CN113302858B - Demodulation circuit, demodulation method, and transmitter - Google Patents

Abstract

The transmission device is provided with: a demodulation circuit that concentrates a plurality of TMCC signals, which are distributed in a frame including a main signal and a TMCC signal and transmitted by being superimposed on a broadcast wave, outputs the concentrated TMCC signals before or after the main signal, and individually demodulates the main signal and the TMCC signal for the frame to generate a variable-length packet including the main signal and the TMCC signal; and a cable retransmission conversion unit which performs QAM modulation on the demodulated signal demodulated by the demodulation circuit in a cable broadcast-oriented manner.

Description

Demodulation circuit, demodulation method, and transmitter

Technical Field

The technology (this technology) according to the present disclosure relates to a demodulation circuit that receives and demodulates a main signal and a TMCC signal transmitted superimposed on a broadcast wave, a demodulation method using the demodulation circuit, and a transmission device including the demodulation circuit.

Background

As a technique for signal processing such as digital broadcasting, for example, as disclosed in patent document 1, a signal line is used to transmit variable-length packets between a processing unit that performs demodulation processing and a processing unit that performs demultiplexing processing.

Patent document 1: international publication No. 2016/199603

However, in the technology disclosed in patent document 1, an ethernet (registered trademark) is assumed as an interface for synthesizing and receiving variable length packets outputted from a plurality of broadcast television stations. Therefore, even when the interface for receiving the synthesized variable length packet is an LSI provided in the receiver, there is a problem in that a lengthy and complex format is required because the synthesized variable length packet is received via ethernet.

Disclosure of Invention

In view of the above-described problems, an object of the present invention is to provide a demodulation circuit capable of demodulating a data packet having a variable length, which is synthesized by LSI reception, in a simple format, a demodulation method using the demodulation circuit, and a transmission apparatus including the demodulation circuit.

The demodulation circuit according to one aspect of the present technology concentrates a plurality of TMCC signals, which are distributed in a frame including a main signal and a TMCC signal, and which are transmitted by being superimposed on a broadcast wave. Further, the main signal and the TMCC signal are individually demodulated for a frame by outputting the concentrated TMCC signal before or after the main signal, thereby generating a variable length packet containing the main signal and the TMCC signal.

The demodulation method according to one aspect of the present technology is a method of concentrating a plurality of TMCC signals distributed in a frame including a main signal and a TMCC signal, which are transmitted by being superimposed on a broadcast wave. In addition, a method of generating a variable length packet including a main signal and a TMCC signal by separately demodulating the main signal and the TMCC signal for a frame by outputting a concentrated TMCC signal before or after the main signal.

The transmission device according to one aspect of the present technology includes: a demodulation circuit that generates variable length packets containing the main signal and the TMCC signal by demodulating the main signal and the TMCC signal individually for the frame; and a cable retransmission conversion unit which performs QAM modulation on the demodulated signal demodulated by the demodulation circuit in a cable broadcast-oriented manner. The demodulation circuit concentrates a plurality of TMCC signals distributed in a frame including a main signal and TMCC signals transmitted by being superimposed on a broadcast wave, and outputs the concentrated TMCC signals before or after the main signal.

Drawings

Fig. 1 is a diagram showing a configuration of a broadcast system.

Fig. 2 is a block diagram showing the configuration of a transmitting apparatus and a receiving apparatus.

Fig. 3 is a diagram showing a process performed by the transmitting-side demodulation unit.

Fig. 4 is a diagram showing a process performed by the transmitting-side demodulation unit.

Fig. 5 is a diagram showing the structure of a TLV packet.

Fig. 6 is an explanatory diagram of conversion from TLV packets to split TLV packets.

Fig. 7 is a diagram showing the structure of a TLV packet.

Fig. 8 is a diagram showing a structure of an IP packet.

Fig. 9 is a flowchart showing the operation of the transmitting apparatus.

Fig. 10 is a diagram showing a configuration example of a personal computer.

Detailed Description

Hereinafter, embodiments of the present technology will be described with reference to the drawings. In the description of the drawings, the same or similar portions are denoted by the same or similar reference numerals, and repetitive description thereof will be omitted. The drawings are schematic drawings, including situations different from reality. The embodiments described below exemplify an apparatus and a method for embodying the technical idea of the present technology, and the technical idea of the present technology is not limited to the apparatus and the method exemplified in the embodiments described below. The technical idea of the present technology can be variously modified within the technical scope described in the claims.

(embodiment 1)

As shown in fig. 1, a transmitting apparatus 1 constitutes a broadcasting system 10 together with a receiving apparatus 2 and a network 3.

The broadcast system 10 is a system related to digital cable television broadcasting.

The transmitting apparatus 1 is an apparatus on a broadcast station side that performs digital cable television broadcasting.

The reception device 2 receives the broadcast wave transmitted from the transmission device 1 via the network 3. Further, transmission via the network 3 can also be a transmission of information related to the broadcasted content.

The broadcast wave transmitted from the transmitting apparatus 1 is transmitted in a format called MMT (MPEG Media Transport, moving picture experts group media transport), TLV (Type Length Value ), and received by the receiving apparatus 2.

The MMT and TLV methods are methods for storing and transmitting video signals, audio signals, and control signals in IP (Internet Protocol ) packets. The broadcast wave is transmitted by using the TLV scheme, thereby eliminating the distinction between broadcasting and communication as a transmission path. In addition, according to the MMT and TLV schemes, the broadcast radio wave and the communication path can be simultaneously utilized. Thus, for example, a broadcast format in which video of a main camera for a large number of viewers is transmitted by radio waves for broadcasting, and video of a sub-camera selected by each viewer is transmitted by a communication path (via the network 3) can be implemented. In embodiment 1, a case where only broadcast radio waves are transmitted by the MMT and TLV method will be described.

Structure of transmitting device

As shown in fig. 2, the transmitting apparatus 1 includes a satellite tuner 11, a demodulation circuit 12, and a cable retransmission conversion section 13. The satellite tuner 11 and the demodulation circuit 12 may be constituted by an LSI that integrates the satellite tuner 11 and the demodulation circuit 12.

The antenna 4 is connected to the satellite tuner 11. The antenna 4 is an antenna for receiving satellite broadcasting.

The demodulation circuit 12 includes a transmission-side demodulation section 12a and a transmission-side error correction section 12b.

The transmission-side demodulation unit 12a performs the following processing for each frame, triggered by the detection of a frame synchronization signal, which is a signal for synchronizing frames.

The transmission-side demodulation unit 12a demodulates a main signal of APSK (amplitude phase modulation) system or PSK system. In addition, the transmission-side demodulation unit 12a demodulates the transmission TMCC signal of the pi/2 shift BPSK modulation scheme. The Transmission TMCC signal is a signal obtained by adding a BCH code and an LDPC code to a TMCC (Transmission & Multiplexing Configuration Control) signal. Further, the TMCC signal of each frame includes TMCC information related to each slot constituting the frame. The transmitting-side demodulation unit 12a performs an outer code error detection correction process for decoding the BCH code and an inner code error detection correction process for decoding the LDPC code on the TMCC signal, thereby obtaining TMCC information. The transmission-side demodulation unit 12a demodulates the main signal included in each time slot of the target frame based on the information necessary for demodulation of the main signal included in each time slot of the target frame included in the TMCC information. The information required for demodulation of the main signal is, for example, a parameter indicating the carrier modulation scheme of each slot or a parameter indicating the coding rate of the LDPC code. The transmitting-side demodulation unit 12a performs a de-interleaving process on the main signal of the slot.

The transmission-side demodulation unit 12a also sets a plurality of TMCC signals, which are distributed and arranged, in one frame when demodulating the transmission TMCC signal. As shown in fig. 3, the transmission-side demodulation unit 12a outputs concentrated TLV TMCC signals after the demodulated main signal. Thus, the transmitting-side demodulation unit 12a generates a demodulation signal by including TMCC information in a part of TLV packets that are variable-length packets. In fig. 3, a plurality of TMCC signals distributed and arranged are denoted by "T", respectively. In fig. 3, the concentrated TLV-based TMCC signal is denoted as "TLV-based TMCC". In fig. 3, the demodulated plurality of main signals are denoted by "tlv#1", "tlv#2" … "tlv#00" in this order from the beginning. Further, as shown in fig. 3, the number of TLV packets forming the main signal may vary.

Here, the configuration of the transmitting-side demodulation unit 12a is not limited to the configuration in which the concentrated TLV TMCC signal is output after the main signal is demodulated, and may be a configuration in which the concentrated TLV TMCC signal is output before the main signal is demodulated, as shown in fig. 4. In fig. 4, similarly to fig. 3, a plurality of TMCC signals distributed and arranged are denoted by "T", and concentrated TLV TMCC signals are denoted by "TLV TMCC". In fig. 4, like fig. 3, the demodulated plurality of main signals are represented by "tlv#1", "tlv#2" … "tlv#00" in this order from the beginning. In addition, as in fig. 3, the number of TLV packets forming the main signal may vary.

When the transmission-side demodulation unit 12a outputs the concentrated TMCC signals after or before the main signal, the plurality of TMCC signals are concentrated, for example, until the number of bits of the concentrated TMCC signals reaches a preset upper limit value. The transmission-side demodulation unit 12a may output the TMCC signal, which is one after or before the main signal, at the time when the number of bits reaches the upper limit value.

The packet type (e.g., "0 xFD") of the TMCC signal is selected from the types shown in fig. 5, which are assigned undefined values. That is, the packet type of the TMCC signal is an undefined type different from the type to which the definition set in advance is assigned.

Furthermore, the value assigned to the TMCC signal is not selected from only one value assigned as undefined. That is, the value to which the TMCC signal is assigned may be selected from a plurality of values (for example, "0x05", "0x06", "0x 07") to which undefined values are assigned.

The data length of the TMCC signal is a fixed value (e.g., "0x049 a").

The transmission-side error correction unit 12b performs error correction of the demodulation signal received from the transmission-side demodulation unit 12a by an error correction method using BCK code or LDPC code as an error correction code. The transmission-side error correction unit 12b supplies the TLV packet obtained by performing error correction to the cable retransmission conversion unit 13.

That is, the demodulation circuit 12 outputs a main signal (a plurality of TLV packets) obtained by TLV-converting a TMCC signal included in a broadcast wave of satellite broadcasting received through the antenna 4 to the cable retransmission conversion section 13. Thereby, the demodulation circuit 12 transmits TMCC information to the cable retransmission conversion section 13.

In accordance with the above, the demodulation circuit 12 concentrates a plurality of TMCC signals, which are distributed and arranged in a frame including the main signal and the TMCC signals, which are transmitted by being superimposed on the broadcast wave. The demodulation circuit 12 outputs the concentrated TMCC signal before or after the main signal, and demodulates the main signal and the TMCC signal for each frame. In addition, the demodulation circuit 12 generates a main signal (TLV) and a TLV-formatted TMCC signal as variable-length packets by concentrating a plurality of TMCC signals distributed in one frame and outputting them before or after the main signal.

The cable retransmission conversion section 13 converts the broadcast wave supplied from the satellite tuner 11 into a broadcast wave of digital cable television broadcasting. The converted broadcast wave (digital broadcast wave) is transmitted to the reception device 2 via a cable (cable television transmission path).

In embodiment 1, as an example, a case will be described in which a digital broadcast wave transmitted from the transmitting apparatus 1 to the receiving apparatus 2 is divided and transmitted so as to include two carriers modulated by a 256QAM modulation scheme and one carrier modulated by a 64QAM modulation scheme.

The transmission device 1 uses a 64QAM modulation scheme and a 256QAM modulation scheme as modulation schemes corresponding to transmission capacities required for transmission of the main signal. The transmitting apparatus 1 generates a main signal in units of time slots. At this time, the transmitting apparatus 1 modulates the main signal of each slot in a modulation scheme selected for the slot of the main signal.

In view of the above, the transmission device 1 converts the TLV packet into a divided TLV packet, applies cable modulation, and transmits the divided TLV packet to the reception device 2 via the cable.

As described above, the transmitting apparatus 1 includes the demodulation circuit 12 as the front-end processing circuit, and the demodulation circuit 12 outputs the TMCC signal in a concentrated state before or after the main signal and demodulates the main signal and the TMCC signal individually for the frame. In addition, the transmitting apparatus 1 includes a cable retransmission converting section 13, and the cable retransmission converting section 13 performs QAM modulation on the demodulation signal demodulated by the demodulation circuit 12 so as to be used for broadcasting of digital cable television broadcasting.

As described above, satellite broadcasting is broadcast as digital broadcast waves of MMT and TLV systems. Accordingly, the cable retransmission conversion section 13 converts the digital broadcast wave of the MMT and TLV scheme into a divided TLV packet and transmits the divided TLV packet as a broadcast wave of the digital cable television broadcast.

Specifically, as shown in fig. 6, the wired retransmission converting section 13 performs processing of converting the received TLV packet into a divided TLV packet. The broadcast wave supplied to the cable retransmission conversion section 13 is a set of TLV packets of variable length (variable length TLV packets). The wired retransmission conversion section 13 converts the aggregated variable-length TLV packets into divided TLV packets of a fixed length. That is, the cable retransmission converting unit 13 performs the cable retransmission conversion processing using the transmission information in the satellite broadcast.

The TLV packet is split into 188 bytes of fixed length packets.

For a fixed length packet of 188 bytes, 3 bytes out of 188 bytes are the header and 185 bytes are the payload. In fig. 6, TLV data packet 1 and TLV data packet 2 are shown as TLV data packets, and split TLV data packet 1 through split TLV data packet 3 are shown as split TLV data packets.

In the example shown in fig. 6, TLV packet 1 is split into split TLV packet 1, split TLV packet 2, and split TLV packet 3. In addition, a part of the TLV packet 2 is split into split TLV packets 3.

The split TLV packet 3 is set to be a packet including data of the TLV packet 1 and the TLV packet 2. As such, sometimes the payload of the fragmented TLV packet also includes a plurality of TLV packets that are fragmented.

As shown in fig. 6, the split TLV packet is composed of a sync byte, a transmission error indicator, a TLV packet start indicator, a PID, and a payload. Sometimes the payload includes a beginning TLV indication. The sync byte is defined as "0x47", for example.

The transmission error indicator is a flag indicating whether or not there is a bit error in the split TLV packet. For example, when the transmission error indicator is "1", an error indicating that at least 1 bit cannot be corrected exists in the split TLV packet.

When the TLV packet start indicator is "1", the payload of the split TLV packet includes the head of the TLV packet. For example, split TLV packet 2 includes only TLV packet 1 and does not include the beginning of TLV packet 1, and thus the TLV packet start indicator of split TLV packet 2 is "0". In addition, for example, the split TLV packet 3 includes the TLV packet 1 and the TLV packet 2, and includes the beginning of the TLV packet 2, and thus, the TLV packet start indicator of the split TLV packet 3 is "1".

The PID is an area used to identify the data of the payload as TLV data.

The beginning TLV indication is the first 1 byte of the payload used when the TLV packet start indicator is "1". The value indicated by the start TLV indicates the start position of the TLV packet at which byte of the payload exists. Thus, the reception side can detect the head position of the TLV packet included in the payload of the divided TLV packet. When the TLV packet start indicator is "0", the start TLV indicates that no payload is inserted.

< TLV data packet >)

The TLV packet will be described with reference to fig. 1 to 6 and with reference to fig. 7 and 8.

As shown in fig. 7, the TLV packet is constituted by a packet header region composed of 2 bits and 6 bits, an 8-bit packet type region, a 16-bit data length region, and a variable length data region.

The area of the packet type is allocated as an area for identifying the type of the packet stored in the TLV, as shown in fig. 5.

The area of the data length is an area in which the number of data bits succeeding the writing is written. The data area (data area) is 8×n bits, is an area of variable length, and is an area where data is written.

For example, when a value of "0x01" is recorded in an area of the packet type, the data format of the data area is an IPv4 packet. When the data format of the data area is an IPv4 packet, the IP packet in the data area has a structure as shown in layer 2 from above in fig. 8.

As illustrated in layer 2 from above in fig. 8, an IP packet in the data area is composed of an IPv4 header portion, a UDP header portion, and a data portion.

For example, when a value of "0x02" is recorded in a packet type area, the data format of the data area is an IPv6 packet. When the data format of the data area is an IPv6 packet, the IP packet in the data area has a structure shown in layer 3 from above in fig. 8.

As illustrated in layer 3 from above in fig. 8, an IP packet in the data area is composed of an IPv6 header portion, a UDP header portion, and a data portion.

For example, when a value of "0x03" is recorded in a packet type field, the data format of the data field is an IP packet whose header is compressed. When the data format of the data area is an IP packet whose header is compressed, the IP packet in the data area has a structure as shown in layer 4 from the top in fig. 8.

As illustrated in fig. 8 from layer 4, the IP packet in the data area includes a header portion and a data portion.

According to the above, the TLV packet includes an IP packet.

Structure of receiver

As shown in fig. 2, the receiving apparatus 2 includes a receiving-side tuner 21, a front-end processing circuit 22, and a back-end processing circuit 23.

The reception-side tuner 21 receives a digital broadcast wave (split TLV packet) transmitted from the transmission apparatus 1 via a cable, and supplies the received digital broadcast wave to the front-end processing circuit 22.

The front-end processing circuit 22 is an LSI that performs demodulation processing. The back-end processing circuit 23 is an LSI that performs demultiplexing processing. The front-end processing circuit 22 and the back-end processing circuit 23 may be configured by one LSI, or may be configured as different LSIs. In the case where the front-end processing circuit 22 and the back-end processing circuit 23 are configured by different LSIs, the front-end processing circuit 22 needs to output data so that the back-end processing circuit 23, which is a circuit of a subsequent stage, can process the data, that is, so that the condition requested by the back-end processing circuit 23 is satisfied.

From the above, the front-end processing circuit 22 supplies the demodulated data in a form satisfying the condition requested by the back-end processing circuit 23. In the following description, the front-end processing circuit 22 and the back-end processing circuit 23 are configured as different LSIs, as an example.

The front-end processing circuit 22 includes a reception-side demodulation section 22a and a reception-side error correction section 22b.

The reception-side demodulation unit 22a demodulates the QAM modulation of the reception signal supplied from the reception-side tuner 21. The reception-side demodulation unit 22a outputs the generated demodulation signal to the reception-side error correction unit 22b.

The reception-side error correction unit 22b performs error correction of the demodulation signal received from the reception-side demodulation unit 22a by an error correction method using a reed-solomon code as an error correction code. The reception-side error correction unit 22b supplies the divided TLV packet obtained by performing error correction or the converted TLV packet to the back-end processing circuit 23.

As described above, the front-end processing circuit 22 acquires the split TLV packet. Thus, the fragmented TLV packet or the converted TLV packet is output from the front-end processing circuit 22 to the back-end processing circuit 23.

The back-end processing circuit 23 is formed using, for example, an SOC (System-on-a-chip). The processing performed by the back-end processing circuit 23 is processing (demultiplexing processing) of dividing the divided TLV packets or the converted TLV packets, for example, the moving picture content, which are output from the front-end processing circuit 22, into video parts, voice parts, caption parts, and the like.

The back-end processing circuit 23 includes a multiplexing/demultiplexing unit 23a and a decoder 23b.

The multiplexing/demultiplexing unit 23a is supplied with output signals (a synchronization signal, a valid signal, a data signal, and a clock signal) outputted from the front-end processing circuit 22. The multiplexing/demultiplexing unit 23a demultiplexes data included in the supplied signal, such as video data and audio data.

The decoder 23b generates video and audio signals by performing a process of decoding video data into a video signal and a process of decoding audio data into an audio signal, and outputs the video and audio signals to the display 5.

< action >

The operation of the transmitting apparatus 1 will be described below with reference to fig. 1 to 8 with reference to fig. 9.

As shown in fig. 9, the transmitting apparatus 1 executes a series of processes from step S2 to step S5 each time a frame synchronization signal is received in step S1.

In step S2, the transmitting-side demodulation unit 12a sets a plurality of main signals, which are distributed, into one in a frame in which the frame synchronization signal is received.

In step S3, the transmitting-side demodulation unit 12a sets a plurality of TMCC signals distributed and arranged in one in a frame in which the frame synchronization signal is received.

In step S4, the transmitting-side demodulation unit 12a configures the TMCC signal concentrated to one in step S3 before or after the main signal concentrated to one in step S2.

In step S5, the cable retransmission conversion section 13 QAM-modulates the demodulation signal demodulated by the demodulation circuit 12 so as to face the cable broadcast, and outputs the result to the reception device 2.

Demodulation method

The demodulation method using the demodulation circuit 12 according to embodiment 1 concentrates a plurality of TMCC signals distributed in a frame including a main signal and a TMCC signal, which are transmitted by being superimposed on a broadcast wave. And, in order to output the concentrated TMCC signal before or after the main signal, the main signal and the TMCC signal are individually demodulated for the frame.

In the demodulation method using the demodulation circuit 12, a plurality of TMCC signals distributed in a frame are concentrated and outputted before or after the main signal, and demodulated, thereby generating a variable length packet including the main signal and the TMCC signal.

As in the prior art, when the interface for receiving the combined variable length packet is an LSI provided in the receiver, the rate per unit time is high, and therefore, there is a problem that the clock frequency is high.

In contrast, with the configuration of embodiment 1, the demodulated TMCC signal is included in the main signal and outputted, whereby the cable retransmission conversion section 13 can recognize the TMCC information included in the frame. Thus, the combined variable length packets can be received without requiring a lengthy and complex format.

Therefore, with the configuration of embodiment 1, it is possible to provide the demodulation circuit 12 capable of demodulating in a simple format even with a configuration in which the LSI receives the combined variable length packet.

Further, with the configuration of embodiment 1, it is possible to provide a demodulation method capable of demodulating in a simple format even with a configuration in which a synthesized variable length packet is received by an LSI.

In addition, with the configuration of embodiment 1, it is possible to provide the transmitting apparatus 1 including the demodulation circuit 12, and the demodulation circuit 12 can demodulate the variable length packet in a simple format even with a configuration in which the variable length packet is received by LSI.

< description of computer to which the present technology is applied >

However, the series of processes described above can be performed by hardware, but can also be performed by software. In the case where a series of processes are performed by software, a program constituting the software is installed from a recording medium on a computer or the like in which dedicated hardware is installed. Alternatively, a program constituting the software may be installed from a recording medium to a general-purpose personal computer or the like capable of executing various functions by installing various programs.

Fig. 10 shows an example of a general-purpose personal computer. A general-purpose personal computer has a CPU (Central Processing Unit ) 100 built therein. The CPU100 is connected to an input/output interface 102 via a bus 101. A ROM (Read Only Memory) 103 and a RAM (Random Access Memory ) 104 are connected to the bus 101.

An input unit 105 formed by using an input device such as a keyboard or a mouse for inputting an operation instruction by a user, and an output unit 106 for outputting a processing operation screen and an image of a processing result to a display device are connected to the input/output interface 102. In addition, a storage unit 107 including a hard disk drive or the like storing programs and various data is connected to the input/output interface 102. A communication unit 108, which is configured by a LAN (Local Area Network ) adapter or the like and performs communication processing via a network typified by the internet, is connected to the input/output interface 102.

Further, a magnetic disk (including a flexible disk), an optical disk (including a CD-ROM (Compact Disc-Read Only Memory), and a DVD (Digital Versatile Disc, digital versatile disk)) are connected to the input/output interface 102. A drive 110 for reading and writing data from and to a removable medium 109 such as an optical disk (including an MD (Mini Disc)) or a semiconductor memory is connected to the input/output interface 102.

The CPU100 executes various processes based on programs stored in the ROM103 and programs loaded from the storage unit 107 to the RAM104 by being installed in the storage unit 107. The program installed in the storage unit 107 is read from a removable medium 109 such as a magnetic disk, an optical disk, or a semiconductor memory.

In addition, data and the like necessary for the CPU100 to execute various processes are also appropriately stored in the RAM 104.

In the computer configured as described above, the CPU100 loads the program stored in the storage unit 107 into the RAM104 via the input/output interface 102 and the bus 101, for example, and executes the program. Thus, the above-described series of processes are performed.

The program executed by the computer (CPU 100) can be provided by being recorded on a removable medium 109 such as a packaging medium. In addition, the program can be provided through a wired or wireless transmission medium such as a local area network, the internet, digital satellite broadcasting, or the like.

In the computer, the program can be installed in the storage unit 107 via the input/output interface 102 by mounting the removable medium 109 on the drive 110. The program can be received by the communication unit 108 via a wired or wireless transmission medium, and installed in the storage unit 107. The program can be installed in advance in the ROM103 and the storage unit 107.

In this specification, the processing performed by the computer according to the program is not necessarily performed in time series in the order described as a flowchart. That is, the processing by the computer according to the program also includes processing (e.g., parallel processing or object-based processing) performed in parallel or individually.

The program may be a program that is processed by one computer (processor), or may be a program that is distributed and processed by a plurality of computers. The program may be executed by being transmitted to a remote computer.

In this specification, a system refers to a collection of a plurality of constituent elements (devices, modules (components), etc.), and it is not important whether or not all the constituent elements are in the same housing. Therefore, a plurality of devices that are housed in a single case and connected via a network, and one device that houses a plurality of modules in one case are both systems.

(other embodiments)

As noted above, embodiments of the present technology are described, but the discussion and drawings forming a part of this disclosure should not be construed as limiting the present technology. Various alternative implementations, examples, and techniques of use will be apparent to those skilled in the art from this disclosure.

It is needless to say that the present technology includes various embodiments and the like not described herein, which are arbitrarily applied to the structures and the like described in the above embodiments. Therefore, the technical scope of the present technology is determined only by the specific matters of the invention according to the appropriate claims from the above description.

In the demodulation circuit, the demodulation method, and the transmission device of the present disclosure, it is not necessary to provide all the components described in the above embodiments and the like, but other components may be provided in the contrary.

The effects described in the present specification are merely examples, and are not limiting, and other effects may be also provided.

For example, the present technology can also employ a configuration of cloud computing commonly handled by sharing one function by a plurality of devices via a network.

In addition, the present technology can adopt the following configuration.

(1) A demodulation circuit concentrates a plurality of TMCC signals distributed in a frame including a main signal and TMCC signals, which are transmitted by being superimposed on a broadcast wave, and outputs the concentrated TMCC signals before or after the main signal, and individually demodulates the main signal and the TMCC signals for the frame.

(2) In the demodulation circuit according to (1) above, the variable length packet is a TLV packet.

(3) The demodulation circuit according to (1) or (2) above, wherein the packet type of the TMCC signal is an undefined type different from the type to which a predetermined definition is assigned.

(4) The demodulation circuit according to any one of (1) to (3) above, wherein the data length of the TMCC signal is a fixed value.

(5) A demodulation method concentrates a plurality of TMCC signals distributed in a frame including a main signal and TMCC signals transmitted by being superimposed on a broadcast wave, outputs the concentrated TMCC signals before or after the main signal, and demodulates the main signal and the TMCC signals individually for the frame.

(6) The demodulation method according to (5) above, wherein the variable length packet is a TLV packet.

(7) The demodulation method according to (5) or (6) above, wherein the packet type of the TMCC signal is an undefined type different from the type to which the predetermined definition is assigned.

(8) The demodulation method according to any one of (5) to (7) above, wherein the data length of the TMCC signal is a fixed value.

(9) A transmitting device is provided with: a demodulation circuit that sets a plurality of TMCC signals, which are distributed in a frame including a main signal and a TMCC signal and transmitted by being superimposed on a broadcast wave, and outputs the set TMCC signals before or after the main signal, and individually demodulates the main signal and the TMCC signals for the frame to generate a variable-length packet including the main signal and the TMCC signal; and a cable retransmission conversion unit which performs QAM modulation on the demodulated signal demodulated by the demodulation circuit so as to face cable broadcasting.

(10) The transmitting apparatus according to (9) above, wherein the variable-length packet is a TLV packet.

(11) The transmitting apparatus according to (9) or (10) above, wherein the packet type of the TMCC signal is an undefined type different from the type to which the predetermined definition is assigned.

(12) The transmitting apparatus according to any one of (9) to (11) above, wherein a data length of the TMCC signal is a fixed value.

Description of the reference numerals

1 … transmitting means; 11 … satellite tuner; 12 … demodulation circuit; a 12a … transmitting-side demodulating unit; 12b … transmission-side error correction unit; 13 … wired retransmission converting section; 2 … receiving means; 21 … receiving side tuner; 22 … front-end processing circuitry; 22a … receiving-side demodulating section; 22b … reception-side error correction unit; 23 … back-end processing circuitry; 23a … multiplexing/separating section; 23b … decoder; 3 … network; 4 … antenna; 5 … display; 10 … broadcast system; 100 … CPU;101 … bus; 102 … input-output interface; 103 … ROM;104 … RAM;105 … input; 106 … output; 107 … storage; 108 … communication unit; 109 … removable media; 110 … driver.

Claims (6)

1. A kind of demodulation circuit, which is composed of a demodulation circuit,

concentrating a plurality of TMCC signals distributed in a frame including a main signal and a TMCC signal transmitted superimposed on a broadcast wave, outputting the concentrated TMCC signals before or after the main signal, demodulating the main signal and the TMCC signal individually for the frame, thereby generating a variable-length data packet including the main signal and the TMCC signal,

the packet type of the TMCC signal is an undefined type different from the type assigned with the definition set in advance,

the data length of the TMCC signal in the variable length data packet is a fixed value.

2. The demodulation circuit of claim 1, wherein,

the variable length packets are TLV packets.

3. A method of demodulation, in which a signal is received,

concentrating a plurality of TMCC signals distributed in a frame including a main signal and a TMCC signal transmitted superimposed on a broadcast wave, outputting the concentrated TMCC signals before or after the main signal, demodulating the main signal and the TMCC signal individually for the frame, thereby generating a variable-length data packet including the main signal and the TMCC signal,

the packet type of the TMCC signal is an undefined type different from the type assigned with the definition set in advance,

the data length of the TMCC signal in the variable length data packet is a fixed value.

4. The demodulation method according to claim 3, wherein,

the variable length packets are TLV packets.

5. A transmitting device is provided with:

a demodulation circuit that sets a plurality of TMCC signals, which are distributed in a frame including a main signal and a TMCC signal and transmitted by being superimposed on a broadcast wave, and outputs the TMCC signals in the set before or after the main signal, and individually demodulates the main signal and the TMCC signals for the frame, thereby generating a variable-length packet including the main signal and the TMCC signals; and

a cable retransmission conversion section performing QAM modulation on a demodulation signal demodulated by the demodulation circuit in a cable broadcasting-oriented manner,

the packet type of the TMCC signal is an undefined type different from the type assigned with the definition set in advance,

the data length of the TMCC signal in the variable length data packet is a fixed value.

6. The transmitting apparatus according to claim 5, wherein,

the variable length packets are TLV packets.