JP5582720B2 - Receiver for receiving emergency information in digital terrestrial television broadcasting - Google Patents

Description

  The present invention relates to a technology for transmitting and receiving emergency information such as emergency warning broadcasting and emergency earthquake bulletin in terrestrial digital television broadcasting, and in particular, reception for receiving emergency information to reliably receive emergency information when necessary. The present invention relates to a receiving device that informs a recipient whether or not the device can reliably receive the emergency information.

  Currently, for example, an ISDB-T (Integrated Services Digital Broadcasting-Terrestrial, ARIB standard STD-B31) system has been put into practical use as a transmission method for terrestrial digital television broadcasting.

  In response to a large-scale earthquake and tsunami warning, and a request from local governments, a broadcasting station that receives emergency terrestrial warning broadcasting will continue to install a digital terrestrial television broadcasting receiver that is not turned on. There is a mechanism for starting.

  For example, there is a signal called TMCC (Transmission and Multiplexing Configuration Control) signal provided for transmitting information related to the demodulation operation of the receiving apparatus.

  In this TMCC signal, information called an emergency warning broadcast activation flag, which changes the bit value based on emergency warning broadcasting, is described. When this emergency warning broadcast activation flag is detected and the value is 1, emergency warning broadcast is performed, and thus the reception device can be started up by this emergency warning broadcast activation flag.

  A technique is disclosed that operates while suppressing standby power consumption and activates a receiving apparatus that is not turned on to notify the receiving apparatus (for example, see Patent Document 1). This technology includes a transmission control signal receiving unit that detects an emergency warning broadcast activation flag. When the emergency warning broadcast activation flag is 1, the terrestrial digital television broadcast reception device is turned on. This is a technology that encourages viewers to watch emergency warning broadcasts.

  On the other hand, the Japan Meteorological Agency started providing earthquake early warnings (see Non-Patent Document 1, for example) to the general public from October 1, 2007. Along with this, when an earthquake early warning was announced, television and radio broadcast stations also started broadcasting such as displaying them on a television screen or transmitting them with sound together with a chime sound. In addition, a part of the earthquake early warning radio broadcast started on April 1, 2008.

  In addition, for transmission in terrestrial digital television broadcasting of disasters, disaster prevention information including emergency earthquake alerts, etc., a technique using an AC (Auxiliary Channel) carrier in addition to transmission / reception of emergency warning broadcast activation flag by TMCC signal is disclosed. (For example, refer to Patent Document 2). The type of emergency information and the start or end of the emergency information are presented by a combination of the emergency warning broadcast activation flag of the TMCC carrier and, for example, the signal type bit placed on a specific AC carrier in the partial reception segment. In addition, the emergency information descriptor of ARIB standard STD-B10 and the video / audio of emergency information are transmitted using an AC carrier. This emergency information descriptor includes the signal type bit and is stored in the AC signal of the partially received segment, and the video / audio is stored and transmitted in the AC signal of the other segment.

  Also in the technique of Patent Document 2, it is disclosed that when the power of the receiving apparatus is not turned on, or when another channel is received, prompting to turn on the power or switching the channel. Techniques have been proposed for receiving TMCC signals and AC signals in a segment and reproducing other disaster / disaster prevention information and video / audio after power-on or channel switching.

JP 2006-319771 A JP 2007-243936 A

“Technical reference materials on overview and processing methods of earthquake early warnings,” Japan Meteorological Agency Earthquake Volcano, [Search on January 31, 2008], Internet <URL: http://www.seisvol.kishou.go.jp/ eq / EEW / kaisetsu / Whats_EEW / reference.pdf>

  In order to use emergency information such as emergency alert broadcasting and earthquake early warning, it is necessary to have a receiving device capable of receiving the emergency information and to turn on the power when necessary.

  In the case of emergency warning broadcasting, as disclosed in Patent Document 1, the emergency warning broadcasting activation flag on the TMCC signal is constantly monitored, and by detecting 1 of the flag, reception of terrestrial digital television broadcasting is performed. It is possible to start the device.

  Even in the case of the earthquake early warning, although not in the current system, as disclosed in Patent Document 2, for example, the same TMCC signal reserve bits, other signals, and AC signals can be used for transmission. Similarly to the case of emergency alert broadcasting, it is possible to start up a digital terrestrial television broadcast receiving apparatus using a technique such as that disclosed in Patent Document 1.

  However, in order to detect such an emergency information activation flag, it is preferable to recognize that the receiving apparatus is installed in an environment where the activation flag can be received with sufficient quality.

  In particular, there is a demand for a solution that informs the receiver of the receiving device that the emergency information can be received even when the power of the receiving device is turned off.

  An object of the present invention is to provide a receiving apparatus that informs a receiver whether or not a receiving apparatus that receives emergency information can reliably receive emergency information in order to reliably receive emergency information when necessary. It is to provide.

  Digital terrestrial television broadcasting that receives the partial carrier and demodulates the earthquake early warning stored in the partial carrier when transmitting the earthquake early warning using a partial carrier of the terrestrial digital television broadcast And a reception power detection unit, a guard interval correlation peak detection unit, a frame synchronization establishment information detection unit, or a MER detection unit, or a combination of any two, or a combination of any three Or have everything. Furthermore, a level display setting unit is provided, and the reception unit receives and demodulates the reception of the emergency earthquake early warning, the received power detection unit, the guard interval correlation peak detection unit, the frame synchronization establishment information detection unit, or the MER Based on information obtained from any one of the detection units, or any two combinations, or any three combinations, or all, in the level display setting unit, the result is displayed on the display device, Whether or not the recipient of the earthquake early warning is in a situation where the emergency earthquake bulletin can be received is explicitly notified in advance to the receiver.

That is, the receiving device according to the present invention is a receiving device that receives an AC signal or a TMCC signal from a terrestrial digital television broadcast wave, and includes an activation signal that identifies the presence or absence of an earthquake early warning and emergency earthquake early warning information. Telegram information for storing information is preliminarily defined to be transmitted by an AC signal or a TMCC signal, means for receiving a terrestrial digital television broadcast wave and extracting an AC signal or a TMCC signal; symbol synchronization detection information obtained from the calculation results of the guard interval correlation is calculated when performing the symbol synchronization on the received signal wave,及 beauty, is generated based on the information necessary for frame synchronization contained in the message information Means for detecting one or more pieces of emergency information synchronization establishment information indicating whether or not frame synchronization of emergency information is established, and based on the detected value , Characterized in that it comprises a means for determining a value of the level meter indicating the reception state of the emergency information.

In the receiving device according to the present invention, the telegram information includes a start signal of emergency earthquake warning, monitors the information of the start signal, and supplies power to the receiving device by an intra-frame intermittent reception operation or an inter-frame intermittent reception operation. It is characterized by including a control means.

Further, in the receiving device according to the present invention, when all the contents of the message information are decoded, the presence / absence of an error is detected from the means for correcting the error of the message information and the parity check information at the time of the error correction, Means for determining whether or not the reception information of emergency information can be received, and generating a determination result of the reception availability as information of a predetermined level value, and means for determining a level meter value indicating the reception state of the emergency information It includes: the reception permission determination result information, the detection information of the symbol synchronization, the information of the MER, and, based on one or more of the emergency information synchronization establishment information, the reception state of the emergency information It is characterized by determining the value of the level meter to be represented.

  According to the present invention, a receiver of emergency information such as an emergency warning broadcast or an emergency earthquake bulletin can determine whether or not the receiver of its terrestrial digital television broadcast can receive the emergency information by turning on the power of the receiver. Even if it is not inserted, it can be known in advance, so that it is possible to quickly determine whether to move to a place where the emergency information can be received or to substitute by another means.

It is a figure which shows the receiver of Example 1 by this invention. It is a figure which shows an example which displays the value of the level meter showing a receiving state on the display screen of the display apparatus in the receiver of Example 1 by this invention. It is a figure which shows an example which displays the value of the level meter showing a receiving state on the flame | frame of the display apparatus in the receiver of Example 1 by this invention. It is a figure which shows an example which displays the value of the level meter showing a receiving state on the partial screen of the display apparatus in the receiver of Example 1 by this invention. It is a figure which shows an example which displays the value of the level meter showing a receiving state on the partial screen of the display apparatus in the receiver of Example 1 by this invention. It is a figure which shows the receiver of Example 2 by this invention. It is a figure explaining an OFDM symbol and guard interval correlation calculation. It is a figure which shows the result of a guard interval correlation calculation, and the influence of noise and multipath. It is a figure which shows the receiver of Example 3 by this invention. It is a figure which shows the receiver of Example 4 by this invention.

  First, the receiving apparatus according to the first embodiment of the present invention will be described.

  The receiving apparatus 1 according to the first embodiment of the present invention uses an AC signal to transmit emergency information (hereinafter, information including emergency alert broadcasts and emergency earthquake warnings is collectively referred to as emergency information). It is a device that receives a signal transmitted by the AC signal in a broadcast service, and a device that can notify the receiver of the receiving device 1 whether or not emergency information can be received.

  For example, in the case of the mode 3 synchronous modulation section of the partial reception segment (segment number # 0) of the ISDB-T terrestrial digital television broadcast wave, the AC signal is carrier numbers # 7, # 89, # 206, # 209. , # 226, # 244, # 377 and # 407 are signals carried by AC carriers at eight locations.

  For example, when a broadcaster receives an earthquake early warning from the Japan Meteorological Agency, an earthquake early warning based on the format example of the telegram information shown in Table 1 as a representative example is transmitted by a transmission apparatus related to ISDB-T digital terrestrial television broadcasting. Information, that is, information on emergency earthquake warnings such as the name of the area, the maximum predicted seismic intensity in the area and the predicted arrival time of the main motion of the earthquake, are stored in all the AC information carried by the eight AC carriers, and the receiving device 1 Send to. The hardware configuration of the transmission apparatus related to ISDB-T digital terrestrial television broadcasting is known and not shown.

  That is, the same frame length as the TMCC signal, the same differential demodulation reference and synchronization signal as the TMCC signal, the activation signal for identifying the presence or absence of the earthquake early warning, and the emergency information including the information on the earthquake early warning The telegram information to be stored (the telegram information format exemplified in Table 1) is preliminarily defined so as to be transmitted from the transmission device by the AC carrier.

  In order to facilitate understanding of the present invention, the case where all the AC information carried by the mode 3 AC carrier in ISDB-T terrestrial digital television broadcasting will be described below. Note that is also applicable.

  “Activation signal” identifies the presence or absence of emergency information and enables reception of emergency information even when the receiver of the terrestrial digital television broadcast is not turned on, that is, when the receiver is not watching the program. To do. A 1-bit (or 2-bit) activation signal is assigned following a “synchronization signal” (described later in detail). The value of the “activation signal” is the value representing the bit of “1” when there is emergency information, the phase of the last symbol of the “synchronization signal” is inverted, and “0” when there is no emergency information. The phase continues as a value representing the bits of. When transmitting with 8 AC carriers, if the same information is multiplexed and transmitted on each carrier, the value of each carrier is divided by the value of “reference of differential demodulation” (details will be described later). Therefore, diversity combining is possible.

  When the “activation signal” is set to 2 bits, the same value is put in these 2 bits to provide redundancy to increase the probability of the signal value. In addition, an “update flag” is provided immediately after the “activation signal”, and the value is updated (updated from 1 to 0 or from 0 to 1) every time the content of the transmitted emergency information is updated. By using the “flag” (1 bit), it is possible to efficiently reduce the internal processing amount of the receiving apparatus 1 receiving emergency information if it is controlled to perform the receiving operation only at the time of update. Alternatively, the “update flag” can be set to start with the same value as the flag value at the time of activation of the “activation signal” in order to provide further redundancy of the “activation signal”. Note that the “update flag” is a 1-bit case in which the content of the emergency information is updated while the “activation signal” continues the value indicating that there is emergency information. However, 2 bits or more can be assigned to the “update flag” when the update frequency is two or more in actual operation.

  Table 1 shows an example of transmitting emergency information about when and how large / seismic magnitude earthquakes are desired in the distribution of earthquake early warnings. Regional information can be transmitted.

  In order to deliver the earthquake early warning, it is necessary to transmit the minimum necessary information for the receiving device 1 accurately, quickly and reliably. The information that is effective when the earthquake early warning is distributed is how much magnitude / seismic intensity of the earthquake occurs in the area where the receiving device 1 is located. At present, it is desired that emergency earthquake warnings for general public transmit information on the name of the region and the name of the region where the seismic intensity of 4 or more is estimated when strong shaking (seismic intensity of 5 or less) is estimated. .

  That is, the area name, the maximum seismic intensity in the area, the predicted arrival time of the area, or the remaining time until a strong shake due to the earthquake occurs in the area is desired. Based on this idea, examples of telegram information storing emergency information are configured.

  “No. ○ region” (○ is a positive integer of 1, 2,..., 8) is a region of “regional unit”, which is a unit of region such as Hokkaido, Tohoku, Kanto, Hokuriku, etc. It is an area. For example, a 6-bit numerical code is assigned and described in the “region code” indicating these regions.

  The “maximum predicted seismic intensity” corresponds to seismic intensity 4 or higher of 4, 5 weak, 5 strong, 6 weak, 6 strong, or 7. “Strong” and “Weak” are distinguished by numerical values of 1 and 0, respectively. For example, each is divided into 4 bits “0100”, “0101”, “1101”, “0110”, “1110”, “0111”. Separately written.

  The “estimated arrival time” is the time when the earthquake will reach the area in hours, minutes and seconds. The “arrival predicted difference time” (simply referred to as “difference time”) is the first This is the difference time from the predicted arrival time in the region. The first region is assumed to be the point where the earthquake occurs the earliest, and after the second region, the strong shaking (main motion) due to the earthquake reaches the region with a positive delay time. When the receiving device calculates the time in seconds by subtracting the current time from the “estimated arrival time” (excluding the first region, the estimated arrival time of the first region plus the difference time of each region), Remaining time until strong shaking reaches the area can be obtained.

  The “estimated arrival time” is expressed in 12 hours, the hour display is 4 bits, and the minutes and seconds are 6 bits. For example, 10:25:37 is “1010 | 011001 | 100101” (16 bits in total) ) And binary numbers in units of hours, minutes, and seconds. Note that “|” is inserted only as a notation here to make it easy to see the distinction between hour, minute, and second, and is not inserted in actual transmission. On the other hand, the “difference time” is a 6-bit binary number because it represents only seconds.

  The format of the main information is as described above, but flags and bits for assisting the transmission of information are also assigned.

  “Number of districts (total)” describes the total number of districts corresponding to the earthquake early warning. For example, if Hokuriku, Koshin, and Tohoku are the targets, 3 corresponds. Since the region classification is 14 at the maximum (the format of Table 1 stores up to 4 information. For example, if transmission is performed in units of 2 frames, a maximum of 8 regions can be targeted). assign. On the other hand, “the number of regions (remaining number)” is a value counted down every time one region is displayed, and indicates that there is no data after “0000”.

  The “emergency information identification signal” presents information such as “emergency warning broadcast activation”, “emergency earthquake bulletin activation / identification”, “normal” / “training” identification, “presence of news breaking”, and the like. For example, 8 bits are assigned to the “emergency information identification signal”. Basic information classification is performed by the upper 6 bits. From the 7th bit onwards, the copy bit of “Earthquake Early Warning activation / identification” is put in the 7th bit, and 1 or 0 is put in the value of the 8th bit so that the number of 1s in the first 8 bits is an even number. I have to. The former deals with a reception error of “emergency information identification signal”, particularly “emergency earthquake early warning activation / identification”. In the latter, even numbers are formed by converting the number of 1s in the first 8 bits into even numbers, and even number errors can be detected on the receiving side.

  Specifically, the “emergency information identification signal” is configured by a flag that can identify the presence / absence of an emergency earthquake news program, the presence / absence of a data broadcast, the presence / absence of an emergency warning broadcast, and a normal time. For example, the receiving side can recognize a combination of bits corresponding to the activation of “Earthquake Early Warning”. As an example, from a state of “none” (00000101) in a normal state, a combination of bits corresponding to an emergency earthquake warning, for example, “emergency warning broadcast, emergency earthquake warning (with program, no data) (11010010)” state Is received by the receiving device 1. As a result, the receiving device can know that “there is an emergency earthquake news program and no data broadcast”.

  The “differential demodulation reference”, “synchronization signal”, and “parity bit” are the same as those of the TMCC signal, and in the case of ISDB-T terrestrial digital television broadcasting, one symbol of the OFDM (Orthogonal Frequency Division Multiplexing) method Based on the above, 204 bits of the DBPSK signal are allocated to the same 204 symbols as the TMCC signal to form one frame. Therefore, the signal of the format described in Table 1 is transmitted in one frame of the OFDM signal. The “parity bit” is, for example, a parity bit used for error correction based on a predetermined difference set cyclic code system.

  The “synchronization signal” is used for synchronization in the same manner as the TMCC signal, is transmitted 16 bits per frame, and the phase is inverted between the odd frame and the even frame. The value is “0011010111101110” in odd frame notation.

The “differential demodulation reference” is a value based on the same generator polynomial (x ¹¹ + x ⁹ +1) as the value W _{i of the} BPSK signal assigned to the SP (Scattered Pilot) signal of the carrier number i, similarly to the TMCC signal. However, an AC carrier is used to transmit the message information. For example, the AC carrier in the partial reception segment (segment number # 0) of the ISDB-T terrestrial digital television broadcast wave is carrier number # 7, # 89, # 206, # 209 in the case of the mode 3 synchronous modulation unit. , # 226, # 244, # 377 and # 407. _{W i} are stored as "reference for differential demodulation" description in AC information this eight of AC carrier carries are each 0,0,0,0,0,1,1 and 0. Note that a modulation method other than BPSK can be used, and a method to be used on the transmission side and the reception side is determined in advance together with the above-described difference set cyclic code method.

  FIG. 1 shows a schematic diagram of a receiving apparatus according to a first embodiment of the present invention. The receiving part of the AC signal that constitutes the receiving apparatus 1 includes an AC synchronization establishing unit 2, an AC information analyzing unit 3, and a warning generating unit 20. The AC synchronization establishment unit 2 includes a frequency conversion unit 6, an AD conversion unit 7, an FFT processing unit 8, an AC extraction unit 9, and a frame synchronization detection unit 10. Further, the AC information analysis unit 3 includes an error correction unit 16, an AC decoding unit 17, and an information processing unit 18.

  The main reception status determination control unit of the present invention, which grasps the reception status of emergency information and controls the display device, monitors the signal of a specific component in the reception device 1, the received power detection unit 13, and frame synchronization establishment information It comprises a detection unit 11, a MER detection unit 12, a level display setting unit 14, and a display control unit 15.

  The frequency conversion unit 6 removes unnecessary frequency components from a digital terrestrial television broadcast wave input from the antenna 5 using a predetermined filter, selects a designated channel, converts the frequency into an intermediate frequency signal, and appropriately converts the frequency. Amplify and output. This channel selection can also be predetermined by the receiving device.

  The AD conversion unit 7 converts the intermediate frequency signal output from the frequency conversion unit 6 into digital, and transmits a digital baseband signal.

  The FFT processing unit 8 performs an FFT (Fast Fourier Transform) operation on the effective symbol period of the OFDM symbol, and demodulates it into an OFDM format stream. The effective symbol period can be defined by performing symbol synchronization by guard interval correlation or the like, and performs an FFT operation at an FFT sample frequency according to a predetermined transmission mode.

  The AC extraction unit 9 performs delay detection by DBPSK from the OFDM format stream, performs 0 or 1 level determination, and obtains a bit stream of the AC signal.

  The frame synchronization detection unit 10 detects the coincidence between the demodulated AC signal and a pattern such as the synchronization signal of the telegram information stored in the AC signal, and at the beginning timing of the demodulated AC signal when the two match. A frame synchronization signal (reset pulse) is generated. Further, the frame synchronization detection unit 10 determines whether or not the frame synchronization of the emergency information is established based on the frame synchronization signal generated based on the information necessary for frame synchronization (such as the synchronization signal of the message information) included in the message information. The emergency information synchronization establishment information shown is generated and sent to the level display setting unit 14.

  The error correction unit 16 synchronizes with the frame synchronization signal generated by the frame synchronization detection unit 10 and outputs the emergency information (AC signal) based on the error code (for example, the parity bit of the difference set cyclic code method). correct.

  The AC decoding unit 17 decodes the emergency information in a decoding format corresponding to the encoding method on the transmission side.

  From the decoded emergency information, the information processing unit 18 calculates prediction information of seismic intensity and arrival time of each region, for example, if it is an emergency earthquake warning. The information processing unit 18 preferably includes a position detection unit that detects the position of the reception device using GPS and the like, and a current time detection unit (not shown) that detects the current time of the reception device, and the reception device 1 is located. When the receiving device 1 recognizes the local information and the current time, it is possible to selectively calculate the seismic intensity and the arrival time prediction information of the region where the receiving device 1 is located.

  In order to deliver the earthquake early warning, it is necessary to transmit the minimum necessary information for the receiving device 1 accurately, quickly and reliably. For example, when strong shaking (seismic intensity of 5 or less) is estimated, it is desired to transmit information that enables the receiving side to know the area name and the area name whose seismic intensity is 4 or more. Therefore, the broadcaster uses the terrestrial digital television broadcast transmitter to convert the AC signal in the partial reception segment of the terrestrial digital television broadcast to the telegraphic information of the emergency earthquake warning as shown in Table 1, It is also possible to multiplex and transmit the telegram information of the earthquake early warning as shown in FIG. For example, a broadcaster uses a digital terrestrial television broadcasting transmitter to send an “earthquake occurrence time”, location (seismic location information: “seismic latitude”, “seismic longitude”, “seismic depth”), And the magnitude of the earthquake (“magnitude”) is transmitted together with an activation signal for identifying the earthquake early warning (for example, “1” at the time of early warning and “0” otherwise).

  In this case, the information processing unit 18 can preliminarily define the telegraphic information of the emergency earthquake warning as shown in Table 2, that is, the location information (latitude, longitude, depth) of the earthquake source and the magnitude (magnitude) of the earthquake. The predicted seismic intensity and the predicted arrival time of strong ground motion (main motion) are calculated from the information on the possible ground enhancement. Furthermore, the information processing unit 18 can also calculate the absolute time of the predicted arrival time by adding the earthquake occurrence time.

  Specifically, the information processing unit 18 calculates the predicted seismic intensity and the predicted arrival time of strong ground motion (main motion) as follows.

The predicted seismic intensity is _calculated as a measured seismic intensity I _INSTR by the calculation formula described in Non-Patent Document 1 below.

I _INSTR = 2.68 + 1.72 log (PGV) ± 0.21 (1)

Here, PGV is the maximum velocity [cm / s] at each point on the ground surface, and as described in Non-Patent Document 1, the reference substrate (hard substrate, S wave velocity calculated by the maximum velocity attenuation formula is used. It is a value obtained by multiplying the maximum speed PGV ₆₀₀ at 600 m / s) and the ground amplification degree ARV _i at each target point in the national land numerical information.

PGV = 1.31 PGV ₆₀₀ × ARV _i (2)

As described in Non-Patent Document 1, the maximum velocity attenuation equation is expressed by Equation (3), and information necessary for calculating PGV ₆₀₀ [cm / s] is magnitude M, depth of the hypocenter. Only D [km] and the shortest fault distance x [km].

log (PGV ₆₀₀ ) = 0.58 (M−0.171) +0.0038 D−1.29
−log (x + 0.028 × 10 ^{0.50 (M−0.171)} ) −0.002x (3)

  Assuming that the receiving device 1 has a function of acquiring the position information and the point where the receiving device 1 currently exists is known, x can be easily calculated from the position information of the epicenter and the position information of the receiving device 1. it can.

Further, since ARV _i is a value depending on the location, it can be selectively used based on the position information by being stored in the receiving apparatus 1 in advance.

Therefore, the measured seismic intensity I _INSTR can be easily calculated in the receiving apparatus 1 by acquiring the position information and magnitude of the epicenter which is unknown in the receiving apparatus 1 from the transmitting side.

Since the measured seismic intensity I _INSTR is calculated as a numerical value including a decimal point, for example, as shown in Table 3, it is converted into the maximum predicted seismic intensity in the seismic intensity class.

  On the other hand, the predicted arrival time (time required for arrival) from the time of the occurrence of the earthquake at the point where the receiver 1 is located is the travel time indicated by the Japan Meteorological Agency based on the epicenter distance Δ [km] and the depth D [km] of the epicenter It can be calculated using a table (for example, JMA2001). The epicenter distance Δ is a value that can be calculated from the location information (latitude, longitude) of the epicenter and the location information of the receiving device 1.

  Therefore, the predicted arrival time of the main motion can be easily calculated in the receiving device 1 by transmitting the location information of the epicenter and the occurrence time of the earthquake which are unknown in the receiving device 1.

  Of the message information format shown in Table 2, parts different from the message information format shown in Table 1 will be described below.

  The “various identification signals” are information signals accompanying emergency information such as “breaking ID” (12 bits), “information number” (4 bits), “message type” (2 bits), and signals such as broadcaster identification. Is applicable.

  The “breaking news ID” is inserted as an emergency information identification number (ID number). For example, an earthquake early warning published by the Japan Meteorological Agency has an earthquake identification number that starts with “ND” and is created by arranging (year), month, day, hour, minute, and second. The lower 12 bits of this number are allocated and used. In other cases such as emergency alert broadcasting, an identification number is assigned in the same way.

  This “breaking news ID” makes it possible to distinguish between the breaking news and other breaking news, even if a follow-up or cancellation information is generated in the same emergency information.

  The “information number” is a number that is incremented by one each time a subsequent bulletin is announced. It is given in order for the receiving apparatus 1 to recognize that it is emergency information and a series of information that comes out first, and is used repeatedly in the range of 0-15.

  The “message type” is used to indicate whether normal transmission in which emergency information is issued or whether the emergency information previously issued is canceled (cancellation information). Store it so that it can be canceled if a false report of emergency information occurs. Using two bits, for example, “00” indicates emergency warning broadcast or emergency earthquake early warning for general public, and “01” indicates cancel information. If there is no emergency information, “11” can be transmitted to provide insurance against the determination of the “activation signal”.

  For broadcaster identification, an identification signal based on the ARIB standard STD-B14 can be used. In this case, “broadcast area identification” (6 bits), “prefectural compound flag” (1 bit), and “area operator identification” (4 bits) are stored.

  “Earthquake occurrence time” is expressed in 24 hours, the hour display is 5 bits, the minutes and seconds are 6 bits, for example, 13:25:37 is “01101 | 011001 | 100101” (total 17 bits ) And binary numbers in units of hours, minutes, and seconds. In order to make it easy to see the distinction between hour, minute, and second, “|” is inserted only as a notation here, and is not inserted in actual transmission.

  “Latitude of the epicenter” and “longitude of the epicenter” represent the position of the epicenter on the ground surface. For example, latitude and longitude expressed with 1/10 degree accuracy such as 36.3 degrees north latitude and 136.5 degrees east longitude. Longitude. These are expressed as a numerical value of 10 times excluding the decimal point, with north latitude and east longitude being positive values, south latitude and west longitude being negative values.

  In other words, the “seismic latitude” and “seismic longitude” are 363 and 1365, respectively, and 11 bits and 12 bits are assigned and expressed in binary numbers such as “00101101011” and “010101010101”. Note that the negative value of south latitude or west longitude is a one's complement. For example, 36.3 degrees south latitude is expressed as “11010010100”.

  The “depth of the epicenter” is the depth of the epicenter from the ground surface, and is expressed as a numerical value with the unit [km]. For example, in the case of 30 km, it is 30, and is represented by a 10-bit binary number “0000011110”.

  “Magnitude” is a magnitude value indicating the magnitude of the earthquake, and is a numerical value with one decimal place, for example, 3.5. This is expressed as a 10-fold numerical value. That is, it is 35 and is a 7-bit binary number “0010011”.

  The warning generation unit 20 displays characters on a display (not shown) that can be provided in the receiving device 1 or sounds from a speaker (not shown) that can be provided in the receiving device 1. Generate a vibration warning by a vibrator (not shown) that can be generated or provided in the receiving apparatus 1, or generate a warning perceptually in an operation different from the normal operation. Alternatively, when the receiving device 1 is provided in any device such as a mobile phone, a personal digital assistant (PDA), a wristwatch, a table clock, a personal computer, etc., the sound is generated from a speaker using the function of these devices. Alternatively, a vibration warning by a vibrator may be issued, or a warning may be generated perceptually by an operation different from that during normal operation.

  The reception power detection unit 13 is configured with a directional coupler, monitors the output signal from the antenna 5, and determines the reception power value of all segments or partial reception segments of the digital terrestrial television broadcast signal received by the antenna 5. Output. For example, the received power detector 13 converts the voltage output of a detector such as a diode into a digital signal using another AD converter, and outputs the digital signal to the level display setting unit 14. The reception power detector 13 may be connected to the output terminal of the AD converter 7 so as to calculate the value of the reception power from the digital signal of the intermediate frequency signal.

  The frame synchronization establishment information detection unit 11 receives the emergency information establishment information output from the frame synchronization detection unit 10 of the AC synchronization establishment unit 2, detects whether or not frame synchronization is established, and sends the information to the level display setting unit 14. Output.

  The MER detector 12 calculates and outputs a MER (modulation error ratio) calculated from the constellation of the DBPSK signal before the delay detection of the AC signal extracted by the AC extractor 9.

  As will be described later, the reception power detection unit 13, the frame synchronization establishment information detection unit 11, and the MER detection unit 12 select one or two of the display methods of the level display setting unit 14. It can be configured as a combination.

  The level display setting unit 14 receives the received power value (reception field strength may be calculated) output from the received power detection unit 13, the frame synchronization establishment information detection unit 11, and the MER detection unit 12. One or more of information establishment information (whether or not AC signal frame synchronization is established) and each value of AC signal MER are acquired, and based on the value, a predetermined reception condition evaluation criterion (for example, each The value is expressed as an evaluation value of the reception state in several stages, and a weighted average is performed with arbitrary weighting), and the level meter value indicating the reception state of the emergency information is determined, and the determined level meter value is displayed. The signal is output to the display control unit 15.

  The display control unit 15 receives the control signal output from the level display setting unit 14 and displays the value of the level meter on the display device connected to the receiving device 1 based on the control signal. For example, when the receiving device 1 is applied to a receiving terminal dedicated to digital terrestrial television broadcasting, the level meter value M1 is displayed on the display screen 31-1 of the display device 31 of the receiving terminal (FIG. 2). reference). Further, when the power of the display device 31 is off, there is a method of displaying with a plurality of LEDs (LED1, LED2, LED3) on the frame surface of the display screen 31-1 (see FIG. 3).

  When the receiving device 1 is installed in a portable terminal of digital terrestrial television broadcasting or the like, a level meter value M2 is displayed on a screen 32 of another liquid crystal or the like included in the portable terminal, for example, a cellular phone. It can also be displayed above (see FIG. 4).

  The display device 31 may be configured in the same way as the emergency information warning generation unit 20 or may be configured to be shared.

  In addition to a portable terminal for digital terrestrial television broadcasting, when a receiving device 1 is installed in a device used for receiving emergency information, such as a table clock, in a predetermined display device 33 of the clock, It is possible to display the earthquake early warning on the upper screen 33-1, and to display the level meter value M3 on the lower screen 33-2 (see FIG. 5).

  Hereinafter, the receiving operation of the receiving device 1 according to the first embodiment will be described in more detail.

  First, in the receiving apparatus 1 according to the first embodiment, the AC synchronization establishing unit 2 performs symbol synchronization by using guard interval correlation or the like from the OFDM signal received in the selected channel, and extracts the AC signal through FFT calculation.

  Furthermore, in the receiving apparatus 1 according to the first embodiment, the AC synchronization establishment unit 2 performs frame synchronization of the AC signal based on the synchronization signal multiplexed on the AC signal.

  Then, the receiving apparatus 1 according to the first embodiment performs DBPSK demodulation according to the timing obtained based on the frame synchronization, receives it by the AC information analysis unit 3, recognizes the emergency information, and outputs it to the warning generation unit 20. To do.

  In order to ensure the above-described AC signal reception operation, the display control unit 15 according to the first embodiment includes any one of the reception power detection unit 13, the frame synchronization establishment information detection unit 11, and the MER detection unit 12. Alternatively, based on information obtained from any two combinations or all, the level display setting unit 14 estimates whether or not the emergency signal for receiving and demodulating the AC signal by the receiving apparatus 1 is received, and the estimation result Is displayed on a predetermined display device via the display control unit 15. Thereby, it is possible to explicitly notify in advance whether or not the receiver of the receiving device 1 that receives the emergency information is in a situation where the emergency information can be received.

  The receiver 1 of the first embodiment described above has been described as receiving an emergency earthquake bulletin transmitted by an AC signal, but is configured to receive an emergency warning broadcast or an emergency earthquake bulletin transmitted by a TMCC signal. The same effect can be obtained. In other words, considering the future expandability of TMCC, the emergency earthquake bulletin is transmitted using the currently unused portion of the TMCC, the reserve bit, the emergency earthquake bulletin transmission using the AC signal described above, or the emergency It can be operated in the same manner as in the case of alarm broadcast transmission.

  In the case of the mode 3 synchronous modulation unit of the partial reception segment (segment number # 0) of the ISDB-T terrestrial digital television broadcast wave, for example, the TMCC signal is carrier numbers # 101, # 131, # 286 and It is known as a signal provided for transmitting information related to the demodulation operation of the receiving apparatus 1 carried by TMCC carriers at four locations # 349.

  According to the receiving device 1 of the first embodiment, in order for the receiver of the receiving device 1 to reliably receive emergency information when necessary, the receiving device 1 that receives the emergency information reliably receives the emergency information. Whether it can be done or not can be grasped beforehand in advance.

  Next, the receiving device 61 according to the second embodiment of the present invention will be described. The same components as those in the first embodiment will be described with the same reference numerals.

  FIG. 2 shows a receiving apparatus 61 according to the second embodiment of the present invention. The receiving part of the AC signal that constitutes the receiving device 61 of the second embodiment is composed of an AC synchronization establishing unit 2, an AC information analyzing unit 3, and a warning generating unit 20, and is basically the same as the receiving device 1 of the first embodiment. It is the same.

  The AC synchronization establishment unit 2 includes a frequency conversion unit 6, an AD conversion unit 7, a symbol synchronization unit 21, an FFT processing unit 8, an AC extraction unit 9, and a frame synchronization detection unit 10. The symbol synchronization unit 21 has a function of performing symbol synchronization by guard interval correlation or the like, and the description thereof is omitted in the first embodiment.

  The AC information analysis unit 3 includes an error correction unit 16, an AC decoding unit 17, and an information processing unit 18, and is the same as the reception device 1 of the first embodiment.

  The main reception status determination control unit of the reception device 61 according to the second embodiment of the present invention monitors a signal of a specific component in the reception device 61, a received power detection unit 13, a guard interval correlation peak detection unit 22, a frame This embodiment is different from the first embodiment in that a synchronization establishment information detection unit 11, a MER detection unit 12, and a level display setting unit 14 are added, and a guard interval correlation peak detection unit 22 is added. In the receiving apparatus 61 according to the second embodiment of the present invention, when evaluating the reception quality of the emergency information reception state, the symbol synchronization obtained from the calculation result of the guard interval correlation calculated when performing symbol synchronization is used as an evaluation criterion. The evaluation information is evaluated based on whether or not the detected information is equal to or higher than a predetermined threshold condition.

  In the description of the receiving device 61 of the second embodiment, the details of the same components as those of the receiving device 1 of the first embodiment are omitted.

  As described for the FFT processing unit 8 of the receiving apparatus 1 of the first embodiment, the effective symbol period can be defined by performing symbol synchronization by guard interval correlation or the like, and the symbol synchronization unit 21 is responsible for this symbol synchronization. Works.

Here, the principle of symbol synchronization is confirmed. FIG. 7A illustrates an example of the symbol synchronization unit 21 including the guard interval correlation calculation unit 211 and the symbol detection unit 211, and FIG. 7B illustrates the relationship between the effective symbol period and the guard interval period. FIG. In general, as shown in FIG. 7B, an OFDM symbol has a length defined by a guard interval ratio R _GI , for example, 1/8, before an effective symbol period T _U (N _U samples) for carrying data information. Guard interval period T _GI (= R _GI × T _U ) (N _GI sample = R _GI × N _U ) is provided (FIG. 1b). Since the purpose of the guard interval is to alleviate the influence of multipath, a copy (N in the figure) of _NGI samples at the end of the effective symbol period is used.

Therefore, the last between the parts, always autocorrelation coefficients delay time difference of the same length as the effective symbol period T _U there is a correlation between the guard interval period T _GI and the effective symbol period T _U of the OFDM symbol When calculated, a peak value is observed in the correlation coefficient just in the period of the OFDM symbol. Symbol synchronization uses this relationship.

Referring to FIG. 7A, in the symbol synchronization unit 21, the received signal input to the guard interval correlation calculation unit 211 via the AD conversion unit 7 is branched into two, and one is input to the multiplication unit 2112. The other is input to the delay unit 2111. Delay unit 2111 delays the effective symbol period length _{T U,} i.e., inputs the _{N U} samples delayed sample signal was of the multiplication unit 2112. The multiplying unit 2112 performs multiplication between each sample signal of the received signal and each corresponding sample signal delayed by _NU samples, and then the accumulating unit 2113 outputs the result, which is output from the multiplying unit 2112. each of the samples to the multiplication result of each sample subjected to sliding integration guard interval period T _GI, i.e. N _GI recorded in samples of buffers, the corresponding delayed for each sample signal and N _U samples of the received signal to The multiplication result with the signal is integrated every symbol and output. The absolute value calculation unit 2114 performs the absolute value calculation on the output of the integration unit 2113, and the calculation result of the guard interval correlation output thereby is T _U + T _GI (as shown in FIG. 8A). Alternatively, a signal having a correlation peak in a period of (N _U + N _GI ) samples is transmitted. Symbol detector 212 detects the period that matches the period of the OFDM symbols, each OFDM symbol of the N _U samples of the received signal cut out by this period is sampled and sent to the FFT processing unit 8.

  At this time, the calculation result of the guard interval correlation output from the guard interval correlation calculation unit 211 is ideally a result as shown in FIG. 8A. Due to changes in the environment of the propagation path of the broadcast wave such as a path, it may fluctuate with changes in the magnitude of received power. For example, as shown in FIG. 8B and FIG. 8C, the magnitude of the peak value and the number of peaks observed in the calculation result of the guard interval correlation vary depending on the poor propagation environment.

  This is related to the reception quality of the received OFDM signal. FIG. 8B shows a case where the received power is low and the noise is large. Compared to the case of FIG. 8A, the peak is small, and fluctuations due to noise in portions other than the peak are conspicuous, indicating that the ratio between the two is small. FIG. 8C shows an example in which a plurality of peaks are observed due to the presence of the reflected wave, and as a result, the width of the peak becomes wider and the value of the peak becomes smaller. Compared to FIG. 8A, FIG. 8B and FIG. 8C show that the reception characteristics deteriorate.

  Therefore, the symbol detection unit 212 sends a symbol obtained by sampling each OFDM symbol of the reception signal cut out between the peaks to the FFT processing unit 8 and also detects detection information of this symbol synchronization (for example, its peak value or The number of peaks, peak width, or distribution state) can be sent to the guard interval correlation peak detector 22. In the receiving device 61 according to the second embodiment of the present invention, the detection information that is sampled by the symbol detection unit 212 is used as one of the evaluation values of the reception state.

  The guard interval correlation peak detection unit 22 outputs the symbol synchronization detection information output from the symbol synchronization unit 21, that is, the symbol detection unit 212, to the level display setting unit 14.

  The level display setting unit 14 is an AC signal receiving device based on information received from the received power detection unit 13, the guard interval correlation peak detection unit 22, the frame synchronization establishment information detection unit 11, and the MER detection unit 12. 61 determines the reception quality of the reception state of emergency information received and demodulated, and sets the level display of the display control unit 15 based on the estimation result.

  Thereby, when the receiving device 61 is not in a situation where the emergency information can be received, it is possible to notify the receiver of the receiving device 61 that an error may occur in receiving the emergency information depending on the degree. .

  The received power detector 13, the guard interval correlation peak detector 22, the frame synchronization establishment information detector 11, and the MER detector 12 are urgent information that the level display setting unit 14 receives and demodulates from the AC signal receiver 61. Can be configured as any one, any two combinations, any three combinations, or all of them.

  The receiver 61 according to the second embodiment allows the receiver to determine in advance whether or not the receiver 61 that receives the emergency information can reliably receive the emergency information in order to reliably receive the emergency information when necessary. In addition, it becomes possible to always grasp.

  Next, the receiving device 41 according to the third embodiment of the present invention will be described. The same components as those in the first embodiment will be described with the same reference numerals.

  The receiving device 41 according to the third embodiment intermittently receives only AC information between a plurality of OFDM frames as intermittent reception between frames, and intermittently receives only necessary information within an OFDM frame as intermittent reception within a frame. Configured to receive.

  FIG. 9 shows a receiving apparatus 41 according to the third embodiment of the present invention. The receiving device 41 of the third embodiment is different from the configuration of the receiving device 41 of the first embodiment in that the power source 25, the first power switch 19 that controls the power-on to the AC synchronization establishing unit 2, and the AC information analysis A second power switch 24 that controls the power-on of the unit 2 and a power control unit 4 are further provided. Detailed description of the same components as those of the receiving device 1 of the first embodiment will be omitted.

  For simplification of explanation, the MER detector 12 is omitted from the configuration of the receiving device 1 of the first embodiment, but can be used similarly. Moreover, the guard interval correlation peak detection part 22 added in Example 2 can be used similarly.

  Although not shown, the power control unit 4 is always supplied with power from the power source 25. The output of the frame synchronization detection unit 11 of the AC synchronization establishment unit 2 is input, and the frame synchronization is held inside the power supply control unit 4. This consists of, for example, a clock generator and a counter. The clock generated by the clock generator is counted by the counter, and a frame pulse is generated every time the count value reaches a predetermined value, and the count value is converted to a frame synchronization signal (reset pulse). ), And according to this frame pulse, the two switches connected to the power control unit 4, the first power switch 19 and the second power switch 24 are opened and closed, and the power supply for intermittent reception between frames and intermittent reception within the frame Control the supply.

  The control signals for opening and closing the two switches of the power supply control unit 4 include the internally held frame pulse and emergency information synchronization establishment information from the frame synchronization detection unit 10 (in this case, to the frame synchronization establishment information detection unit 11 The emergency information synchronization establishment information is input via the power supply control unit 4), based on intermittent reception between a plurality of OFDM frames, or intermittent reception of only predetermined information within the same OFDM frame, or It is a control signal that determines intermittent reception of these combinations and is turned on / off (a value of 0 or 1) at each necessary intermittent reception timing.

  The first power switch 19 opens and closes at the timing of the control signal output from the power control unit 4 and operates to control the power supply of the AC synchronization establishment unit 2.

  On the other hand, the power supply control unit 4 monitors whether there is, for example, “Earthquake Early Warning” in the emergency information transmitted from the AC synchronization establishment unit 2 (for example, in Table 1 or Table 2). The first function is to continuously supply power to the AC synchronization establishing unit 2 when it is determined that there is emergency information. The power switch 19 is switched and the second power switch 24 is switched so as to supply power to the AC information analysis unit 3.

  On the contrary, if the power supply control unit 4 determines that the state is changed to the normal state from the start signal value of the message information indicating that there is emergency information, the control signal from the power supply control unit 4 The power supply to the AC synchronization establishment unit 2 is controlled by the first power switch 19 and the power supply to the AC information analysis unit 3 so that only information necessary for monitoring emergency information is constantly monitored at the timing of The second power switch 24 is switched so as to shut off.

  By performing this operation as inter-frame intermittent reception and intra-frame intermittent reception, it becomes possible to reliably and immediately acquire information in emergency information while saving power consumption extremely.

  The display control unit 15 according to the third embodiment operates in the same manner as the display control unit 15 according to the first or second embodiment. That is, the reception power detection unit 13, the guard interval correlation peak detection unit 22, the frame synchronization establishment information detection unit 11, and the level display setting unit 14 are always powered on, and also in the reception device 41 of the third embodiment. The receiver of the receiving device 41 always knows in advance whether or not the receiving device that receives the emergency information can reliably receive the emergency information in order to reliably receive the emergency information when necessary. can do.

  Next, the receiving device 51 according to the fourth embodiment of the present invention will be described. The same components as those in the first embodiment will be described with the same reference numerals.

  FIG. 10 shows a receiving apparatus 51 according to the fourth embodiment of the present invention. The receiving device 51 according to the fourth embodiment has a state in which the power supply can always be turned on in any of the AC synchronization establishment unit 2 and the AC information analysis unit 3, that is, when all the contents of the telegram information are decoded. A parity detection unit 23 that receives the parity check information output from the error correction unit 16 to detect whether there is an error in the AC signal and determines whether or not the reception information of emergency information is received is provided. The parity detection unit 23 can be provided in place of the reception power detection unit 13 and the MER detection unit 12 of the receiving device 1 of the first embodiment and the guard interval correlation peak detection unit of the second embodiment, but they should be used together. Thus, a more reliable operation can be expected even when a parity check error is missed or erroneously detected.

  The parity detection unit 23 receives the inspection result output in the process of error correction performed by the error correction unit 16 of the AC information analysis unit 3, and uses, for example, the number of errors for a predetermined plurality of OFDM frames as a reference The level of the error is determined to determine whether or not the reception information of the emergency information can be received, and the determination result of whether or not the emergency information is received is generated as information of a predetermined level value, and is output to the level display setting unit 14.

  Note that the check result output in the process of error correction performed by the error correction unit 16 of the AC information analysis unit 3 includes, for example, a result of parity check again after error correction of a differential cyclic code, a CRC (Cyclic Redundancy), or the like. check) code can be added separately, and the result of parity check after error correction can be used.

  As in the first embodiment, the level display setting unit 14 converts this parity information into a display level value along with information on whether or not the frame synchronization of the AC signal output from the frame synchronization establishment information detection unit 11 is established. Output to the display control unit 15. For example, in the three LEDs illustrated in FIG. 3, the leftmost LED indicates that the frame synchronization has been established, and if there is an error several times but an emergency information signal has been received, In the case where light emission is displayed and reception is possible without error, the display level is changed using three LEDs such that all LEDs are light-emitting displayed and output via the display control unit 15.

  As described above, also in the fourth embodiment of the present invention, the receiver of the receiving device 51 ensures that the emergency information is received by the receiving device that receives the emergency information in order to reliably receive the emergency information when necessary. Whether or not it can be received can be known in advance and always.

  Although the above-described embodiments have been described by way of typical evaluation methods for specific reception availability, it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of the present invention. For example, in the above-described embodiments, in order to facilitate understanding of the present invention, the receiving apparatus according to the present invention has been described as being able to be provided in, for example, a mobile phone. And the function of the receiving apparatus according to the present invention can be integrated into the decoding function. For example, when the mobile phone has a function of detecting received power, etc., the detection function such as received power of the present invention is made to function in the same manner as in the above-described embodiment using the function of the mobile phone itself. Can do. Moreover, although emergency information was demonstrated as transmitting with an AC signal, you may comprise so that it may transmit with a TMCC signal. Accordingly, the invention should not be construed as limited by the embodiments described above, but only by the claims.

  The receiving device according to the present invention can surely receive emergency information such as emergency warning broadcasts and emergency earthquake warnings, and thus is useful for various applications related to whether or not digital terrestrial television broadcasting can be received.

DESCRIPTION OF SYMBOLS 1 Receiver 2 AC synchronization establishment part 3 AC information analysis part 4 Power supply control part 5 Antenna 6 Frequency conversion part 7 AD conversion part 8 FFT processing part 9 AC extraction part 10 Frame synchronization detection part 11 Frame synchronization establishment information detection part 12 MER detection Unit 13 received power detection unit 14 level display setting unit 15 display control unit 16 error correction unit 17 AC decoding unit 18 information processing unit 19 first power switch 20 warning generation unit 22 guard interval correlation peak detection unit 23 parity detection unit 24 Power switch 25 2 Power supply 31 Display device 31-1 Display screen 32 Screen 33-1 Upper screen 33-2 Lower screen M1, M2 Level meter values LED1, LED2, LED3 Light emitting diode 41 Receiver 51 Receiver 61 Receiver 211 Guard interval correlation calculation unit 212 Symbol detection unit 2111 Delay unit 211 2 Multiplier 2113 Accumulator 2114 Absolute value calculator

Claims (3)

A receiving device for receiving an AC signal or a TMCC signal from a terrestrial digital television broadcast wave,
The telegram information that stores the activation signal for identifying the presence or absence of the earthquake early warning and the emergency information including the information of the earthquake early warning is prescribed in advance to be transmitted by the AC signal or the TMCC signal,
Means for receiving a terrestrial digital television broadcast wave and extracting an AC signal or a TMCC signal;
The guard interval symbol synchronization detection information obtained from the calculation result of the correlation to be calculated when performing symbol synchronization on the received signal of a broadcast wave,及 Beauty, based on the information necessary for frame synchronization contained in the message information Means for detecting one or more of emergency information synchronization establishment information indicating presence / absence of frame synchronization establishment of generated emergency information;
And a means for determining a value of a level meter representing a reception state of the emergency information based on the detected value. The message information includes an emergency earthquake warning start signal,
The receiving apparatus according to claim 1, further comprising a control unit that monitors information of the activation signal and supplies power to the receiving apparatus in an intra-frame intermittent reception operation or an inter-frame intermittent reception operation. Means for performing error correction of the message information when decoding all the contents of the message information;
Means for detecting the presence or absence of an error from the parity check information at the time of error correction, determining whether or not the reception information of the emergency information is received, and generating a determination result of the reception availability as information of a predetermined level value; Prepared,
The means for determining the value of the level meter indicating the reception state of the emergency information includes the information on the determination result of the reception availability, the detection information of the symbol synchronization, the information on the MER, and the emergency information synchronization establishment information. The receiving device according to claim 1 or 2, wherein a value of a level meter representing a reception state of the emergency information is determined based on one or more of the following.

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