JP4317845B2 - Terrestrial digital broadcast receiving adapter - Google Patents

Description

The present invention relates to an adapter for receiving terrestrial digital broadcasting that receives analog broadcasting together with digital broadcasting.

  In the field of digital broadcasting, it has been decided that BS digital broadcasting will be started in the year 2000 in addition to digital CS broadcasting that has already been implemented, and then terrestrial digital broadcasting is also planned.

  In BS digital broadcasting, each consigned broadcaster to which each frequency is assigned from all possible frequencies by the BS-4 satellite of the broadcasting satellite has already been certified, and these consigned broadcasters have started broadcasting from 2000 AD simultaneously. Is going to be.

  On the other hand, with regard to terrestrial digital broadcasting, among broadcast stations that currently carry out terrestrial analog broadcasting, broadcasters that have completed preparations for digital broadcasting will gradually replace analog broadcasting with digital broadcasting. It is assumed. Therefore, an analog broadcast channel and a digital broadcast channel are mixed. In addition, the time when digital broadcasting starts depends on the region.

  Therefore, it is indispensable that a television receiver to be commercialized in the future can receive BS digital broadcasting and also can receive current terrestrial analog broadcasting that will continue for the time being. Moreover, it is more preferable if it can receive also the terrestrial digital broadcasting by which broadcasting is scheduled. However, as described above, terrestrial digital broadcasting has not yet started, and there is a high possibility that it will be much ahead depending on the region where it is received. It is not always necessary to be able to receive digital broadcasting.

  Therefore, after selling BS digital broadcast receivers that receive terrestrial analog broadcasts as well as BS digital broadcasts as television receivers, attach an adapter for receiving terrestrial digital broadcasts from the region where terrestrial digital broadcasts started. Therefore, it is considered appropriate to configure a digital broadcast receiving system. In the future, the digital broadcast receiving system will incorporate a digital FE (front end) for receiving the terrestrial digital broadcast.

  However, in the digital broadcast receiving system, when the terrestrial broadcast is received, in the state where the analog broadcast channel and the digital broadcast channel are mixed as described above, first, it is determined whether the received terrestrial broadcast is analog or digital. There is a problem that it must be judged. By determining this, it is possible to output a signal appropriately processed through one of the analog FE and digital FE paths.

  In particular, when a digital FE, which is a terrestrial digital broadcast receiving adapter, is externally attached to a BS digital broadcast receiving apparatus, how to control the analog FE built into the BS digital broadcast receiving apparatus and the digital FE. Problems arise.

  In this case, it is conceivable that a signal that has been subjected to processing including MPEG decoding by the digital FE is input to the BS digital broadcast receiving apparatus as a baseband signal. However, a bus based on the IEEE (Institute of Electrical and Electronics Engineers) 1394 standard, It is proposed to connect a digital wave broadcast adapter and a BS digital broadcast receiver. According to this, it is possible to transmit a transport stream (TS) signal that has been subjected to processing such as demodulation and error correction without performing MPEG decoding processing by the terrestrial digital broadcast receiving adapter. The BS digital broadcast receiving apparatus can decode the BS digital broadcast with an MPEG decoder provided for MPEG decoding. That is, it is not necessary to provide an MPEG decoder in the terrestrial digital broadcast receiving adapter, and a single MPEG decoder in the digital broadcast receiving system can decode not only BS digital broadcast but also terrestrial digital broadcast signals.

  Here, the specifications of command sets and tuner commands for audio / video devices using the IEEE 1394 standard are decided by the 1394 Trade Association Steering Committee. However, this arrangement is not intended for connection between a BS digital broadcast receiving apparatus and a terrestrial digital broadcast receiving adapter externally attached to the BS digital broadcast receiving apparatus, and is therefore used in the digital broadcast receiving system. There is a problem that a new command needs to be defined.

The present invention, these problems was made in order to solve the terrestrial capable of BS digital broadcasting, terrestrial analog broadcasting, and displays or the like to efficiently receive a video or the like of a program by the digital terrestrial broadcasting An object of the present invention is to provide a digital broadcast receiving adapter .

In order to solve the above problems, terrestrial digital broadcasting receiving adapter of the present invention is a terrestrial digital broadcasting receiving adapter for transmitting a transport stream by demodulating the land on wave digital broadcasting separated BS digital broadcasting receiver A decoding means for inputting a channel-selected signal from a terrestrial broadcast receiving antenna and decoding a TMCC signal and determining whether OFDM frame synchronization is locked; and the BS digital broadcast receiving apparatus. And an IEEE 1394 interface for connecting the terrestrial digital broadcast receiving adapter, the IEEE 1394 interface having a defined command for transmitting information multiplexed in a transport stream, and the terrestrial digital broadcast Demodulated by the receiving adapter Isolated transport stream, and transmits the information to be multiplexed into the transport stream in accordance with said command, said information that the frame synchronization of the OFDM includes information indicating a frame lock state of whether it is locked Features.

As described above, according to the terrestrial digital broadcasting receiving adapter of the present invention, met terrestrial digital broadcasting receiving adapter transmits a transport stream by demodulating the land on wave digital broadcasting separated BS digital broadcasting receiver Receiving a channel-selected signal from a terrestrial broadcast receiving antenna, decoding the TMCC signal, and determining whether OFDM frame synchronization is locked , the BS digital broadcast receiving apparatus, An IEEE 1394 interface for connecting the adapter for receiving the terrestrial digital broadcast, the IEEE 1394 interface having a defined command for transmitting information multiplexed in a transport stream, and receiving the terrestrial digital broadcast For demodulated and separated by adapter And transmitting the transport stream, and the information is multiplexed into the transport stream in accordance with said command, said information, since the frame synchronization of the OFDM is assumed to include information indicating whether the frame locked state is locked is demodulated by the adapter, the TS signal on which information is multiplexed showing a frame lock state such as a frame lock signal, the receiving apparatus interprets the content of the information, such as the frame lock signal, the tuned ground channel wave broadcast is determined whether digital broadcast or analog broadcast is demodulated by the adapter digital broadcasting decoded by the receiving device, either video sequence to the demodulation and decoding analog broadcast receiving apparatus and There is an effect that audio can be output.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is a block diagram showing an example of the configuration of a digital broadcast receiving system having a terrestrial digital broadcast receiving adapter according to Embodiment 1 of the present invention.

  In the figure, reference numeral 11 denotes an adapter UHF / VHF tuner, which selects a selected frequency band from UHF / VHF band radio waves input from a terrestrial broadcast receiving antenna. TMCC decoding means 12 detects a TMCC (Transmission Multiplexing Configuration Control) signal and a frame synchronization signal added to the received modulation signal, and establishes synchronization of the TMCC by the frame synchronization signal. To decrypt. Therefore, it is determined in this part whether the modulation signal in the selected frequency band is digital or analog. An OFDM demodulating unit 14 demodulates an OFDM frame configured by orthogonal frequency division multiplexing (OFDM) based on a decoded TMCC signal and a frame synchronization signal from a modulation signal in a selected frequency band. An error correction unit 15 corrects an error in the transmission path of the demodulated signal and separates a transport stream (TS) signal. Reference numeral 16 denotes a frame lock signal adding means for adding a frame lock signal to the synchronization byte position of the TS signal in accordance with the frame lock and the frame non-lock. Reference numeral 17 denotes an adapter-side IEEE 1394 interface, which transmits a TS signal with TMCC signal information added in accordance with a predefined command. Reference numeral 100 denotes an adapter for terrestrial digital broadcast reception. From the adapter UHF / VHF tuner 11, TMCC decoding means 12, OFDM demodulation means 14, error correction means 15, frame lock signal addition means 16, and adapter-side IEEE 1394 interface 17. Composed.

  Reference numeral 111 denotes a UHF / VHF tuner, which selects a selected frequency band from UHF / VHF band radio waves input from a terrestrial broadcast receiving antenna, just like the adapter UHF / VHF tuner 11. . Reference numeral 112 denotes VIF detection means that demodulates a modulation signal in a selected frequency band. Reference numeral 113 denotes an NTSC decoder which decodes an analog signal encoded according to the NTSC standard. Reference numeral 115 denotes BS tuner transmission path demodulation means for demodulating and outputting a BS digital broadcast modulation signal. Reference numeral 116 denotes an IEEE 1394 interface, which interprets information such as a frame lock signal added to a TS signal transmitted from the adapter-side IEEE 1394 interface 17 in accordance with a predefined command. Reference numeral 117 denotes a system controller that determines which channel of BS digital broadcasting or terrestrial broadcasting is selected by the viewer. When a channel of terrestrial broadcasting is selected, a frame lock signal is further transmitted from the IEEE 1394 interface 116. In response to this information, it is determined whether the signal of the selected channel is digital or analog, and the output from the BS tuner transmission path demodulation means 115, the terrestrial digital broadcast receiving adapter 100 and the NTSC decoder 113 is switched. Reference numeral 118 denotes a switching circuit A which selects and outputs one of the BS tuner transmission path demodulation means 115 and the IEEE 1394 interface 116 according to an instruction from the system controller 117. Reference numeral 119 denotes an MPEG decoder, which decodes a digital signal encoded by the MPEG standard broadcast by BS digital broadcasting and terrestrial digital broadcasting. Reference numeral 120 denotes a switching circuit B, which selects and outputs either the NTSC decoder 113 or the MPEG decoder 119 according to an instruction from the system controller 117. Reference numeral 200 denotes a BS digital broadcast receiver, which includes a UHF / VHF tuner 111, a VIF detector 112, an NTSC decoder 113, a BS tuner transmission path demodulator 115, an IEEE 1394 interface 116, a system controller 117, a switching circuit A 118, an MPEG decoder 119, and It is configured by a switching circuit B120.

  Here, in the digital broadcast receiving system, when terrestrial broadcasting is selected, the output from the digital FE and analog FE is switched according to whether the selected channel is digital broadcasting or analog broadcasting, and the FE is selected by any FE. Video and the like that have been correctly demodulated and decoded must be output. Therefore, in order to determine whether the broadcast is digital broadcast or analog broadcast, the synchronization byte of the TS signal according to the MPEG2 standard is used. FIG. 2 is a diagram showing the data format of the TS. The TS is composed of a series of units consisting of 188 bytes of actual data such as video and audio and 16 bytes of data for error correction, and the head of the data part of 188 bytes. Is assigned to one byte (8 bits) of synchronization bytes.

  Specifically, if the TMCC decoding means 12 determines that OFDM frame synchronization is established (when locked), the selected channel is digital broadcasting, and the frame lock signal adding means 16 When 47H (H represents hexadecimal, 47H indicates “01000111”) is added to the synchronization byte position of the TS signal that has been error-corrected and separated, and the frame synchronization is not established (when unlocked) If it is determined, assuming that the channel is an analog broadcast, a frame lock signal is added by adding other data to the synchronization byte position (see FIG. 2). In the case of an analog signal, data other than 47H indicating the analog signal is added to the synchronization byte position of the TS signal to obtain a frame lock signal. The system controller 117 determines whether the signal transmitted via the IEEE 1394 bus is digital broadcast or analog broadcast depending on whether the added frame lock signal is 47H, and in response to the determination, analog FE and One of the routes of the digital FE is selected, and an image appropriately processed by the selected route is output.

  However, the command for handling the information that the frame lock signal is added is not in the command specification for the IEEE 1394 standard decided by the 1394 Trade Association Steering Committee. Therefore, a new command for handling the information is defined. The adapter-side IEEE 1394 interface 17 and the IEEE 1394 interface 116 transmit and receive a frame lock signal according to a defined command, and interpret whether the frame lock signal is 47H.

  In addition, decoding of a signal by digital broadcasting must be performed according to the contents of the TMCC signal added to the signal. However, in the above digital broadcast receiving system, the signal from the terrestrial digital broadcast is identified by the OFDM demodulating means 14 of the terrestrial digital broadcast receiving adapter 100 to identify the content of the TMCC signal added to the signal. After the main signal is demodulated and error-corrected, the TS to which the TMCC signal information is added is transmitted to the BS digital broadcast receiving apparatus 200 via the IEEE1394 bus, and the MPEG decoder in the BS digital broadcast receiving apparatus 200 is transmitted. Decode at 119. However, the command for handling the information of the TMCC signal is not in the command specification for the IEEE 1394 standard. Therefore, it is necessary to newly define a command for handling information on the TMCC signal.

  Here, the information coding and transmission system of the TMCC signal is defined in the ARIB (Association of Radio Industries and Businesses) standard, and the TMCC information includes system identification, transmission parameter switching index, activation for emergency warning broadcasting Transmit flags, etc. In the above case, a command for handling the transmission parameter switching index information in the TMCC information is necessary, but the emergency warning broadcast activation flag information is also indispensable information for the broadcast receiving apparatus, and this is handled. The command is defined similarly.

  These commands are defined according to the tuner command specifications for the IEEE 1394 standard determined by the 1394 Trade Association Steering Committee, and can be handled by the adapter-side IEEE 1394 interface 17 and the IEEE 1394 interface 116.

For example, AV / C Tuner Broadcast System Specification-DVB, Rev. 2 decided by the 1394 Trade Association Steering Committee. 1.0 DVB Tuner
Extend Status Descriptor. FIG. 3 is a diagram showing the DVB Tuner Status Descriptor. Msb and lsb indicate the most significant bit and the least significant bit, respectively, and each address has a size of 8 bits. Addresses 00H to 08H are already defined, but after 09H are undefined and have room for expansion. Specifically, an address offset 09 describing manufacturer_dependent_info is used to enter a transmission parameter switching index, an emergency warning broadcast activation flag, and a frame lock state descriptor. For the transmission parameter switching index and the emergency warning broadcast activation flag, 4-bit and 1-bit values according to the ARIB standard are used, respectively. The frame lock state is 0 when the frame is locked and 1 when the frame is not locked. The information on the frame lock state is used as an alternative to the frame lock signal. When the frame lock signal is added, the frame lock state is not described.

  As described above, the descriptor expanded by the adapter-side IEEE 1394 interface 17 is referred to by the IEEE 1394 interface 116 and a command (Tuner Status Command) is issued. That is, when the frame lock state is transmitted by the 1394 command, first, the IEEE 1394 interface 116 on the receiving device 200 side makes an inquiry about the state to the adapter side IEEE 1394 interface 17, and the adapter side IEEE 1394 interface 17 sends the extended descriptor. Used to notify the receiving device side of the frame lock state.

  Next, the operation of the digital broadcast receiving system according to Embodiment 1 of the present invention will be described with reference to FIGS.

  First, a terrestrial broadcast channel is selected from the outside by a user using a remote controller or the like, and information on the selected channel is input to the adapter UHF / VHF tuner 11, UHF / VHF tuner 111, and system controller 117. (S1).

  Next, the system controller 117 grasps that the channel of the terrestrial broadcasting is selected based on information from the remote controller or the like, and instructs the switching circuit A118 to switch to the output from the IEEE1394 interface 116 and output it. (S2).

  Next, the switching circuit A 118 selects an output from the IEEE 1394 interface 116 out of outputs from the IEEE 1394 interface 116 and the BS tuner transmission path demodulation means 115 in accordance with an instruction from the system controller 117 (S 3).

  At the same time, the adapter UHF / VHF tuner 11 and the UHF / VHF tuner 111 select and output the frequency band of the selected channel from the UHF / VHF band radio wave input from the terrestrial broadcast receiving antenna. (S4).

  Next, the digital FE performs operations for demodulating and decoding video and audio by terrestrial digital broadcasting.

  That is, in the terrestrial digital broadcast receiving adapter 100, the TMCC decoding means 12 detects the TMCC signal and the frame synchronization signal added to the modulation signal from the adapter UHF / VHF tuner 11, and detects the frame synchronization signal. The TMCC signal is decoded based on The detected frame synchronization signal and the decoded TMCC signal are output to the OFDM demodulating means 14 to determine whether or not a frame is established, and the decoded TMCC signal is sent to the frame lock signal adding means 16 and the adapter-side IEEE 1394 interface 17. Output (S5).

  Next, the OFDM demodulator 14 demodulates and outputs the OFDM frame of the main signal of the modulated signal from the adapter UHF / VHF tuner 11 based on the decoded TMCC signal and the frame synchronization signal from the TMCC decoder 12. (S6).

  Next, the error correction means 15 corrects an error in the transmission path for the demodulated signal, and separates and outputs the TS signal (S7).

  Next, the frame lock signal adding means 16 adds a frame lock signal to the synchronization byte position of the TS signal from the error correction means 15 according to the determination result from the TMCC decoding means 12. Specifically, if the judgment result in the TMCC decoding means 12 is a judgment that OFDM frame synchronization is established (when locked), the TS signal is assumed to be a digital signal, and the synchronization byte position of the TS signal is determined. 47H is added. If it is determined that it is not established (during non-locking), it is assumed that the signal is an analog signal, and other data (for example, data indicating empty data) is added to the synchronization byte position of the TS signal of the analog signal. (S8).

  Next, the adapter-side IEEE 1394 interface 17 converts the TMCC signal transmission parameter switching index information from the TMCC decoding unit 12 according to the ARIB standard into information conforming to the IEEE 1394 standard from the error correction unit 15 according to a predefined command. The TS signal to which the frame lock signal is added is multiplexed and transmitted (S9).

  Next, in the IEEE 1394 interface 116 of the BS digital broadcast receiving apparatus 200, in accordance with the command defined above, information on the transmission parameter switching index multiplexed on the TS signal transmitted from the adapter-side IEEE 1394 interface 17, and the added frame lock signal Interpret the contents of. Information on the frame lock signal is output to the system controller 117, and the TS signal is output to the switching circuit A 118 (S10).

  Next, the system controller 117 determines whether the selected channel is a digital broadcast or an analog broadcast based on information from the IEEE 1394 interface 116 (that is, information indicating whether a frame lock signal is raised) (S11). In the case of digital broadcasting, the switching circuit B is instructed to output the output from the MPEG decoder 119, and in the case of analog broadcasting, the output from the NTSC decoder 113 is instructed.

  At the same time, the switching circuit A118 has already selected the output from the IEEE 1394 interface 116 in accordance with the instruction from the system controller 117, and outputs the output (S12).

  Next, the MPEG decoder 119 decodes and outputs the output signal from the switching circuit A 118 based on the information of the transmission parameter switching index. In the case of analog broadcasting, correct decoding is not performed (S13).

  During the operation in these digital FEs, in the analog FE, the modulation signal from the UHF / VHF tuner 111 is demodulated by the VIF detection means 112, and the demodulated signal is decoded by the NTSC decoder 113 to the switching circuit B. Output (S14). At this time, naturally, correct demodulation and decoding are not performed in the case of digital broadcasting.

  Next, the switching circuit B120 selects and outputs one of the outputs of the NTSC decoder 113 and the MPEG decoder 119 in accordance with an instruction from the system controller 117. That is, if it is a digital broadcast, the output from the MPEG decoder 119 is selected, and if it is an analog broadcast, the output from the NTSC decoder 113 is selected and output (S15).

  Therefore, BS digital broadcast receiving apparatus 200 outputs video and audio of digital broadcast and terrestrial digital broadcast, respectively, when the selected terrestrial broadcast channel is digital broadcast and analog broadcast.

  In S8 to S10, the frame lock signal is used as information indicating whether the frame is locked or not. However, the frame lock state descriptor described in the DVB Tuner Status Descriptor may be used. .

  In that case, in S8, the frame lock signal adding means 16 adds the frame lock signal to the synchronization byte position of the TS signal from the error correction means 15 according to the judgment result from the TMCC decoding means 12 without adding the frame lock signal. Output a signal. Next, the adapter-side IEEE 1394 interface 17 converts the TMCC signal transmission parameter switching index information from the TMCC decoding unit 12 according to the ARIB standard to information conforming to the IEEE 1394 standard according to a predefined command, and the TMCC decoding unit. In accordance with the determination result from 12, the frame-locked bit is set and multiplexed with the TS signal from the error correction means 15 and transmitted. Next, in the IEEE 1394 interface 116 of the BS digital broadcast receiving apparatus 200, the transmission parameter switching index information multiplexed on the TS signal transmitted from the adapter-side IEEE 1394 interface 17 and the contents of the frame lock state are displayed in accordance with the defined command. Interpret. The frame lock state information is output to the system controller 117 and the TS signal is output to the switching circuit A118.

  Next, the operation of the digital broadcast receiving system when an emergency warning broadcast activation flag of the TMCC signal is set and received in terrestrial digital broadcasting will be briefly described.

  First, when emergency warning broadcasting is started and the viewer has selected the channel, the adapter UHF / VHF tuner 11 selects from the UHF / VHF band radio wave input from the terrestrial broadcast receiving antenna. The frequency band of the channel of the digital broadcasting being stationed is output (S31).

  Next, the TMCC decoding means 12 detects the TMCC signal and the frame synchronization signal added to the modulation signal from the adapter UHF / VHF tuner 11, and decodes the TMCC signal based on the frame synchronization signal. The detected frame synchronization signal and the decoded TMCC signal are output to the OFDM demodulator 14 and the decoded TMCC signal is output to the adapter-side IEEE 1394 interface 17 (S32).

  Next, the OFDM demodulator 14 demodulates and outputs the OFDM frame of the main signal of the modulated signal from the adapter UHF / VHF tuner 11 based on the decoded TMCC signal and the frame synchronization signal from the TMCC decoder 12. (S33).

  Next, the error correction means 15 corrects the error in the transmission path for the demodulated signal, and separates and outputs the TS signal (S34).

  Next, the frame lock signal adding means 16 outputs the TS signal from the error correcting means 15 without adding the frame lock signal (S35).

  Next, the adapter-side IEEE 1394 interface 17 changes the emergency warning broadcast activation flag information of the TMCC signal according to the ARIB standard from the TMCC decoding unit 12 into information according to the IEEE 1394 standard according to a predefined command, and the error correction unit 15 Is multiplexed and transmitted on the TS signal from (S36).

  Next, the IEEE 1394 interface 116 of the BS digital broadcast receiving apparatus 200 interprets the emergency warning broadcast activation flag information multiplexed on the TS signal transmitted from the adapter-side IEEE 1394 interface 17 in accordance with the above defined command. Information on the emergency warning activation flag is output to the system controller 117, and the TS signal is output to the switching circuit A118 (S37).

  Next, the system controller 117 instructs the switching circuit A to output the output from the IEEE 1394 interface 116 based on the information from the IEEE 1394 interface 116, and outputs the output from the MPEG decoder 119 to the switching circuit B. (S38).

  At the same time, the switching circuit A 118 selects an output from the IEEE 1394 interface 116 according to an instruction from the system controller 117, and outputs the output (S39).

  Next, the MPEG decoder 119 decodes and outputs the output signal from the switching circuit A118 (S40).

  Next, the switching circuit B120 selects and outputs the output from the MPEG decoder 119 in accordance with the instruction from the system controller 117 (S41).

  Therefore, the BS digital broadcast receiving apparatus 200 can output an emergency alert broadcast video or the like when receiving the terrestrial digital broadcast with the emergency alert broadcast activation flag of the TMCC signal set.

  Incidentally, when BS digital broadcasting is selected by the user from the outside using a remote controller or the like, the selection contents are input to the BS tuner transmission path demodulation means 115 and the system controller 117 (S51).

  Next, the system controller 117 grasps that the BS digital broadcast is selected based on the selection content from the remote controller or the like, and switches to the output from the BS tuner transmission path demodulation means 115 to the switching circuit A118 and outputs it. In addition to issuing an instruction, the switching circuit B120 is also instructed to switch to the output from the MPEG decoder 119 (S52).

  Next, the switching circuit A 118 selects an output from the BS tuner transmission path demodulation means 115 in accordance with an instruction from the system controller 117. Similarly, the switching circuit B120 also selects the output from the MPEG decoder 119 (S53).

  At the same time, the BS tuner transmission line demodulation means 115 demodulates and outputs a digital signal from the satellite radio wave input from the BS-IF (S54).

  Next, since the switching circuit A118 has already selected the output from the IEEE1394 interface 116 in accordance with the instruction from the system controller 117, the switching circuit A118 outputs the output (S55).

  Next, the MPEG decoder 119 decodes and outputs the output signal from the switching circuit A118 (S56).

  Next, since the switching circuit B120 has already selected the output from the MPEG decoder 119 in accordance with the instruction from the system controller 117, the switching circuit B120 outputs the output (S57).

  Therefore, BS digital broadcast receiving apparatus 200 outputs BS digital broadcast video and audio.

  As described above, when the terrestrial broadcast is selected by the external input, the digital broadcast receiving system according to the first embodiment of the present invention detects whether the selected channel is digital broadcast or analog broadcast, and the detection result. Therefore, the selection means (system controller) selects one of the paths for demodulating and decoding the terrestrial analog broadcast and the terrestrial digital broadcast, respectively. Even in a state where channels and digital broadcasting channels coexist, it is possible to output video and audio appropriately processed through one of the analog FE and digital FE paths.

  The digital broadcast receiving system includes a receiver that demodulates and decodes BS digital broadcast and terrestrial analog broadcast, and an adapter that demodulates and outputs terrestrial digital broadcast to the receiver. The decoder that decodes the BS digital broadcast also serves as a decoder that decodes the signal demodulated by the adapter, and the selection means (system controller) includes the BS digital broadcast signal demodulated by the receiver and the adapter. Since the demodulated terrestrial digital broadcast signal is selected and output to the decoder, one MPEG decoder in the digital broadcast receiving system can select one of the BS digital broadcast and terrestrial digital broadcast images and Audio can be decoded.

  The digital broadcast or the analog broadcast is detected by determining the frame lock state in the demodulation of the terrestrial digital broadcast. When the frame is locked by the selecting means, the path of the terrestrial digital broadcast is selected, Since the terrestrial analog broadcast path is selected when the lock is not set, it is possible to easily detect whether the selected channel is digital broadcast or analog broadcast without providing a special circuit in the digital broadcast receiving system. Can do.

  Also, the adapter detects whether the broadcast is digital broadcast or analog broadcast by judging the frame lock state in the demodulation of the terrestrial digital broadcast, and the selection means selects the path of the terrestrial digital broadcast when the frame is locked. Since the terrestrial analog broadcast route is selected when the frame is not locked, it is possible to easily detect whether the selected channel is digital broadcast or analog broadcast without providing a special circuit in the adapter. Can do.

  Further, the receiving device and the adapter are connected by transmission means according to the IEEE 1394 standard, and the transmission means is for transmitting information such as a transmission parameter switching index or an emergency warning broadcast activation flag multiplexed in a transport stream. In addition, a newly defined command is provided, and in accordance with the command, the transport stream and the information multiplexed on the transport stream are transmitted. Therefore, the TS signal of the terrestrial digital broadcast demodulated by the adapter is transmitted. The receiver can decode and output video and audio of terrestrial digital broadcasting including emergency warning broadcasting.

  The receiving apparatus and the adapter are connected by transmission means according to the IEEE 1394 standard, and the transmission means multiplexes a frame such as a frame lock signal that is multiplexed according to whether or not the frame is locked. For the transmission of information indicating the lock state, a newly defined command is provided, and according to the command, the transport stream and the information multiplexed on the transport stream are transmitted. For the TS signal multiplexed with information indicating the frame lock state such as the frame lock signal, the receiving device interprets the content of the information such as the frame lock signal and the selected terrestrial broadcast channel is digital. Judge whether it is broadcast or analog broadcast, Has been digital broadcast decoded by the receiving device, and can output either the video and audio of the demodulation and decoding analog broadcast by the receiving device.

(Embodiment 2)
FIG. 4 is a block diagram showing an example of the configuration of a digital broadcast receiving system having a terrestrial digital broadcast receiving adapter according to Embodiment 2 of the present invention.

  In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. However, unlike the means in FIG. 1, the TMCC decoding means 12 does not determine whether the modulation signal in the selected frequency band is digital or analog, and the system controller 117 selects from the digital analog detection means instead of from the IEEE 1394 interface 116. Information on whether the signal of the terrestrial broadcast channel is digital or analog is acquired. Reference numeral 114 denotes digital / analog detecting means for detecting whether the modulated signal is digital or analog based on the signal level of a specific frequency for the modulated signal in the selected frequency band.

FIG. 5 is a diagram for explaining the detection principle in the digital analog detection means of FIG.
In the figure, the signal level of the modulated signal transmitted by the carrier wave is shown. The case where the modulated signal is an analog signal is shown in (a), and the case where it is a digital signal is shown in (b). In the case of an analog signal, since the video signal and the audio signal are respectively modulated by frequency-modulating the video carrier and the audio carrier, the valley between the video signal and the audio signal is 107.75 MHz in the case of the third channel, for example. Can be. On the other hand, in the case of a digital signal, since it is carried as a video and audio digital signal, there is no gap between the signals. Therefore, even if the possibility of a slight interference between the video signal and the audio signal in the valley is considered, if the 107.75 MHz signal level of the modulated signal transmitted by the terrestrial broadcast is equal to or higher than the D level shown in the figure. If it is a digital signal and is less than the D level, it can be determined as an analog signal.

  Therefore, the digital analog detection means 114 detects the signal level of a specific frequency component for each channel of the modulation signal transmitted by terrestrial broadcasting, and determines whether the modulation signal is digital depending on whether it is above a certain level. Judge whether it is analog.

  Also in the present second embodiment, a command for handling TMCC signal information is defined as in the first embodiment.

  Next, the operation of the digital broadcast receiving system in Embodiment 2 of the present invention will be described with reference to FIGS.

  First, in exactly the same manner as in S1 to S4 in the first embodiment, a terrestrial broadcast channel is selected by a user from the outside using a remote controller or the like, and the adapter UHF / VHF tuner 11, UHF / VHF tuner 111, Operating in the system controller 117 and the switching circuit A, the switching circuit A 118 selects an output from the IEEE 1394 interface 116 in accordance with an instruction from the system controller 117, and the adapter UHF / VHF tuner 11 and UHF / VHF. The tuner 111 selects and outputs the frequency band of the selected channel from the UHF / VHF band radio wave input from the terrestrial broadcast receiving antenna (S101).

  Next, in the BS digital broadcast receiving apparatus 200, the digital analog detection means 114 detects the signal level of a specific frequency in the frequency band selected by the UHF / VHF tuner 111. If the signal level is equal to or higher than a preset level, it is determined that the selected channel is digital broadcasting, and if it is less than the level, it is determined that it is analog broadcasting, and the determination result is output to the system controller. (S102).

  Next, the system controller 117 receives the determination result from the digital / analog detection means 114, and switches to the switching circuit B120 according to the determination result and outputs it to one of the outputs of the NTSC decoder 113 and the MPEG decoder. Give instructions. In the case of digital broadcasting, the switching circuit B is instructed to output the output from the MPEG decoder 119, and in the case of analog broadcasting, the output from the NTSC decoder 113 is instructed (S103).

  On the other hand, in the analog FE, the VIF detection means 112 demodulates the modulation signal from the UHF / VHF tuner 111, and the demodulated signal is decoded by the NTSC decoder 113 and output to the switching circuit B. At this time, if it is a digital broadcast, of course, correct demodulation and decoding are not performed (S104).

  On the other hand, the digital FE including the terrestrial digital broadcast receiving adapter 100 performs an operation for demodulating and decoding video and audio by the terrestrial digital broadcast.

  That is, the TMCC decoding means 12 decodes the TMCC signal added to the modulation signal from the adapter UHF / VHF tuner 11 and outputs it to the OFDM demodulation means 14 and the adapter-side IEEE 1394 interface 17 (S105).

  Next, the OFDM demodulation unit 14 demodulates and outputs the OFDM frame of the main signal of the modulation signal from the adapter UHF / VHF tuner 11 based on the TMCC signal decoded by the TMCC decoding unit 12 (S106).

  Next, the error correction means 15 corrects the error in the transmission path for the demodulated signal, and separates and outputs the TS signal (S107).

  Next, the adapter-side IEEE 1394 interface 17 converts the TMCC signal transmission parameter switching index information from the TMCC decoding unit 12 according to the ARIB standard into information conforming to the IEEE 1394 standard from the error correction unit 15 according to a predefined command. The TS signal is multiplexed and transmitted (S108).

Next, the IEEE 1394 interface 116 of the BS digital broadcast receiving apparatus 200 interprets the transmission parameter switching index information multiplexed on the TS signal transmitted from the adapter-side IEEE 1394 interface 17 according to the above defined command, and the T
The S signal is output to the switching circuit A118 (S109).

  Next, since the switching circuit A118 has already selected the output from the IEEE1394 interface 116 in accordance with the instruction from the system controller 117, the switching circuit A118 outputs the output (S110).

  Next, the MPEG decoder 119 decodes and outputs the output signal from the switching circuit A118 based on the transmission parameter switching index (S111). In the case of analog broadcasting, correct decoding is not performed.

  Next, the switching circuit B120 selects and outputs one of the outputs of the NTSC decoder 113 and the MPEG decoder 119 in accordance with an instruction from the system controller 117 (S112). That is, for digital broadcasting, the output from the MPEG decoder 119 is selected, and for analog broadcasting, the output from the NTSC decoder 113 is selected and output.

  Therefore, BS digital broadcast receiving apparatus 200 outputs video and audio of digital broadcast and terrestrial digital broadcast, respectively, when the selected terrestrial broadcast channel is digital broadcast and analog broadcast.

  In the case of receiving a terrestrial digital broadcast in which an emergency warning broadcast activation flag of the TMCC signal is set, a BS digital broadcast receiving apparatus is performed by performing the same operations as in S31 to S41 of the first embodiment. In 200, an emergency alert broadcast video or the like can be output.

  When BS digital broadcast is selected by the user from the outside using a remote controller or the like, the BS digital broadcast receiving apparatus 200 performs the same operation as S51 to S57 in the first embodiment, BS digital broadcast video and audio are output.

  As described above, when the terrestrial broadcast is selected by the external input, the digital broadcast receiving system according to the second embodiment of the present invention detects whether the selected channel is digital broadcast or analog broadcast, and the detection result. Therefore, the selection means (system controller) selects one of the paths for demodulating and decoding the terrestrial analog broadcast and the terrestrial digital broadcast, respectively. Even in a state where channels and digital broadcasting channels coexist, it is possible to output video and audio appropriately processed through one of the analog FE and digital FE paths.

  The digital broadcast receiving system includes a receiver that demodulates and decodes BS digital broadcast and terrestrial analog broadcast, and an adapter that demodulates and outputs terrestrial digital broadcast to the receiver. The decoder that decodes the BS digital broadcast also serves as a decoder that decodes the signal demodulated by the adapter, and the selection means (system controller) includes the BS digital broadcast signal demodulated by the receiver and the adapter. Since the demodulated terrestrial digital broadcast signal is selected and output to the decoder, one MPEG decoder in the digital broadcast receiving system can select one of the BS digital broadcast and terrestrial digital broadcast images and Audio can be decoded.

  The digital broadcast or analog broadcast is detected by detecting the signal level of a specific frequency component in the channel selected by the external input, and the signal level detected by the selection means is a predetermined level. In the above case, the terrestrial digital broadcast path is selected, and when it is below the predetermined level, the terrestrial analog broadcast path is selected. Therefore, it takes time to detect the signal level of a specific frequency component. Instead, it is possible to quickly determine whether the selected channel is digital broadcast or analog broadcast, and output video and audio demodulated and decoded through an appropriate path.

  Further, the receiving device and the adapter are connected by transmission means according to the IEEE 1394 standard, and the transmission means is for transmitting information such as a transmission parameter switching index or an emergency warning broadcast activation flag multiplexed in a transport stream. In addition, a newly defined command is provided, and in accordance with the command, the transport stream and the information multiplexed on the transport stream are transmitted. Therefore, the TS signal of the terrestrial digital broadcast demodulated by the adapter is transmitted. The receiver can decode and output video and audio of terrestrial digital broadcasting including emergency warning broadcasting.

(Embodiment 3)
FIG. 6 is a block diagram showing an example of the configuration of a digital broadcast receiving system having a terrestrial digital broadcast receiving adapter according to Embodiment 3 of the present invention.

  In the figure, the same reference numerals as those in FIGS. 1 and 4 denote the same or corresponding parts. However, the system controller 117 operates the digital analog detection means 114 in accordance with the electric field strength signal transmitted from the terrestrial digital broadcast receiving adapter 100 through the IEEE 1394 bus in addition to the operations in FIGS. 1 and 4.

  Reference numeral 18 denotes an electric field strength detecting means for detecting the electric field strength of the selected channel. Therefore, the IEEE 1394 interface 17 transmits information on the electric field strength detected by the electric field strength detection means 18 as a field strength signal. The command for transmitting the electric field strength signal is defined in the command specification for the IEEE 1394 standard.

  Therefore, the digital broadcast receiving system according to the third embodiment has the configuration of the digital broadcast receiving system according to the first and second embodiments. That is, as a configuration for determining whether a modulation signal transmitted by terrestrial broadcasting is a digital signal or an analog signal, a configuration for determining whether or not frame synchronization is established, and a signal of a specific frequency component of the modulation signal A configuration for detecting and determining the level is provided. The electric field strength detecting means 18 is provided to determine whether or not frame synchronization is established in the normal electric field according to the electric field strength of the selected channel, and the electric field strength falls below a certain level. Sometimes it is determined by detecting the signal level of a specific frequency component. In other words, when the reception state is poor due to rain or the like and the electric field is weak, even if a digital signal is transmitted in terrestrial broadcasting, frame synchronization of the digital signal may not be established, and it may be determined as an analog signal. Because.

  FIG. 7 is a flowchart for explaining the operation in the digital broadcast receiving system shown in FIG.

  Next, the operation of the digital broadcast receiving system according to Embodiment 3 of the present invention will be described with reference to FIGS.

  First, in the same manner as in S1 to S4 in the first embodiment and S101 in the second embodiment, a terrestrial broadcast channel is selected from the outside by a user using a remote controller or the like, and the adapter UHF / VHF tuner 11, the UHF / VHF tuner 111, the system controller 117, and the switching circuit A operate. The switching circuit A118 selects an output from the IEEE1394 interface 116 in accordance with an instruction from the system controller 117, and the adapter UHF / VHF The VHF tuner 11 and the UHF / VHF tuner 111 select and output the frequency band of the selected channel from the UHF / VHF band radio wave input from the terrestrial broadcast receiving antenna (S201).

  Next, the electric field strength detecting means 18 receives the signal from the adapter UHF / VHF tuner 11 and detects and outputs the electric field strength of the selected channel.

  Next, the adapter-side IEEE 1394 interface 17 transmits the electric field intensity detected by the electric field intensity detecting unit 18 as an electric field intensity signal in accordance with a command defined in the command specification for the IEEE 1394 standard.

  Next, the IEEE 1394 interface 116 of the BS digital broadcast receiving apparatus 200 interprets the electric field strength signal transmitted from the adapter-side IEEE 1394 interface 17 according to the above command, and outputs it to the system controller 117.

Next, the system controller 117 acquires information on the electric field strength, and if the electric field strength is below a certain level, instructs the digital analog detection means 114 to detect the signal level. On the other hand, if the electric field strength is above a certain level, no instruction is given to the digital analog detection means 114 (S202).
Therefore, thereafter, the operation differs depending on the electric field strength.

  That is, when the electric field strength is equal to or higher than a certain level, the BS digital broadcast receiving apparatus 200 operates in the same manner as S5 to S15 in the first embodiment, and the selected terrestrial broadcast channel is digital broadcast or analog broadcast. In this case, video and audio of digital broadcasting and terrestrial digital broadcasting are output (S203, S205, and S206), respectively.

  On the other hand, when the electric field strength is below a certain level, the BS digital broadcast receiving apparatus 200 operates in the same manner as S102 to S112 in the second embodiment, and the selected terrestrial broadcast channel is digital broadcast. In the case of analog broadcasting, video and sound of digital broadcasting and terrestrial digital broadcasting are output (S204, S205, and S206), respectively.

  Here, when the electric field strength is below a certain level, it is a weak electric field, so even if a digital signal is transmitted, the signal level is low, and the digital / analog detecting means 114 determines that the broadcast is analog broadcasting. There is a possibility.

  Therefore, it is preferable to set the signal level (D level) of the specific frequency used as a determination criterion by the digital analog detection means 114 to be low. It should be noted that the electric field strength is considerably low and the signal level of the digital signal is too low, and it is determined that the broadcast is analog broadcast. The system controller 117 receives the determination that the broadcast is analog broadcast and outputs the output of the switching circuit B to the NTSC decoder 113. Of course, the analog broadcast video or the like is not output if the output is switched to the output from, but even if the output of the switching circuit B is switched to the output from the MPEG decoder 119, the digital demodulation itself is not performed. Video is not output. That is, there is no disadvantage caused by determining that digital broadcasting is analog broadcasting.

  In the case of receiving a terrestrial digital broadcast in which an emergency warning broadcast activation flag of the TMCC signal is set, the BS digital broadcast reception is performed by performing the same operation as S31 to S41 in the first embodiment. The device 200 can output an emergency warning broadcast video or the like.

  When BS digital broadcast is selected by the user from the outside using a remote controller or the like, the BS digital broadcast receiving apparatus 200 performs the same operation as S51 to S57 in the first embodiment, BS digital broadcast video and audio are output.

  As described above, when the terrestrial broadcast is selected by the external input, the digital broadcast receiving system according to the third embodiment of the present invention detects whether the selected channel is digital broadcast or analog broadcast, and the detection result. Therefore, the selection means (system controller) selects one of the paths for demodulating and decoding the terrestrial analog broadcast and the terrestrial digital broadcast, respectively. Even in a state where channels and digital broadcasting channels coexist, it is possible to output video and audio appropriately processed through one of the analog FE and digital FE paths.

  The digital broadcast receiving system includes a receiver that demodulates and decodes BS digital broadcast and terrestrial analog broadcast, and an adapter that demodulates and outputs terrestrial digital broadcast to the receiver. The decoder that decodes the BS digital broadcast also serves as a decoder that decodes the signal demodulated by the adapter, and the selection means (system controller) includes the BS digital broadcast signal demodulated by the receiver and the adapter. Since the demodulated terrestrial digital broadcast signal is selected and output to the decoder, one MPEG decoder in the digital broadcast receiving system can select one of the BS digital broadcast and terrestrial digital broadcast images and Audio can be decoded.

  Further, the apparatus further comprises a detecting means for determining a frame lock state in the demodulation of the terrestrial digital broadcast, and a second detecting means for detecting a signal level of a specific frequency component in the selected channel, and an electric field strength detecting means. Then, the electric field strength of the channel selected by the external input is detected, and the selecting means selects the detecting means when the detected electric field strength is equal to or higher than a predetermined level. 2 is selected, the terrestrial digital broadcasting path is selected when the frame is locked, the terrestrial analog broadcasting path is selected when the frame is not locked, and the signal level detected by the second detecting means is equal to or higher than a predetermined level. When the terrestrial digital broadcast path is less than a predetermined level, the terrestrial analog broadcast path is selected. Depending on, by selecting the appropriate detection means may be a selected channel to reliably detect whether the digital broadcast or analog broadcast.

  The receiver and the adapter are connected by transmission means according to the IEEE 1394 standard, and the electric field strength detection means is provided in the adapter, and the transmission means is an electric field indicating a field strength level multiplexed in a transport stream. In order to transmit a strength signal or the like, a newly defined command is provided, and in accordance with the command, a transport stream and information multiplexed on the transport stream are transmitted. With respect to the electric field strength signal added to the signal, the receiving device interprets the content of the electric field strength signal and grasps the electric field strength, and determines whether the selected terrestrial broadcast channel is digital broadcasting or analog broadcasting. Digital broadcast demodulated by the adapter and decoded by the receiver, and the receiver It is possible to output either the video and audio of the demodulation and decoding analog broadcast system.

  In the third embodiment, the two types of means for determining whether the broadcast is digital broadcasting or analog broadcasting are properly used according to the field strength of the selected channel detected by the field strength detection means. The case where these means are used properly without detecting the electric field strength will be described.

  In other words, the adapter UHF / VHF tuner 11 and UHF / VHF tuner 111 select and output the frequency band of the selected channel by operating in the same manner as S201 of the third embodiment.

  Next, without detecting the electric field strength, the same operation as S203 at the time of the normal electric field is performed to determine whether or not the frame synchronization is established. At the time of locking, it is determined that the digital broadcasting is performed, and similarly to S206. In operation, terrestrial digital broadcast video and audio are output. On the other hand, at the time of non-locking, frame synchronization may not be established even for digital broadcasting due to weak electric field. Therefore, it is determined that the system controller 117 does not establish frame synchronization, and digital analog is performed in the same manner as in S204. The detection means 114 detects the signal level of a specific frequency component, reconfirms whether it is digital broadcast or analog broadcast, and operates in the same manner as in S205 or S206 to perform video and audio of terrestrial digital broadcast or terrestrial analog broadcast. Is output.

  In the first to third embodiments, the digital broadcast receiving system receives and demodulates the terrestrial digital broadcast to the BS digital broadcast receiver that receives and demodulates and decodes the BS digital broadcast and the terrestrial analog broadcast. Although a terrestrial digital broadcast receiving adapter is externally attached, if a digital CATV broadcast receiving adapter that receives and demodulates digital CATV is similarly attached, digital CATV is similarly received and displayed. It is possible.

  As described above, the present invention is suitable for use in applications that enable reception of terrestrial digital broadcasts by connecting to a BS digital broadcast receiver capable of receiving terrestrial analog broadcasts and BS digital broadcasts.

It is a block diagram which shows the structural example of the digital broadcasting receiving system which has the adapter for terrestrial digital broadcasting receiving by Embodiment 1 of this invention. It is a figure which shows the data format of TS. It is a figure which shows the example of the descriptor extended for use of IEEE1394 bus | bath. It is a block diagram which shows the structural example of the digital broadcast receiving system which has a terrestrial digital broadcast receiving adapter by Embodiment 2 of this invention. It is a figure for demonstrating the detection principle in the digital analog detection means of FIG. It is a block diagram which shows the structural example of the digital broadcast receiving system which has a terrestrial digital broadcast receiving adapter by Embodiment 3 of this invention. FIG. 7 is a flowchart for explaining an operation in the digital broadcast receiving system shown in FIG. 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Adapter UHF / VHF tuner 12 TMCC decoding means 14 OFDM demodulation means 15 Error correction means 16 Frame lock signal addition means 17 Adapter side IEEE1394 interface 18 Electric field strength detection means 100 Terrestrial digital broadcast reception adapter 111 UHF / VHF tuner 112 VIF Detection means 113 NTSC decoder 114 Digital analog detection means 115 BS tuner transmission path demodulation means 116 IEEE1394 interface 117 System controller 118 Switching circuit A
119 MPEG decoder 120 switching circuit B
200 BS digital broadcast receiver

Claims (1)

A terrestrial digital broadcasting receiving adapter that transmits a transport stream separated by demodulating the land on wave digital broadcasting to the BS digital broadcasting receiver,
Decoding means for inputting a channel-selected signal from a terrestrial broadcast receiving antenna, decoding a TMCC signal, and determining whether OFDM frame synchronization is locked ;
An IEEE 1394 interface for connecting the BS digital broadcast receiver and the terrestrial digital broadcast receiver adapter;
The IEEE 1394 interface has a defined command for transmission of information multiplexed in a transport stream, the transport stream demodulated and separated by the terrestrial digital broadcast receiving adapter, and the command according to the command. Transmits information that is multiplexed into the transport stream,
The terrestrial digital broadcast receiving adapter according to claim 1, wherein the information includes information indicating a frame lock state indicating whether or not the OFDM frame synchronization is locked .

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