JP2004363806A - Device and method for receiving broadcast - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide broadcast reception device/method with which determining time of presence or absence of broadcast to one channel is shortened and time required for channel scanning is shortened, and presence or absence of broadcast can precisely be determined and which is suitable for practical use. <P>SOLUTION: Presence or absence of digital broadcast in the selected channel is temporarily determined according to whether a TMCC signal is obtained or not by a demodulation processing. Then, presence or absence of digital broadcast in the selected channel is determined according to whether section information (NIT) is obtained or not by a channel selection information extraction processing in a state where a present state of digital broadcast is temporarily determined. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a broadcast receiving apparatus and a broadcast receiving method particularly suitable for receiving terrestrial digital broadcasts.
[0002]
[Prior art]
As is well known, in recent years, digitalization of television broadcasting has been promoted. In Japan, not only satellite digital broadcasting such as BS (Broadcasting Satellite) digital broadcasting and 110-degree CS (Communication Satellite) digital broadcasting, but also terrestrial digital broadcasting is being started.
[0003]
Since this terrestrial digital broadcasting is based on the current terrestrial analog broadcasting base, the concept of 12 positions with 12 keys for direct channel selection or the division of the whole of Japan into multiple regions The concept of a regional unit where a broadcasting station is set up for each region is included in the operation regulations.
[0004]
For this reason, for example, in a cross-border area, not only a broadcast from a broadcast station in the area, but also a broadcast from a broadcast station in another area is received, or a broadcast from a broadcast station in the area is not received. For example, when only the broadcasts of the local broadcast stations are received, there are some areas where it is impossible to know which broadcast stations can be received without actually receiving them.
[0005]
Therefore, in a broadcast receiver compatible with terrestrial digital broadcasting, a UHF (Ultra High Frequency) band physical channel is sequentially scanned while being installed at a predetermined position, and a receivable terrestrial digital broadcast broadcasting station is detected. So-called channel scan is performed.
[0006]
In such a channel scan, whether or not terrestrial digital broadcasting is being performed on the selected channel can be determined by section data such as NIT (Network Information Table) transmitted by terrestrial digital broadcasting. It is determined based on whether or not.
[0007]
The determination as to whether or not section data can be obtained is made by maintaining a reception state on one channel for a certain period of time, and if section data is obtained within the certain period of time, a broadcast exists, and if not, broadcast is not performed. Is realized by timeout processing.
[0008]
However, the NIT, which is section data, is extracted from a TS (Transport Stream) packet obtained by performing demodulation processing on a received signal based on a packet ID (identifier), and after receiving a predetermined channel. Until NIT is obtained, it takes as long as 3 seconds at the worst, so that there is a problem that the time required for channel scanning becomes long.
[0009]
In particular, in the channel scan processing of terrestrial digital broadcasting, usually, all 50 channels in the UHF band, and up to 113 channels including the VHF (Very High Frequency) band, the UHF band, and the CATV (Cable Television) are selected one by one. On the other hand, since the presence of NIT has been confirmed, the above problem has become serious.
[0010]
Here, Japanese Patent Application Laid-Open No. H11-157572 discloses that a preparatory scan process for temporarily registering a channel number whose received signal has a certain quality or higher as a receivable channel candidate is performed, thereby shortening a channel information registration work time. A disclosed configuration is disclosed.
[0011]
Further, in Patent Document 2, in a digital broadcast receiver, identification information ESPID (Elementary Stream Packet Identification) of video and audio is predicted, thereby speeding up channel selection processing and improving responsiveness to a user operation. Such a configuration is disclosed.
[0012]
Further, Patent Document 3 discloses that a plurality of receiving circuits are provided, and a receiving circuit that does not perform a program receiving process receives channel selection information and program information of a program, thereby effectively utilizing a data transmission path and always using the same. A configuration for obtaining the latest channel selection information is disclosed.
[0013]
However, in each of these Patent Documents 1 to 3, the time required for channel scanning is long due to the time required from receiving a predetermined channel to obtaining NIT in the channel scanning process. There is no mention of addressing the problem of becoming.
[0014]
[Patent Document 1]
JP-A-2002-218335
[Patent Document 2]
JP 2001-346109 A
[Patent Document 3]
JP 2000-13696 A
[Problems to be solved by the invention]
Therefore, the present invention has been made in consideration of the above circumstances, and aims to shorten the time required for channel scanning by determining the presence / absence of broadcasting for one channel, and to accurately determine the presence / absence of broadcasting. It is an object of the present invention to provide a broadcast receiving apparatus and a broadcast receiving method which can be performed and are suitable for practical use.
[0018]
[Means for Solving the Problems]
A broadcast receiving apparatus according to the present invention includes: a channel selecting unit for selecting a predetermined digital broadcast channel; a demodulating unit for performing demodulation processing on a signal output from the channel selecting unit; Channel selection information extracting means for extracting specific channel selection information, and a channel selected by the channel selection means depending on whether the first information is obtained in a state where the demodulation processing by the demodulation means has reached the first stage. Tentatively determining means for tentatively determining the presence or absence of digital broadcasting in the above, and in a state in which the presence of digital broadcasting is tentatively determined by the tentative determination means, the channel selection information extraction processing by the election information extraction means is performed after the first stage. Determining means for determining whether or not digital broadcasting is present in the channel selected by the channel selecting means depending on whether or not the second information has been obtained in the state where the second stage has been reached.
[0019]
Also, the broadcast receiving method according to the present invention includes a step of selecting a predetermined digital broadcast channel, a step of performing demodulation processing on a signal obtained by selecting the channel, and a specific selection from the demodulated signal. The presence or absence of digital broadcasting on the selected channel is temporarily determined based on the step of performing channel selection information extraction processing for extracting station information and whether or not the first information has been obtained in a state where the demodulation processing has reached the first stage. The step of determining and whether or not the second information is obtained in a state where the channel selection information extraction process has reached a second stage after the first stage in a state where the presence state of the digital broadcast is provisionally determined. A step of determining the presence or absence of a digital broadcast in the selected channel.
[0020]
According to the configuration and method as described above, the presence / absence of digital broadcasting on the selected channel is provisionally determined based on whether or not the first information has been obtained in a state where the demodulation processing has reached the first stage. In a state in which the broadcast presence state has been provisionally determined, channel selection was performed based on whether or not second information was obtained in a state where the channel selection information extraction process reached a second stage after the first stage. Since the presence / absence of digital broadcasting in a channel is determined, the time required to determine the presence / absence of digital broadcasting for one channel can be shortened, and the time required for channel scanning can be shortened. Presence or absence can be accurately determined, which is suitable for practical use.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a digital broadcast receiver described in this embodiment. That is, the broadcast signal received by the terrestrial digital broadcast antenna 11 is supplied to the terrestrial broadcast tuner 12, and the signal of the designated channel is selected.
[0022]
The signal selected by the terrestrial broadcast tuner 12 is supplied to a demodulation circuit 13 and subjected to a predetermined demodulation process, whereby the signal is converted into a TS (Transport Stream) packet. Then, the TS packet output from the demodulation circuit 13 is supplied to the TS processor 14.
[0023]
The TS processor 14 identifies a packet ID (PID) added to each input TS packet and extracts an ES (Elementary Stream) of channel selection information such as a section, video, and audio.
[0024]
The control control circuit 23, which will be described later, acquires each section of a PAT (Program Association Table) and a PMT (Program Map Table) using the TS processor 14, and recognizes necessary PIDs such as video and audio to be received.
[0025]
The PID of the recognized video and audio to be received is set in the TS processor 14, and a TS packet having the same PID is output to an MPEG (Moving Picture Experts Group) decoder 15.
[0026]
The MPEG decoder 15 performs a decoding process on the input TS packet to generate a digital video signal and a digital audio signal. The digital video signal is supplied to a video D / A (Digital / Analog) conversion circuit 16 and converted into an analog video signal.
[0027]
The digital audio signal output from the MPEG decoder 15 is supplied to an audio D / A conversion circuit 18, converted into an analog audio signal, and reproduced by a speaker 19.
[0028]
On the other hand, the satellite broadcasting antenna 20 receives satellite digital broadcasting such as BS digital broadcasting and 110-degree CS digital broadcasting. The broadcast signal received by the satellite broadcast antenna 20 is supplied to a satellite broadcast tuner 21 to select a signal of a designated channel.
[0029]
The signal selected by the satellite broadcast tuner 21 is supplied to a demodulation circuit 22 and subjected to a predetermined demodulation process, thereby being converted into a TS packet. Then, the TS packet output from the demodulation circuit 22 is supplied to the TS processor 14, and thereafter, is provided for video display and audio reproduction in the same manner as terrestrial digital broadcasting.
[0030]
Here, the digital broadcast receiver is entirely controlled by the control control circuit 23 in all its operations. The control control circuit 23 incorporates a microcomputer (not shown), receives operation information sent from the remote controller 24, and controls each circuit unit so that the operation content is reflected.
[0031]
Next, channel scanning in digital terrestrial broadcasting will be described. There are three types of channel scan: initial scan, rescan, and automatic scan.
[0032]
In the initial scan, the area setting is performed on the digital broadcasting receiver newly purchased and installed at the predetermined position, or the area setting is performed on the digital broadcasting receiver installed at the predetermined position by moving, etc. In this state, it is performed based on the user's request.
[0033]
The rescan is performed based on the user's request. The automatic scan is automatically performed in a state where the digital broadcast receiver has not performed a reception operation for a predetermined time or more, or at a predetermined cycle.
[0034]
Requests for the initial scan and the re-scan are made by operating the remote controller 24. As shown in FIG. 2, a menu key 25 is provided on the remote controller 24. When the menu key 25 is operated, a scan selection screen is displayed on the monitor 17.
[0035]
As shown in FIG. 3, this scan selection screen displays an “initial scan” item and a “rescan” item. Then, by selecting one of the items with the direction keys 26 of the remote controller 24 and operating the enter key 27, the user can request an initial scan or a rescan.
[0036]
Here, in the digital broadcast receiver, in the process in which the signal selected by the terrestrial broadcast tuner 12 is subjected to demodulation processing by the demodulation circuit 13, when the TMCC signal is detected, the broadcast is transmitted to that channel. If it exists and no TMCC signal is detected, it is provisionally determined that there is no broadcast on that channel. Then, it is determined whether or not NIT can be obtained only for a channel that is provisionally determined to have a broadcast by the TMCC signal.
[0037]
In this case, the TMCC signal, which will be described in detail later, is a signal necessary for demodulating the NIT, and can be naturally obtained before the NIT. That is, since a TMCC signal requires only about 300 ms from the time when a predetermined channel is received to the time when it is obtained, the time required to determine the presence or absence of broadcasting for one channel is shortened to shorten the time required for channel scanning. Can be achieved.
[0038]
Here, the standard for the transmission system in digital broadcasting is defined in ARIB (Association of Radio Industries and Businesses) STD-B20 version 3.0.
[0039]
FIG. 4 schematically shows a configuration of transmission data based on this standard. The transmission data is divided into frame units, and one frame mainly includes a part of the TMCC signal and a transmission main signal. As shown in FIG. 5, the transmission main signal is divided into 204 bytes (one slot) including a synchronization signal and a parity code, and one frame is composed of 48 slots.
[0040]
As shown in FIG. 6, a TMCC signal is composed of 64 bytes obtained by adding a 16-byte parity code to 48-byte TMCC information. The TMCC signal is divided into eight 8-byte units, and divided into eight frames. It is to be added.
[0041]
FIG. 7 shows the configuration of the TMCC information. The TMCC information includes a change instruction, transmission mode / slot information, relative TS / slot information, a relative TS / TS ID correspondence table, an activation control signal, uplink control information, and extended information.
[0042]
The change instruction is incremented by one each time the content of the TCMM information is changed, and returns to “00000” when the value becomes “11111”. The transmission mode / slot information indicates a modulation scheme of a signal obtained by performing error correction inner coding on a transmission main signal, a combination of coding rates of an error correcting inner code, and the number of used slots. As shown.
[0043]
In FIG. 8, the transmission mode indicates a combination of the modulation scheme and the coding rate of the error correction inner code, as shown in FIG. 9, and the phase number of the modulation scheme is high, and in the case of the same modulation scheme, The error correction inner codes are assigned to the transmission modes 1, 2, 3, and 4 in order from the one with the highest coding rate. When the combination of the modulation scheme and the coding rate of the error correction inner code used at the same time is less than 4, the value of the transmission mode with no allocation is set to “1111” and the number of allocated slots is set to “000000”. The total number of slots to which each transmission mode is assigned is 48.
[0044]
The relative TS / slot information is an area for transmitting a relative TS number assigned to 48 slots (including invalid slots), and has a configuration as shown in FIG. In FIG. 10, the relative TS numbers are 0 to 7.
[0045]
The relative TS / TS ID correspondence table is an area showing a correspondence relationship between a TS ID for identifying an encoded signal and a relative TS number for efficiently transmitting a plurality of TSs at the same frequency. This is as shown in FIG.
[0046]
The activation control signal is set to “1” when transmitting an emergency alert signal and performing activation control of the receiver, and is set to “0” otherwise. The uplink control information can be used for switching control of the earth station. The extended information has a configuration shown in FIG. In FIG. 12, when the TMCC signal is extended, the extension flag is set to “1”, and the subsequent extension area is made valid. When the extension flag is “0”, stuffing is performed with all 61 bits of the extension area set to “1”.
[0047]
FIG. 13 shows a flowchart summarizing the channel scanning operation using the above-described TMCC signal for determining the presence or absence of digital broadcasting. That is, when the channel scan is started (step S1), in step S2, the range of all physical channels to be scanned is set.
[0048]
The channel scan is usually performed on 50 channels from UHF13 channel to UHF62 channel. However, in consideration of the co-listening equipment and the like, VHF1 channel to VHF12 channel, UHF13 channel to UHF62 channel, CATV13 channel to CATV63 channel. Since it is conceivable that all 113 channels may be targeted, it is desirable that the channels can be selected by a user interface or the like.
[0049]
When the range of all the physical channels to be channel-scanned is set in this way, the control control circuit 23 selects the channel with the smallest number from the set channel range in step S3, and In S4, the channel selection state in the demodulation circuit 13 is confirmed. In this case, the control control circuit 23 detects a TMCC signal from the selected channel.
[0050]
Thereafter, in step S5, the control control circuit 23 determines whether or not the channel selection has been completed. If it is determined that the channel selection has not been completed (NO), the process returns to step S4 to select the channel. Is completed (YES), a tentative determination is made in step S6 as to whether or not a TMCC signal has been detected, that is, whether or not digital broadcasting is being performed.
[0051]
Then, when it is provisionally determined that the digital broadcasting is being performed (YES), the control control circuit 23 executes a process for obtaining the NIT in step S7, and determines whether or not the NIT has been obtained in step S8. Is determined.
[0052]
Here, if it is determined that the NIT cannot be acquired (NO), the control control circuit 23 determines in step S9 whether a predetermined time that has been set in advance has elapsed, that is, whether a timeout has occurred. If not (NO), the process returns to step S7.
[0053]
Here, if it is provisionally determined in step S6 that the broadcast is a digital broadcast (YES), if it is determined in step S8 that the NIT has been obtained (YES), or if it is determined in step S9 that the timeout has occurred. (YES), the control control circuit 23 updates the channel number by +1 in step S10, and determines in step S11 whether or not channel selection for all channels has been completed.
[0054]
Then, when it is determined that the tuning of all the channels is not completed (NO), the control control circuit 23 returns to the process of step S3, and executes the tuning of the channel of the number set in step S10. .
[0055]
If it is determined in step S11 that channel selection for all channels has been completed (YES), the control control circuit 23 performs processing for terminating the channel scan in step S12, and terminates the processing (step S13). ) Is done.
[0056]
According to the above-described embodiment, the NIT is acquired only for the channel that is provisionally determined to have a broadcast by the TMCC signal. The required time can be reduced, and the presence or absence of broadcasting can be accurately determined, which is suitable for practical use.
[0057]
The confirmation of the channel selection state in the demodulation circuit 13 in step S4 in FIG. 13 and the determination as to whether or not the channel selection is completed in step S5 include monitoring the state obtained in the demodulation circuit 13 and performing a plurality of stages of demodulation processing. By determining at what point in time digital broadcasting is being performed, it is possible to make a quicker decision than to check the presence or absence of digital broadcasting based on the presence or absence of NIT. Therefore, the channel scanning process is determined by how this determination is made. This leads to speeding up.
[0058]
The state obtained by the demodulation circuit 13 starts from an initial state in which no signal is input, completes signal synchronization establishment, and determines that TS output is normal. Until the state of the circuit 13 can be confirmed, a final state is reached through several steps.
[0059]
In order to determine whether or not terrestrial digital broadcasting is being performed, it is possible to determine the presence or absence of a digital broadcasting signal in each stage of processing until synchronization is completed. It is possible to determine which stage to use depending on whether or not digital broadcast is determined.
[0060]
As a result, it is possible to determine the presence or absence of digital broadcasting without waiting for the time until the complete synchronization is established. Possible judgment factors include, besides the TMCC signal, detection of an OFDM (Orthogonal Frequency Division Multiplex) frame synchronization signal and detection of a PAT.
[0061]
Furthermore, the provisional determination of the presence or absence of terrestrial digital broadcasting in the demodulation circuit 13 can be used for the determination of the presence or absence of satellite digital broadcasting in the demodulation circuit 22.
[0062]
It should be noted that the present invention is not limited to the above-described embodiments as they are, and can be embodied by variously modifying constituent elements in an implementation stage without departing from the scope of the invention.
[0063]
Various inventions can be formed by appropriately combining a plurality of components disclosed in the above-described embodiments. For example, some components may be deleted from all the components described in the embodiments. Further, constituent elements according to different embodiments may be appropriately combined.
[0064]
【The invention's effect】
As described in detail above, according to the present invention, it is possible to shorten the time required for channel scanning by shortening the time for determining the presence / absence of broadcasting for one channel, and to accurately determine the presence / absence of broadcasting. And a broadcast receiving apparatus and a broadcast receiving method suitable for practical use.
[Brief description of the drawings]
FIG. 1 shows an embodiment of the present invention and is a block diagram illustrating a digital broadcast receiver.
FIG. 2 is an exemplary view for explaining a remote controller in the digital broadcast receiver.
FIG. 3 is an exemplary view for explaining a scan selection screen in the digital broadcast receiver.
FIG. 4 is an exemplary view showing a schematic configuration of transmission data based on a standard in the digital broadcasting.
FIG. 5 is a diagram shown to explain a transmission main signal in the transmission data.
FIG. 6 is a view for explaining a TMCC signal in the transmission data.
FIG. 7 is a view for explaining TMCC information in the transmission data.
FIG. 8 is a view for explaining the configuration of transmission mode / slot information in the TMCC information.
FIG. 9 is a view for explaining a combination of a modulation scheme and a coding rate of an error correction inner code in the transmission mode.
FIG. 10 is a view for explaining a configuration of relative TS / slot information in the TMCC information.
FIG. 11 is a view for explaining the configuration of a relative TS / TS ID correspondence table in the TMCC information.
FIG. 12 is a view for explaining the configuration of extended information in the TMCC information.
FIG. 13 is a flowchart illustrating a channel scan operation in the digital broadcast receiver.
[Explanation of symbols]
11 terrestrial broadcasting antenna, 12 terrestrial broadcasting tuner, 13 demodulation circuit, 14 TS processor, 15 MPEG decoder, 16 video D / A conversion circuit, 17 monitor, 18 audio D / A Conversion circuit, 19: speaker, 20: satellite broadcast antenna, 21: satellite broadcast tuner, 22: demodulation circuit, 23: control control circuit, 24: remote controller, 25: menu key, 26: direction key, 27: determination Key.

Claims (11)

Channel selection means for selecting a predetermined digital broadcast channel;
Demodulation means for performing demodulation processing on a signal output from the channel selection means;
Tuning information extracting means for extracting specific tuning information from a signal demodulated by the demodulating means;
A temporary determining means for temporarily determining whether or not digital broadcasting is present in a channel selected by the channel selecting means, depending on whether or not first information is obtained in a state where the demodulation processing by the demodulating means has reached a first stage; ,
In a state in which the existence state of the digital broadcast is provisionally determined by the provisional determination means, a state in which the tuning information extraction processing by the tuning information extracting means has reached a second stage after the first stage. A broadcast receiving apparatus comprising: a determination unit configured to determine the presence or absence of a digital broadcast on a channel selected by the channel selection unit based on whether second information is obtained. Channel selection means for selecting a predetermined digital broadcast channel;
Demodulation means for performing demodulation processing on a signal output from the channel selection means;
Tuning information extracting means for extracting specific tuning information from a signal demodulated by the demodulating means;
A tentative determination means for tentatively determining the presence or absence of a digital broadcast on a channel selected by the tuning means depending on whether or not a TMCC signal is obtained by the demodulation means;
In a state where the existence state of the digital broadcast is provisionally determined by the provisional determination means, the presence or absence of digital broadcast on the channel selected by the selection means depends on whether section information is obtained by the selection information extraction means. A broadcast receiving apparatus comprising: a determination unit that determines Channel selection means for selecting a predetermined digital broadcast channel;
Demodulation means for performing demodulation processing on a signal output from the channel selection means;
Tuning information extracting means for extracting specific tuning information from a signal demodulated by the demodulating means;
Provisional determination means for temporarily determining the presence or absence of digital broadcasting on the channel selected by the channel selection means, depending on whether an OFDM frame synchronization signal is obtained by the demodulation means;
In a state where the existence state of the digital broadcast is provisionally determined by the provisional determination means, the presence or absence of digital broadcast on the channel selected by the selection means depends on whether section information is obtained by the selection information extraction means. A broadcast receiving apparatus comprising: a determination unit that determines In the state where the non-state of the digital broadcast is provisionally determined by the provisional determination unit, or in the state where the presence or absence of the digital broadcast is determined by the determination unit, the channel selected by the channel selection unit is automatically updated. 4. The broadcast receiving apparatus according to claim 1, further comprising an updating unit that performs the updating. 5. The broadcast according to claim 4, wherein the updating unit automatically updates a channel selected by the channel selecting unit within a range of all physical channels set in advance for channel scanning. Receiver. The broadcast receiving apparatus according to claim 2, wherein the section information is NIT. The broadcast receiving apparatus according to claim 1, wherein the digital broadcast is at least one of a terrestrial digital broadcast and a satellite digital broadcast. Selecting a predetermined digital broadcast channel;
Performing a demodulation process on the signal obtained by tuning,
A step of performing channel selection information extraction processing for extracting specific channel selection information from a signal obtained by demodulation,
A step of tentatively determining the presence or absence of a digital broadcast on the selected channel based on whether or not the first information has been obtained in a state where the demodulation processing has reached the first stage;
Whether or not the second information has been obtained in a state where the channel selection information extraction / demodulation processing has reached a second stage after the first stage in a state where the existence state of the digital broadcast is provisionally determined. Determining whether or not there is a digital broadcast on the selected channel. Selecting a predetermined digital broadcast channel;
Performing a demodulation process on the signal obtained by tuning,
A step of performing channel selection information extraction processing for extracting specific channel selection information from a signal obtained by demodulation,
A step of tentatively determining the presence or absence of a digital broadcast on the selected channel depending on whether or not a TMCC signal is obtained by the demodulation processing;
A step of determining whether or not digital broadcasting is present in the selected channel by determining whether section information is obtained by the channel selection information extraction process in a state where the existence state of the digital broadcast is provisionally determined. A broadcast receiving method characterized by the above-mentioned. Selecting a predetermined digital broadcast channel;
Performing a demodulation process on the signal obtained by tuning,
A step of performing channel selection information extraction processing for extracting specific channel selection information from a signal obtained by demodulation,
A step of tentatively determining the presence or absence of a digital broadcast on the selected channel depending on whether an OFDM frame synchronization signal is obtained by the demodulation processing;
A step of determining whether or not digital broadcasting is present in the selected channel by determining whether section information is obtained by the channel selection information extraction process in a state where the existence state of the digital broadcast is provisionally determined. A broadcast receiving method characterized by the above-mentioned. 9. The method according to claim 8, further comprising a step of automatically updating the channel to be selected in a state in which the absence of the digital broadcast is provisionally determined, or in a state in which the presence or absence of the digital broadcast is determined. 11. The broadcast receiving method according to any one of claims 10 to 10.

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