JP5781458B2 - Digital broadcast receiver - Google Patents

Description

  The present invention relates to a digital broadcasting receiver that receives program data in accordance with DAB (Digital Audio Broadcasting) / T-DMB (Terrestrial-digital media broadcasting) broadcasting standards.

  2. Description of the Related Art Conventionally, there is known a digital broadcast receiver that notifies various causes of silence and supports taking measures against each cause (see, for example, Patent Document 1). In this receiver, as a cause of the silent state, (1) when broadcast radio waves cannot be received, (2) when a non-contracted channel is selected, (3) when a channel that is currently suspended is selected, (4) When a channel that is restricted for viewing is selected, (5) when a channel that is not supported by the broadcast receiver is selected, etc. are considered, and a warning corresponding to the cause is detected when a silent state is detected Sound is output.

JP 2005-354505 A

By the way, in the receiver disclosed in Patent Document 1 described above, when the sound of the received program cannot be normally decoded due to a deviation from the broadcast standard on the broadcasting station side, and a periodic silent state or a continuous silent state continues. Cannot detect these silences. For example, in the case of broadcasting according to the DAB / T-DMB broadcasting standard that can be received in each European city, the following five cases (A) are representative of the cause of such a silent state. ~ (E) is considered.
(A) Although registered as SC (Service Component) in FIC (Fast Information Channel), the contents of the SC are actually NULL (filled with 0xFF).
(B) The FIC is registered as an SC and there is an SC main body and MPEG2-TS in the SC main body, but there is no PAT / PMT that can be said as a table of contents.
(C) The FIC is registered as an SC and exists in the PAT / PMT, which can be referred to as a table of contents, but there is no Audio TS (sound body).
(D) MPEG2 TS is normal, but MPEG4 content is abnormal. For example, there is no IOD (Initial Object Descriptor), idleFlag = ON in the IOD, silence in continuity_counter NG, and the like.
(E) When the MPEG4 content is normal but the actual sound is silent.

  Among them, (A) to (D) are cases where the broadcasting standard is violated, and (E) is a case where a broadcasting accident occurs. In these five cases (A) to (E), since the FIC of the received data is normal, the abnormality determination based on the FIC cannot be performed. Also, when trying to correct errors in received data, if many errors occur due to broadcast standard violations and cannot be corrected, periodically (for example, once every 3 seconds, about 500 milliseconds) Silence occurs.

  When such program data is received, the output sound is periodically or continuously silenced, so that there is a problem that the quality of the received sound is deteriorated even though the digital broadcast is originally of good sound quality. It was. Such a problem can be avoided by switching to another program having the same content, but for this purpose, the program is actually switched in order to search for a program to be switched to. Therefore, a new problem arises that the operation becomes complicated. Furthermore, if the silent state continues, the user who misunderstood that there is no sound because the volume setting is low and raises the volume setting, then performs some operation (such as switching to another program or CD When switching to another music source, etc.), there is a problem that the sound may be suddenly output at a loud volume.

  The present invention was created in view of the above points, and its purpose is to perform a complicated operation to reduce the quality of received audio due to periodic or continuous silence in broadcasting standards violations or broadcasting accidents. It is an object of the present invention to provide a digital broadcast receiver that can be prevented. Another object of the present invention is to provide a digital broadcast receiver capable of preventing sudden output of a loud sound by suddenly increasing the sound volume when a silent state occurs.

  In order to solve the above-described problems, a digital broadcast receiver according to the present invention includes a broadcast signal reception / reproduction unit that receives a broadcast signal and performs a predetermined audio reproduction operation, and an audio signal reproduced by the broadcast signal reception / reproduction unit. When the silent state is detected by the silent state detecting means and the silent state detecting means, the broadcast signal receiving / reproducing means is instructed to send the broadcast signal to be received to the other having the same contents Broadcast signal switching means for switching to a broadcast signal.

  Even when there is a periodic or continuous silence in a broadcast standard violation or broadcast accident, it can be switched to another broadcast signal with the same content when the silence of the received audio signal is detected Therefore, it is possible to receive a substitute broadcast signal and perform normal sound output, and to prevent the quality of received sound from being deteriorated. For this reason, the user does not need to perform a complicated operation, and the operability can be improved.

  The broadcast signal receiving / reproducing means described above receives a digital broadcast signal modulated by the digital modulation method, and the broadcast signal switching means has another digital broadcast signal having the same content as the digital broadcast signal being received. In addition, it is desirable to send an instruction to the broadcast signal receiving / reproducing means to switch to another digital broadcast signal. This makes it possible to maintain the quality of the output sound completely.

The broadcast signal receiving / reproducing means described above can receive both the digital broadcast signal modulated by the digital modulation method and the analog broadcast signal modulated by the analog modulation method, and the broadcast signal switching means can receive the digital signal being received. When there are both other digital broadcast signals and analog broadcast signals having the same content as the broadcast signal, an instruction is sent to the broadcast signal receiving / reproducing means to switch to the other digital broadcast signal . By preferentially receiving digital broadcasting with excellent sound quality, it is possible to prevent the output sound from being degraded as much as possible.

  The silent state described above includes a periodic silent state and a continuous silent state. When the silent state is detected by the silent state detecting means, the same content as that of the digital broadcast signal being received is detected. It is desirable to further include first silence processing means for forcibly stopping the output of the audio signal reproduced by the broadcast signal receiving / reproducing means and maintaining a continuous silence state when there is no other broadcast signal. . As a result, it is possible to avoid annoying sound output due to the occurrence of periodic silence.

  Further, it is desirable to further include a silence state notifying unit for notifying the user when a silence state is detected by the above-described silence state detecting unit. Thereby, when switching a broadcast signal etc., it can inform a user that it is based on generation | occurrence | production of a silence state.

  Also, when the silent state is detected by the above-described silent state detecting means, if there is no other broadcast signal having the same content as the digital broadcast signal being received, an audio signal reproduced by the broadcast signal receiving / reproducing means is output. It is desirable to further include a volume restriction means for restricting the change of the volume setting at the time. As a result, it is possible to prevent the user from excessively raising the volume without knowing that a continuous silent state has occurred and then suddenly outputting a loud sound.

The apparatus further includes history information storage means for storing history information in which the silence state is detected by the above-described silence state detection means, and a broadcast signal that matches the history information stored in the history information storage means is received by the broadcast signal receiving / reproducing means. In this case, until the operation of the silence state detecting means and the broadcast signal switching means is finished, the output of the audio signal reproduced by the broadcast signal receiving / reproducing means is forcibly stopped to maintain the continuous silence state. It is desirable to further include the silent processing means. By setting a continuous silence state in advance for a broadcast signal that is highly likely to cause a silence state, it is possible to prevent an unpleasant periodic silence state from occurring in advance.

  The broadcast signal receiving / reproducing means described above preferably receives at least a digital broadcast signal modulated by a digital modulation method corresponding to the DAB / T-DMB broadcast standard. Further, it is desirable that the above-described silent state detecting means detects the silent state based on the sound data after the sound reproduction operation by the broadcast signal receiving / reproducing means. Specifically, it is desirable that the above-described silent state detecting means detects the silent state based on the result of integration after calculating the square of the amplitude value of the audio data. Alternatively, it is desirable that the above-described silent state detecting means detects the silent state based on the contents of the service component SC registered in the high-speed information channel FIC included in the broadcast signal received by the broadcast signal receiving / reproducing means. Specifically, it is desirable that the above-described silence state detection means detects a silence state when the content of the service component SC is null. Further, it is desirable that the above-described silent state detection means determines that there is a silent state when the PAT and PMT do not exist in the MPEG2-TS included in the service component SC. In addition, it is desirable that the above-described silent state detection means determines that the silent state is present when the audio TS is not included in the MPEG2-TS included in the service component SC. Further, it is desirable that the silent state detecting means described above determines that the audio TS included in the MPEG2-TS of the service component SC is silent as MPEG4 content. As a result, it is possible to reliably detect a silence state caused by a broadcast standard violation or a broadcast accident.

It is a figure which shows the structure of the digital broadcast receiver of one Embodiment. It is a figure which shows the flame | frame structure of the broadcast signal according to DAB / T-DMB broadcast standard. It is a flowchart which mainly shows the operation | movement procedure of the main control part which implements various countermeasures corresponding to a silence state. It is a figure which shows the example of a display during service reception. It is a flowchart which shows the operation | movement procedure of the modification of the main control part which implements various countermeasures corresponding to a silence state using history information.

  Hereinafter, a digital broadcast receiver according to an embodiment to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a digital broadcast receiver according to an embodiment. This digital broadcast receiver is for receiving a digital broadcast signal mainly in accordance with the DAB / T-DMB broadcast standard used in Europe, but an AM broadcast signal and an FM broadcast signal which are analog broadcast signals. It also has a configuration for receiving. For example, this digital broadcast receiver is mounted on a vehicle.

  As shown in FIG. 1, the digital broadcast receiver of this embodiment includes a DAB / T-DMB tuner unit 20, an FM / AM tuner unit 40, an output processing unit 50, an amplifier 52, a speaker 54, a main control unit 60, a display. A device 70, an operation unit 80, and a history information storage unit 90 are provided.

  The DAB / T-DMB tuner unit 20 receives a digital broadcast signal broadcast by a multicarrier method using OFDM (Orthogonal Frequency Division Multiplexing) as a modulation method, performs demodulation processing and decoding processing, and reproduces audio data. To do. For example, the DAB / T-DMB tuner unit 20 is modularized and includes an RF unit 22, an analog-digital converter (A / D) 24, a decoder 26, and a silent state detection unit 28. . The RF unit 22 converts a broadcast signal received via the antenna 10 into an intermediate frequency signal. The analog-digital converter 24 converts an analog intermediate frequency signal into digital data (intermediate frequency data). The decoder 26 performs demodulation processing and decoding processing on the intermediate frequency data to generate audio data for each service. The silence state detection unit 28 detects a silence state that occurs during service reception based on the processing content of the decoder 26. In the present embodiment, a silent state mainly due to a broadcast standard violation and a silent state due to a broadcast accident are targeted. Specific examples and detection methods thereof will be described later.

  In the DAB / T-DMB tuner unit 20, the intermediate frequency signal output from the RF unit 22 is converted into digital data, and then the demodulating process and the decoding process are performed by the decoder 26. It is possible to appropriately change which part is performed by digital processing. Further, the DAB / T-DMB tuner unit 20 may not be configured with one module, but may be modularized including other configurations, or similar processing may be performed by combining individual components.

  FIG. 2 is a diagram showing a frame structure of a broadcast signal according to the DAB / T-DMB broadcast standard. As shown in FIG. 2, the frame is composed of a synchronization channel, a first information channel FIC, and a main service channel MSC.

  The synchronization channel is composed of a NULL symbol and a phase reference symbol PRS (Phase Reference Symbol), and is used for frame synchronization by detecting the head portion of the frame. The first information channel FIC is an area for explaining the contents of the main service channel MSC, and includes time / date data, service (program) arrangement data, service label (name), service identification code SID (Service Identification). Code). A plurality of FIGs (first information groups) are energy-spread to form one FIB (first information block) which is a predetermined information unit. Each FIB is convolutionally encoded, and the three FIBs subjected to the convolutional coding constitute one FIC. The main service channel MSC mainly includes music data corresponding to each of a plurality of services. The main service channel MSC includes a plurality of sub-channels (SubCh) that are energy spread, convolutionally encoded, and time interleaved.

  The FM / AM tuner unit 40 reproduces audio data by performing demodulation processing (FM detection processing or AM detection processing) corresponding to each of the FM broadcast signal and the AM broadcast signal as analog broadcasts received via the antenna 30. . Each program corresponding to the FM broadcast signal is associated with a program identification code (PI), and an FM broadcast program having the same contents as the service included in the digital broadcast signal corresponds to the service. The service identification code SID and the program identification code PI corresponding to the FM broadcast program have the same number. Therefore, when searching for an FM broadcast program having the same content as a digital broadcast service, a program having the program identification code PI having the same value as the service identification code SID may be detected.

  The output processing unit 50 receives audio data output from each of the DAB / T-DMB tuner unit 20 and the FM / AM tuner unit 40. The output processing unit 50 switches the audio data to be output, controls the volume, etc. And the like (for example, operation sounds) are overlaid. The amplifier 52 amplifies the audio data output from the output processing unit 50 and outputs the amplified audio from the speaker 54. Actually, it is necessary to convert the audio data after the various processes in the output processing unit 50 into an analog audio signal. This conversion processing may be performed in the output processing unit 50, but the output processing unit 50 You may make it carry out by providing a digital-analog converter in the back | latter stage.

  The main control unit 60 controls the reception operation of the entire digital broadcast receiver, and implements various measures corresponding to the silence state when the silence state detection unit 28 detects the silence state. In order to implement these various measures, the main control unit 60 includes a service switching unit 62, a silence notification unit 64, a silence processing unit 66, a volume restriction unit 68, and a history processing unit 69. Regarding the configuration related to the control of normal reception operations other than various countermeasures corresponding to the silence state (the configuration necessary for the operation of selecting the service to be received and the operation of displaying the received contents of the service being received) The illustration is omitted.

  When a silence state is detected by the silence state detection unit 28 for the service being received, the service switching unit 62 searches for a service of another frequency (ensemble) having the same service identification code SID as this service and switches the service. Or a process of searching for and switching an FM broadcast program having the program identification code PI having the same value as the service identification code SID of this service.

  The silence notification unit 64 notifies that a silence state has occurred when a silence state is detected by the silence state detection unit 28 for the service being received. For example, this notification is performed by displaying a predetermined message on the display device 70. The silence processing unit 66 performs processing for setting the sound output from the speaker 54 to the silence state when the silence state detection unit 28 detects the silence state for the service being received. For example, if a periodic silence occurs, the quality of the received voice will deteriorate and give the user an unpleasant feeling. Can be eliminated.

  The volume restriction unit 68 restricts a process in which the user operates the operation unit 80 to change the volume when a silence state is detected by the silence state detection unit 28 for the service being received. This “restriction” includes not only the case where the volume changing process itself is disabled, but also the case where the volume cannot be changed to a predetermined level or higher even if an instruction to increase the volume is given.

  When a silence state is detected by the silence state detection unit 28 for the service being received, the history processing unit 69 receives the service identification code SID of this service, the information of the ensemble that includes this service, the content of the silence state (periodic (Historically) is stored in the history information storage unit 90.

  The display device 70 displays an operation screen indicating an operation state of the digital broadcast receiver, an operation screen for performing various operations, and the like. The operation unit 80 is for a user to give an operation instruction, and includes various operation keys and operation knobs. An instruction to change the volume by the user, an instruction to switch the service to be received, and the like are performed using the operation unit 80.

  The RF unit 22, analog-digital converter 24, and decoder 26 described above are broadcast signal reception / playback means, the silence state detection unit 28 is a silence state detection unit, the service switching unit 62 is a broadcast signal switching unit, and the silence processing unit 66. Corresponds to the first and second silence processing means, the silence notification section 64 corresponds to the silence state notification means, the volume restriction section 68 corresponds to the volume restriction means, and the history information storage section 90 corresponds to the history information storage means.

  The digital broadcast receiver according to the present embodiment has such a configuration. Next, when a silence state is detected for a service being received, operations for implementing various countermeasures corresponding to the silence state will be described. To do.

  FIG. 3 is a flowchart mainly showing an operation procedure of the main control unit 60 for implementing various countermeasures corresponding to the silent state. When the digital broadcast receiver is activated and starts receiving the service (step 100), the main control unit 60 displays the received content on the display device 70 in relation to the received service (step 102), and the reception target. A voice output corresponding to the service is instructed to the output processing unit 50 and a voice is output from the speaker 54 (step 104).

  FIG. 4 is a diagram illustrating a display example during service reception. In FIG. 4, an example of the display screen displayed in the above-described step 102 is indicated by D1. In this example, five services (“KISS KISS ITALIA”, “Radio 105”, etc.) are included in a specific ensemble indicated by “13F: CR DAB + ROMA”, and “KISS KISS ITALIA” is included in these services. "" Is selected and a station list screen D1 indicating that reception is in progress is displayed.

  In parallel with the service reception operation, the silence state detection unit 28 detects a silence state for the output sound of the service, and the service switching unit 62 determines whether or not the silence state is detected based on the detection result. Is determined (step 106).

The following five cases (A) to (E) can be considered as typical silent states to be detected in the present embodiment.
(A) Although the FIC is registered as an SC (Service Component), the MSC SubCh that is the contents of the SC is actually NULL (filled with 0xFF).
(B) The FIC is registered as an SC, and there is an MSC SubCh, which is the main body of the SC, and an MPEG2-TS, but there is no PAT / PMT that can be said as a table of contents.
(C) The FIC is registered as an SC and exists in the PAT / PMT, which can be referred to as a table of contents, but there is no Audio TS (audio main body) in the SubCh of the MSC.
(D) Up to MPEG2-TS is normal, but MPEG4 content of Audio TS is abnormal. For example, there is no IOD (Initial Object Descriptor), idleFlag = ON in the IOD, silence in continuity_counter NG, and the like.
(E) When the audio TS MPEG4 content is normal but the actual sound is silent.

  Among these, for cases (A) to (D) corresponding to violations of broadcasting standards, it is possible to detect the presence or absence of the corresponding silent state by examining the contents of the corresponding data during the decoding process by the decoder 26. it can. In case (E) corresponding to a broadcast accident, the presence or absence of a corresponding silent state is detected by examining the contents of audio data after decoding by the decoder 26 or compressed audio data obtained during the decoding process. be able to.

  If no silence is detected, a negative determination is made in step 106, and the process returns to step 100 to continue the service reception operation. If a silent state is detected, an affirmative determination is made in step 106. Next, the service switching unit 62 determines whether there is a service (service having the same content) having the same service identification code SID at a frequency (ensemble) different from the frequency (ensemble) of the service being received (ensemble) ( Step 108). If a service with the same SID exists, an affirmative determination is made, and the service switching unit 62 sends an instruction to the DAB / T-DMB tuner unit 20 to switch to a service with the same SID at a different frequency (step 110). Thereafter, the silence notification unit 64 displays the received content on the display device 70 in relation to the switched service (step 112), and the service switching unit 62 outputs the audio output corresponding to the switched service to the output processing unit. 50 is instructed to output sound from the speaker 54 (step 114). In FIG. 4, an example of the display screen displayed in step 112 described above is indicated by D2. In this example, the station list screen D2 indicating that the service is being switched to the service “KISS KISS ITALIA” of the same SID included in the ensemble indicated by “14F: CR DAB + MILANO” is displayed. D2 includes an icon A indicating that the service has been switched to the same SID service. Since the station list display itself is the same as the normal service receiving operation, the station control screen D2 is created by the main control unit 60, and only the icon A is created by the silent notification unit 64. The user may be notified that the service has been switched.

  Next, the main control unit 60 determines whether or not service switching has been instructed by the user by operating the operation unit 80 (step 116). If service switching is not instructed, a negative determination is made, and the process returns to step 110 and the service reception operation after switching is continued. If service switching is instructed, an affirmative determination is made in the determination in step 116, and the main control unit 60 performs service switching in response to the switching instruction (step 118). Thereafter, returning to step 100, the service reception operation is continued for the switched service.

  If there is no service with the same SID, a negative determination is made in step 108. Next, the silence notification unit 64 performs display for notifying that the output sound is abnormal (silent state) (step 120). In the example illustrated in FIG. 4, a notification screen D <b> 3 is created and displayed by the silence notification unit 64 to notify that a silence state has occurred. The notification screen D3 includes a display such as “DAB sound is abnormal!” Indicating that the output sound is abnormal.

  Further, the service switching unit 62 determines whether there is an FM broadcast program having the program identification code PI having the same value as the service identification code SID of the service being received (step 122). If an FM broadcast program with the same PI as the SID exists, an affirmative determination is made, and the service switching unit 62 sends an instruction to the FM / AM tuner unit 40 and has the same content as the service received so far. Switch to the FM broadcast program (step 124). Thereafter, the silence notification unit 64 displays the received content on the display device 70 in relation to the FM broadcast program after switching (step 126), and the service switching unit 62 outputs the audio corresponding to the FM broadcast program after switching. Is output to the output processing unit 50 and audio is output from the speaker 54 (step 128). In FIG. 4, an example of the display screen displayed in the above-described step 126 is indicated by D4. In this example, the station list screen D4 indicating that the FM broadcast program corresponding to the service “KISS KISS ITALIA” before switching included in the ensemble indicated by “13F: CR DAB + ROMA” has been received is displayed. This screen D4 includes an icon B indicating that the screen has been switched to the FM broadcast program.

  Since the station list display itself is the same as the normal service receiving operation, the station control screen D4 is created by the main control unit 60, and only the icon B is created by the silent notification unit 64. You may make it notify a user that it switched to FM broadcast program.

  Next, the main control unit 60 determines whether or not service switching has been instructed by the user by operating the operation unit 80 (step 130). If service switching is not instructed, a negative determination is made, and the process returns to step 124 to continue the FM broadcast program receiving operation after switching. If service switching is instructed, an affirmative determination is made in the determination in step 130, and the main control unit 60 performs service switching in response to the switching instruction (step 132). Thereafter, returning to step 100, the service reception operation is continued for the switched service.

  If there is no FM broadcast program with the same PI as the SID, a negative determination is made at step 122. Next, the silence processing unit 66 sends a silence instruction to the output processing unit 50 to place the output sound of the speaker 54 in the silence state (step 134). Further, the volume limiter 68 limits the process in which the user operates the operation unit 80 to change the volume (step 136). In this case, the display of the notification screen D3 notifying that the silent state has occurred is continued.

  Next, the main control unit 60 determines whether or not service switching has been instructed by the user by operating the operation unit 80 (step 138). If service switching is not instructed, a negative determination is made, and the process returns to step 134 to continue the silence process. If service switching is instructed, an affirmative determination is made in the determination in step 138, and the main control unit 60 performs service switching in response to the switching instruction (step 140). Thereafter, returning to step 100, the service reception operation is continued for the switched service.

  As described above, in the digital broadcast receiver of the present embodiment, when the silence state of the received audio signal is detected, the broadcast signal can be switched to another broadcast signal having the same content. Alternatively, even when a continuous silent state occurs, a substitute broadcast signal can be received and normal audio output can be performed, and a reduction in the quality of received audio can be prevented. For this reason, the user does not need to perform a complicated operation, and the operability can be improved.

  In particular, when switching to a service with the same SID, it becomes possible to maintain the quality of the output voice completely. In addition, when switching to an FM broadcast program having the same PI as the SID, the sound quality itself may be slightly lowered, but it is possible to perform audio output that does not include a silent state, and a silent state has occurred. Compared with the case, it is possible to prevent the quality of the received voice from being lowered. In addition, by giving priority to switching to the service of the same SID over FM broadcast programs, it is possible to prevent deterioration of the quality of output audio as much as possible.

  Further, when there is no service of the same SID or FM broadcast program of the same PI, the output sound is made silent (step 134 in FIG. 3), thereby avoiding annoying sound output due to the occurrence of periodic silence. be able to. In addition, when a silence state is detected, a message to that effect is displayed (step 120 in FIG. 3), so that when a broadcast signal is switched, it is based on the occurrence of a silence state. Can be informed. Note that the operation of step 120 in FIG. 3 may be performed before step 108 (determination operation of the same SID).

  In addition, a continuous silent state occurred by restricting the change in the volume setting when setting the silent state without the same SID service or FM broadcast program with the same PI (step 136 in FIG. 3). It is possible to prevent the user from increasing the volume too much without knowing that the sound is suddenly output after that.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the above-described embodiment, the silence state is detected and the countermeasure is performed without using the history information stored in the history information storage unit 90. However, the history information may be used.

  FIG. 5 is a flowchart showing an operation procedure of a modified example of the main control unit 60 that implements various countermeasures corresponding to the silence state using the history information. The operation procedure shown in FIG. 5 is different from the operation procedure shown in FIG. 3 in that steps 200 and 202 are added. In the following, the explanation will be given focusing on these added steps.

  After the received content is displayed on the display device 70 in relation to the reception service (step 102), the history processing unit 69 determines whether the same history information as the reception service is stored in the history information storage unit 90. (Step 200). Here, it is determined that the history information is the same when both the ensemble and the SID are the same. If the same history information as the reception service is not stored, a negative determination is made, and the process proceeds to step 104 (voice output). If the same history information as the reception service is stored, an affirmative determination is made in the determination of step 200. In this case, the silence processing unit 66 then sends a silence instruction to the output processing unit 50 so that the output sound of the speaker 54 is silenced (step 202). Thereafter, the process proceeds to step 106 (silence state determination). In this way, when a service that matches the history information is newly received, the output sound is set to the silent state, so that a service that is likely to generate a silent state can be set to a continuous silent state in advance. It is possible to prevent in advance the occurrence of annoying periodic silence. In addition, it takes a certain period of time to accurately detect the occurrence of a silent state, but since it is known in advance that the silent state is highly likely to occur based on history information, it is assumed that a silent state will occur. Therefore, the time required for accurately detecting the silent state can be shortened.

  In the above-described embodiment, the silent state detection unit 28 in the DAB / T-DMB tuner unit 20 detects the silent state that occurs during service reception based on the processing content of the decoder 26. However, the silent state detection unit 28 Is generated in the main control unit 60 and received during service reception based on audio data (audio data after audio reproduction operation by the DAB / T-DMB tuner unit 20) input (or output) to the output processing unit 50 A silent state may be detected. Specifically, the silence state may be detected based on the result of integration after calculating the square of the amplitude value of the audio data input (or output) to the output processing unit 50. By appropriately setting the cycle for detecting the silent state in this way (for example, when it is assumed that a silent state of about 500 milliseconds is periodically generated every few seconds, the cycle for detecting the silent state is set. It is possible to reliably detect a silence state that occurs during service reception.

  In the above-described embodiment, the DAB / T-DMB tuner unit 20 that receives a broadcast signal in accordance with the DAB / T-DMB broadcast standard has been described. However, the other contents having the same contents as the service (program) being received are described. The present invention can also be applied to other digital broadcast receivers that can specify services (programs). In the above-described embodiments, the FM broadcast program having the same PI as the SID is considered to be received by the FM / AM tuner unit 40. However, the present invention is also applied to a receiver that does not have the FM / AM tuner unit 40. can do. In this case, steps 122 to 132 included in FIGS. 3 and 5 may be omitted.

  As described above, according to the present invention, when the silence state of the received audio signal is detected, it can be switched to another broadcast signal having the same content, so that it is periodic or continuous in broadcast standard violations or broadcast accidents. Even when a silent state occurs, a substitute broadcast signal can be received and normal sound output can be performed, and deterioration in the quality of received sound can be prevented.

10, 30 Antenna 20 DAB / T-DMB tuner section 22 RF section 24 Analog-digital converter (A / D)
26 Decoder 28 Silent state detection unit 40 FM / AM tuner unit 50 Output processing unit 52 Amplifier 54 Speaker 60 Main control unit 62 Service switching unit 64 Silence notification unit 66 Silence processing unit 68 Volume limit unit 69 History processing unit 70 Display device 80 Operation 90 History information storage

Claims (14)

Broadcast signal receiving and reproducing means for receiving a broadcast signal and performing a predetermined sound reproducing operation;
A silent state detecting means for detecting a silent state of the audio signal reproduced by the broadcast signal receiving and reproducing means;
Broadcast signal switching means for sending an instruction to the broadcast signal receiving / reproducing means and switching the broadcast signal to be received to another broadcast signal having the same contents when the silent state detecting means detects the silent state; ,
The broadcast signal receiving and reproducing means is capable of receiving both a digital broadcast signal modulated by a digital modulation method and an analog broadcast signal modulated by an analog modulation method,
The broadcast signal switching means sends an instruction to the broadcast signal receiving / reproducing means when there are both other digital broadcast signals and analog broadcast signals having the same contents as the digital broadcast signal being received. digital broadcasting receiver, wherein the switching Rukoto the digital broadcast signal. In claim 1,
The broadcast signal receiving / reproducing means receives a digital broadcast signal modulated by a digital modulation method,
The broadcast signal switching means sends an instruction to the broadcast signal receiving / reproducing means to switch to another digital broadcast signal when another digital broadcast signal having the same content as the digital broadcast signal being received exists. A digital broadcast receiver. In claim 1 or 2,
The silent state includes a periodic silent state and a continuous silent state,
When the silent state is detected by the silent state detecting means, if there is no other broadcast signal having the same content as the digital broadcast signal being received, the audio signal reproduced by the broadcast signal receiving / reproducing means is forcibly output. The digital broadcast receiver further comprising first silence processing means for stopping the operation and maintaining a continuous silence state. In any one of Claims 1-3,
When the silent state is detected by the silent state detecting means, the digital broadcast receiver further comprises a silent state notifying means for notifying the user to that effect. In claim 4,
When outputting a sound signal reproduced by the broadcast signal receiving / reproducing means when there is no other broadcast signal having the same content as the digital broadcast signal being received when the silence condition is detected by the silence condition detecting means A digital broadcast receiver, further comprising volume limiting means for limiting a change in the volume setting. In any one of Claims 1-5,
History information storage means for storing history information in which a silence state is detected by the silence state detection means;
When the broadcast signal matching with the history information stored in the history information storage means is received by the broadcast signal receiving / reproducing means, until the operations of the silence state detecting means and the broadcast signal switching means are completed, A digital broadcast receiver, further comprising second silence processing means for forcibly stopping output of the audio signal reproduced by the signal reception / reproduction means to maintain a continuous silence state. In any one of Claims 1-6,
The broadcast signal receiving / reproducing means receives at least a digital broadcast signal modulated by a digital modulation method corresponding to the DAB / T-DMB broadcast standard. In claim 7,
The digital broadcast receiver characterized in that the silent state detecting means detects a silent state based on audio data after an audio reproduction operation by the broadcast signal receiving / reproducing means. In claim 8,
The digital broadcast receiver according to claim 1, wherein the silent state detecting means detects a silent state based on a result obtained by integrating a square of an amplitude value of the audio data. In claim 7,
The silent state detecting means detects a silent state based on the contents of the service component SC registered in the high-speed information channel FIC included in the broadcast signal received by the broadcast signal receiving / reproducing means. Machine. In claim 10,
The silent state detecting means detects a silent state when the content of the service component SC is null. In claim 10,
The digital broadcast receiver according to claim 1, wherein the silent state detecting means determines that there is a silent state when the PAT and PMT do not exist in the MPEG2-TS included in the service component SC. In claim 10,
The digital broadcast receiver according to claim 1, wherein the silent state detecting means determines that the silent state is detected when the audio TS is not included in the MPEG2-TS included in the service component SC. In claim 10,
2. The digital broadcast receiver according to claim 1, wherein the silent state detecting means determines that the silent state is present when the audio TS included in the MPEG2-TS of the service component SC is abnormal as MPEG4 content.

Images