CN113302858A - Demodulation circuit, demodulation method, and transmission device - 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 in a superimposed manner on a broadcast wave, outputs the concentrated TMCC signal 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 for QAM-modulating the demodulated signal demodulated by the demodulation circuit in a cable broadcast-oriented manner.

Description

Demodulation circuit, demodulation method, and transmission device

Technical Field

The technology (present technology) related 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 used for signal processing of digital broadcasting and the like, for example, as disclosed in patent document 1, a variable-length packet is transmitted between a processing unit that performs demodulation processing and a processing unit that performs demultiplexing processing using a signal line.

Patent document 1: international publication No. 2016/199603

However, in the technique disclosed in patent document 1, ethernet (registered trademark) is assumed as an interface for combining and receiving variable-length packets output from a plurality of broadcast stations. Therefore, even when the interface for receiving the combined variable-length packet is an LSI included in the receiver, the combined variable-length packet is received via the ethernet, and thus a lengthy and complicated format is required.

Disclosure of Invention

In view of the above problems, it is an object of the present technology to provide a demodulation circuit capable of demodulating with a simple format even in a configuration in which a combined variable-length packet is received by an LSI, a demodulation method using the demodulation circuit, and a transmission apparatus including the demodulation circuit.

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

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

A transmission device according to an aspect of the present technology includes: a demodulation circuit that generates a variable-length packet including the main signal and the TMCC signal by demodulating the main signal and the TMCC signal separately for a frame; and a cable retransmission conversion unit for QAM-modulating 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 a TMCC signal, which are transmitted 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 broadcasting system.

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

Fig. 3 is a diagram illustrating a process performed by the transmission side demodulation unit.

Fig. 4 is a diagram illustrating a process performed by the transmission side demodulation unit.

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

Fig. 6 is an explanatory diagram of the conversion from TLV data packet to split TLV data packet.

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

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

Fig. 9 is a flowchart showing the operation of the transmission device.

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 parts are denoted by the same or similar reference numerals, and overlapping description is omitted. The drawings are schematic drawings including cases different from reality. The embodiments described below exemplify apparatuses and methods for embodying the technical idea of the present technology, and the technical idea of the present technology is not specific to the apparatuses and methods 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, a receiving apparatus 2, and a network 3 together constitute a broadcasting system 10.

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

The transmission device 1 is a device on the 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, the transmission via the network 3 can also be transmission of information related to the broadcasted content.

The broadcast wave transmitted from the transmitting apparatus 1 is transmitted in a system called MMT (MPEG Media Transport) and TLV (Type Length Value), and is received by the receiving apparatus 2.

The MMT and TLV modes are modes in which an image signal, a voice signal, and a control signal are stored in an IP (Internet Protocol) packet and transmitted. The broadcast wave is transmitted by using the TLV scheme, thereby eliminating the difference between the broadcast as a transmission path and the communication. Further, according to the MMT and TLV systems, broadcast waves and communication paths can be used at the same time. Thus, for example, a broadcast format can be implemented in which video from a main camera for an unspecified large number of viewers is transmitted by using broadcast radio waves, and video from a sub-camera selected by the viewer person is transmitted by using a communication path (via the network 3). In embodiment 1, a case where only a broadcast wave is transmitted by the MMT or TLV method will be described.

< Structure of Transmission apparatus >

As shown in fig. 2, the transmission device 1 includes a satellite tuner 11, a demodulation circuit 12, and a cable retransmission conversion unit 13. The satellite tuner 11 and the demodulation circuit 12 may be constituted by an LSI in which the satellite tuner 11 and the demodulation circuit 12 are integrated.

An 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 unit 12a and a transmission side error correction unit 12 b.

The transmitting-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 demodulator 12a demodulates a main signal of an APSK (amplitude phase modulation) system or a PSK system. In addition, the transmission side demodulation section 12a demodulates the transmission TMCC signal of the pi/2 shift BPSK modulation scheme. The Transmission TMCC signal is a signal in which a BCH code or an LDPC code is added to a TMCC (Transmission & Multiplexing Configuration Control) signal. Further, the TMCC signal of each frame includes TMCC information associated with each time slot constituting the frame. The transmitting-side demodulation unit 12a obtains TMCC information by performing an outer code error detection and correction process for decoding BCH codes and an inner code error detection and correction process for decoding LDPC codes on TMCC signals. The transmitting-side demodulation unit 12a demodulates the main signal included in each slot of the target frame based on the information necessary for demodulation of the main signal included in each slot of the target frame, which is included in the TMCC information. The information required for demodulating the main signal is, for example, a parameter indicating a carrier modulation scheme of each slot and a parameter indicating an encoding rate of the LDPC code. The transmitting side demodulator 12a performs deinterleaving processing on the main signal of the slot.

The transmitting-side demodulation unit 12a collects a plurality of TMCC signals distributed in each frame into one when demodulating the transmission TMCC signal. As shown in fig. 3, the transmission side demodulation unit 12a outputs the TMCC signal that is subjected to TLV processing collectively after the demodulated main signal. Thus, the transmitting-side demodulation unit 12a includes TMCC information in a part of TLV packets, which are variable-length packets, and generates a demodulation signal. In fig. 3, the plurality of TMCC signals arranged in a distributed manner are denoted as "T". In addition, in fig. 3, the centralized TLV-formed TMCC signal is denoted as "TLV-formed TMCC". In fig. 3, the demodulated main signals are denoted as "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 transmission side demodulation unit 12a is not limited to the configuration in which the centralized TLV-formed TMCC signals are output after the demodulated main signal, but may be the configuration in which the centralized TLV-formed TMCC signals are output before the demodulated main signal, as shown in fig. 4. In fig. 4, similarly to fig. 3, the plurality of distributed TMCC signals are denoted as "T", and the centralized TLV-formed TMCC signal is denoted as "TLV-formed TMCC". In fig. 4, the demodulated main signals are denoted as "TLV # 1", "TLV # 2", … ", and" TLV #00 "in this order from the beginning, as in fig. 3. Further, as in fig. 3, the number of TLV packets forming the main signal may vary.

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

The packet type (for example, "0 xFD") of the TMCC signal is selected for an undefined value from among the types shown in fig. 5. That is, the packet type of the TMCC signal is an undefined type different from a predefined type assigned in advance.

Further, the value to which the TMCC signal is allocated is not selected from only one value allocated as undefined. That is, the value to which the TMCC signal is assigned may be selected from a plurality of values (for example, "0 x 05", "0 x 06", and "0 x 07") assigned as undefined values.

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

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

That is, the demodulation circuit 12 outputs to the wired retransmission conversion unit 13 a main signal (a plurality of TLV packets) in which a TMCC signal included in a broadcast wave of a satellite broadcast received by the antenna 4 is TLV-converted. Thereby, the demodulation circuit 12 delivers TMCC information to the wired retransmission conversion unit 13.

According to the above, the demodulation circuit 12 concentrates a plurality of TMCC signals which are distributed in a frame including the main signal and the TMCC signal and transmitted 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 individually for the frame. In addition to this, the demodulation circuit 12 generates a main signal (TLV) as a variable-length packet and a TLV-formed TMCC signal by collecting and outputting a plurality of TMCC signals arranged dispersed in one frame before or after the main signal and demodulating them.

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

In embodiment 1, a case will be described where, as an example, a digital broadcast wave transmitted from a transmission device 1 to a reception device 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.

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

According to the above, in the transmitting apparatus 1, the TLV packet is converted into the split TLV packet, and cable modulation is applied to transmit the packet to the receiving apparatus 2 via the cable.

As described above, the transmission device 1 includes the demodulation circuit 12 as a front-end processing circuit, and the demodulation circuit 12 outputs the concentrated TMCC signal before or after the main signal and demodulates the main signal and the TMCC signal individually for the frame. In addition, the transmission device 1 includes a cable retransmission conversion unit 13, and the cable retransmission conversion unit 13 QAM-modulates the demodulated 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 MMT and TLV digital broadcast waves. Therefore, the cable retransmission conversion unit 13 converts the MMT and TLV digital broadcast waves into the divided TLV packets and transmits the divided TLV packets as broadcast waves of the digital cable television broadcast.

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

The split TLV packet is a fixed length packet of 188 bytes.

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

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

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

As shown in fig. 6, the split TLV packet includes a sync byte, a transport 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 "0 x 47", for example.

The transport error indicator is a flag indicating whether a bit error is present in the fragmented TLV packet. For example, when the transmission error indicator is "1", it indicates that at least 1-bit uncorrectable error exists in the split TLV packet.

In addition, when the TLV packet start indicator is "1", it indicates that the start of the TLV packet is included in the payload of the fragmented TLV packet. For example, the 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 the split TLV packet 2 is "0". In addition, for example, the split TLV packet 3 includes TLV packet 1 and TLV packet 2 and includes the beginning of TLV packet 2, and thus, the TLV packet start indicator of the split TLV packet 3 is "1".

The PID is a region used to identify data of the payload as TLV data.

The first 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 that there is a start position of the TLV packet at the several bytes of the payload. Thus, the receiving side can detect the start position of the TLV packet included in the payload of the split TLV packet. When the TLV packet start indicator is "0", the start TLV indicates that no payload is inserted.

< TLV packet >

TLV packets are described with reference to fig. 1 to 6 and using fig. 7 and 8.

As shown in fig. 7, the TLV packet includes a packet header region composed of 2 bits and 6 bits, a packet type region of 8 bits, a data length region of 16 bits, and a data region of variable length.

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

The data length area is an area in which the number of data bits following the data length area is written. The data area (data area) is an area of 8 × N bits, variable length, and in which data is written.

For example, when a value of "0 x 01" is recorded in the packet type area, 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 the top in fig. 8.

As shown in the upper layer 2 of fig. 8, the 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 "0 x 02" is described in the packet type field, the data format of the data field 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 the top in fig. 8.

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

For example, when a value of "0 x 03" is described in the 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 the 4 th layer from the top in fig. 8.

As shown in the upper layer 4 of fig. 8, an IP packet in the data area is composed of a header portion and a data portion.

According to the above, the TLV data packets comprise IP data packets.

< architecture of receiving apparatus >

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 (divided TLV packet) transmitted from the transmission device 1 via a cable, and supplies the 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 constituted by one LSI, or may be constituted as different LSIs. In the case where the front-end processing circuit 22 and the back-end processing circuit 23 are constituted by different LSIs, the front-end processing circuit 22 needs to output data in such a manner as to be able to be processed by the back-end processing circuit 23 as a circuit of a subsequent stage, that is, in such a manner as to satisfy a condition requested by the back-end processing circuit 23.

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

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

The reception-side demodulator 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 demodulated signal to the reception side error correction unit 22 b.

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

As described above, the front-end processing circuit 22 acquires the split TLV packet. Thus, the split TLV data packet or the converted TLV data 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) for dividing the divided TLV packets or converted TLV packets output from the front-end processing circuit 22 into video portions, audio portions, caption portions, and the like, for example, moving picture contents.

The back-end processing circuit 23 includes a multiplexer/demultiplexer 23a and a decoder 23 b.

The output signals (synchronization signal, valid signal, data signal, clock signal) output from the front-end processing circuit 22 are supplied to the multiplexer/demultiplexer 23 a. The multiplexing/demultiplexing unit 23a demultiplexes data included in the supplied signal, for example, video data and audio data.

The decoder 23b generates a video signal and a speech signal by performing processing for decoding video data into a video signal and processing for decoding speech data into a speech signal, and outputs the signals to the display 5.

< action >

Hereinafter, the operation performed by the transmission device 1 will be described with reference to fig. 1 to 8, with reference to fig. 9.

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

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

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

In step S4, the transmission-side demodulation unit 12a arranges the TMCC signals grouped together in step S3 before or after the main signal grouped together in step S2.

In step S5, the cable retransmission/conversion unit 13 QAM-modulates the demodulated signal demodulated by the demodulation circuit 12 for cable broadcasting, and outputs the modulated signal to the reception device 2.

< demodulation method >

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

In the demodulation method using the demodulation circuit 12, a plurality of TMCC signals arranged in a dispersed manner in a frame are collected and output 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 included in the receiver, the rate per unit time is high, and thus the clock frequency is high.

In contrast, with the configuration of embodiment 1, the wired retransmission/conversion unit 13 can recognize the TMCC information included in the frame by including the demodulated TMCC signal in the main signal and outputting the signal. Thus, the combined variable-length packet can be received without requiring a lengthy and complicated 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 variable-length packets combined are received by an LSI.

In addition, 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 variable-length packets combined are received by an LSI.

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

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

However, the series of processes described above can be executed by hardware, but can also be executed by software. When a series of processes is executed by software, a program constituting the software is installed from a recording medium to a computer or the like in which dedicated hardware is installed. Alternatively, the 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 personal computer. A general-purpose personal computer has a CPU (Central Processing Unit) 100 built therein. An input/output interface 102 is connected to the CPU100 via a bus 101. A ROM (Read Only Memory) 103 and a RAM (Random Access Memory) 104 are connected to the bus 101.

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

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)) 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 MD (Mini Disc)) or a semiconductor memory is connected to the input/output interface 102.

The CPU100 executes various processes in accordance with a program stored in the ROM103 and a program loaded from the storage unit 107 to the RAM 104. 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 stored in the RAM104 as appropriate.

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

The program executed by the computer (CPU100) can be provided by being recorded on a removable medium 109 such as a package 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, by mounting the removable medium 109 to the drive 110, the program can be installed in the storage unit 107 via the input/output interface 102. 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 or the storage unit 107.

Here, in the present specification, the processing performed by the computer according to the program does not necessarily need to be performed in time series in the order described as the flowchart. That is, the processing performed by the computer according to the program also includes processing executed in parallel or individually (e.g., parallel processing or object-based processing).

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

In the present specification, a system refers to a set of a plurality of components (devices, modules (components), and the like), and it does not matter whether or not all the components are in the same housing. Therefore, a plurality of devices housed in separate housings and connected via a network and one device housing a plurality of modules in one housing are both systems.

(other embodiments)

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

It is needless to say that the present technology includes various embodiments and the like not described herein, such as a configuration to which each configuration described in the above embodiments is arbitrarily applied. 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 according to the present disclosure, it is not necessary to include all of the components described in the above-described embodiments and the like, and conversely, other components may be included.

The effects described in the present specification are merely exemplary and not restrictive, and other effects may be provided.

For example, the present technology can also adopt a configuration of cloud computing that is collectively handled by a plurality of devices sharing one function via a network.

The present technology can adopt the following configuration.

(1) A demodulation circuit collects a plurality of TMCC signals distributed in a frame including a main signal and a TMCC signal transmitted superimposed on a broadcast wave, outputs the collected 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) In the demodulation circuit according to (1) or (2), a packet type of the TMCC signal is an undefined type different from a predefined type assigned in advance.

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

(5) A demodulation method for individually demodulating a main signal and a TMCC signal by collecting a plurality of TMCC signals distributed in a frame including the main signal and the TMCC signal transmitted superimposed on a broadcast wave, outputting the collected TMCC signals before or after the main signal, and demodulating the main signal and the TMCC signal for the frame.

(6) In the demodulation method according to (5), the variable-length packet is a TLV packet.

(7) In the demodulation method according to (5) or (6), the packet type of the TMCC signal is an undefined type different from a predefined type assigned in advance.

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

(9) A transmission device is provided with: a demodulation circuit that collects a plurality of TMCC signals distributed in a frame including a main signal and a TMCC signal, which is transmitted in a superimposed manner on a broadcast wave, outputs the collected TMCC signal 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 configured to perform QAM modulation on the demodulated signal demodulated by the demodulation circuit in a cable broadcast-oriented manner.

(10) In the transmitter according to (9), the variable-length packet is a TLV packet.

(11) In the transmitter according to (9) or (10), a packet type of the TMCC signal is an undefined type different from a predefined type assigned in advance.

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

Description of the reference numerals

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

Claims (12)

1. A kind of demodulation circuit is disclosed, which comprises a demodulation circuit,

a plurality of TMCC signals which are distributed in a frame including a main signal and a TMCC signal and transmitted superimposed on a broadcast wave are collected, the collected TMCC signals are output before or after the main signal, and the main signal and the TMCC signals are individually demodulated for the frame, thereby generating a variable-length packet including the main signal and the TMCC signals.

2. The demodulation circuit according to claim 1,

the variable-length data packet is a TLV data packet.

3. The demodulation circuit according to claim 1,

the packet type of the TMCC signal is an undefined type different from a predefined type assigned in advance.

4. The demodulation circuit according to claim 1,

the data length of the TMCC signal is a fixed value.

5. A method for demodulating a digital signal includes the steps of,

a plurality of TMCC signals which are distributed in a frame including a main signal and a TMCC signal and transmitted superimposed on a broadcast wave are collected, the collected TMCC signals are output before or after the main signal, and the main signal and the TMCC signals are individually demodulated for the frame, thereby generating a variable-length packet including the main signal and the TMCC signals.

6. The demodulation method according to claim 5,

the variable-length data packet is a TLV data packet.

7. The demodulation method according to claim 5,

the packet type of the TMCC signal is an undefined type different from a predefined type assigned in advance.

8. The demodulation method according to claim 5,

the data length of the TMCC signal is a fixed value.

9. A transmission device is provided with:

a demodulation circuit that collects a plurality of TMCC signals that are distributed in a frame including a main signal and a TMCC signal and transmitted in superimposition with a broadcast wave, outputs the collected 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

and a wired retransmission conversion unit configured to perform QAM modulation on the demodulated signal demodulated by the demodulation circuit in a wired broadcast-oriented manner.

10. The transmission apparatus according to claim 9,

the variable-length data packet is a TLV data packet.

11. The transmission apparatus according to claim 9,

the packet type of the TMCC signal is an undefined type different from a predefined type assigned in advance.

12. The transmission apparatus according to claim 9,

the data length of the TMCC signal is a fixed value.

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