ID. A table changing step for changing the network information table to be adapted to the network; and a network information table for digital broadcasting data supplied from the demodulation step.
A table replacement step for replacing the information table with an information table, a modulation step for modulating the digital broadcast data supplied from the table replacement step, and a second conversion for converting the second digital modulation signal supplied from the modulation step to a predetermined transmission frequency. And a frequency conversion step.

According to a third aspect of the present invention, there is provided a medium for transmitting a first digital broadcast signal having a predetermined transmission frequency on a first network to a second digital broadcast signal having a predetermined transmission frequency on a second network. A first frequency conversion step of performing a predetermined frequency conversion process on a first digital broadcast signal in a providing medium that provides a computer program used for a signal processing device that converts the signal into a digital signal; A demodulating step of demodulating a first digital modulation signal, a table detecting step of detecting a network information table having physical information on a transmission path from the digital broadcast data supplied from the demodulating step, and a table detecting step. Supplied network information table Of these, the network ID is supplied from the table changing step of changing the network ID of the first network as it is without changing the network to the second network so as to be adapted to the second network, and the demodulation step. Replacing a network information table of digital broadcast data with a network information table supplied from a table changing step, modulating digital broadcast data supplied from the table replacing step, and modulating the digital information. And a second frequency conversion step of converting the supplied second digital modulation signal into a predetermined transmission frequency.

In the signal processing apparatus according to the first aspect, the first frequency conversion means performs a predetermined frequency conversion process on the first digital broadcast signal, and the demodulation means includes:
The first digital modulation signal supplied from the first frequency conversion means is demodulated, and the table detection means outputs network information data having physical information on a transmission path from the digital broadcast data supplied from the demodulation means.
The table is detected, and the table changing means uses the network ID of the first network without changing the network ID to the second network in the network information table supplied from the table detecting means. Other than the above, the network information table of the digital broadcast data supplied from the demodulation means is changed to the network information table supplied from the table change means.
A table, and modulating means modulates the digital broadcast data supplied from the table replacing means.
Frequency converting means converts the second digital modulation signal supplied from the modulating means into a predetermined transmission frequency.

In the signal processing method according to the second aspect and the providing medium according to the third aspect, in the first frequency conversion step, a predetermined frequency conversion process is performed on the first digital broadcast signal, and demodulation is performed. In a step, a first digital modulation signal supplied from the first frequency conversion step is demodulated, and in a table detection step, network information having physical information on a transmission path from the digital broadcast data supplied from the demodulation step. Detecting a table, and in a table changing step, in the network information table supplied from the table detecting step, the network ID uses the network ID of the first network without changing to the second network, Otherwise it fits the second network In the table replacement step, the network information table of the digital broadcast data supplied from the demodulation step is replaced with the network information table supplied from the table change step. In the modulation step, the network information table is supplied from the table replacement step. And modulates the digital broadcast data, and in a second frequency conversion step,
The second digital modulation signal supplied from the modulation step is converted to a predetermined transmission frequency.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In order to clarify the correspondence between each means of the invention described in the claims and the following embodiments, When the features of the present invention are described by adding the corresponding embodiments (however, examples) in parentheses after the means, the following is obtained.
However, of course, this description does not mean that each means is limited to those described.

According to a first aspect of the present invention, there is provided a signal processing apparatus for converting a first digital broadcast signal having a predetermined transmission frequency on a first network into a second digital broadcast signal having a predetermined transmission frequency on a second network. In a signal processing device for converting a signal into a signal, a first frequency converting means (for example, a tuner 40 shown in FIG. 11) for performing a predetermined frequency converting process on the first digital broadcast signal, and a first frequency converting means. Demodulation means (for example, a demodulator 41 shown in FIG. 11) for demodulating the supplied first digital modulation signal, and network information information having physical information on a transmission path from digital broadcast data supplied from the demodulation means. A table detecting means (for example, an NIT detecting circuit 47 shown in FIG. 11) for detecting a table, and a network supplied from the table detecting means. In the network information table, the network ID is not changed to the second network, and the network ID of the first network is used as it is, and the other network ID is changed to be compatible with the second network. For example,
A controller 31 shown in FIG. 11 and table replacement means for replacing the network information table of the digital broadcast data supplied from the demodulation means with the network information table supplied from the table changing means (for example, as shown in FIG. 11). NIT replacement circuit 43) and modulation means (for example, FIG. 1) for modulating digital broadcast data supplied from table replacement means.
The modulator 45) shown in FIG.
And a second frequency conversion means (for example, a frequency converter 46 shown in FIG. 11) for converting the digital modulation signal into a predetermined transmission frequency.

FIG. 1 shows the configuration of an embodiment of a digital CATV system to which the signal processing device of the present invention is applied. In this system, a digital broadcast signal transmitted from a plurality of transponders (satellite repeaters) attached to a satellite 1 is received by an antenna 2 and supplied to a modulation converter 3. The modulation conversion device 3 changes the transmission frequency and the modulation method of the digital broadcast signal supplied from the antenna 2 so as to be compatible with CATV, and transmits the digital broadcast signal to the transmission line 4. The transmission path 4 has an STB (Set Top
Box) 5-1 to 5-m are connected. STB5-1
Monitors 6-1 to 6-m are connected to the monitor programs 6-1 to 6-m, and an image of the program number selected in each STB is displayed on each monitor.

Next, a digital broadcast signal transmitted from the satellite 1 will be described below. In the present embodiment, a digital broadcast signal transmitted from the satellite 1 is a digital broadcast standard DVB (Digital V
(ideo Broadcasting) system.

FIG. 2 shows MPEG2 (Moving Picture Experts).
2 shows a multimedia multiplexing method using TS (Transport Stream) of Group 2). The data of each medium constitutes a variable-length packet called a PES (Packetized Elementary Stream) packet. The PES packet is further divided into several transport stream packets. The transport stream packet is composed of a header and a payload, and the header contains an identification number of the transport stream packet called a PID (Packet Identifier). Using the PID, data of each medium is identified.

FIG. 3 shows a detailed structure of the above-described MPEG2 TS packet. One packet is composed of 188 bytes, and the first four bytes are used as a packet header. Synchronization byte (= '47H'H means hexadecimal)
The usage of the packet header area containing the PID and the PID is basically based on MPEG2. The sync byte is
An 8-bit synchronization signal, which is data for a decoder to detect the head of a TS packet. Transport error
The indicator indicates whether there is a bit error in the TS packet. The payload unit start indicator indicates that a new PES packet starts with the payload of this TS packet. The transport priority indicates the importance of this TS packet. PID is
13-bit TS packet identification information indicating the attribute of the individual stream of the packet.

The transport scramble control has two
Bits indicate the presence or absence and type of scrambling of the payload of this packet. The adaptation field control indicates the presence or absence of an adaptation field in this packet and the presence or absence of a payload. The continuity index is information for detecting whether or not a packet having the same PID is partially rejected on the way, and is detected based on continuity of 4-bit cyclic count information.

The payload area (data section) has a program specific information (PS) described later.
A program association table (PAT (Program Association Table)) as a program specific information (I (Program Specific Information));
Map table (PMT (Program Map Table)) and network information table (NIT (N
etwork Information Table)).

FIG. 4 shows a frame structure of digital broadcast data in the DVB system. FIG. 4 (A)
Indicates an MPEG2 TS packet. FIG. 4 (B)
A state is shown in which eight MPEG2 TS packets shown in FIG. 4A are collected to form one frame. FIG.
In (B), the synchronization byte (= '47H' means hexadecimal) contained in the TS packet of MPEG2 is used to invert the synchronization byte once every eight packets (= 'B8H').
H means hexadecimal) to synchronize the frames. When a frame is constructed, an error correction code of Reed-Solomon (204, 188) is added to the data contained in each MPEG2 TS packet (accordingly, one packet corresponds to 204
Bytes). The digital broadcast data shown in FIG. 4B is QPSK (Quadrature Phase Shift Keying).
Is modulated by

PSI specified in MPEG2 system
(Program specification information) is information for simplifying selection of a program (program). The PSI includes a table and a descriptor (descriptor) used for each purpose in the table. The table and the descriptor will be described with reference to FIGS.

FIG. 5 is a diagram for explaining the configuration of the PAT. PAT is for each program number (16 bits)
The PID of a PMT (program correspondence table) (to be described later) that transmits information of a packet constituting the program is shown. PAT
As its own PID, PID = “0x0000” (where 0x is 1)
(Indicating hexadecimal notation).

The table ID indicates the type of the table, and is "0x00" in PAT. The section syntax indicator indicates that the section header has a long form (= “1”) or a short form (=
“0”). The reserve indicates a flag that will be given meaning in the future. The section length is from immediately after this to the end of the section (if there is a CRC32,
Section length) in bytes. The TSID identifies a transport stream (multiplexed encoded data), and corresponds to a transponder in the case of a satellite. The version number indicates the PAT version, and is updated each time the content is updated.
The current next indicator indicates which version the PAT is for when the new and old versions of the PAT are transmitted simultaneously.

The section number indicates the number of the section. The first section is “0x00” and is incremented by one. The last section number indicates the section number of the last section of the same subtable. The program numbers identify individual channels. The network PID indicates the NID PID described later when the program number is “0x0000”. The program map PID indicates a PMT PID described later. CRC is an error detection code for the entire section.

FIG. 6 is a diagram for explaining the structure of the PMT. The PMT indicates, for each program number, the PID of a packet to which a stream of video, audio, additional data, and the like that constitute the program is transmitted. PI of PMT itself
D is specified by PAT.

The table ID indicates the type of the table.
In PMT, it is “0x02”. The description of the above-described PAT is omitted. PCR (Program Clock Refer
ence: program time reference value) The PID indicates a PID of a packet including a clock serving as a reference when decoding. The program information length describes information common to this service in the immediately following loop. The descriptor describes individual information to supplement the information of the section.

The stream type indicates the type of a signal transmitted in a stream, such as video, audio, and data. The elementary PID indicates a PID of an elementary stream. The ES information length describes the information of the elementary stream in the immediately following loop.

FIG. 7 is a diagram for explaining the configuration of the NIT. The NIT indicates physical information about the transmission path, that is, for a satellite, the orbit of the satellite, the polarization, the frequency for each transponder, and the like. The PID of the NIT itself is “0x0010”. For the above-mentioned PAT and PMT, the details of the data configuration are defined in the MPEG2 system, but only the necessity of the NIT is indicated, and the data configuration is private.

The table ID indicates the type of the table. The network is "0x40" and the other networks are "0x41". The description of the above-described PAT is omitted. The network ID identifies a network, and in the case of a satellite, corresponds to an individual satellite. The network descriptor length describes common information of the network in a loop immediately after. T
The S loop length lists the transport streams belonging to the network in the immediately following loop. The TS descriptor length describes the information of the transport stream in the immediately following loop.

FIG. 8 is a diagram for explaining a satellite delivery system descriptor. This descriptor is used as the first of the descriptors repeated according to the TS descriptor length (see FIG. 7), and is paired with the TS ID (see FIG. 7). The descriptor tag is defined by DVB, and indicates the type of the descriptor. In this descriptor,
It is “0x43”. The frequency indicates a transmission frequency for each stream (here, a transponder). The orbit represents the longitude of the orbital position of the satellite. The west longitude and east longitude flags represent the east longitude and the west longitude of the orbital position of the satellite. Polarization indicates the polarization of the transmitted signal. The modulation indicates a modulation method. The symbol rate indicates the symbol rate. FEC (Forward Error Correction:
"Forward error correction" indicates a convolution rate.

FIG. 9 is a diagram for explaining the service list descriptor. This descriptor is
It is used as the second and subsequent descriptors repeated according to the TS descriptor length (see FIG. 7) and indicates the ID of a service (channel) multiplexed in the stream (here, transponder). That is, one
A service list descriptor is attached to the TS ID. The descriptor tag is defined by DVB, and indicates the type of the descriptor. In this descriptor, it is “0x41”. The service ID is
It identifies the service. Usually, the service matches the channel that the viewer tunes to. The service type indicates the content of a service such as video, audio, and data. FIG. 10 is a diagram for explaining the cable delivery system descriptor. The descriptor tag is defined by DVB, and indicates the type of the descriptor. In this descriptor, “0x
44 ”. The frequency indicates the transmission frequency of each stream (here, CATV channel) in CATV. The FEC (Forward Error Correction) outer code is an error correction code as an outer code. In this descriptor, the descriptor is “0010.” The modulation indicates a modulation scheme, the symbol rate indicates a symbol rate, and the FEC indicates a convolution rate. .

FIG. 11 is a block diagram showing the configuration of one embodiment of the modulation conversion device 3 of the present invention. The modulation conversion device 3 changes a transmission frequency and a modulation method of a digital broadcast signal (a plurality of channels are multiplexed) transmitted from a transponder (satellite repeater) attached to the satellite 1, and modulates a CATV signal. A digital broadcast signal is generated and supplied to the transmission path 4.

The modulation converter 3 is transmitted from the satellite 1.
A digital broadcast signal in the SHF (Super High Frequency) band is processed, and the VHF (Very High Frequency) band or the UHF (U
ltraHigh Frequency) band CATV digital broadcast signal B
Signal processing units 30-1 to 30 that generate S1 to BSm
−m, a control unit 31 for controlling the entire apparatus, a signal processing unit 30
-1 to 30-m, an operation unit 32 for setting a reception frequency of a built-in tuner, and a display unit 3 for displaying a state of the apparatus
3 and an adder 34 for adding the digital broadcast signals BS1 to BSm and sending the sum to the transmission line 4.

The configuration of the signal processing unit 30-1 will be described. The tuner 40 selects a digital broadcast signal transmitted from the first transponder from the digital broadcast signals supplied from the antenna 2, performs a frequency conversion process on the selected digital broadcast signal, and performs QPSK.
(Quadrature Phase Shift Keying) signal is supplied to the demodulator 41.

The demodulator 41 demodulates the QPSK signal supplied from the tuner 40, converts the demodulated signal into a signal having a DVB frame structure, and supplies the signal to an ECC (Error Correction Code) decoder 42.

The ECC decoder 42 performs error correction on the signal of the DVB frame configuration supplied from the demodulator 41 and supplies an MPEG2 TS packet as digital broadcast data to the NIT replacement circuit 43 and the NIT detection circuit 47. .

The NIT detection circuit 47 detects NIT1 from the MPEG2 TS packet supplied from the ECC decoder 42, writes the NIT1 in the memory 48, and stores it in the memory 48.

The control unit 31 reads out the NIT1 stored in the memory 48 via the interface 50 as necessary, changes it to conform to CATV, and obtains the result.
NIT2 is written to the memory 49 and stored. Control unit 31
Changes the satellite delivery system descriptor (see Figure 8) to the cable when changing NIT1 to NIT2.
Delivery system descriptor (see Figure 10)
Change to At this time, the network ID of the received satellite is used as it is without changing the network ID for identifying the network. The control unit 31 also controls the reception frequency of the tuner 40 via the interface 50.

If the satellite 1 has L transponders and the number of digital broadcasting signals in satellite digital broadcasting is M (M <L), CATV selectively selects M digital broadcasting signals. May be used.
In this case, when the control unit 31 changes NIT1 to NIT3,
Of the TSID corresponding to the digital broadcast signal not used in the CATV (TSID to descriptor information in FIG. 7).

The NIT replacement circuit 43 replaces the NIT1 of the MPEG2 TS packet supplied from the ECC decoder 42 with the NIT2 or NIT3 supplied from the memory 49 and supplies it to the ECC encoder 44. In addition, the NIT replacement circuit 43
When NIT3 is replaced with NIT3, a dummy bit is inserted into the deleted portion.

The ECC encoder 44 applies Reed-Solomon (204,188) to the MPEG2 TS packet in which the NIT has been replaced.
, And the resulting data is supplied to the modulator 45 in a DVB frame configuration.

The modulator 45 applies 64QAM (Quad) to the signal of the DVB frame configuration supplied from the ECC encoder 44.
The signal is modulated by Adrature Amplitude Modulation and supplied to the frequency converter 46.

The frequency converter 46 converts the 64QAM signal supplied from the modulator 45 into a predetermined transmission frequency in the VHF band or UHF band, and supplies the signal BS1 to the adder 34.

Each of the signal processing units 30-2 to 30-m has a configuration in which the NIT detection circuit 47, the memory 48, and the memory 49 are removed from the signal processing unit 30-1. In the signal processing units 30-2 to 30-m,
The second from the digital broadcast signal supplied from the antenna 2
To the m-th transponder are selected, and the NIT stored in the memory 49 is selected.
Is read to perform NIT replacement, and BS2 to BSm having different transmission frequencies are supplied to the adder 34.

The adder 34 adds the CATV digital broadcast signals BS1 to BSm and outputs the added signal to the transmission path 4
Sent to

FIG. 12 is a flowchart for explaining the operation of an STB (receiving terminal) for receiving a digital broadcast signal transmitted from satellite 1. In PAT and PMT, the program number corresponds, and in NIT, the service ID corresponds to the channel number selected by the viewer. Furthermore,
The NIT contains information of the entire network, ie, all transponders, and the same table is transmitted in parallel by all transponders. On the other hand, the PAT and the PMT are composed only of information of the program in the transponder to be transmitted, and have different contents for each transponder.

First, in step S1, the viewer sets ST
The channel number is input with B (here, the "X" channel is selected).

Next, in step S2, the STB receives the NIT, and proceeds to step S3. In step S3,
It is determined whether the channel is present in the transponder currently being received. In step S3,
If it is determined that “X” does not exist, step S4
Proceed to.

In step S4, the NIT service
Service ID in list descriptor (see FIG. 9)
Is searched for “X”. After identification, service ID
Receiving the combined satellite delivery system descriptor (see FIG. 8) before the service list descriptor containing "X", recognizing the frequency of the transponder transmitting "X", Proceed to S5.

In step S5, the STB receives the PAT after changing the receiving transponder, and proceeds to step S6.

If it is determined in step S3 that "X" exists, the process proceeds to step S6. Step S
At 6, the STB receives the PMT by the program map PID associated with the program number "X" in the PAT, and proceeds to step S7.

In step S7, after recognizing an elementary PID for each stream type (video, audio, etc.) corresponding to the program number "X" in the PMT, a TS packet having a PID matching the elementary PID is separated. And
Proceed to step S8. In step S8, the separated packets are decoded by each decoder and output to the monitor.

In this specification, provided media for providing a user with a computer program for executing the above processing include information recording media such as a magnetic disk and a CD-ROM, and networks such as the Internet and digital satellites. Transmission media is also included.

[0056]

As described above, according to the signal processing apparatus according to the first aspect, the signal processing method according to the second aspect, and the providing medium according to the third aspect, when the NIT is changed, the network ID is changed. Only when the digital broadcast data is received from a third network different from the first network, the digital broadcast data received by the receiving terminal of the second network is transmitted from the first network. , Or from the third network. Further, when the distribution service is provided using a fourth network different from the second network, the configuration of the receiving terminal for the first network (or the third network) can be used as it is.

[Brief description of the drawings]

FIG. 1 is a digital CA to which a modulation converter according to the present invention is applied.
FIG. 1 is a diagram illustrating a configuration of an embodiment of a TV system.

FIG. 2 is a diagram for explaining a multimedia multiplexing method using TS of MPEG2.

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

FIG. 4 is a diagram illustrating a frame configuration of a DVB system.

FIG. 5 is a diagram for explaining a program association table.

FIG. 6 is a diagram for explaining a program map table.

FIG. 7 is a diagram illustrating a network information table.

FIG. 8 is a diagram for describing a satellite delivery system descriptor.

FIG. 9 is a diagram illustrating a service list descriptor.

FIG. 10 is a diagram for describing a cable delivery system descriptor.

FIG. 11 is a block diagram showing a configuration of an embodiment of the modulation conversion device 3 of the present invention.

FIG. 12 is a flowchart for explaining an operation of a receiving terminal using the modulation conversion device 3 of the present invention.

[Explanation of symbols]

1 satellite, 2 antennas, 3 modulation converter, 4
Transmission line, 5-1 to 5-m STB, 6-1 to 6
-M monitor, 30-1 to 30-m signal processing unit,
31 control unit, 32 operation unit, 33 display unit,
34 adders, 40 tuners, 41 demodulators, 4
2 ECC decoder, 43 NIT replacement circuit, 44 ECC
Encoder, 45 modulator, 46 frequency converter,
47 NIT detection circuit, 48, 49 memory, 50
interface

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Keiji Fukuzawa 6-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation

Claims (3)

[Claims] 1. A signal processing apparatus for converting a first digital broadcast signal having a predetermined transmission frequency on a first network into a second digital broadcast signal having a predetermined transmission frequency on a second network, First frequency conversion means for performing a predetermined frequency conversion process on the first digital broadcast signal; demodulation means for demodulating a first digital modulation signal supplied from the first frequency conversion means; Table detecting means for detecting a network information table having physical information on a transmission path from digital broadcast data supplied from the demodulating means; and a network ID in the network information table supplied from the table detecting means.
Is a table changing unit that uses the network ID of the first network as it is without changing the network to the second network, and otherwise changes the network ID so as to be compatible with the second network. Table replacement means for replacing a network information table of digital broadcast data with a network information table supplied from the table change means; modulation means for modulating digital broadcast data supplied from the table replacement means; And a second frequency conversion means for converting the second digital modulation signal supplied from the modulation means into a predetermined transmission frequency. 2. A signal processing method for converting a first digital broadcast signal having a predetermined transmission frequency on a first network into a second digital broadcast signal having a predetermined transmission frequency on a second network, A first frequency conversion step of performing a predetermined frequency conversion process on the first digital broadcast signal; a demodulation step of demodulating a first digital modulation signal supplied from the first frequency conversion step; A network that has physical information about the transmission path from digital broadcast data supplied from the demodulation step
A table detecting step for detecting an information table; and a network ID in the network information table supplied from the table detecting step, wherein a network ID of the first network is used without changing to the second network. Using
Otherwise, a table changing step of changing the table to be suitable for the second network; and a network information table of the digital broadcast data supplied from the demodulating step, supplied from the table changing step. And a modulation step for modulating the digital broadcast data supplied from the table replacement step; and a second frequency for converting the second digital modulation signal supplied from the modulation step to a predetermined transmission frequency. And a conversion step. 3. A signal processing apparatus for converting a first digital broadcast signal having a predetermined transmission frequency on a first network into a second digital broadcast signal having a predetermined transmission frequency on a second network. A providing medium for providing a computer program, wherein: a first frequency conversion step of performing a predetermined frequency conversion process on the first digital broadcast signal; and a first digital modulation supplied from the first frequency conversion step A demodulating step of demodulating a signal; and a network having physical information on a transmission path from the digital broadcast data supplied from the demodulating step.
A table detecting step for detecting an information table; and a network ID in the network information table supplied from the table detecting step, wherein a network ID of the first network is used without changing to the second network. Using
Otherwise, a table changing step of changing the table to be suitable for the second network; and a network information table of the digital broadcast data supplied from the demodulating step, supplied from the table changing step. And a modulation step for modulating the digital broadcast data supplied from the table replacement step; and a second frequency for converting the second digital modulation signal supplied from the modulation step to a predetermined transmission frequency. Providing a computer program comprising a conversion step.