JP2011244037A - Digital broadcast receiver and digital broadcast reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide detailed operation of a transmitter and a receiver capable of reproducing with minimum delay an emergency earthquake report transmitted by digital broadcast.SOLUTION: This digital broadcast receiver comprises: a broadcast reception unit which receives a transmitted signal transmitted by broadcasting, the signal including a digital broadcast signal and emergency earthquake information; and an emergency earthquake information reception unit which detects the emergency earthquake information from the transmitted signal received by the broadcast reception unit and outputs the same.

Description

  The present invention relates to a technique for transmitting and receiving emergency information transmitted by digital broadcasting.

  Conventionally, the emergency warning broadcast activation flag included in the digital broadcast transmission signal is monitored, and if the emergency warning broadcast activation flag is “1”, forced service switching or normal energization from the standby state is performed. It is possible to provide emergency warning broadcasts to viewers quickly by shifting to. (See Patent Document 1)

JP 2005-333512 A

  The above-mentioned patent document 1 discloses a reduction in power consumption in a so-called standby state in which emergency alert broadcasting is monitored.

  However, the emergency alert broadcast activated by the emergency alert broadcast activation flag has the emergency alert broadcast signal compressed and encoded on the transmission side, and it has been necessary to perform decompression decoding processing on the receiver side for reproduction. . For this reason, a delay time for compression / decompression has occurred before the emergency warning broadcast is reproduced.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide detailed operations of a transmission device and a reception device capable of reproducing emergency earthquake warnings transmitted by digital broadcasting without delay as much as possible. There is.

  In order to achieve the above object, for example, the configuration described in the claims is adopted.

  According to the present invention, when it is necessary to issue an earthquake early warning, a transmission method and a reception device having a transmission method and a reception method capable of reproducing the emergency earthquake early warning on the receiver side without delay as much as possible. Can be provided.

It is a block diagram which shows the structure of the digital broadcast receiver which can receive the earthquake early warning based on the 1st Embodiment of this invention. It is a block diagram which shows one Example of the digital broadcast transmitter which transmits the digital broadcast which the digital broadcast receiver of this invention receives. It is explanatory drawing which shows the structure of the emergency earthquake information received with the emergency earthquake information receiving part 120 which is a main block of this invention. It is explanatory drawing which shows the structure of the emergency earthquake information received with the emergency earthquake information receiving part 120 which is a main block of this invention. It is explanatory drawing which shows the structure of the emergency earthquake information received with the emergency earthquake information receiving part 120 which is a main block of this invention. It is explanatory drawing which shows the structure of the emergency earthquake information received with the emergency earthquake information receiving part 120 which is a main block of this invention. It is explanatory drawing which shows the structure of the emergency earthquake information received with the emergency earthquake information receiving part 120 which is a main block of this invention. It is explanatory drawing which shows the structure of the emergency earthquake information received with the emergency earthquake information receiving part 120 which is a main block of this invention. It is explanatory drawing which shows the structure of the emergency earthquake information received with the emergency earthquake information receiving part 120 which is a main block of this invention. It is a flowchart of a process when the digital broadcast receiver which concerns on the 1st Embodiment of this invention starts digital broadcast reception by the telephone call start. 4 is a flowchart of processing during a call by the digital broadcast receiving apparatus according to the first embodiment of the present invention. It is a flowchart of a process when the digital broadcast receiver which concerns on the 2nd Embodiment of this invention starts digital broadcast reception by an incoming call. It is a flowchart of the process at the time of the digital broadcast receiver which concerns on the 3rd Embodiment of this invention starting digital broadcast reception, when an electromagnetic wave intensity is below a threshold value. 1 is a configuration diagram of a digital broadcast transmission / reception system including a digital broadcast receiver according to the present invention. It is explanatory drawing which shows the structure of the emergency earthquake information received with the emergency earthquake information receiving part 120 which is a main block of this invention. It is explanatory drawing which shows the structure of the emergency earthquake information received with the emergency earthquake information receiving part 120 which is a main block of this invention. It is explanatory drawing which shows the structure of the emergency earthquake information received with the emergency earthquake information receiving part 120 which is a main block of this invention. It is explanatory drawing of the digital broadcast transmitted with the digital broadcast transmission apparatus of this invention. It is explanatory drawing of the digital broadcast transmitted with the digital broadcast transmission apparatus of this invention. It is a flowchart of a process when the digital broadcast receiver which concerns on the 4th Embodiment of this invention starts digital broadcast reception. It is a flowchart of the process which receives earthquake motion warning information from the digital broadcast which concerns on the 4th Embodiment of this invention. It is a flowchart of the process which notifies the earthquake motion warning information which concerns on the 4th Embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. Further, the present invention is not limited to the illustrated example.

  FIG. 14 shows a digital broadcast transmission / reception system including the digital broadcast receiver 121, the earthquake bulletin center 300, the broadcast provider 400, the broadcast facility 500, the portable wireless communication provider 600, the base station 700, and the like according to the present invention. . Note that there may be a plurality of these digital broadcast receivers 121, base stations 700, and broadcast facilities 500.

  The digital broadcast receiving apparatus 121 includes means for receiving a digital broadcast and means for communicating with the base station 700. In addition, the broadcaster 400 and the portable radio carrier 600 can receive the emergency earthquake bulletin transmitted from the earthquake bulletin center 300 and transmit the emergency earthquake bulletin to the digital broadcast receiver 121 via the broadcast facility 500 and the base station 700. it can.

  In this way, the digital broadcast receiving apparatus 121 can receive the earthquake early warning from both the broadcast facility 500 and the base station 700.

  FIG. 1 is a block diagram showing a configuration of a digital broadcast receiving apparatus that receives emergency earthquake information transmitted using an AC signal included in segment number # 0 in the digital broadcast system according to the first embodiment of the present invention.

  FIG. 2 is a block diagram showing an embodiment of a digital broadcast transmitting apparatus for transmitting a digital broadcast received by the digital broadcast receiving apparatus of the present invention.

  In this digital broadcasting system, a plurality of MPEG-2 transport streams (hereinafter referred to as TS) are re-multiplexed into one TS, subjected to transmission path encoding processing, and then subjected to IFFT (Inverse Fast The signals are collectively converted into an OFDM (Orthogonal Frequency Division Multiplexing) transmission signal composed of a plurality of subcarriers by Fourier Transform and transmitted as a broadcast wave.

  Here, the OFDM transmission signal in this digital broadcasting system has a configuration in which 13 OFDM segments obtained by dividing a transmission bandwidth of 6 MHz into 14 parts are connected, and hierarchical transmission of up to three layers is possible in units of OFDM segments. It has become. In addition, among the 13 segments of the OFDM transmission signal, the central segment (segment number # 0) can be set as a partial reception layer assuming reception by a mobile receiver such as a mobile phone. FIG. 18 shows the segment structure. A receiver that can receive all 13 segments of the OFDM transmission signal is called a 13-segment receiver, and a receiver that can receive one central segment of the OFDM transmission signal is called a one-segment receiver.

  In this digital broadcasting system, TMCC (Transmission and Multiplexing Configuration) that transmits control information for smooth demodulation of the receiver, such as system identification, transmission parameter switching index, emergency warning broadcast activation flag, transmission parameters of each layer, etc. Control) signal and an AC (Auxiliary Channel) signal that is an extension signal for transmitting additional information related to transmission control of the modulated wave. This frame configuration is shown in FIG. In FIG. 19, the carrier positions and the number of carriers of TMCC signals and AC signals added as OFDM subcarriers differ depending on transmission parameters. Details will be described later.

  Here, an emergency warning system (EWS: Emergency Warning System) activated by an emergency warning broadcast activation flag transmitted by TMCC refers to emergency information to viewers when a tsunami warning due to the occurrence of an earthquake is issued. It is used to inform more quickly. When operating the emergency alert broadcast, the broadcast station sets the emergency alert broadcast activation flag included in the TMCC signal to “ON” and broadcasts the content with the content that can be recognized as the emergency alert broadcast.

  Further, as a system for transmitting more advanced emergency information, there is an earthquake early warning (EEW) announced by the Japan Meteorological Agency. The Earthquake Early Warning is a method for immediately estimating the magnitude of an epicenter or earthquake by analyzing initial microtremors (so-called P waves) and main motions (so-called S waves) captured by a seismometer near the epicenter immediately after the occurrence of the earthquake. This is information that estimates the seismic intensity of major motions in each location based on the information and informs it as quickly as possible. In addition, the Earthquake Early Warning is intended to ensure the safety of the viewer without panicking according to the surrounding situation by notifying the viewer before a strong shake arrives. This earthquake early warning is transmitted using an AC signal included in segment number # 0.

  In general, the name “Earthquake Early Warning” is used, but in the ministerial ordinance notification, the name “earthquake motion warning information” is used, and “earthquake motion warning information” will be used in the future.

  The seismic motion warning information is information related to seismic motion warning performed in accordance with the provisions of Article 13, Paragraph 1 of the Meteorological Business Law (Act No. 165 of 1974).

  The operation of the digital transmission / transmission apparatus that realizes the present digital broadcasting system will be described with reference to FIG.

  201 is an information source encoding unit, 202 is an MPEG2 multiplexing unit, 203 is a TS remultiplexing unit, 204 is an RS (Reed-Solomon) encoding unit, and 205 is a layer division unit. Reference numeral 206 denotes a parallel processing unit, which includes three systems a, b, and c. 207 is a hierarchical synthesis unit, 208 is a time interleaving unit, 209 is a frequency interleaving unit, 210 is an OFDM frame configuration unit, 211 is an inverse fast Fourier transform (hereinafter IFFT) unit, 212 is a guard interval addition unit, 213 is a transmission unit, 214 is a pilot signal component, 215 is a TMCC signal component, and 216 is an AC signal component.

  In this digital broadcasting system, a transport stream (TS) defined by MPEG2 Systems is converted into one TS by re-multiplexing one or a plurality of inputs, and after a plurality of transmission path encodings are performed according to the service intention, Finally, it is transmitted as one OFDM signal. The transmission spectrum of television broadcasting is formed by connecting 13 OFDM blocks (hereinafter referred to as OFDM segments) obtained by dividing the channel bandwidth of television broadcasting into 14 equal parts. By structuring the carrier configuration of the OFDM segment so that a plurality of segments can be connected, a transmission bandwidth suitable for media can be realized in segment width units. Since channel coding is performed in units of OFDM segments, a part of one television channel can be a fixed reception service and the rest can be a mobile reception service. Such transmission is defined as hierarchical transmission. Each layer is configured by one or a plurality of OFDM segments, and parameters such as a carrier modulation scheme, an inner code coding rate, and a time interleave length can be set for each layer. The number of possible layers is up to 3 levels, and partial reception is also counted as one layer. The number of segments and transmission path coding parameters in each layer are determined according to the organization information, and are transmitted by the TMCC signal as control information for assisting the operation of the receiver. For the OFDM segment at the center of a television broadcast signal composed of 13 segments, transmission path coding can be performed to perform frequency interleaving only within that segment. Thereby, a part of television service can be partially received.

  Considering the adaptability to the inter-station distance of SFN or the resistance to Doppler shift in mobile reception, this digital broadcasting system has three different OFDM carrier intervals. These are identified as system modes. The carrier interval is about 4 kHz in mode 1, about 2 kHz in mode 2, and about 1 kHz in mode 3. Although the number of carriers varies depending on the mode, the information bit rate that can be transmitted in any mode is the same.

  The information source encoding unit 201 encodes the video signal, the audio signal, and the data, respectively, and the MPEG2 multiplexing unit 202 generates one TS. The plurality of TSs output from the plurality of MPEG2 multiplexing units are input to the TS remultiplexing unit 203 so as to have an arrangement suitable for signal processing in units of data segments. In the TS re-multiplexing unit 203, it is converted into a burst signal format of 188 bytes by a clock four times the IFFT sample clock, and the Reed-Solomon outer code is added and converted into a single TS by the RS encoding unit 204. The After that, when performing hierarchical transmission, the hierarchical division unit 205 divides the hierarchy according to the designation of the hierarchical information, and inputs it to a maximum of three parallel processing units 206a, 206b, 206c. In the parallel processing units 206a, 206b, and 206c, digital data processing such as error correction coding and interleaving, and carrier modulation are mainly performed, respectively. In addition, a delay correction is performed in advance for a delay time difference between hierarchies caused by a time axis operation of byte interleaving and bit interleaving, thereby adjusting timing. Error correction, interleave length, and carrier modulation scheme are set independently in each layer. After parallel processing in the parallel processing units 206a, 206b, and 206c, the signal layered by the layer combining unit 207 effectively demonstrates error correction coding capability against electric field fluctuations and multipath interference in mobile reception. For this purpose, the data is input to the time interleaving unit 208 and the frequency interleaving unit 209. The time interleaving method is convolutional interleaving in order to shorten the combined delay time and suppress the memory capacity of the receiver. Further, the frequency interleave unit is configured by combining inter-segment and inter-segment interleaving so that a sufficient interleaving effect can be exhibited while ensuring a segment structure.

  A TMCC (Transmission and Multiplexing Configuration Control) signal is transmitted using a specific carrier as control information in order to assist demodulation and decoding of the receiver for hierarchical transmission in which a plurality of transmission parameters are mixed. Also, an AC (Auxiliary Channel) signal assigned to a specific carrier is used to transmit additional information related to broadcasting.

  In OFDM frame configuration section 210, information data from frequency interleaving section 209, pilot signal for synchronous reproduction from pilot signal configuration section 214, TMCC signal from TMCC configuration section 215, and AC signal from AC signal configuration section 216 are used. An OFDM frame is constructed. This frame configuration is shown in FIG. Si, j represents a carrier symbol in the data segment after interleaving. SP (Scattered Pilot) is a reference pilot symbol for the receiver to perform quasi-synchronous detection. As shown in FIG. 19, it is inserted once in 12 carriers in the carrier direction and once in 4 symbols in the symbol direction. If SP is interpolated in the symbol direction on the receiving side, SP of 3 (12/4) carrier interval can be obtained. Since the maximum value of the guard interval length is 1/4 of the effective symbol length, multipath up to the maximum delay time that does not cause intersymbol interference is achieved by interpolation processing (transmission path characteristics estimation) by SP of 3 carrier intervals. Is possible. When the guard interval ratio is 1/4, an SP of 4 carrier intervals may be used in principle, but it is inserted once in 4 symbols in the symbol direction in consideration of the characteristics of the interpolation filter.

  The example of FIG. 19 is mode 1, but the carrier numbers of mode 1 are 0 to 107, whereas in modes 2 and 3, they are 0 to 215 and 0 to 431, respectively.

  The AC signal is arranged as shown in FIG. 19 and has a data amount of 204 bits per carrier. In addition, two AC signals are arranged for each segment in mode 1, four in mode 2, and eight in mode 3.

  The TMCC signal is arranged as shown in FIG. 19 and has a data amount of 204 bits per carrier. Further, one TMCC signal is arranged for each segment in mode 1, two in mode 2, and four in mode 3.

  All signals after the frame configuration are converted into OFDM signals by IFFT operation of IFFT section 211, guard intervals are added by guard interval adding section 212 and converted to OFDM transmission signals, and digital broadcasting at a frequency determined by transmitting section 213 Converted to a signal.

  Next, the operation of the digital broadcast receiving apparatus that receives a transmission signal transmitted by the digital broadcast transmitting apparatus of FIG. 2 will be described with reference to FIG.

  101 is an antenna, 102 is a tuning unit, 103 is an orthogonal demodulation unit, 104 is a fast Fourier transform (hereinafter referred to as FFT) unit, 105 is a demodulation / decoding unit that performs digital demodulation and decoding operations from the FFT unit 104 to the TS output, 106 is a descrambling unit, 107 is a demux unit, 108 is a video signal / audio signal decoding unit, 109 is a video output unit that outputs a decoded video signal, and 110 is an audio output that outputs a decoded audio signal. These are mainstream blocks for reproducing video signals and audio signals. Reference numeral 111 denotes a synchronous reproduction unit, 112 denotes a frame extraction unit, and 113 denotes a TMCC decoding unit. The channel selection unit 102 to the TMCC decoding unit 113 constitute a broadcast reception unit 119.

  On the other hand, 114 is a flag detection unit, 115 is a data extraction unit, 116 is a discrimination unit, and 117 is an output unit for earthquake motion warning information.

  Reference numeral 118 denotes a control unit that performs operation control and power control of the broadcast reception unit 119, the earthquake motion warning information reception unit 120, and the communication unit 135.

  Also, 131 is a communication unit, 132 is a microphone, 133 is a speaker, and 134 is a storage unit.

  The communication unit 131 transmits / receives call voice, various data, and the like via the base station. In addition, various data and the like are transmitted / received to / from other devices such as a personal computer and a mobile phone via a wireless LAN (Local Area Network) or infrared communication. In addition, various types of data may be transmitted and received via a cable or the like using a method such as USB (Universal Serial Bus).

  The microphone 132 collects an audio signal and supplies it to the communication unit 131 during a call or the like.

  The speaker 133 includes a DAC (Digital Analog Converter) or the like, for example, performs DA conversion on the audio signal received by the communication unit, and outputs audio. Note that the speaker 133 may be the same as the audio output unit 110.

  The storage unit 134 is configured by an appropriate storage device such as a RAM or an auxiliary storage device, and stores various data and various programs. The storage unit 134 also has a work area for the control unit 118. The storage unit 134 may be configured by at least one of a memory built in the digital broadcast receiving apparatus or a removable external memory. Further, as long as the control unit 118 can access the storage unit 134, a part of the function may be provided outside the digital broadcast receiving apparatus.

  The control unit 118, the broadcast receiving unit 119, the earthquake motion warning information receiving unit 120, and the calling unit 135 constitute a digital broadcast receiving device 121.

Hereinafter, the operation will be described in detail. A channel frequency band to be received by the channel selection unit 102 is extracted from the digital broadcast received by the antenna 101, converted into a baseband signal by the orthogonal demodulation unit 103, and frequency axis processed by the FFT unit 104. In response, the demodulation / decoding unit 105 performs demodulation processing on each carrier on the frequency axis (for example, scattered pilots for QPSK, 16QAM, and 64QAM).
(SP: perform synchronous demodulation using SP) and detect amplitude and phase information), frequency axis and time axis deinterleaving, Viterbi decoding, RS (Reed-Solomon) decoding, and other error correction The digital signal is demodulated and, for example, a transport stream (hereinafter abbreviated as TS) signal defined by MPEG2 Systems is output to the descrambling unit 106. The descramble unit 106 scrambles the TS signal that has been scrambled for copyright protection, and outputs the descrambled signal to the demax unit 107. In the demux unit 107, a desired compressed broadcast video signal and a compressed digital signal of the broadcast audio signal are extracted and output to the decoding unit 108. The decoding unit 108 decodes the compressed broadcast video signal and the compressed broadcast audio signal, and outputs the decoded broadcast video signal to the video output unit 109 and the decoded broadcast audio signal to the audio output unit 110.

  On the other hand, synchronous reproduction section 111 receives a baseband signal from orthogonal demodulation section 103, reproduces a symbol synchronization signal, and detects the frequency position of the TMCC signal from the output signal of FFT section 104. The frame extraction unit 112 demodulates the TMCC signal at the detected frequency position and reproduces the frame synchronization signal. The frame synchronization signal is output to the synchronization reproduction unit 111, and phase adjustment with the symbol synchronization signal is performed. The TMCC decoding unit 113 performs error correction of the differential cyclic code on the demodulated TMCC signal to obtain TMCC information such as a hierarchical structure and transmission parameters. The TMCC information is output to the demodulation / decoding unit 105 and used as information for demodulation / decoding processing.

  The control unit 118 manages the operation states of the flag detection unit 114, the data extraction unit 115, the determination unit 116, and the output unit 117 using the control signals 122, 124, 125, and 126, respectively.

  Next, the configuration of the earthquake motion warning information that is configured by the AC signal configuration unit 216 and received by the earthquake motion warning information reception unit 120 will be described with reference to FIGS. 3 to 9 and FIGS. 15 to 17.

  The AC signal is an additional information signal related to broadcasting. Additional information related to broadcasting refers to additional information related to transmission control of modulated waves or earthquake motion warning information. Earthquake motion warning information is transmitted using the segment No. 0 AC carrier. The AC signal is arranged as shown in FIG. 19 and has a data amount of 204 bits per carrier.

  FIG. 3 shows the bit assignment of 204 bits B0 to B203 of the AC signal arranged in segment No.0.

  One bit of B0 is used as a reference for differential demodulation. The 3 bits from B1 to B3 are used as configuration identification to distinguish whether it is additional information or earthquake motion warning information. Additional information or earthquake motion warning information is sent out by 200 bits B4 to B203. When transmitting earthquake motion warning information, the same ground motion warning information is transmitted on all AC carriers in segment No. 0. By using the same seismic motion warning information for all AC carriers in segment No. 0, seismic motion warning information transmitted on different AC carriers can be analog-added on the receiver side, so that even smaller CN ratios can be received. .

  FIG. 4 shows a reference for differential demodulation of B0. The modulation method of the AC carrier is DBPSK, and the amplitude and phase reference for differential demodulation are given by Wi in FIG.

  FIG. 5 shows bit allocation when the seismic motion warning information is transmitted by the AC signal of segment No. 0.

  When the configuration identification is 000,010,011,100,101,111, the AC is used for broadcasters as usual, and transmits additional information related to transmission control of modulated waves.

  When the configuration identification is 001, 110, earthquake motion warning information is transmitted.

  ‘001’ and ‘110’ representing the transmission of the earthquake motion warning information have the same code as the first 3 bits (B1 to B3) of the TMCC synchronization signal, and are alternately transmitted for each frame at the same timing as the TMCC signal.

  The 13 bits of B4 to B16 are used as synchronization signals.

  In the case of the earthquake motion warning information, the code obtained by concatenating the configuration identification and the synchronization signal is the same code as the TMCC synchronization signal, and is composed of a 16-bit word. There are two kinds of synchronization signals: w0 = 0011010111101110 and w1 = 1100101000010001 obtained by bit-inverting it. The same bits as the TMCC synchronization signals (B1 to B16) are allocated, and w0 and w1 are alternately transmitted for each frame at the same timing to transmit the same code as TMCC. Since analog addition can be performed between the TMCC and the AC signal, the reception sensitivity of frame synchronization in the receiver can be improved.

  The two bits B17 to B18 are used as the start / end flag of the earthquake motion warning information.

  FIG. 6 shows the meaning of the start / end flag of the earthquake motion warning information.

  When the earthquake motion warning information is issued, 2 bits are assigned as a start / end flag of the earthquake motion warning information in order to indicate that the receiver is automatically activated and the earthquake motion warning information is transmitted by an AC signal.

  In the AC signal, when there is no information to be transmitted, all bits are modulated with ‘1’, so that the start / end flag when representing the seismic motion warning detailed information or its test signal is set to ‘00’. In addition, in order to improve the reliability of the start / end flag, 2 bits are used for the start / end flag, and the inverted signal has the maximum intersymbol distance. Also, “10” and “01” are not used in order to ensure the reliability of the start / end flag.

  When transmission of earthquake alarm information is started, the start / end flag is changed from '11' to '00'. When the transmission of the earthquake motion warning information is finished, the start / end flag is changed from “00” to “11”. The start / end flag can be used as an activation signal for the receiver.

  The two bits B19 to B20 are used as an update flag.

  FIG. 7 shows the meaning of the earthquake motion warning information update flag.

  The signal identification (B21 to B23) or the contents of the earthquake motion information (B56 to B111) shown in FIG. 15 (described later) is updated while the value of the start / end flag of the earthquake motion warning information is “00”. 7 increments the value of the update flag by 1 as shown in FIGS. 7 and 8, and notifies the receiver that the signal identification or the earthquake motion information has been updated.

  The update flag is incremented by 1 each time a change occurs in the details of the series of seismic motion warning details transmitted when the start / end flag is '00', '00' is the start value, and '11' Next to, it shall return to '00'. When the start / end flag is “11”, the update flag is set to “11”.

  An example of sending the update flag is shown in FIG. The first report, the second report,... Indicate the state in which the signal identification shown in FIG. 9 (described later) or the contents of the earthquake motion information shown in FIG. Even if the current time or page type shown in FIG. 15 (described later) changes, the value of the update flag does not change.

  The three bits B21 to B23 are used for signal identification.

  FIG. 9 shows the meaning of signal identification.

  The signal identification of earthquake motion warning information is a signal used to identify the type of earthquake motion warning detailed information. When the start / end flag is '00', signal identification '000' / '001' / '010' / '011' is transmitted, and when the start / end flag is '11', signal identification '111' Is sent out. Also, the seismic motion warning detailed test signal (with / without corresponding area) and the seismic motion warning detailed information (with / without corresponding area) are not sent simultaneously.

  The signal identifications '100' / '101' / '110' are for future expansion and are all set to '1'.

  As shown in FIG. 17 (described later), the total number of seismic motion information can be sent up to two, but the test signal and this signal are not sent simultaneously. In addition, when transmitting ground motion information with and without the signal identification at the same time, send the information as ground motion information with the corresponding region, so that at least one earthquake motion information is in the corresponding region. Can be promptly notified to the receiver.

  The 88 bits from B24 to B111 are detailed detailed information on earthquake motion warning.

  The details are shown in FIG. Bit allocation of detailed information on earthquake motion warning is specified for each signal identification.

  First, detailed information on earthquake motion warning when the signal identification is '000' / '001' / '010' / '011' is shown.

For the current time, the number of seconds that have elapsed since a reference year / month / day / hour / minute / second is specified in binary notation, and the lower 31 bits are assigned MSB first. When transmitting earthquake motion warning information, in a receiver that supports automatic startup with time adjustment by TOT (Time Offset Table) or communication line, etc., by collating the time of the receiver with the time information sent,
The reliability of the received earthquake motion warning information can be confirmed.

  In the seismic motion information, the allocation of information to be transmitted differs depending on the page type code. The receiver can know which information is transmitted by checking the page type. When the page type is “0”, as shown in FIG. 16 (described later), information indicating the target area of the earthquake motion warning is transmitted. When the page type is ‘1’, information on the earthquake motion alarm source is transmitted as shown in FIG. 17. However, the seismic motion information of both page types “0” and “1” is not necessarily transmitted.

  When earthquake motion information is not transmitted, the page type is set to “0”, and all the earthquake motion information is set to “1”.

  Next, detailed information on earthquake motion warning when the signal identification is “111” will be described.

  Broadcaster identification 11 bits are uniquely assigned to broadcasters nationwide. Broadcasters can be identified only by AC signals.

  When the start / end flag is “11”, the signal identification “111” is transmitted.

  FIG. 16 shows earthquake motion information when the page type is “0”. When the page type is “0”, the information indicates the target area of the earthquake motion warning, and FIG. 16 shows the bit allocation of the target area. The bit assigned to the area including the target area of the earthquake motion warning is “0”, and the bit allocated to the area not including the target area of the earthquake motion warning is “1”. If earthquake information is not sent, set all to '1'.

  When multiple earthquake motion warnings occur simultaneously (maximum total number 2), the earthquake motion information (regional information) of page type '0' may be sent as the first and second, respectively. The update flag is not updated when the transmission of alarm information (regional information) changes from the first to the second, or from the second to the first.

  FIG. 17 shows earthquake motion information when the page type is “1”.

  In the “earthquake motion warning identification”, 9 bits are assigned to identify earthquake motion warning information when a plurality of earthquake motion warnings are generated. If it is determined based on the time (in seconds) to distinguish multiple earthquake motion warning information, it is possible to identify the earthquake motion warning information for the past 8 minutes and 32 seconds with 9-bit earthquake motion warning identification. . By comparing the current time of B24 to B54 with the occurrence time of B101 to B110, the number of seconds that have elapsed since the occurrence of the earthquake motion can be known.

  The earthquake motion information identification of B57 is “0” when the transmitted ground motion information is the first information, and “1” when the second information is the second information.

  The occurrence time is based on the same reference year, month, day, hour, minute, and second as the current time indicated by B24 to B54, the elapsed seconds from the reference time are expressed in binary notation, and the lower 10 bits are assigned MSB first.

  The 10 bits of B112 to B121 are CRC-10.

  Since the information related to the detailed information on the seismic motion warning is important information and requires high reliability, error detection by CRC is possible after decoding by an error correction code using the following parity bits.

  The parity bits generated by using the shortened code (187,105) of the difference set cyclic code (273,191) are set in the 82 bits of B122 to B203 similarly to the error correction code of TMCC.

  Since earthquake motion warning information is important information and requires high reliability, it is protected by an error correction code using a differential cyclic code as in TMCC. The configuration identifications B1 to B3 and the synchronization signals B4 to B16 are not subject to error correction. The information of B17 to B121 is subjected to error correction coding with the shortened code (187,105) of the difference set cyclic code (273,191).

  The operation method of the earthquake motion warning information described with reference to FIGS. 3 to 9 and FIGS. 15 to 17 will be briefly described with reference to FIG.

  When seismic motion warning information is transmitted by the AC carrier of segment No. 0, the configuration identification is set to the value shown in FIG. When an earthquake occurs and a seismic motion warning is issued, the start / end flag is set to “with seismic motion warning detailed information: '00” ”, and at the same time, an update flag, signal identification, seismic motion warning detailed information, and a parity bit are set. At the end of the earthquake motion warning, the start / end flag is set to “No earthquake motion warning detailed information: '11'”.

  The operation of receiving the earthquake motion warning information described with reference to FIGS. 3 to 9 and FIGS. 15 to 17 will be described with reference to FIG.

  The frame extraction unit 112 in FIG. 1 extracts and demodulates the AC carrier in the segment number # 0, confirms the transmission of earthquake motion warning information by the configuration identification shown in FIG. 5, and further establishes synchronization. At this time, since the same earthquake motion warning information is transmitted for all AC carriers in segment number # 0, by adding all the AC carriers in segment number # 0 in analog, the earthquake motion warning information can be reduced even with low noise. Demodulation becomes possible. For example, if there are N AC carriers, the amplitude of the seismic motion warning information is N times, whereas the noise is uncorrelated in each AC carrier and therefore does not become N times (in terms of power, the seismic motion warning information Is only N times the square of N).

  Further, in the frame synchronization signal reproduction by the frame extraction unit 112, when the configuration identification part shown in FIG. 5 is checked and it is confirmed that the earthquake motion warning information is sent to the AC, as explained in FIG. Since the code connecting the configuration identification and the synchronization signal is the same as the TMCC synchronization signal, by analog addition of the code identifying the configuration identification and the synchronization signal and the TMCC synchronization signal, It is possible to reproduce a synchronization signal with lower noise than reproduction using only TMCC.

  Furthermore, as a method for examining the configuration identification portion shown in FIG. 5 in the frame extraction unit 112, the 3-bit portion from the beginning of the TMCC synchronization signal and the configuration identification portion shown in FIG. 5 of the AC carrier in the segment number # 0 It is possible to determine that the earthquake motion warning information has been sent to the AC when all three bits are correlated.

  The demodulated signal from the frame extraction unit 112 is output to the flag detection unit 114 and the data extraction unit 115.

  In the flag detection unit 114, the start / end flag shown in FIG. 5 is monitored in the sense shown in FIG. 6. In the initial stage, that is, the stage where the earthquake motion warning is not issued, the “earthquake motion warning detailed information” is changed to “earthquake motion”. The status of switching to “alarm detail information available” is monitored. At the same time, the data extraction unit 115 extracts the start / end flag, seismic motion warning information update flag, seismic motion warning detailed information, and parity bit shown in FIG. 5, and error correction of the shortened code of the differential cyclic code is performed. Each piece of extracted information is confirmed.

When an earthquake occurs and a seismic motion warning is issued, that is, when the start / end flag is “with seismic motion warning detailed information”, the flag detection unit 114 starts “no seismic motion warning detailed information” to “earthquake motion warning detailed information”. A state of switching to “there is information” is detected, and the control signal 123 notifies the control unit 118 and the data extraction unit 115 of “there is detailed earthquake motion warning information”, that is, the information on which the earthquake motion warning is issued.
On the other hand, the data extraction unit 115 receives the control signal 123, the update flag of the seismic motion warning information, the seismic motion warning detailed information, the parity bit of the seismic motion warning information that has been extracted and confirmed when the start / end flag becomes “earthquake motion warning detailed information exists”. Data is output to the determination unit 116.

  The determination unit 116 receives the data from the data extraction unit 115 and performs a CRC check. Then, the signal identification shown in FIG. 5 is confirmed, and the meaning shown in FIG. 9 is determined. Then, a preset process is performed according to each meaning, and if necessary, a control signal 127 and data are sent to the output unit 117.

  When receiving the control signal 127 from the determination unit 116, the output unit 117 receives data from the determination unit 116 and issues an earthquake motion warning.

  Detailed operations of the determination unit 116 and the output unit 117 will be described with reference to FIG.

  When the determination unit 116 determines “earthquake motion warning detailed information (there is a corresponding area)”, the determination unit 116 sends information “there is a corresponding area” to the output unit 117. In response to this, the output unit 117 receives information on “there is a corresponding area” and performs a warning by a buzzer sound or voice, or a warning display by flashing light or display. At the same time, the determination unit 116 sends earthquake detailed information and time information such as prefectural information and epicenter information where strong shaking shown in FIGS. 15 to 17 is expected to the output unit 117, and the output unit 117 receives this, Sound output of earthquake motion warning information, video output, or countdown to the time when an earthquake is expected to occur.

  When the determination unit 116 determines “earthquake motion warning detailed information (no corresponding area)”, the control signal and data output to the output unit 117 are not performed. However, in some cases, although not shown in FIG. 1, the video output unit 109 outputs earthquake detailed information such as prefectural information and epicenter information where strong shaking is expected, or the audio output unit 110 performs audio. It may be output.

  When the discriminating unit 116 discriminates "the test signal for the detailed earthquake motion warning information (there is a corresponding area)" or "the test signal for the detailed earthquake motion warning information (there is no corresponding region)" This is effective when the operation is confirmed in the test mode, ignored in the normal operation mode, and does not output a control signal or data to the output unit 117. In the test mode, for example, video information or audio information indicating that it is in the test mode is multiplexed with each operation of the detailed earthquake motion warning information (with applicable area) or the detailed information with earthquake motion warning (without applicable area). .

  The discriminating unit 116 needs to always check the signal identification when the start / end flag is “detailed information on earthquake motion warning”, but at least when the state of the update flag of the earthquake motion warning information changes, always confirm the signal identification. I do.

  The flag detection unit 114 monitors the state of switching from “with detailed earthquake motion warning information” to “without detailed earthquake motion warning information”, and when the start / end flag becomes “without detailed earthquake motion warning information”, the flag The detection unit 114 detects the state of switching from “with detailed earthquake motion warning information” to “without detailed earthquake motion warning information”, and the control signal 123 causes the control unit 118 and the data extraction unit 115 to receive “no detailed earthquake motion warning information” information. Reportedly. On the other hand, the data extraction unit 115 receives the control signal 123 and stops outputting data to the determination unit 116.

  Next, a processing flow until the digital broadcast receiving apparatus according to the present embodiment starts receiving a digital broadcast when receiving a voice call in a standby state will be described with reference to FIG.

  Since the paging channel cannot be used during a call, the earthquake motion warning information cannot be received, and even if the earthquake motion warning is issued during this time, the user cannot know it.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a digital broadcast receiving apparatus capable of receiving seismic motion warning information transmitted by digital broadcasting. An object of the present invention is to provide a digital broadcast receiver capable of receiving alarm information.

  The receiving apparatus of the present invention periodically receives a paging channel (PCH) transmitted from the base station in order to confirm whether there is an incoming call such as voice call or SMS (step S101).

  In the PCH, the user ID called from the base station is written. For example, the user ID is represented by 32 bits. Further, a Cause ID indicating why the call was made is also added. This Cause ID indicates a communication type, for example, voice, short message service (SMS), etc., and is about 2-3 bits.

  If the received user ID does not match the user ID stored in the storage unit (step S102; No), the paging channel is received again (step S101). In order to reduce power consumption, it is desirable to receive the paging channel again after a predetermined time has elapsed.

  If the received user ID matches the user ID stored in the storage unit 134 (step S102; Yes), the type of CauseID is confirmed.

  When the type of CauseID is a value indicating an incoming voice call (step S103; “voice incoming call”), the user is notified of an incoming call (not shown). Incoming call notification is performed by sound, light, vibration by a vibrator, or the like.

  Then, when the user performs an operation such as pressing the speech key, reception of a traffic channel for calling other than PCH is started, and the calling is started (step S104; Yes).

  Thereafter, the control unit 118 detects the start of the call, operates the broadcast receiving unit 119 and the earthquake motion warning information receiving unit 120, and starts receiving digital broadcast (step S105). Thus, as described with reference to FIGS. 1 to 9, it is possible to receive and output earthquake motion warning information transmitted by digital broadcasting. Then, a transition is made to a busy state (step S106).

  If the type of CauseID is a value indicating SMS (step S103; “SMS”), the SMS is received (step S107).

  If the received SMS is earthquake motion warning information (step S108; Yes), the output unit 117 issues a warning by voice and video to notify the user that the earthquake motion warning information has been received. (Step S109).

  In addition, when normal SMS is received instead of earthquake motion warning information (step S108; No), normal notification is performed (step S110).

  In order to determine whether the received SMS is earthquake motion warning information, for example, a user ID may be used. Specifically, when the user ID is a value indicating not only its own ID but an ID addressed to all terminals communicating with the base station, it is determined as earthquake motion warning information.

  Next, a processing flow during a call will be described with reference to FIG.

  First, the broadcast receiving unit 119 receives a digital broadcast transmission signal (step S201), and the seismic motion warning information receiving unit 120 determines whether the start / end flag is “with detailed seismic motion warning information” (step S202). ). If it is “there is detailed earthquake motion warning information” (step S202; Yes), the user is notified that the earthquake motion warning information has been received (step S203). If the start / end flag is not “earthquake motion warning detailed information exists” (step S202; No), the process proceeds to step S204 without doing anything.

  Next, if the call has not ended yet (step S204; No), the process returns to the process of receiving the digital broadcast transmission signal (step S201).

  If the call is terminated by the user pressing a key for instructing the end of the call (step S204; Yes), the state transits to the waiting state (step S205), and the broadcast receiving unit 119 ends the reception of the digital broadcast. (Step S206). When the call ends, paging channel reception is started again (step S101 in FIG. 10).

  By controlling in this way, earthquake motion warning information is received by SMS using a mobile phone wireless system in the standby state, and digital broadcast earthquake motion warning information is received in a busy state. Therefore, it is possible to notify the user of earthquake motion warning information even during a call.

  ADVANTAGE OF THE INVENTION According to this invention, in the digital broadcast receiver which can receive the seismic-motion warning information transmitted by digital broadcasting, seismic-motion warning information can be received even during a telephone call.

  In the digital broadcast receiving apparatus according to the first embodiment of the present invention, the digital broadcast starts to be received after the start of the call (step S105 in FIG. 10). , It will take a predetermined time. Therefore, there may occur a state in which the start / end flag cannot be acquired even though the earthquake motion warning has been issued.

  Therefore, in the digital broadcast receiving apparatus according to the second embodiment of the present invention, in order to receive the earthquake motion warning information as soon as possible, reception of the digital broadcast is started when it is determined that the incoming call is a voice call. This processing flow is shown in FIG.

  The processing flow of FIG. 12 differs from the processing flow of FIG. 10 only in that step S105 is performed before step S104 and step S111 is added.

  The processing flow of FIG. 12 is performed by controlling the operation of the broadcast receiving unit 119, the earthquake motion warning information receiving unit 120, or the communication unit 135 based on the determination of the control unit 118.

  First, the processing from step S101 to step S103 is performed, and it is confirmed that a message addressed to itself has arrived by receiving a paging channel. Then, when it is found that the type of CauseID is an incoming voice call (step S103; “voice incoming call”), the control unit 118 operates the broadcast receiving unit 119 and the earthquake motion warning information receiving unit 120 to immediately perform digital broadcasting. Is started (step S105). Then, if the user gives an instruction to start a call, the call is started (step S104; Yes), and the state is changed to a busy state (step S106).

  If the user does not give an instruction to start a call, the reception of the digital broadcast is terminated (step S111). Then, the paging channel is received again (step S101).

  Thus, by starting reception of the digital broadcast before the call starts, the start / end flag can be quickly acquired.

  In the first embodiment, when the radio wave condition is bad and communication with the base station is not possible, the SMS cannot be received, and therefore the earthquake motion warning information cannot be received. Depending on the location where the digital broadcast receiving apparatus is located, the digital broadcast may be received even if communication with the base station is not possible. Therefore, in this embodiment, when the radio wave condition of communication with the base station deteriorates, digital broadcasting is received and earthquake motion warning information can be received. The processing flow is shown in FIG.

  The processing flow of FIG. 13 is performed by controlling the operation of the broadcast receiving unit 119, the earthquake motion warning information receiving unit 120, or the communication unit 135 based on the determination of the control unit 118.

  First, the communication unit 131 acquires the strength of radio waves that communicate with the base station (step S301). When the acquired radio wave intensity is smaller than the predetermined threshold value P (step S302; No), a timer (not shown) built in the calling unit 135 is started (step S304). Before starting the timer, a process for determining whether or not the timer is operating is performed (step S308). Since the timer is not operating for the first time (step S308; No), the timer is started. If the timer is operating (step S308; Yes), nothing is done and the process proceeds to step S305 to check whether the timer has expired.

  If the timer has not expired (step S305; No), the radio wave intensity is acquired again (step S301), and the threshold value P is compared with the value (step S302).

  When the predetermined time has elapsed and the timer has expired (step S305; Yes), the control unit 118 operates the broadcast receiving unit 119 and the earthquake motion warning information receiving unit 120 to start receiving digital broadcasting (step S306). ). This timer is for controlling not to start reception of digital broadcasting when the radio wave condition deteriorates in bursts and falls below the threshold value P for a short time.

  In addition to using the timer, for example, when the number of times that the threshold value has been exceeded exceeds a predetermined number, it may be determined that the radio wave has deteriorated and reception of the digital broadcast may be started.

  If the acquired radio wave intensity is larger than the predetermined threshold P (step S302; Yes), the timer is ended (step S303), and the reception of the digital broadcast is ended (step S307). Of course, if the radio wave condition is stable and larger than the threshold value P and the timer has not started, the process of ending the timer (step S303) is omitted, and if the digital broadcast is not received, the reception end process (step S303). S307) can also be omitted. Thereafter, the same processing as step S101 and subsequent steps in FIG. 10 or step S101 and subsequent steps in FIG. 12 is performed.

  By controlling in this way, it is possible to receive earthquake motion warning information even in situations where the radio wave of the mobile phone is poor and communication with the base station is not possible.

  In addition, it is important to promptly notify the user of earthquake motion warning information. If earthquake motion warning information can be received early, the user can prepare for an earthquake. Therefore, when the digital broadcast receiving apparatus according to the present embodiment is in a state where the earthquake motion warning information can be acquired from the base station or the digital broadcast, this is notified as soon as the earthquake motion warning information is acquired.

  For example, while watching 1Seg, earthquake motion warning information included in digital broadcasting can be acquired, and earthquake motion warning information from a base station can also be acquired. In this case, the previously received information is first notified. After that, when earthquake motion warning information is received again, it may be notified again.

  The above processing will be described with reference to FIG.

  First, the same processing as in Steps S101 to S103 and Steps S107 to S110 in FIG. 10 is performed, and when a paging channel is received and earthquake motion warning information is received from the base station, the user is notified (Step S101). S109). However, if the user IDs do not match in step S102 (step S102; No), or if the call is not started in step S104 (step S104; No), the process does not return to step S101 and the next process is performed. move on.

  Next, digital broadcasting is received (step S401). If the start / end flag is “earthquake motion warning detailed information exists” (step S402; Yes), the earthquake motion warning information is notified (step S403). And it returns to the process of step S101 again and starts reception of a paging channel.

  In this way, if earthquake motion warning information can be obtained from both the base station and the digital broadcast, the emergency information can be quickly transmitted to the user by notifying the earthquake motion warning information of the one received earlier, It is possible to provide a device that can ensure the safety of the user.

  In the above description, the earthquake motion warning information from the digital broadcast or the base station is described. However, the means for acquiring the earthquake motion warning information is not limited to this. If the same processing is performed for the case of receiving by another earthquake motion warning information acquisition means, notification can be made as soon as the earthquake motion warning information is received.

  Also, the notification operation differs depending on whether the earthquake motion warning information is received from the base station or the digital broadcast. When it is received from the base station, as shown in FIG. 10, it is received as SMS, and the received character or voice data is notified to the user.

  On the other hand, as described above, regional information may be described in the earthquake motion warning information received from digital broadcasting. The receiving device refers to the area information and notifies the user according to the area where the terminal is located. This process will be described with reference to FIG.

  First, a digital broadcast is received (step S501), and it is determined whether the start / end flag is a value indicating “there is detailed earthquake motion warning information”. If so (step S502; Yes), earthquake motion information is acquired. (Step S503). Next, the area of the receiving device is acquired (step S504). Here, as a region acquisition method, region information may be acquired from a communicating base station, or latitude / longitude is acquired using position information acquisition means such as GPS, and the region is determined from the value. It may be determined. In either case, it can be realized by holding a correspondence table between IDs and latitude / longitudes indicating predetermined areas and the areas.

  Next, it is determined whether or not the area expected to be shaken by the earthquake in the area acquired from the earthquake motion information and the area of the receiving device match, and if they match (step S505; Yes), the earthquake motion Alarm information is notified (step S506). If they do not match (step S505; No), the process ends without doing anything.

  In this way, more useful information can be provided to the user by performing different operations depending on whether the digital broadcast is received from the base station.

  Further, when the user is browsing the earthquake motion warning information, it is desirable to display the information being browsed by the user so as not to be hidden when new earthquake motion warning information is notified. Whether or not the user is browsing can be determined by whether or not there is a key input after notifying the earthquake motion warning information.

  This process will be described with reference to FIG.

  First, earthquake motion warning information is received (step S601). The earthquake motion warning information here may be received from either a digital broadcast or a base station. Next, it is determined whether or not the earthquake motion warning information has already been notified. If the notification has not been made (step S602; No), the earthquake motion warning information is notified (step S604). If the earthquake motion warning information has been notified (step S602; Yes), it is determined whether the earthquake motion warning information is being browsed by the user (step S603). As the determination process, for example, when the up / down key is pressed and it is determined that the user is reading the alarm, or when the value of the acceleration sensor is acquired and the value is changed, the user selects the receiving device. It can be determined that the hand is browsing. If it is determined that the user is browsing (step S603; Yes), the process ends without doing anything. If it is determined that the user is not browsing (step S603; No), earthquake motion warning information is notified (step S604).

  By controlling in this way, even when another earthquake motion warning information is received while the user is checking the earthquake motion warning information, usability can be improved without disturbing the user.

  In order to notify the user that new earthquake motion warning information has been received, for example, a mark or the like may be displayed above the display unit of the receiving device.

  Even in the standby state, digital broadcasts may always be received in order to quickly obtain earthquake motion warning information. In this case, in order to reduce power consumption, it is sufficient to operate only the means necessary for acquiring the seismic motion warning information, and the demax unit 107 and the decoding unit 108 of the broadcast receiving unit 119 are not operated. Good. By controlling in this way, power consumption is suppressed, and the user can use the digital broadcast receiving apparatus for a longer time, so that usability is improved.

  1 may be a 13-segment receiver or a one-segment receiver.

DESCRIPTION OF SYMBOLS 101 ... Antenna 102 ... Channel selection part 103 ... Orthogonal demodulation part 104 ... Fast Fourier transform (FFT) part 105 ... Demodulation decoding part 106 ... Descramble part 107 ... Demax part 108 ... Decoding part 109 ... Video output part 110 ... Audio | voice output part 111 ... Synchronous playback unit 112 ... Frame extraction unit 113 ... TMCC decoding unit 114 ... Flag detection unit 115 ... Data extraction unit 116 ... Discrimination unit 117 ... Output unit 118 ... Control unit 119 ... Broadcast reception unit 120 ... Earthquake motion warning information reception unit 121 ... Digital broadcast receiving apparatus 130 ... antenna 131 ... communication unit 132 ... microphone 133 ... speaker 134 ... storage unit 135 ... calling units 122, 123, 124, 125, 126 ... control signal 201 ... information source encoding unit 202 ... MPEG2 multiplexing unit 203 ... TS remultiplexing unit 204 ... RS (Reed-Solomon) encoding unit 205 ... Floor Layer division unit 206a, b, c ... parallel processing unit 207 ... layer synthesis unit 208 ... time interleaving unit 209 ... frequency interleaving unit 210 ... OFDM frame configuration unit 211 ... inverse fast Fourier transform (IFFT) unit 212 ... guard interval adding unit 213 ... Transmission unit 214 ... Pilot signal configuration unit 215 ... TMCC signal configuration unit 216 ... AC signal configuration unit 300 ... Earthquake Bulletin Center 400 ... Broadcaster 500 ... Broadcast facility 600 ... Mobile silent communication carrier 700 ... Base station

Claims (2)

A broadcast receiving unit that receives a transmission signal that is transmitted by broadcasting and includes a digital broadcasting signal and emergency earthquake information;
An emergency earthquake information receiving unit that detects and outputs emergency earthquake information from a transmission signal received by the broadcast receiving unit;
A call unit for making calls by wireless communication;
As the call unit starts a call, the broadcast receiving unit starts receiving, and when emergency earthquake information is detected by the emergency earthquake information receiving unit, the emergency earthquake information receiving unit outputs emergency earthquake information. A control unit;
A digital broadcast receiving apparatus comprising: A broadcast reception step for receiving a transmission signal transmitted by broadcasting, including a digital broadcast signal and a transmission signal including emergency earthquake information;
Emergency earthquake information receiving step for detecting and outputting emergency earthquake information from the transmission signal received in the broadcast receiving step;
A call step for making a call by wireless communication, and when the call is started in the call step, reception of the broadcast reception step is started and emergency earthquake information is detected in the emergency earthquake information reception step. A method for receiving digital broadcasts characterized in that emergency earthquake information is output.

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