JP5710825B2 - Digital audio broadcast receiving apparatus and label information display method thereof - Google Patents

Description

  The present invention relates to a digital audio broadcast receiving apparatus and a service label display method thereof, and more particularly, to a digital audio broadcast receiving apparatus having a function of displaying a name (label) given to a selected program (service) being received and It relates to the label information display method.

  In recent years, broadcasting has shifted from analog broadcasting to digital broadcasting that can output high-quality and high-quality sound and can multiplex various data. In Europe, digital audio broadcasting (DAB) has already been put into practical use.

  FIG. 2 shows an example of a DAB service structure, which basically has a three-layer tree-like hierarchical structure. An ensemble (Ensemble) in the upper layer is a unit of service transmitted by radio waves having the same carrier center frequency. A plurality of services (Services) belong to one ensemble as a middle hierarchy, and a plurality of service components (Service components) belong to each service as a lower hierarchy.

  In such a DAB system, as will be described in detail later, label data for realizing a function of displaying the name (label) assigned to each service by multiplexing the data for various services is provided by the broadcasting station. Has been sent. The receiving side (DAB receiving apparatus) uses the label to display character data indicating the name of the service being received on the display means. By viewing this display, the user can recognize the content of the service being received and determine whether it is the desired service.

  As a technique related to this, there is known a technique in which a service label is acquired and displayed from a fast information group (FIG) of the ensemble being received (for example, Patent Document 1 and FIG. 8).

  Also, in the DAB system, in order to detect whether broadcast signal data is transmitted without error from the transmission side to the reception side, an error detection code called cyclic redundancy check (CRC) is added to the broadcast signal data. In addition, packet data is transmitted at a predetermined cycle. On the receiving side, the packet data is divided into “data body” and “CRC value”, the CRC of the data is calculated from the received “data body”, and the calculated CRC value and the received “CRC value” are calculated. Comparing. The “data body” and “CRC value” here correspond to “FIB data field” and “CRC” in the FIB structure shown in FIG. 4, respectively.

  On the receiving side (DAB receiving apparatus), if there is no error (error) in both the received “data body” and “CRC value”, the CRC comparison results match, and therefore it is assumed that there is no error in the received data. The received “data body” is taken in and the required processing is performed. For example, the service label information is acquired from the FIG included in the FIB data, and the service name related to the program is displayed on the screen of the display means.

  On the other hand, if there is an error in one of the received “data body” and “CRC value”, the CRC comparison result is inconsistent. Therefore, it is assumed that the received data has an error. ”Is discarded. At this time, the display of the displayed service name is maintained as it is.

  In addition, when there is an error in both the received “data body” and “CRC value”, the CRC comparison result usually does not match, but there is a possibility that they coincide.

JP 2001-358673 A

  As described above, in the conventional DAB receiver, the CRC calculation is performed on the FIB data included in the broadcast signal data transmitted from the broadcasting station, and based on the comparison between the calculation result and the CRC data included in the FIB data. Controls the display of service names (label information display).

  However, in the current technology, when a data error occurs in both the received data body (FIB data area) and the CRC value, and the CRC comparison result is coincident, the CRC result matches the received data. I don't know if there was no error or if there was an error or if there was an error but it happened to match. That is, it is not possible to determine whether the transmission data is correct or incorrect only from the CRC calculation result and the CRC comparison result coincides with the accident.

  The case where the CRC comparison result coincides accidentally even though an error has occurred as described above is likely to occur when the reception state is poor, particularly in a weak electric field environment. As a result, an incorrect service name (label information) may be displayed on the display unit.

  In addition, if an incorrect service name is displayed, the display data is not updated until the next CRC result is matched, so that the incorrect service name continues to be displayed during that time, which is inconvenient for the user. .

  The present invention was created in view of the problems in the prior art. Digital audio that can effectively cope with CRC misdetection even when the reception state deteriorates and can reduce the display of erroneous label information. It is an object to provide a broadcast receiving apparatus and a label information display method thereof.

  In order to solve the above-described problems of the prior art, according to one aspect of the present invention, a display station and a broadcast station corresponding to an instruction are transmitted from a digital broadcast radio wave transmitted by multiplexing a plurality of broadcast programs. A CRC for selecting a broadcast wave signal, and CRC calculation for a plurality of specific data included in the selected broadcast wave signal, and based on a comparison between the calculation result and CRC data included in the specific data, Control means for controlling display of label information relating to the program being received on the display means, and the control means is configured to receive a plurality of signals when the reception state of the selected broadcast wave signal becomes less than a predetermined level. Specific data is read and CRC calculation is performed, and when a CRC error has occurred with a predetermined probability or more from the calculation result, the label information being displayed is displayed on the display means. Digital audio broadcasting reception apparatus which controls to equity is provided.

  In the digital audio broadcast receiving apparatus according to this aspect, when a CRC error has occurred with less than a predetermined probability from the calculation result, the display means is based on label information included in specific data that finally matches the CRC value. The label information display may be updated.

  According to another aspect of the present invention, a display means, a tuner for selecting a broadcast wave signal of a broadcasting station according to an instruction from digital broadcast radio waves transmitted by multiplexing a plurality of broadcast programs, CRC calculation is performed on a plurality of specific data included in the selected broadcast wave signal, and a program being received is displayed on the display means based on a comparison between the calculation result and CRC data included in the specific data. Control means for controlling the display of the label information, and when the reception state of the selected broadcast wave signal becomes less than a predetermined level, the control means sequentially reads specific data and performs CRC calculation respectively. If the CRC values are consistent with each other a plurality of times from the calculation result, a label is displayed on the display means based on the label information included in the last specific data that is continuous. Digital audio broadcasting reception apparatus is provided for controlling so as to update the display of information.

  According to still another aspect of the present invention, there is provided a label information display method implemented in the digital audio broadcast receiving apparatus according to each of the above aspects.

  According to the digital audio broadcast receiving apparatus and the label information display method thereof according to an aspect of the present invention, in response to instructions from radio waves of a digital broadcast (for example, DAB broadcast) in which a plurality of broadcast programs are multiplexed and transmitted. CRC calculation is performed on a plurality of specific data (FIB in the DAB signal) included in the selected broadcast wave signal, and the display means is compared with the CRC data included in the specific data. Specific data (FIB) read at that time when the reception status of the selected broadcast wave signal becomes less than a predetermined level while the label information (service name) relating to the program being received is displayed. In addition to stopping the CRC calculation, the display of the label information being displayed is controlled to be maintained.

  In other words, as in the state of the art, the correctness / incorrectness of transmission data is not determined only from the CRC calculation result, but the reception state is also referenced, so even if the reception state deteriorates (particularly in a weak electric field), CRC error detection is possible. It can respond effectively. This can reduce the display of incorrect label information (service name).

  Also in the digital audio broadcast receiving apparatus and the label information display method thereof according to another aspect of the present invention, the same effect as described above can be obtained because the CRC calculation is performed in consideration of the reception state. Further, additional merits are also obtained, which will be described in the embodiment.

It is a block diagram which shows the structure of the digital audio broadcasting (DAB) receiver which concerns on embodiment of this invention. It is a figure which shows an example of the service structure of DAB. It is a figure which shows the structure of the transmission frame of DAB. It is a figure which shows the structure of FIB in DAB. FIG. 5 is a diagram showing a structure of a FIG data area when the FIG type is 1 in the FIB of FIG. 4. 6 is a flowchart illustrating an example of processing relating to service name display as the first embodiment, which is performed in the DAB receiving apparatus of FIG. 1. FIG. 7 is a diagram for supplementarily explaining the processing content of FIG. 6. 7 is a flowchart showing an example of processing related to service name display as a second embodiment performed in the DAB receiving apparatus of FIG. 1. FIG. 9 is a diagram for supplementarily explaining the processing content of FIG. 8. 12 is a flowchart illustrating an example of processing relating to service name display as a third embodiment, which is performed in the DAB receiving apparatus of FIG. 1. It is a figure for supplementary explanation of the processing content of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In this embodiment, a DAB receiver will be described as an example of a digital audio broadcast receiving apparatus.

  FIG. 1 is a block diagram showing the configuration of a digital audio broadcast (DAB) receiver 20 according to an embodiment of the present invention. As shown in FIG. 1, the DAB receiver 20 includes an antenna 1, a tuner 2, an A / D converter 3, a baseband decoder 4, a control unit 5, a storage unit 6, an operation unit 7, And a display unit 8. The antenna 1 receives radio waves of digital broadcasting of an orthogonal frequency division multiplexing (OFDM) system.

  The tuner 2 selectively extracts a broadcast wave signal having a reception frequency matching a desired channel from a digital broadcast wave such as DAB (Digital Audio Broadcasting) or DMB (Digital Multimedia Broadcasting) received via the antenna 1. , Downconvert to baseband and output. The A / D converter 3 converts the down-converted analog baseband signal into a digital signal.

  The baseband decoder 4 includes an FFT 11, a demultiplexer 12, a channel decoder 13, an audio decoder 14, a PAD decoder 15, and a packet mode decoder 16. The FFT 11 performs fast Fourier transform on the baseband signal digitally converted through the A / D converter 3 to obtain a received symbol. The demultiplexer 12 separates the multiplexed digital signal (OFDM demodulation).

  The channel decoder 13 extracts an arbitrary music channel and an arbitrary data channel from a DAB transmission frame composed of received symbols obtained by the OFDM demodulation. The channel decoder 13 separates the transmission frame into a high-speed information channel (FIC) and a main service channel (MSC) having a plurality of music channels and a plurality of data channels. Further, processing such as deinterleaving, Viterbi decoding, and energy spread descrambling is performed on the channel selected by the user from the MSC. Similarly, processing such as Viterbi decoding and energy diffusion descrambling is performed for the FIC.

  Of the digital signal decoded by the channel decoder 13, audio data included in the MSC is sent to the audio decoder 14, and FIG data (described later) such as a program type other than the audio data included in the FIC is sent to the control unit 5. .

  The audio decoder 14 decodes the audio data of the subchannel indicated by the control unit 5 among the audio data output from the channel decoder 13. The decoded signal (audio data) is output as audio through a D / A converter, an amplifier, and a speaker (not shown). The PAD decoder 15 decodes program-related data (PAD: Program Associated Data) and MOT (Multimedia Object Transfer) data added to the service extracted by the channel decoder 13 to reconstruct the data. The packet mode decoder 16 decodes the packet constituting the service extracted by the channel decoder 13 and reconstructs data.

  The control unit 5 is composed of a microcomputer and cooperates with other functional blocks (tuner 2, baseband decoder 4, storage unit 6, operation unit 7, display unit 8) to perform various processes related to reception of digital audio broadcasts. To control.

  First, when a channel setting control signal is input by an operation from the operation unit 7 by the user, a channel that the tuner 2 receives is determined, and a reception frequency that matches this channel is set in the tuner 2. More specifically, the control unit 5 includes a plurality of ensembles (each ensemble is transmitted by a radio broadcast radio wave modulated by DQPSK-OFDM, and one ensemble has a bandwidth of about 1.5 MHz). One ensemble is designated from the inside and sent to the tuner 2 as designation information. In response to this, the tuner 2 extracts a designated ensemble signal (selected broadcast wave signal), down-converts it to a baseband, and outputs it.

  In addition, the control unit 5 cooperates with the PAD decoder 15 to reconfigure the MOT object or to form a part of a high-speed information block (FIB) included in the FIC separated by the channel decoder 13 (FIG. Information group) is analyzed to determine whether there is a broadcasting station broadcasting the same content, or the display of label information (service name) is controlled as will be described later.

  The storage unit 6 is composed of, for example, a hard disk or a semiconductor memory. The storage unit 6 temporarily stores program information of the broadcast being received and control information such as FIG in the FIC via the control unit 5.

  The operation unit 7 includes various operation keys and buttons necessary for the user to operate the DAB receiver 20. The operation unit 7 gives an input instruction for selecting a desired broadcast station to the tuner 2 via the control unit 5. The operation unit 7 gives an input instruction for displaying label information (service name) to the display unit 8 via the control unit 5.

  The display unit 8 is composed of, for example, a liquid crystal display device (LCD), and displays data acquired by being decoded by the PAD decoder 15 or the packet mode decoder 16. In addition, a menu screen for inputting various instructions by the user is displayed. Furthermore, as information related to the present invention, character data (label) indicating the name of the selected program (service) being received is displayed. When a touch panel is provided on the display unit 8, the display unit 8 functions as the operation unit 7.

  In the digital audio broadcast (DAB) receiving apparatus 20 configured as described above, when the reception state deteriorates while receiving a program (service) of a broadcasting station selected by the user, the control unit 5 is connected thereto. The display of label information (service name) is controlled in cooperation with other functional blocks (channel decoder 13, storage unit 6, display unit 8, etc.).

  Hereinafter, processing relating to display of label information (service name) performed in the digital audio broadcast (DAB) receiving apparatus 20 of the present embodiment will be described with reference to FIGS.

  FIG. 2 shows an example of the DAB service structure, which is extracted from the DAB standard (EN300401). The DAB service structure is basically a three-layer tree-like hierarchical structure as illustrated in FIG. An ensemble (Ensemble) in the upper layer is a unit of service transmitted by radio waves having the same carrier center frequency. A plurality of services (Services) belong to one ensemble as a middle hierarchy, and a plurality of service components (Service components) belong to each service as a lower hierarchy.

  Ensemble with ensemble label (ensemble name) DAB ENSEMBLE ONE, service labels are alpha 1 radio (ALPHA 1 RADIO), beta radio (BETA RADIO), alpha 2 radio (ALPHA 2 RADIO), etc. (For example, 6) services are included. The user receives a service selected from these services by the DAB receiver.

  Alpha 1 radio has one primary service component and two secondary service components. The primary service component is Audio, and the secondary service component is a traffic message channel and service information. Audio components and service information are transmitted on separate subchannels (SubCh) in an MSC (Main Service Channel), and TMC is transmitted on an FIDC (Fast Information Data Channel) in an FIC (Fast Information Channel). Beta radio has two service components, both of which are audio and transmitted on the MSC subchannel. The alpha 2 radio has the same TMC and SI as the alpha 1 radio, and depending on the switch, the audio may be the same as the alpha 1 radio.

  FIG. 3 shows the structure of a DAB transmission frame. As shown in FIG. 3, the transmission frame has a synchronization channel, a high-speed information channel (FIC), and a main service channel (MSC) in order from the front. The synchronization channel identifies the frame and is used for basic demodulator such as transmission frame synchronization, automatic frequency control, channel state estimation, transmitter identification.

  The FIC is a channel for enabling a receiver to quickly access necessary information, and includes various control information necessary for selecting a program (service). As shown in FIG. 3, the FIC is composed of a plurality of FIBs (Fast Information Blocks). On the other hand, the MSC is a channel used to carry video, audio, and data service components, and includes a plurality of CIFs (Common Interleaved Frames) as shown in FIG. In each CIF, a plurality of music subchannels and a plurality of general data subchannels are multiplexed, and one subchannel corresponds to one program. In the DAB system, specifications are determined from modes 1 to 4, and the time of one transmission frame and the number of FIBs and CIFs in one transmission frame are different for each mode. For example, in mode 1, the time of one transmission frame is 96 ms, and the number of FIB and CIF in one transmission frame is 12 and 4, respectively.

  FIG. 4 shows the structure of the FIB in DAB. One FIB consists of 256 bits as a whole, and consists of a 30-byte FIB data field (FIB data field) followed by a 16-bit CRC (Cyclic Redundancy Check word). The FIB data area has a plurality of FIGs (Fast Information Groups), one end marker (End marker), and one padding (Padding) in order from the front. This padding is an area for putting 0 in the remaining bits in order to match the FIB data area to bytes. The FIG portion constitutes a useful data field. Each FIG has, in order from the front, a FIG type, a length (representing the bit length of the subsequent FIG data area), and a FIG data field. The FIG type and length constitute a FIG header.

  FIG. 5 shows the structure of the FIG data area when the FIG type in the FIB of FIG. 4 is 1 (“001” in the 3-bit binary display). The FIG data area has a Charset (Character set), an OE (Other Ensemble), an extension (Extension), and a Type 1 field (Type 1 field) in order from the front. The Charset 4-bit code identifies the Charset to limit the character information contained in FIG type 1, the OE identifies whether the information is for the ensemble or another ensemble, and the extension is , Represents an extension number in type 1. The type 1 area includes label information (data indicating a name assigned to a service) and the like as will be described later.

  For example, FIG type 1 field for extension 0 (Fig. 1 field for extension 0) (also written as “FIG 1/0”) has an Id (Ensemble Id) identifying the ensemble and its label (ensemble label). FIG. 1/1 includes data that associates an Id (Service Id) that identifies a service and its label (service label), and FIG. 1/4 identifies a service component. There is data in which an Id (Service component Id) and a label (service component travel) are associated with each other. Also, in the DAB signal, for each ensemble currently being broadcast, the list information of all services and all service components belonging to the ensemble is transmitted in FIG0 / 2.

  In addition to the above-mentioned FIG types, there are various FIG types (eight types of FIG types 0 to 7 in total). For details, refer to the DAB standard (EN300401).

  Hereinafter, a process related to the display of the service name (label information) performed in the DAB receiving apparatus 20 (FIG. 1) will be described for each embodiment.

(First embodiment)
FIG. 6 is a flowchart showing an example of processing related to service name display as the first embodiment performed in the DAB receiving apparatus 20, and FIG. 7 is a diagram for supplementarily explaining the processing contents.

  First, as an initial state, it is assumed that a program (service) is being received from a broadcast station selected by the user, and the reception state is in a good state. At this time, referring to the information of FIG. 0/2 extracted from the received signal by the control unit 5, the Id of the selected service component and its label, the Id of the service to which the service component belongs and its The storage unit 6 stores the label, Id of the ensemble to which the service belongs, and data of the label. Further, it is assumed that “service”, which is a middle hierarchy, is selected as a label display hierarchy via the operation unit 7 based on a user instruction.

  In such a state, in the first step S11 (FIG. 6), the control unit 5 reads the FIB (FIB1 in the example of FIG. 7) and checks the CRC. The CRC check is performed by dividing the read FIB data into a data body and a CRC value (corresponding to “FIB data area” and “CRC” in FIG. 4), performing CRC calculation of the data from the received data body, This is performed by comparing the calculation result (CRC value) with the received CRC value.

  In the next step S12, the control unit 5 determines whether or not both CRC values match (YES) or not (NO) based on the CRC check result. If the determination result is YES, the process proceeds to step S13, and if the determination result is NO, the process proceeds to step S14.

  In step S14, it is determined that there is an error in the received data due to the mismatch of the CRC values, and the FIB (data body part) is discarded.

  Further, in step S15, it is determined whether there is a next FIB (FIB2 in the example of FIG. 7) following the discarded FIB (YES) or not (NO). If the determination result is YES, the process returns to step S11 and the above processing is repeated. If the determination result is NO, the process flow is “end”.

  On the other hand, in step S13, it is determined that there is no error in the received data due to the match of the CRC value, and label information (data indicating the service name) is acquired from the FIG in the FIB. 8 displays the service name on the screen. In the example of FIG. 7, “ALPHA1” is displayed as the service name.

  In the next step S16, the control unit 5 determines whether the reception state of the currently received broadcast wave signal has deteriorated (YES) or not (NO). If the determination result is YES, the process proceeds to step S17, and if the determination result is NO, the process returns to step S11 and the above process is repeated.

  The reception state can be detected, for example, by obtaining information such as the electric field strength and BER (bit error rate) of the received signal from the channel decoder 13. When the reception strength is reduced below a predetermined threshold level due to the detection of the reception state, or when the BER (or the number of error corrections) is reduced below a predetermined threshold level, the reception state is deteriorated. to decide.

  In step S17, CRC check (such as CRC calculation) is stopped for the FIB (FIB3 in the example of FIG. 7) read at that time when it is determined that the reception state has deteriorated. Also, the acquisition of label information from the FIG in the FIB is stopped.

  In the next step S18, the control unit 5 controls the display unit 8 to maintain the display of the displayed service name (“ALPHA1” in the example of FIG. 7) and “gray out” the display unit. .

  Furthermore, in step S19, the control unit 5 uses the reception state detection method performed in step S16 to check whether the reception state has recovered to a predetermined threshold level (or a predetermined threshold value) or more (YES). It is determined whether or not (NO). If the determination result is YES, the process returns to step S11 and the above processing is repeated, and if the determination result is NO, the process returns to step S18 to maintain the “gray out” display on the display unit.

  As described above, according to the process relating to the service name display performed in the DAB receiving apparatus 20 according to the first embodiment, the user has selected the broadcast station program (service) selected during reception. CRC calculation is performed on a plurality of FIBs (FIG. 4) included in the broadcast wave signal, and the service name related to the program is displayed on the display unit 8 based on comparison between the calculation result and CRC data included in the FIB. When the reception state deteriorates in the active state (FIG. 7), the CRC calculation is stopped for the FIB read at that time (the acquisition of the label information from the FIG included in the FIB is also stopped). Further, the display of the service name being displayed (“ALPHA1” in FIG. 7) is maintained, and the display portion is “grayed out”.

  As described above, according to the first embodiment, the correctness of transmission data is not determined only from the CRC calculation result as in the state of the art, but the reception state is also referred to. Even in the case of a weak electric field), it is possible to effectively cope with CRC erroneous detection. As a result, it is possible to reduce the display of an incorrect service name.

(Second Embodiment)
FIG. 8 is a flowchart showing an example of processing relating to service name display as the second embodiment performed in the DAB receiving apparatus 20, and FIG. 9 is a diagram for supplementarily explaining the processing contents.

  In the second embodiment, it is assumed that the same initial state as that in the first embodiment (FIG. 6) is present. In addition, under this initial state, it is assumed that the same processing as the processing of steps S11 to S15 is performed.

  Under such circumstances, in the first step S21 (FIG. 8), whether the reception state of the broadcast wave signal being received has deteriorated (YES) in the control unit 5 in the same manner as the process performed in step S16. It is determined whether or not (NO). If the determination result is YES, the process proceeds to step S22, and if the determination result is NO, the process returns to step S11 (FIG. 6) and the above process is repeated.

  In the next step S22 (when the reception state deteriorates), the control unit 5 reads a plurality of FIBs (four FIBs FIB3 to FIB6 in the example of FIG. 9), and checks each CRC. The CRC check method is the same as the method performed in step S11.

  Here, the timing for reading each FIB is set to a multiple of the transmission period of the broadcast wave signal sent from the broadcast station. For details on the transmission cycle, see Guidelines and rules for implementation and operation (Part 1: System outline) issued by the European Telecommunications Standards Association.

  As a mode of setting the reading timing, all the FIGs included in the FIB may be set uniformly or may be set individually for each FIG. Alternatively, a plurality of FIGs may be grouped and set in accordance with the transmission cycle (the importance of the FIG data (the necessity for quick access) varies depending on the FIG type for each FIG).

  In the next step S23, the control unit 5 determines whether or not a CRC error has occurred with a predetermined probability or more (YES) or not (NO) for the checked CRCs. If the determination result is yes, the process proceeds to step S24, and if the determination result is no, the process proceeds to step S26. In the example of FIG. 9, a CRC error (x mark) has occurred in the data of three FIBs (FIB3, FIB5, FIB6) out of four FIBs. That is, CRC value mismatch occurs with a probability of 75%.

  In step S24, the control unit 5 determines that an error has occurred in the received data from the CRC error of the predetermined probability or higher, and in the same way as the processing performed in step S18 (FIG. 6), the display unit 8, the display of the service name being displayed (“ALPHA1” in the example of FIG. 9) is maintained, and the display unit is controlled to be “grayed out”.

  In the next step S25, similarly to the process performed in step S19 (FIG. 6), the control unit 5 determines whether the reception state has been recovered (YES) or not (NO). If the determination result is YES, the process returns to step S11 (FIG. 6) and the above process is repeated. If the determination result is NO, the process returns to step S22 and the above process is repeated.

  On the other hand, in step S26, the control unit 5 determines that no error has occurred in the received data from the CRC error less than the predetermined probability, and the label information from the FIG in the FIB that is the last CRC check OK. (Data indicating the service name) is acquired. Then, the service name is displayed on the screen of the display unit 8. For example, in the example of the CRC result shown in FIG. 9, the display of the service name is updated based on the label information acquired from the FIG. 4 in the FIB 4 in which the CRC check is OK (◯ mark) last among the FIB 3 to FIB 6. .

  Further, in step S27, similarly to the process performed in step S25, the control unit 5 determines whether the reception state has been recovered (YES) or not (NO). If the determination result is YES, the process returns to step S11 (FIG. 6) and the above process is repeated. If the determination result is NO, the process returns to step S22 and the above process is repeated.

  As described above, according to the process related to the service name display performed in the DAB receiving apparatus 20 according to the second embodiment, the CRC is also taken into account in the same manner as in the first embodiment described above, taking the reception state into consideration. Since the calculation is performed, the same effect as described above can be obtained.

  Further, in the first embodiment described above, erroneous determination is further reduced in consideration of the reception state. However, it is assumed that the operation speed is decreased due to an increase in discarding of data as an erroneous determination. Is done. On the other hand, in the second embodiment, since the CRC calculation is not stopped (the acquisition of label information is stopped), it is possible to suppress a decrease in the operation speed compared to the case of the first embodiment.

  Furthermore, in the second embodiment, when a CRC error has occurred with less than a predetermined probability for a plurality of FIBs read after the reception state deteriorates (step S26 in FIG. 8), the received data It is determined that no error has occurred, and display data is updated based on the label information acquired from the FIG in the FIB that has finally been subjected to CRC check OK. As a result, inconvenience as seen in the state of the art (if an incorrect service name is displayed, the display data will not be updated until the next CRC result matches, so the incorrect service name will continue to be displayed during that time. Problem).

(Third embodiment)
FIG. 10 is a flowchart showing an example of processing related to service name display as the third embodiment performed in the DAB receiving apparatus 20, and FIG. 11 is a diagram for supplementarily explaining the processing contents.

  In the third embodiment, it is assumed that the same initial state as that in the first embodiment (FIG. 6) is present. In addition, under this initial state, it is assumed that the same processing as the processing of steps S11 to S15 is performed.

  Under such circumstances, in the first step S31 (FIG. 10), whether the reception state of the broadcast wave signal being received has deteriorated (YES) in the control unit 5 in the same manner as the process performed in step S16. It is determined whether or not (NO). If the determination result is YES, the process proceeds to step S32, and if the determination result is NO, the process returns to step S11 (FIG. 6) and the above process is repeated.

  In the next step S32 (when the reception state deteriorates), the control unit 5 sequentially reads FIB (FIB3, FIB4, FIB5,... In the example of FIG. 11), and checks each CRC. The CRC check method is the same as the method performed in step S11. The setting of the FIB reading timing is also the same as the method performed in step S22 (FIG. 8).

  In the next step S33, in the process of checking the CRC, the control unit 5 determines whether or not the CRC value is matched N times (YES) or not (NO) continuously from the first FIB. If the determination result is YES, the process proceeds to step S34, and if the determination result is NO, the process proceeds to step S36. In the example of FIG. 11, the CRC values of three consecutive FIBs (FIB3 to FIB5) coincide with each other (◯ mark).

  In step S34, the control unit 5 determines that no error has occurred in the received data from the match of the N consecutive CRC values, and the Nth FIB (the last one whose CRC value matched) The label information (data indicating the service name) is acquired from the FIG. Then, the service name is displayed on the screen of the display unit 8. In the example of FIG. 11, the display data is updated based on the label information acquired from the FIG in the last FIB 5 whose CRC values match N times in succession, and “ALPHA2” is displayed as the service name.

  In the next step S35, similarly to the process performed in step S19 (FIG. 6), the control unit 5 determines whether the reception state has been recovered (YES) or not (NO). If the determination result is YES, the process returns to step S11 (FIG. 6) and the above process is repeated. If the determination result is NO, the process returns to step S32 and the above process is repeated.

  On the other hand, in step S36, the control unit 5 determines that an error has occurred in the received data because the CRC values do not match N times, and the processing performed in step S18 (FIG. 6). In the same manner as described above, the display unit 8 maintains the display of the name of the service being displayed (in the example of FIG. 11, “ALPHA1” displayed before the reception state deteriorates) and the display unit is displayed as “grayed out”. To control.

  Further, in step S37, similarly to the process performed in step S35, the control unit 5 determines whether the reception state has been recovered (YES) or not (NO). If the determination result is YES, the process returns to step S11 (FIG. 6) and the above process is repeated. If the determination result is NO, the process returns to step S32 and the above process is repeated.

  As described above, according to the process related to the service name display performed in the DAB receiving apparatus 20 according to the third embodiment, the reception state is also taken into account as in the case of the first and second embodiments described above. Since the CRC calculation is performed, the same effect as described above can be obtained.

  Furthermore, in this third embodiment, when the CRC values coincide continuously for a plurality of FIBs read sequentially after the reception state deteriorates (FIG. 11), no error has occurred in the received data. The display data is updated based on the label information acquired from the FIG in the last consecutive FIB. As a result, inconvenience as seen in the state of the art (if an incorrect service name is displayed, the display data will not be updated until the next CRC result matches, so the incorrect service name will continue to be displayed during that time. Problem).

DESCRIPTION OF SYMBOLS 2 ... Tuner, 4 ... Baseband decoder, 5 ... Control part, 6 ... Memory | storage part, 7 ... Operation part, 8 ... Display part, 12 ... Demultiplexer, 13 ... Channel decoder, 14 ... Audio decoder, 15 ... PAD decoder, 16 ... Packet mode decoder, 20 ... Digital audio broadcast (DAB) receiver.

Claims (8)

Display means;
A tuner for selecting a broadcast wave signal of a broadcast station according to an instruction from radio waves of a digital broadcast transmitted by multiplexing a plurality of broadcast programs;
A CRC calculation is performed on a plurality of specific data included in the selected broadcast wave signal, and a program being received by the display means based on a comparison between the calculation result and CRC data included in the specific data Control means for controlling the display of the label information according to
When the reception state of the selected broadcast wave signal is less than a predetermined level, the control means reads a plurality of specific data and performs a CRC calculation, and from the calculation result, a CRC error is detected with a predetermined probability or more. The digital audio broadcast receiving apparatus is characterized in that control is performed so as to maintain the display of the label information being displayed on the display means in a case where the error occurs.   The control means, when a CRC error has occurred with less than a predetermined probability from the calculation result, based on the label information included in the specific data with the last matching CRC value, provides label information to the display means. The digital audio broadcast receiving apparatus according to claim 1, wherein the display is controlled to be updated. Display means;
A tuner for selecting a broadcast wave signal of a broadcast station according to an instruction from radio waves of a digital broadcast transmitted by multiplexing a plurality of broadcast programs;
A CRC calculation is performed on a plurality of specific data included in the selected broadcast wave signal, and a program being received by the display means based on a comparison between the calculation result and CRC data included in the specific data Control means for controlling the display of the label information according to
When the reception state of the selected broadcast wave signal is less than a predetermined level, the control means sequentially reads specific data and performs CRC calculation, and the CRC value is continuously calculated a plurality of times from the calculation result. Digital audio broadcast reception characterized in that, if they match, the display means is controlled to update the display of the label information based on the label information included in the last specific data that continues. apparatus.   The control means controls the display means to maintain the display of the label information being displayed when the CRC values do not coincide with each other a plurality of times from the calculation result. 4. The digital audio broadcast receiving apparatus according to 3. CRC calculation is performed on a plurality of specific data included in a broadcast wave signal selected according to an instruction from a digital broadcast radio wave transmitted by multiplexing a plurality of broadcast programs, and the calculation result and the specific A label information display method implemented in a digital audio broadcast receiving apparatus having a function of controlling display of label information relating to a program being received on a display means based on comparison with CRC data included in the data. ,
Detecting a reception state of the selected broadcast wave signal;
When the reception state is less than a predetermined level, reading a plurality of specific data and performing CRC calculation respectively;
Label information of the digital audio broadcast receiving apparatus, comprising: maintaining display of label information being displayed on the display means when a CRC error has occurred with a predetermined probability or more from the calculation result. Display method.   Further, when a CRC error has occurred with less than a predetermined probability from the calculation result, the display unit updates the display of the label information based on the label information included in the specific data with the last CRC value match. 6. The label information display method for a digital audio broadcast receiver according to claim 5, further comprising steps. CRC calculation is performed on a plurality of specific data included in a broadcast wave signal selected according to an instruction from a digital broadcast radio wave transmitted by multiplexing a plurality of broadcast programs, and the calculation result and the specific A label information display method implemented in a digital audio broadcast receiving apparatus having a function of controlling display of label information relating to a program being received on a display means based on comparison with CRC data included in the data. ,
Detecting a reception state of the selected broadcast wave signal;
When the reception state becomes less than a predetermined level, sequentially reading specific data and performing CRC calculation respectively;
Updating the display of the label information in the display means based on the label information included in the last specific data that is consecutive when the CRC values match continuously a plurality of times from the calculation result; A label information display method for a digital audio broadcast receiving apparatus.   The digital display device according to claim 7, further comprising a step of maintaining the display of the label information being displayed on the display means when the CRC values do not coincide with each other a plurality of times from the calculation result. Label information display method for audio broadcast receiver.

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