JP2007259053A - Terrestrial digital broadcast receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a terrestrial digital broadcast receiver used for a mobile object capable of easily selecting other transmission station of the same broadcast station and continuously receiving the same program even when the mobile object is deviated from a present reception area. <P>SOLUTION: The terrestrial digital broadcast receiver 10 used by the mobile object includes: a frequency selection section 27 for selecting a broadcast radio wave to be received; and a frequency information detection section 26 that detects and stores transmission station frequency information of all transmission stations recorded in a data signal in the broadcast radio wave received from the transmission station, and when a reception level of the broadcast radio wave during the reception reaches a prescribed reception level or below, the frequency selection section 27 scans receptible broadcast radio waves on the basis of the transmission frequency information detected by the frequency information detection section 26 and selects a broadcast radio wave whose reception level is a prescribed reception level or over. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a terrestrial digital broadcast receiver for receiving terrestrial digital television broadcasts, and in particular, in a mobile body such as an automobile, the reception state of the broadcast radio wave being received as the receiver moves is poor. In this case, by scanning only the transmitting station frequency of the same broadcasting station based on the transmitting station frequency information, broadcast radio waves are received from other transmitting stations, and the same program is continued without taking time for channel scanning. The present invention relates to a terrestrial digital broadcast receiver that can be viewed.

  In recent years, electronic devices have been reduced in size and price, and various electronic devices have been installed in automobiles. For example, various devices such as broadcast receivers such as car radios and car televisions, audio / video devices such as MD / DVD players, and car navigation devices are installed and used in many automobiles.

  Recently, commercial broadcasting of terrestrial digital broadcasting has started and is gradually spreading. However, in terrestrial digital broadcasting, a ghost-resistant transmission method called OFDM is adopted, and even in mobiles such as automobiles. Terrestrial digital broadcast receivers are about to be used.

  However, in these in-vehicle broadcast receiving apparatuses, a phenomenon occurs in which the mobile body is destined to move away from the reception area of the channel currently being received as it moves and cannot be received.

  In general, a broadcasting station places transmitting stations at a plurality of locations in a broadcasting area, and transmits radio waves from these transmitting stations to expand the receivable area of the broadcasting station. If these transmitting stations are transmitting radio waves at the same frequency (SFN: Single Frequency Network), even if they are out of the receiving area of the transmitting station they were receiving, they can watch it if they are within the receiving area of another transmitting station. You can continue. However, there are cases where the transmitting station is transmitting at different frequencies (MFN: Multiple Frequency Network). In this case, if the channel scan is performed again and the frequency from the receivable transmitting station is not received, it is received. I can't continue watching TV programs.

  This channel scan generally takes several minutes, and if this movement between broadcast areas occurs when receiving services such as TV broadcasts, the failure such as the video freezes for several minutes. Will occur. Furthermore, in order to continue receiving the program of the broadcasting station that has been received up to now in the moved area, there is a disadvantage that the channel must be selected again after the channel scan.

  In order to solve such a problem, for example, the following Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-320406) discloses that the terrestrial digital broadcasting is continuously tuned even when moving across broadcasting areas. An in-vehicle broadcast receiving apparatus having a digital automatic channel selection method is disclosed.

  The in-vehicle broadcast receiving apparatus disclosed in Patent Document 1 includes a diversity antenna receiver equipped with a double tuner, and performs reception using signals having better condition with two tuners. When the radio wave is stable, channel search is performed using one tuner, and all channel information in the reception area is stored in the receiver. Also, by broadcasting the channel information of the adjacent area by broadcasting, receiving it with one tuner and storing the channel information of the adjacent area, searching for the broadcast channel of that area when moving to the adjacent area And seamless broadcast reception.

  Patent Document 2 (Japanese Patent Laid-Open No. 2001-285101) below discloses an in-vehicle broadcast receiving apparatus that can easily receive the same program even if it is out of the current receiving area.

When the in-vehicle broadcast receiving apparatus disclosed in Patent Document 2 receives current position information and the like from the car navigation system, the digital broadcast receiver on the mobile body receives the reception range information stored in the memory in advance and the current position information. The position information is compared, the broadcasting station within the receivable range is searched in the memory, and the operation of searching for the program that has been received immediately before is performed.
JP 2004-320406 A JP 2001-285101 A

  However, the technique disclosed in Patent Document 1 has a problem that it is necessary to provide a diversity antenna receiver equipped with a double tuner. The two tuners use the signal with the better condition, and when the radio wave is stable, perform channel search using one tuner and store all channel information in the reception area in the receiver. Let In addition, there is a problem that it is necessary to perform complicated processing for broadcasting the channel information of the adjacent area by broadcasting, receiving it by one tuner, and storing the channel information of the adjacent area.

  Further, in the in-vehicle broadcast receiving apparatus disclosed in Patent Document 2, it is necessary to store information on the receivable area of each broadcasting station together with the map information in the receiver, which increases the data amount of the map information. There was a problem of doing.

  The inventors of the present application have conducted various studies to solve the above-described problems. As a result, in terrestrial digital broadcasting, data signals included in transmission signals (broadcast radio waves) transmitted from each transmission station of a broadcast station are included. Pay attention to the fact that frequency information of all transmitting stations such as the master station / relay station (hereinafter referred to as transmitting station frequency information) is recorded. When the state deteriorates, the present invention has been completed by conceiving that the above problem can be solved by scanning only the frequency of the transmitting station based on the transmitting station frequency information. .

  That is, the present invention has an object to solve the above-mentioned problems, and it does not require a tuning time by a simple configuration and control, and it is easy to change another broadcasting station of the same broadcasting station even if it is out of the receiving area of the current transmitting station. It is an object of the present invention to provide a terrestrial digital broadcast receiver capable of selecting a transmitting station and continuously receiving the same program.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present application is
In a terrestrial digital broadcasting receiver that receives terrestrial digital broadcasting in a mobile object,
The terrestrial digital broadcast receiver includes a frequency selection unit that selects a broadcast radio wave to be received, and a broadcast that is used in all transmission stations of the broadcast station that are recorded in a data signal in the broadcast radio wave received from the broadcast station. A frequency information detection unit that detects and stores frequency information of the transmitting station of the radio wave, and
When the reception level of the broadcast radio wave being received is equal to or lower than the predetermined reception level, the frequency selection unit scans the receivable broadcast radio wave based on the transmission station frequency information detected by the frequency information detection unit, It is characterized in that a broadcast radio wave having a reception level equal to or higher than is selected.

  The invention according to claim 2 of the present application is the terrestrial digital broadcast receiver according to claim 1, wherein the frequency selection unit is based on the storage order of the transmission station frequency information detected and stored by the frequency information detection unit. Receivable broadcast radio waves are scanned, and broadcast radio waves having a predetermined reception level or higher are selected.

  According to a third aspect of the present invention, in the terrestrial digital broadcast receiver according to the first aspect, the frequency selection unit is a broadcast radio wave that can be received based on the transmission station frequency information detected by the frequency information detection unit. When scanning, the frequency received at the time of initial scanning is preferentially scanned, and broadcast radio waves having a predetermined reception level or higher are selected.

  In the invention according to claim 1, the terrestrial digital broadcast receiver includes a frequency selection unit that selects a broadcast radio wave to be received, and the broadcast station data recorded in the data signal in the broadcast radio wave received from the broadcast station. A frequency information detection unit that detects and stores transmission station frequency information of broadcast radio waves used in all transmission stations, and when the reception level of the broadcast radio wave being received is equal to or lower than a predetermined reception level, the frequency The selection unit scans a receivable broadcast wave based on the transmission station frequency information detected by the frequency information detection unit, and selects a broadcast wave having a predetermined reception level or higher.

  With this configuration, the terrestrial digital broadcast receiver selects the broadcast from another transmitting station without any operation when the reception state of the broadcast radio wave being received is deteriorated due to movement or the like, so the same program is selected. Can be received continuously.

  According to a second aspect of the present invention, in the terrestrial digital broadcast receiver according to the first aspect, the frequency selection unit can receive based on the transmission station frequency information storage order detected and stored by the frequency information detection unit. Scanning radio waves are scanned and broadcast radio waves with a predetermined reception level or higher are selected.

  With such a configuration, the terrestrial digital broadcast receiver scans the broadcast radio waves of all transmitting stations in sequence when the reception status of the broadcast radio waves being received has deteriorated due to movement, etc. Since it is received, the same program can be continuously received by selecting a broadcast from another transmitting station without any operation.

  According to a third aspect of the present invention, in the terrestrial digital broadcast receiver according to the first aspect, the frequency selection unit generates a receivable broadcast radio wave based on the transmission station frequency information detected by the frequency information detection unit. When scanning, priority is given to the frequency received at the time of initial scanning, and broadcast waves having a predetermined reception level or higher are selected.

  With this configuration, the terrestrial digital broadcast receiver scans with priority on the frequency received at the initial scan when the reception condition of the broadcast radio wave being received has deteriorated due to movement, etc. It is possible to continuously receive the same program by selecting the broadcast of the broadcasting station that has been received.

  In addition, when a transmission station is newly installed or the frequency used by the transmission station is changed (frequency repacking), the transmission station frequency information of all the transmission stations of the broadcast station described in the NIT, and the actual Even if there is a period when the frequency used by the transmitting station is different, even if the frequency that can be received by the initial scan is not described in the frequency information in the NIT, the broadcast wave of the transmitting station of the new or changed frequency is received. Will be able to.

  Hereinafter, specific examples of the present invention will be described in detail with reference to examples and drawings. However, the embodiment shown below exemplifies the form of an example for embodying the technical idea of the present invention, and is not intended to specify the present invention in the form of this example. However, the present invention is equally applicable to terrestrial digital broadcast receivers of other embodiments included in the scope of claims.

  As shown in FIG. 1, a terrestrial digital broadcast receiver 10 according to an embodiment of the present invention includes an antenna 12, a front end unit 13, a demultiplexer 14, an MPEG decoder 15, an audio signal processing unit 16, a speaker 17, and a video signal. A processing unit 18, a display unit 19, a control unit 22, a ROM 23, a RAM 24, an operation unit 25, a frequency information detection unit 26, a frequency selection unit 27, and the like are provided.

  A transmission signal (broadcast radio wave: hereinafter simply referred to as a transmission signal) transmitted from a broadcasting station is received by the antenna 12, processed by the front end processing unit 14, and then demultiplexed by the data signal (NIT), audio signal, Video signal separation is performed. The video signal is decoded by the MPEG decoder 15, converted into an image signal by the video signal processing unit 18, and the video is displayed on the display unit 19. On the other hand, the audio signal is processed by the audio signal processing unit 16 and output from the speaker 17.

  The control unit 22 includes a microprocessor including a ROM 23 and a RAM 24, and controls each unit of the terrestrial digital broadcast receiver 10. The operation unit 25 is for operating the terrestrial digital broadcast receiver 10 and includes a touch panel, keys, switches, dials, and the like. The frequency information detection unit 26 detects transmission station frequency information recorded in a data signal included in a transmission signal (broadcast radio wave) received from a broadcast station, and the frequency selection unit 27 broadcasts a desired broadcast station. A frequency for receiving radio waves is selected.

  When the user receives a desired broadcast, the operation unit 25 is usually operated to select the transmission station frequency of the broadcast station transmitted from any of the transmission stations. Here, when the terrestrial digital broadcast receiver 10 is used in a mobile body such as an automobile, the broadcast radio wave from the transmitting station that is receiving may not be received as the mobile body moves. For this reason, in general broadcast receivers for mobile objects, area information that is the receivable range of the transmitting station and its broadcast radio waves is stored, and when the mobile object moves to the area of another transmitting station, the area concerned The broadcast stations that can be received are displayed, and a desired broadcast station is selected from the broadcast stations (the frequency of the broadcast wave of the transmitting station is selected).

  In general, if the mobile station moves out of the area of the broadcast station that was being received and cannot receive the broadcast radio waves from that broadcast station, the user wants to continue receiving the same broadcast program even in the moved area. There are many cases. For this reason, a technique such as that stored in Patent Document 2 is used.

  By the way, in terrestrial digital broadcasting, frequency information (hereinafter referred to as a transmitting station) of all transmitting stations such as a master station and a relay station in a data signal included in a transmission signal (broadcast radio wave) transmitted from each transmitting station of a broadcasting station. Frequency information) is recorded. This transmitting station frequency information is described in NIT (Network Information Table). FIG. 2 is a diagram showing transmission station frequency information stored (recorded) in a data signal (NIT) of a transmission signal in terrestrial digital broadcasting. As shown in this figure, the NIT includes an area identification code indicating an area where a broadcasting station provides a broadcasting service, a unique broadcasting station ID identifying a broadcasting station (TS), a broadcasting station name (TS name), The physical frequency of the broadcast radio wave transmitted by the transmitting station such as the master station or relay station of the broadcasting station is stored (recorded).

  In FIG. 2, for example, the broadcast area of the area identification code O1 includes broadcast stations AAA to CCCC..., And the broadcast radio wave data signal (NIT) transmitted from the broadcast station AAA with the broadcast station ID A In addition to the area identification code (O1), broadcast station ID (A), and broadcast station name (AAA), the physical frequency of the broadcast radio waves of all transmitting stations such as the master station and relay station is recorded as UHF13ch, UHF20ch, UHF46ch. Has been. Actually, each physical frequency described above is described in the NIT with a center frequency of 1/7 Mhz.

  Similarly, in the NIT of the broadcast radio wave transmitted from the broadcast station BBB with the broadcast station ID B, in addition to the area identification code (O1), the broadcast station ID (B), and the broadcast station name (BBB), the master station and the relay station The physical frequencies of broadcast radio waves of all transmitting stations such as stations are recorded as UHF14ch, UHF19ch, UHF36ch. In addition, in addition to the area identification code (O1), the broadcast station ID (C), and the broadcast station name (CCC), the NIT of the broadcast radio wave transmitted from the broadcast station CCC with the broadcast station ID C is the master station or relay station. The physical frequency of the broadcast radio waves of the transmitting station such as UHF13ch and UHF20ch is recorded.

  The present invention focuses on the fact that information on the physical frequencies of all transmitting stations to which broadcasts of the broadcasting station such as a master station and a relay station are transmitted is recorded in the NIT. That is, when the reception state of the broadcast radio wave being received is deteriorated due to the movement of the terrestrial digital broadcast receiver (movement of a moving body such as an automobile), the same broadcast station based on the frequency information recorded in the NIT Only the frequencies of other transmitting stations (parent station and relay station) are scanned. For example, when the transmission frequencies of all transmission stations among 13 to 62 ch are recorded in the NIT as transmission station frequency information such as 20 ch, 24 ch, and 36 ch, only the 3 ch frequencies are scanned and the reception state is the best. If a broadcast radio wave or a broadcast radio wave having a predetermined reception level or higher is selected, the broadcast from the broadcast station can be easily continuously received.

  FIG. 3 is a schematic diagram showing the relationship between the transmitting station, the receiving area, and the physical frequency of the broadcasting station broadcast from the transmitting station. The transmitting station A has a receiving area A, and the broadcasting radio wave data signal transmitted by the transmitting station A includes the broadcasting radio wave physics of all transmitting stations (transmitting station a, transmitting station b) such as a master station and a relay station. The frequency (13ch, 14ch) is stored.

  Similarly, the transmitting station B has a receiving area B, and the broadcast radio wave data signal transmitted by the transmitting station B is broadcast by all transmitting stations (transmitting station a, transmitting station b) such as a master station and a relay station. The physical frequency (20ch, 19ch) of the radio wave is stored, the transmission station C has a reception area C, and the data signal of the broadcast radio wave transmitted by the transmission station C includes all transmission stations (such as a master station and a relay station). The physical frequency (20 ch, 19 ch) of the broadcast radio wave of the transmitting station a and the transmitting station b) is stored.

  When the terrestrial digital broadcast receiver 10 moves from the area C to the area B and the reception state of the broadcast wave from the broadcast station C deteriorates, the data signal is stored in the broadcast wave of the broadcast station B that has been received so far. If the physical radio waves 20ch and 19ch are scanned and the broadcast radio wave with the best reception state is selected and received, the program can be continuously received from other transmission stations of the same broadcast station.

  For this reason, the terrestrial digital broadcast receiver 10 shown in FIG. 1 includes a frequency information detection unit 26 and a frequency selection unit 27. The frequency information detector 26 detects the physical frequency of each transmitting station from the transmitting station frequency information recorded in the received broadcast radio wave data signal (NIT). The frequency selection unit 27 selects the frequency of the broadcast radio wave to be received. The frequency selection unit 27 selects the frequency designated by the operation unit 25 or scans and selects the transmission station frequency detected by the frequency information detection unit 26.

  FIG. 4 is a flowchart showing an operation procedure of the terrestrial digital broadcast receiver 10 described above. As shown in FIG. 4, the terrestrial digital broadcast receiver 10 first inputs an area number (area identification code) in the process of step S11, and in the process of step S12, the physical of a predetermined band corresponding to the area number. The frequency is scanned, and the receivable physical frequency is stored in the process of step S13.

  Next, in the process of step S14, the frequency information detecting means 26 receives the broadcast radio wave data signal (NIT) and detects and stores the transmitting station frequency information recorded therein. Then, in the process of step S15, the frequency selecting unit 27 identifies the broadcasting station (TS) corresponding to the channel selection, the receivable physical frequency in the process of step S16, and the transmission station frequency stored by the frequency information detecting unit 26. The information is compared and tuned (tuned) to a physical frequency that matches in the process of step S17.

  In step S18, it is determined whether the reception sensitivity is equal to or higher than a predetermined level (whether the sensitivity is good). If the reception sensitivity is OK (good), display (display of reception sensitivity status etc.) is performed in the process of step S19, and the process returns to the determination process of step S18.

  In the reception sensitivity determination process in step S18, if the reception sensitivity is not higher than a predetermined level (reception sensitivity is poor), the process proceeds to step S21, and the frequency selection means 27 receives and stores the NIT in the frequency information detection means 26. A physical frequency that matches the physical frequency of the other transmitting station is selected. Then, the reception sensitivity is determined in the process of step S22. If the reception sensitivity is good, the reception sensitivity is displayed in the process of step S19, and the process returns to step S18.

  Step S22 In the reception sensitivity determination process, if the reception sensitivity is not equal to or higher than the predetermined level (reception sensitivity is poor), the process proceeds to step S23, and TSI (physical frequency corresponding to the broadcast station ID) is scanned (initial scan). The reception frequency is determined in the process of step S24, and if the reception sensitivity is good, the reception sensitivity is displayed in the process of step S19, and the process of step S18 is performed. Return to.

  Step S24: In the reception sensitivity determination process, if the reception sensitivity is not equal to or higher than a predetermined level (reception sensitivity is poor), the process proceeds to step S25, and the remaining physical frequencies stored by receiving the NIT by the frequency information detecting means 26 Select (tune). Then, the reception sensitivity is determined in the process of step S26. If the reception sensitivity is good, the reception sensitivity is displayed in the process of step S19, and the process returns to step S18. If the reception sensitivity is not equal to or higher than the predetermined level in the determination process of step S26 (reception sensitivity is poor), the process proceeds to step S23, an error is displayed, and the process ends.

  That is, in the processing from step S21 to step S25, the frequency selection unit 27 can scan the physical frequency of the transmitting station such as the master station or relay station that the frequency information detection unit 26 receives and stores the NIT, and can receive it satisfactorily. The physical frequency is selected. As a result, the terrestrial digital broadcast receiver 10 selects the broadcast from another transmission station of the same broadcast station without any operation when the reception state deteriorates due to movement or the like, so the same program is continued. Can be received.

  In addition, when a new transmission station is installed or the frequency used by the transmission station is changed (frequency repacking), the transmission station frequency information of all transmission stations in the broadcast station described in the NIT and the actual Even if there is a period when the frequency used by the transmitting station is different, if the transmitting station frequency received at the initial scan is stored and scanning is performed preferentially, the frequency received at the initial scan is within the NIT. Even when it is not described in the frequency information, it is possible to receive the broadcast wave of the transmitting station having a new or changed frequency.

It is a block diagram which shows the structure of the terrestrial digital broadcast receiver 10 concerning the Example of this invention. It is a figure which shows the frequency information described (recorded) in the data signal (NIT) of the transmission signal in terrestrial digital broadcasting. It is a figure which shows typically the frequency information recorded on the reception area, the broadcasting station, and the data signal of the broadcast radio wave transmitted by the broadcasting station. It is a flowchart which shows the operation | movement procedure of said terrestrial digital broadcast receiver.

Explanation of symbols

10 .. Terrestrial digital broadcast receiver 12 .... Antenna 13 .... Front end unit 14 .... Demultiplexer 15 ... MPEG decoder 16 ... Audio signal processing unit 17 ... ... Speaker 18 ... Video signal processing unit 19 ... Display unit 22 ... Control unit 23 ... ROM
24 ... RAM
25... Operation unit 26... Frequency information detection unit 27.

Claims (3)

In a terrestrial digital broadcasting receiver that receives terrestrial digital broadcasting in a mobile object,
The terrestrial digital broadcast receiver includes a frequency selection unit that selects a broadcast radio wave to be received, and a broadcast that is used in all transmission stations of the broadcast station that are recorded in a data signal in the broadcast radio wave received from the broadcast station. A frequency information detection unit that detects and stores frequency information of the transmitting station of the radio wave, and
When the reception level of the broadcast radio wave being received is equal to or lower than the predetermined reception level, the frequency selection unit scans the receivable broadcast radio wave based on the transmission station frequency information detected by the frequency information detection unit, A terrestrial digital broadcast receiver characterized in that it selects a broadcast radio wave having a reception level equal to or higher than the reception level.   The frequency selection unit scans broadcast radio waves that can be received based on the storage order of the transmission station frequency information detected and stored by the frequency information detection unit, and selects broadcast radio waves that are equal to or higher than a predetermined reception level. The terrestrial digital broadcast receiver according to claim 1. When the frequency selection unit scans a receivable broadcast radio wave based on the transmission station frequency information detected by the frequency information detection unit, the frequency selection unit preferentially scans the frequency received at the initial scan, and exceeds a predetermined reception level. The terrestrial digital broadcast receiver according to claim 1, wherein the broadcast radio wave is selected.

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