JPH10224244A - Radio broadcast reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a receiver to switch to reception of a DAB so as to output the sound with high quality in the case that the same program as a selected FM/AM broadcast station is broadcast in the digital audio broadcast(DAB). SOLUTION: A receiver is provided with reception parts 22a, 23a for an FM/AM broadcast and reception parts 22b, 24 for DAB broadcast, a control part 30 receives a DAB broadcast signal with the DAB reception part and checks whether or not a DAB broadcast of the same program as the selected AM or FM broadcast station is broadcasting and in the case that the DAB broadcast of the same program is broadcasting, the DAB reception part is controlled to receive the DAB broadcast signal, including the program and to output the sound, based on the DAB broadcast in place of the AM or FM broadcast.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio broadcast receiving method, and more particularly to a radio broadcast receiving method for receiving and outputting a DAB broadcast of the same program as an AM broadcast or an FM broadcast after selecting AM or FM.

[0002]

2. Description of the Related Art Digital audio is now widely recognized for its excellent characteristics and ease of use, and is rapidly becoming popular. Against this background, digitalization of audio broadcasting has become active and digital audio broadcasting DAB (Digital Audio Broadcasting) has been realized in Europe.

FIG. 7 shows a DAB broadcast signal frame structure of mode II adopted in a DAB system. One frame length is 24 ms, and a 2-symbol synchronization section SYNC is used.
And FIC (Fast Inf)
or the main service channel (MSC) of 72 symbols. The synchronization unit SYNC includes a null symbol and a phase reference symbol PRS used for recognizing a start point of a frame.
Contains. The high-speed information channel unit FIC includes high-speed information blocks FIB1 to FIB3 of three symbols, and includes a service label, a service component label, service arrangement data, and a program type code PTY (Pro
It contains various information such as gram type code).

The main service channel MSC is divided into 72 data fields (symbols), a broadcast signal of a predetermined service (program) is inserted into each data field, and 6 to 8 services (simultaneously) are transmitted from one broadcasting station. Program) can be transmitted. Which service corresponds to which data field is specified by the service array data included in the high-speed information channel unit FIC. Each high-speed information block FIB1 to FIB3 of the high-speed information channel FIC has a hierarchical structure as illustrated, and is specified by FIG type 131 and extension 141.
Predetermined data is inserted into the datafield 142. That is, each of the high-speed information blocks FIB1 to FIB3 is
6-bit (30-byte) FIB data field
ld) Consists of 111 and CRC 112, FIB data field 111
Is configured to include a plurality of FIG (Fast Information Group) 121-123.

Each FIG (Fast Information Group) 121-12
3 are (1) FIG type 131 and (2) Le
ngth (byte length of FIG data field) 132, (3) FIG data f
ield133, and FIG data field 133 contains Exte
nsion 141 (FIG. extended identification number) and data field 142 are included. In the data field 142, the service label, service component label, service arrangement data, program type code PTY, supported announcement types, frequency information list for each region, broadcast station list for each region, and broadcasting during the same program broadcast Various data such as station information (service linking information) is inserted. The above shows the frame configuration of Mode II for satellite broadcasting using the 1.5 GHz band.
The frame structure of mode I using the frequency band of the above has almost the same configuration, and one frame length is 96 ms.

FIG. 8 is a diagram showing the configuration of a DAB transmitter.
Reference numeral 1m denotes a data compression unit for encoding an analog audio signal (audio signal of each service) into MPEG audio data with high efficiency. 2a to 2m are transmission path coding units for adding an error / detection correction code, and 3 is a multiplexing unit, which outputs output data of each of the transmission path coding units 2a to 2m according to service sequence data. It is mapped to a field (symbol) and time-division multiplexed.
4 is an interleave / OFDM modulator, and IDFT
OFDM (Orthogonal Inverse)
Frequency division multiplexing is performed, and interleaving is performed by rearranging the order of multiplexed signals in a symbol according to a predetermined format. That is, OFD
The M modulator divides each symbol (phase reference symbol, data symbol) into N sets of 2 bits each, differentially encodes the first data of each set as a real part and the second data as an imaginary part, and performs differential coding of the differential code. The real part and the imaginary part are sequentially input to the inverse Fourier transform unit and subjected to IDFT processing to output a baseband modulated wave. Numeral 5 is a quadrature modulation that converts a real part and an imaginary part output from the interleave / OFDM modulator into analog signals, multiplies each by a cos wave and a sin wave of a transmission local frequency fc, and combines the multiplication results to perform orthogonal transformation. A unit 6 is a frequency conversion unit that converts a transmission carrier obtained by quadrature modulation into an RF signal, and 7 is a transmission power amplifier.

FIG. 9 is a configuration diagram of a DAB receiver. 11
Denotes an antenna, 12 denotes a DAB RF signal demodulation unit that outputs a baseband analog signal obtained by multiplying a received signal by a cos wave and a sine wave of a carrier frequency fc, 13
Denotes an AD converter that converts a baseband analog signal into digital data at a predetermined sampling frequency; and 14, performs FFT demodulation processing, differential decoding processing, and the like on digital data input from the AD converter and performs high-efficiency code data ( MP
A transmission line decoding circuit for restoring / outputting EG audio data), an audio decoding unit 15 for decoding MPEG audio data to original PCM audio data, a DA converter 16 for converting PCM audio data to an analog audio signal, Denotes a control microcomputer for controlling the entire DAB receiver, 18 denotes an operation / display unit,
a is a display unit, and 18b is an operation key unit.

The transmission line decoding circuit 14 includes an FFT differential demodulation unit 14a, a selective decoding unit 14b, a deinterleave unit 1
4c and the like. The FFT differential demodulation unit 14a performs FFT processing and differential decoding processing on the digital data output from the AD converter 13, and demodulates the interleaved transmission data. The deinterleave 14c deinterleaves the output data of the FFT differential demodulation unit to return to the original data sequence, and the selective decoding unit 14b performs error detection and correction processing on the deinterleaved data, and the contents of the high-speed information channel unit FIC. Is input to the control microcomputer 17.

The control microcomputer 17 detects the symbol position (data field) of the service (program) specified by the user based on the service arrangement data included in the high-speed information channel unit FIC, and notifies the selective decoding unit 14b.
The selective decoding unit 14b outputs decoded data (MPEG audio data) of the notified symbol (data field) to the audio decoding unit 15. The audio decoding unit 15 converts the input decoded data (MPEG audio data) into the original PCM audio data and outputs it. The control microcomputer 17 appropriately changes a service label or the like included in the high-speed information channel FIC according to a user request.
It is displayed on the display section 18a of the operation / display section 18.

[0010]

At the time of DAB introduction,
Not all areas are covered by DAB broadcasting,
AM / FM broadcast and DAB broadcast are appropriately combined depending on the region. Also, not all broadcast contents are broadcast on DAB. For this reason, the radio receiver includes a DAB receiver and an FM / AM receiver, and the user switches a reception band (receiver) as appropriate to receive a desired broadcast. If the receiver moves and the DAB signal deteriorates while receiving the DAB broadcast, the receiver automatically switches to the FM broadcast or the AM broadcast to continue the reception. By the way, when a user selects and listens to FM or AM broadcast, there is a case where a broadcast of the same content (the same program) is broadcast by DAB. In such a case, it is desirable to listen to DAB broadcasting with high sound quality,
I do not know whether the same service can be obtained by AB broadcasting. Therefore, even in the above case, the user will continue to receive low-quality FM or AM broadcasts.
Further, even if it is found that the same service is provided in the DAB broadcast, there is a problem that the operation until the program can be heard becomes troublesome.

From the above, it is an object of the present invention to provide an
In the case where the same program as the broadcast or AM broadcast is being DAB-broadcasted, the high-quality sound is output by automatically switching to DAB broadcast reception. Another object of the present invention is that when switching to DAB broadcast reception, DB broadcast signal reception field strength degradation or the end of program broadcasting causes D
The purpose is to automatically return from AM broadcast reception to AM / FM reception.

[0012]

According to the present invention, there is provided a receiver for AM / FM broadcast and a receiver for digital audio broadcast (DAB broadcast). , Selected AM broadcast or FM
Whether the DAB broadcast of the same program as the broadcast is being broadcast
A radio broadcast receiving method for receiving and examining a predetermined DAB broadcast signal at a B broadcast receiver and outputting audio based on DAB broadcast instead of AM broadcast or FM broadcast when a DAB broadcast of the same program is being broadcast. Is achieved by Further, according to the present invention, the above object is attained by a radio broadcast receiving method for automatically switching from DAB broadcast reception output to AM / FM reception output when the reception field strength of a DAB broadcast signal is degraded or when the broadcast of a program ends. You.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

(A) Configuration of DAB Receiver FIG. 1 is a configuration diagram of a DAB receiver of the present invention. 21a,
21b is an antenna, 22a is AM from AM / FM station
/ 1 that receives FM broadcast signals and converts them to intermediate frequency signals
The tuner unit 22b is a second tuner unit that receives a DAB signal from a DAB station and converts it into an intermediate frequency signal. Although not shown, each of the tuner sections 22a and 22b is composed of a front end including a tuning section, a high-frequency amplifier, and a frequency converter, and a PLL circuit (local oscillation circuit) that outputs a frequency signal according to a selected frequency. .

Reference numeral 23 denotes an AM / FM broadcast demodulator for demodulating and outputting an AM / FM broadcast signal, 23a an IF filter, 23b a detection circuit for demodulating an audio signal from an intermediate frequency signal, and 23c an S filter of the IF filter. The S-meter is connected to the meter terminal and detects the received electric field strength of the AM / FM broadcast signal being received. Numeral 24 denotes a DAB broadcast demodulator for demodulating a broadcast signal of the program from a frequency multiplexed signal inserted in a data field (symbol) corresponding to the designated program and outputting the demodulated signal. DAB broadcast demodulator 24
24a, a DAB IF filter, 24b a DAB signal demodulator (see FIG. 9), 24c a DA converter for converting PCM audio data to analog,
d is an S-meter connected to the S-meter terminal of the DAB IF filter 24a and detecting the received electric field strength of the DAB broadcast signal being received. The DAB signal demodulation unit 24
B signal demodulation function, demodulated high-speed information channel F
A function of inputting various information included in the IC to the control unit 30;
It has a function of demodulating an MPEG audio signal corresponding to a program specified by a user, a function of converting an MPEG audio signal into PCM audio data, and outputting the same.

Reference numeral 25 denotes an output signal of the FM broadcast demodulator 23 and D
A selection unit for appropriately selecting and outputting an output signal of the AB broadcast demodulation unit 24, a low-frequency amplifier 26, a speaker 27, and an operation unit 28 provided with various keys, a band switching key, a seek key, and a program selection key Having keys, etc., 29
Is a display unit, and 30 is a control unit for controlling the entire radio receiver. The control unit 30 controls the first and the second based on the channel selection operation.
A function of performing electronic tuning / seek control of the tuners 22a and 22b, a function of monitoring whether a DAB broadcast of the same program as the selected AM / FM broadcast is being performed, and a DAB of the same program as the selected AM / FM broadcast Function to switch to DAB broadcast reception when broadcasting is being performed, DAB
When switching to broadcast reception, a function to return from DAB broadcast reception to AM / FM reception by DAB broadcast signal reception electric field strength deterioration, program end of broadcast, or AM / FM channel selection operation, etc. Have.

(B) Various information related to the present invention included in the high-speed information channel FIC In the present invention, when the same program as the selected FM broadcast or AM broadcast is DAB broadcast, DAB broadcast reception is automatically performed. Control to switch. In order to execute such control, frequency information, broadcast station information, and service linking information for each region included in the high-speed information channel FIC are used. The frequency information for each region is
G0 / 21 (Type 0 field for extension 21) is inserted into the data field specified by G0 / 21 (Type 0 field for extension 21). As shown in FIG. The service linking information is inserted into FIG. 0/6 (Type 0 fieldfor
It is inserted in the data field specified by extension 6).

(A) Regional frequency information Regional frequency information is inserted into the data field specified by FIG. 0/21 as shown in FIG.
1, 202,... Each frequency information 201-203
Is a region ID (Region ID) 211, multiple FI lists
(Frequency Information List) 212, 213, ・ ・ ・ 214,
It has a FI list length of 215. Each FI list 212 ~
214 is Id field 221, R & M (Range & Modulatio)
n) 222, Continuity 223, frequency list length 22
4. Frequency list for specifying multiple frequencies (Freq.lis
t) Contains 225. The R & M is composed of 4 bits, and each frequency included in the frequency list 225 is for DAB broadcasting (0000, 1000), for RDS compatible FM broadcasting (1000), and not for RDS. FM broadcasting (1001), ・ AM (9KHz step MW and LW) (1010), ・ AM (5KHz step MW and SW) (1100) Things.

As described above, by referring to the data field of FIG. 0/21, all the broadcasting station frequencies belonging to the area specified by Region Id 211 can be converted to DAB broadcasting stations (R & M = 0000,0001) and FM / AM broadcasting stations. (AM is 9KHz step MW and L
W), AM broadcasting station (MW and SW in 5KHz steps) Can be obtained separately.

(B) Regional Broadcast Station Information Regional broadcast station information is inserted into a data field specified by FIG. 0/11 as shown in FIG. 3, and a plurality of regional identification information (Region Identificatio) 301, 302,.・ ・, 303 is provided. GATy (Geographica
l Area Type) 311, Area Identifier (RegionId) 312, Ge
It has ographical Area information 313, and Geographical Area information 313 has a plurality of Transmitter Groups 321 to 324. Each Transmitter Group 321-324 is a Transmitter
Group identifier (MainId) 331, SubId list length 33
2. It is composed of a SubId list 333, and the SubId list 333 includes a plurality of sub-identifiers (SubId) 341 to 342 of the transmitter.

As described above, by referring to the data field of FIG. 0/11, it is possible to obtain (MainId + SubId) of all transmitters (transmitters) belonging to the area specified by Region Id 312. In the DAB broadcast, MainId and SubId of a transmitter can be recognized from null period information of the DAB broadcast signal. Therefore, the DAB signal is received and the DAB signal transmitter (DA
Recognize the MainId and SubId of B broadcast station), and then
The region identifier RegionId having the recognized MainId and SubId from the data field of FIG 0/11 included in the DAB signal
Is obtained, the region identifier RegionId indicates the region to which the DAB receiver (vehicle) currently belongs.

(C) Service Linking Information The service linking information is, as shown in FIG.
Inserted into the datafield identified by
Linking information 401, 402,... 403 is provided. Each servi
ce linking information 401 to 403 is the Id list flag 411 (I
d indicates the presence or absence of a list), Linkage Actuator (LA) 412 indicating whether the link is active or not, Soft / Hard (S / H) 413 indicating whether the service is the same, Internat
ionalLinkage Set Indicator (ILS) 414, Linkage Set Numbe that indicates whether the same program is being broadcast
r (LSN) 415, Id list usage 416, Id count 417 included in the Id list, and Id list 418.
Note that Id with the same LSN is broadcasting the same service.

Id list usage 416 is a 2-bit Identif
ier List Qualifier (IdLQ) 421 and Shorthand indicator (S
hd) 422, and the Id list 418 has a plurality of Ids 431 to 433. For IdLQ 421, the Id included in the Id list is (1)
DAB SId (00), (2) RDS PI-code (RDS Program I
dentification code) (01), (3) AM or R
Indicates whether the service is an FM service other than DS (10).
From the above, if the Id of the selected AM / FM is known,
The service linking information contained in the Id list 418 is obtained, and the selected AM /
The LSN of FM broadcast is determined. Therefore, if the service identifier SId of the DAB broadcast having the same LSN as the AM / FM broadcast is obtained from the service linking information, the DAB broadcasting the same program as the AM / FM broadcast is obtained.
You can ask for a broadcasting station.

(C) Basic Operation of Radio Receiver The FM band is selected in the operation unit 28.
When the seek key is operated, the control unit 30 performs electronic tuning / seek control on the first tuner unit 22a, searches for an FM station whose received electric field strength is equal to or higher than a set level, and operates the first tuner unit to set the frequency to the FM station frequency. Synchronize. Control unit 3
0 notifies the selection unit 25 that the FM station has been selected.
The first tuner 22a converts the sought FM broadcast signal into an intermediate frequency signal, the FM broadcast demodulator 23 demodulates the FM audio signal from the intermediate frequency signal, and the selector 25 selects the FM audio signal. Output.

On the other hand, when the DAB band is selected on the operation unit 28 and then the seek key is operated, the control unit 30 performs electronic tuning / seek control on the second tuner unit 22b, and the DAB band whose received electric field intensity is equal to or higher than the set level is set. The station is searched, and the second tuner is tuned to the DAB station frequency. Further, the control unit 30 notifies the selection unit 25 that the DAB station has been selected. The second tuner unit 22b receives the frequency-division multiplexed broadcast signal from the DAB station that has been sought and converts it into an intermediate frequency signal. The DAB signal demodulation unit 24b demodulates the DAB signal from the intermediate frequency signal input from the tuner, and inputs PCM data to the DA converter 24c. The DA converter 24c converts the PCM data into an analog signal, and the selector 25 selects and outputs the audio signal output from the DA converter 24c.

(D) Overall Reception Control Process of the Present Invention FIG. 5 is a flowchart of the reception process of the control unit 30 of the present invention. The control unit 30 checks whether a DAB broadcast tuning operation has been performed (step 501), and when the DAB broadcast tuning is performed, receives the selected DAB broadcast (step 502).
The receiving state flag is set to "DAB" (step 50).
3) Return to the beginning. On the other hand, in step 501, DA
If the B broadcast has not been selected, it is checked whether the FM broadcast or the AM broadcast has been selected (step 504). If the FM or AM broadcast is selected, the selected FM or AM broadcast is received (step 505), and the reception state flag is set to "FM" or "AM" (step 506). ), Go back to the beginning.

In step 504, FM broadcast or A
If the M broadcast has not been selected, it is checked whether the reception state flag is set to "FM" or "AM" (step 507). If the reception status flag is "F
If it is not set to "M" or "AM", the process returns to the beginning. If it is set, it is checked whether a DAB broadcast having the same content as the selected FM broadcast or AM broadcast is being received (step 508). If a DAB broadcast having the same content as that of the selected FM broadcast or AM broadcast is not received, the selected FM broadcast is performed by a method described later with reference to FIG.
It is checked whether a DAB broadcast having the same content as the broadcast or AM broadcast is being broadcast (step 509). If it is not broadcasting, the process returns to step 501. However, when a DAB broadcast having the same content as the selected FM broadcast or AM broadcast is being broadcast, the DAB broadcast is received and a DAB sound is output (step 510). repeat.

In step 508, if a DAB broadcast having the same content as that of the selected FM broadcast or AM broadcast is being received, the control unit 30 refers to the output of the S meter 24d and
It is checked whether the received electric field strength of the AB broadcast has dropped below the set level (step 511). Step 511
In the processing of (1), the number of error bits per unit time (for example, 1 to 2 seconds) is counted, and it can be determined that the reception level has decreased because the number of error bits has exceeded the set number. If the level is not equal to or lower than the set level, it is checked whether the DAB broadcast having the same contents as the FM broadcast or the AM broadcast has ended (step 512). If not, the process returns to step 501 and repeats the subsequent processing. Thereafter, if a new channel is not selected, the reception of the DAB broadcast continues. However, during the reception of the DAB broadcast, when the reception level falls below the set value in step 511, or in step 512
In the DA, the same content as FM broadcast or AM broadcast
When the B broadcast is completed, the process returns to the reception of the selected FM broadcast or the AM broadcast (step 513).
The subsequent processing is repeated.

As described above, when the same program as the selected FM broadcast or AM broadcast is DAB broadcast, the D broadcast is automatically performed.
High quality audio can be output by switching to reception of AB broadcast. Also, if the received electric field strength of the DAB broadcast signal deteriorates, D
The reception quality can be maintained by returning from the AB broadcast reception to the original channel selection AM / FM broadcast reception. Also, by the end of the broadcast of the program,
Alternatively, the reception of the DAB broadcast is returned to the reception of the selected AM / FM broadcast by the AM / FM channel selection operation.
A DAB broadcast having the same contents as the M / FM broadcast program can be received and output.

(E) Channel selection D / D of the same content as FM / AM broadcast
AB Broadcast Reception Control FIG. 6 is a reception control processing flow of DAB broadcast having the same contents as the selected FM / AM broadcast, and details of the processing in step 509 in FIG. In step 508 in FIG. 5, if the DAB broadcast having the same content as the selected FM broadcast or AM broadcast has not been received yet, the control unit 30 controls the second tuner 22b (FIG. 1) to set the reception level to the set value. Above D
The AB signal is received (step 509a), and the regional frequency information and the regional broadcast station information inserted in the data field FIG 0/21 (FIG. 2) and FIG 0/11 (FIG. 3) of the DAB signal are respectively incorporated. Store in memory (step 509)
b, 509c).

Next, the control unit 30 transmits a TII list (TransmitterIdentification I) of the regional broadcasting station information (FIG. 3).
The area where the broadcasting station is located is obtained by referring to the “formation list”, and the area identifier Region Id is stored (step 5)
09d). That is, in DAB broadcasting, the MainId and SubId of the transmitter (Transmitter) are obtained from the null period information of the DAB broadcasting signal.
The DAB broadcast demodulation unit 24 analyzes the null period information and recognizes the transmitter (Transmitte).
r) MainId and SubId are obtained, and these are notified to the control unit 30. Thereby, the control unit 30 sends the DAB signal transmitter (D
Recognize the MainId and SubId of the (AB broadcast station), and then find the MainId and SubId from the TII list of the regional broadcast station information (FIG. 3).
Search for a region with SubId, and find the region identifier RegionId
Is searched for and memorized.

Next, by referring to the regional frequency information (FIG. 2), it is checked whether or not there is one that matches the region identifier RegionId determined in step 509d (step 509).
e). If present, select FM broadcast or A
It is checked whether there is an FI list having the same R & M value as that of the M broadcast and the same frequency as that of the FM broadcast or AM broadcast (step 509f). If it exists,
The Id field information (Id information) included in the FI list is stored (step 509g). For example, when an FM station supporting RDS is selected, a frequency list of R & M = 1000 (freq. L
It is checked whether or not the selected FM frequency is included in ist), and if it is, the Id information inserted in the Id field of the header is stored as the Id information of the receiving FM.

Next, the service linking information (FIG. 4) inserted in the data field FIG. 0/6 included in the DAB broadcast signal is stored (step 509h), and thereafter, the Id information saved in step 509g is used as the service linking. It is checked whether the information is included in the Id list 418 (step 509i). That is, RDS compatible FM
When a station is selected, Id list flag = "1", LA = "1"
(During link), S / H = "1" (same service), IdLQ = "0"
Step 5 for the service linking information of 1 "(RDS)
Check if the Id information saved in 09g is included.

If included, the LSN corresponding to the Id information
The value is obtained and stored (step 509j). This LSN
The value is the LSN value of the selected FM broadcast or AM broadcast. Next, the control unit 30 sets a DAB station having the same LSN value as the above obtained LSN value in the service linking information.
(FIG. 4), the search is performed (step 509k). If there is, "YES" is received to receive the DAB station, and the process of step 510 in FIG. 5 is executed.
And the process of step 501 is repeated. As described above, the present invention has been described with reference to the embodiments. However, the present invention can be variously modified in accordance with the gist of the present invention described in the claims, and the present invention does not exclude these.

[0034]

As described above, according to the present invention, a receiver for AM / FM broadcast and a receiver for digital audio broadcast (DAB broadcast) are provided.
DA of the same program as the selected AM or FM broadcast
The DAB receiver receives a predetermined DAB broadcast signal to check whether the B broadcast is being broadcast. If the DAB broadcast of the same program is being broadcast, the DAB broadcast is used instead of the AM broadcast or the FM broadcast. Output audio, so that high-quality audio can be output. According to the present invention,
If the reception electric field strength of the DAB broadcast signal deteriorates, the reception quality can be maintained by returning to the original channel selection AM / FM broadcast reception from the DAB broadcast reception. Further, according to the present invention, when the broadcast of the program ends, or when the AM / FM tuning operation is performed, the DA
From the B broadcast reception, it returns to the selected AM / FM broadcast reception. After that, the DAB broadcast having the same content as the next AM / FM broadcast program can be received and output, and high-quality sound can be output.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a radio receiver according to the present invention.

FIG. 2 is an explanatory diagram of regional frequency information in a high-speed information channel FIC.

FIG. 3 is an explanatory diagram of regional broadcast station information in a high-speed information channel FIC.

FIG. 4 is an explanatory diagram of service linking information in a high-speed information channel FIC.

FIG. 5 is an overall radio reception control processing flow of the present invention.

FIG. 6 is a flowchart of a search process of a DAB station broadcasting the same program.

FIG. 7 is an explanatory diagram of a frame structure of a DAB signal.

FIG. 8 is a configuration diagram of a DAB transmitter.

FIG. 9 is a configuration diagram of a DAB receiver.

[Description of Signs] 21a, 21b Antenna 22a First tuner (for AM / FM) 22b Second tuner (for DAB) 23 AM / FM broadcast demodulator 24 DAB broadcast demodulation Unit 24d S meter 25 selection unit 28 operation unit 29 display unit 30 control unit

Claims (2)

[Claims] A receiver for AM / FM broadcast and a receiver for digital audio broadcast (DAB broadcast) are provided, and when an AM broadcast or FM broadcast is selected, the selected AM is set.
The DAB receiver receives a predetermined DAB broadcast signal to check whether a DAB broadcast of the same program as the broadcast or FM broadcast is being broadcast. If the DAB broadcast of the same program is being broadcast, the AM broadcast or the FM broadcast is performed. A radio broadcast receiving method for outputting audio based on DAB broadcast instead of broadcast. 2. The radio broadcast receiving method according to claim 1, wherein the DAB broadcast signal is switched from the DAB broadcast reception output to the AM / FM reception output when the reception electric field strength of the DAB broadcast signal is degraded or when the broadcast of the program ends.