JP2018082350A - Broadcast receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a broadcast receiver that switches between simultaneous broadcasts so that the volume level of an output voice will not change.SOLUTION: A broadcast receiver sets, to off, a volume adjustment function of an FM broadcast corresponding to reception electric field strength of the FM broadcast performed as noise countermeasures during a period when a speaker 5 is outputting a voice of DAB (Digital Audio Broadcasting). In addition, it adjusts gain of the volume level of the FM broadcast according to difference between the volume level of the DAB received at that time point and the volume level of an FM broadcast having relation of a simultaneous broadcast with a service of the DAB during a period when the voice of the DAB is being output (Figure 5, t0). Then, if the reception quality of the DAB deteriorates after that, the voice output from the speaker 5 is switched to the voice of the FM broadcast, and the voice adjustment function is set to on (Figure 5a, t1).SELECTED DRAWING: Figure 5

Description

  The present invention relates to a technique for switching a reception target from a broadcast service being received to a broadcast service that is broadcasting the same content as the broadcast service in a broadcast receiving apparatus.

  As a technology for switching the reception target from a broadcast service being received to a broadcast service that is broadcasting the same content as the broadcast service (a broadcast service having a relationship between the broadcast service being received and the simulcast), DAB (digital An FM broadcast that broadcasts the same content as that of the DAB service when the reception quality of the DAB service being received deteriorates in a radio broadcast receiving apparatus that receives FM (Digital Audio Broadcasting) and FM broadcast There is known a technique for switching a reception target to a station (for example, Patent Documents 1 and 2).

  In addition, when switching the reception target between the DAB service that broadcasts the same content and the FM broadcast station, the DAB does not cause a difference in the volume level of the sound output before and after the switching. There is also known a technique for adjusting the volume level of output sound at the time of switching according to the service level and the volume level of received sound of an FM broadcast station (for example, Patent Document 3).

  Also, in radio receivers that receive FM broadcasts, high cuts that attenuate high frequency components of audio output when the broadcast reception field strength decreases, and audio output when the broadcast reception field strength decreases There is also known a technique for reducing discomfort caused by noise when the received electric field strength of a broadcast deteriorates, such as soft mute for reducing the sound volume level (for example, Patent Documents 4 and 5).

JP 2013-120967 A JP 2012-249277 A JP 2001-196952 A JP 2008-60774 A Japanese Patent Laid-Open No. 06-232828

  As described above, when switching the reception target between the DAB service that broadcasts the same content and the FM broadcasting station, the DAB's volume level is set so that there is no difference in the volume level of the audio output before and after the switching. In the radio receiving apparatus that adjusts the volume level of the output sound at the time of switching according to the volume level of the received sound of the service and the FM broadcast station, when the above-described high cut or soft mute is executed for the FM broadcast, before and after the switching A relatively large difference in the output volume level may occur, which may cause discomfort to the user.

  That is, in this case, the volume level of the FM broadcast reception sound is detected before switching from DAB to FM broadcast, the volume level of the FM broadcast reception sound is adjusted according to the detected volume level, and the output sound DAB is detected. A procedure of switching to FM broadcasting is performed. Also, the volume level of the received sound of the FM broadcast should be detected in advance before the DAB reception quality deteriorates so that when the DAB reception quality deteriorates, the sound volume level is immediately switched to the FM broadcast. Become. For this reason, the received electric field strength of the FM broadcast changes between the detection of the volume level of the received voice of the FM broadcast and the switching from the DAB of the output voice to the FM broadcast. Depending on the situation, the volume level of the received sound of the FM broadcast may change greatly. When the volume level of the FM broadcast reception sound changes greatly as described above, the volume level adjusted according to the detected FM broadcast reception sound volume level is the volume level of the DAB reception voice at the time of switching. Therefore, a relatively large difference occurs in the output sound volume level before and after switching.

  Therefore, the present invention provides a broadcast receiving apparatus that performs audio processing according to the received electric field strength such as high cut and soft mute, from a receiving broadcast service to a broadcast service that is broadcasting the same content as the broadcast service. An object is to switch the reception target so that the volume level of the output sound does not change.

  In order to achieve the above object, the present invention provides a digital broadcast receiver that receives a digital broadcast and outputs a digital broadcast sound that is a sound received by the digital broadcast to a radio receiver that receives the digital broadcast and the analog broadcast. And receiving the analog broadcast and outputting the analog broadcast sound which is the sound received by the analog broadcast, and receiving the analog broadcast having a sound adjustment function for adjusting the analog broadcast sound to be output according to the reception state of the analog broadcast A volume level adjusting means for adjusting a volume level of the analog broadcast sound with a set gain, and one of the digital broadcast sound and the analog broadcast sound whose volume level is adjusted by the volume level adjusting means. An output means for selectively outputting to the user and a control means are provided. Here, during the period when the output means is outputting the digital broadcast sound, the control means is received by the digital broadcast receiving section in the analog broadcast receiving section with the sound adjustment function disabled. An analog broadcast that has the same content as the digital broadcast is received, and the audio that is output by the output means based on the volume level of the digital broadcast audio and the volume level of the analog broadcast audio is received by the digital broadcast Switching preparation means for setting in the volume level adjustment means a gain at which the volume level does not change even when the volume level adjustment means switches to analog broadcast sound whose volume level has been adjusted by the volume level adjustment means, and the output means converts the digital broadcast sound to When the digital broadcast reception quality of the digital broadcast receiver deteriorates during output, the output And switching output from the digital broadcast sound to analog broadcast sound whose volume level is adjusted by the volume level adjusting means and enabling the sound adjustment function of the analog broadcast receiving device. Yes.

  According to such a broadcast receiving device, since the digital broadcast audio is being output, the audio adjustment function for adjusting the analog broadcast audio to be output in accordance with the reception state of the analog broadcast is invalidated. Based on the volume level of the digital broadcast sound and the volume level of the analog broadcast sound, the volume output even if the sound output by the output means is switched from the digital broadcast sound to the analog broadcast sound whose volume level is adjusted by the volume level adjusting means. After the gain at which the level does not change is set in the volume level adjusting means, the reception quality of the digital broadcast is deteriorated, and the audio output by the output means is converted from the digital broadcast sound to the analog whose volume level adjusting means has adjusted the volume level. Before switching to broadcast audio, the volume level of analog broadcast audio output from the analog broadcast receiver Le has a high probability does not change significantly.

  Therefore, when the sound output by the output means is switched from the digital broadcast sound to the analog broadcast sound whose volume level is adjusted by the volume level adjusting means, it can be expected that the volume level output before and after the switching does not change.

  Here, such a broadcast receiving apparatus adjusts the analog broadcast sound in response to a change in the reception state of the analog broadcast with a set response time characteristic by using the sound adjustment function of the analog broadcast receiving unit. In the control means, during the period when the output means is outputting the digital broadcast sound, the first response time characteristic is set in the sound adjustment function of the analog broadcast receiving unit and is output by the output means. When a predetermined time elapses after the sound is switched from the digital broadcast sound to the analog broadcast sound whose volume level is adjusted by the volume level adjusting means, the response time of the sound adjustment function of the analog broadcast receiving unit is the first time. A second response time characteristic that is shorter than the response time characteristic may be set in the audio adjustment function of the analog broadcast receiving unit.

  Thus, when the sound output from the output unit is switched from the digital broadcast sound to the analog broadcast sound whose volume level is adjusted by the volume level adjusting unit, the sound adjustment function of the analog broadcast receiving device is changed. When activated, it is possible to prevent the volume level of the sound output from the output means from changing sharply due to the invalid / effective switching of the sound adjustment function.

  Here, in the broadcast receiving apparatus described above, the audio adjustment function of the analog broadcast receiving unit includes a high cut function that attenuates a high frequency component of the analog broadcast audio when the reception electric field strength of the analog broadcast decreases. Also good.

  Further, in the broadcast receiving apparatus described above, the sound adjustment function of the analog broadcast receiving unit may include a soft mute function that decreases the volume level of the analog broadcast sound when the reception electric field strength of the analog broadcast decreases. Good.

In the broadcast receiving apparatus described above, the analog broadcast can be FM broadcast, for example.
In the above broadcast receiving apparatus, the digital broadcast may be, for example, DAB (Digital Audio Broadcasting).
Moreover, the above broadcast receiving apparatus may be mounted on a mobile body.

  As described above, according to the present invention, in a broadcast receiving apparatus that performs audio processing according to received electric field strength such as high cut and soft mute, the same content as the broadcast service is broadcast from the broadcast service being received. It is possible to switch the reception target so that the volume level of the output audio does not change to the broadcasting service that is being used.

It is a block diagram which shows the structure of the radio broadcast receiver which concerns on embodiment of this invention. It is a block diagram which shows the structure of the switching process part which concerns on embodiment of this invention. It is a flowchart which shows the FM broadcast switching preparation process which concerns on embodiment of this invention. It is a flowchart which shows the FM broadcast switching process which concerns on embodiment of this invention. It is a figure which shows the operation example of the radio broadcast receiver which concerns on embodiment of this invention. It is a flowchart which shows the DAB broadcast switching process which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows a configuration of a radio receiving apparatus according to the present embodiment.
As shown in the figure, the radio broadcast receiver is a radio broadcast receiver whose position varies, such as a radio receiver or a portable radio receiver mounted on an automobile.
As illustrated, the radio broadcast receiver includes a DAB receiving unit 1, an FM receiving unit 2, a switching processing unit 3, an amplifier 4, a speaker 5, a control unit 6, a display unit 7, and an operation unit 8.
Here, the DAB receiving unit 1 is a receiving unit that receives a radio broadcast according to the DAB (including DAB +) broadcast standard, and includes a DAB front end 11 (DAB F / E11), a DAB decoder 12, and an audio decoder 13. ing.

  The FM receiver 2 is a receiver that receives a radio broadcast according to the FM broadcast standard. The FM front end 21 (FM F / E21), the FM demodulator 22, the RDS decoder 23, and the AD converter 24 (A / D24), and an audio adjustment unit 25 is provided.

  Now, in DAB, a plurality of services each corresponding to a single audio broadcast can be broadcast on one frequency channel, and each service is identified by a service identifier SID broadcast by the service. A collection of services broadcast on the same frequency channel is called an ensemble.

In such a configuration, the DAB receiving unit 1 performs the following service reception operation.
That is, in the service receiving operation, the DAB front end 11 of the DAB receiving unit 1 receives the DAB of the frequency channel set as the DAB receiving channel, and sends the received data to the DAB decoder 12. The DAB decoder 12 sends the audio data received by the service set as the DAB reception service from the received data sent from the DAB front end 11 to the audio decoder 13 and also receives the service identifier SID and service received together with the audio data. The linking information is sent to the control unit 6. The audio decoder 13 decodes the audio data sent from the DAB decoder 12 and outputs the decoded audio data to the switching processing unit 3. Further, the DAB front end 11 and the DAB decoder 12 detect information related to the reception quality of the DAB service, such as the received electric field strength, the SN ratio, and the received data error rate of the DAB reception channel, and notify the control unit 6 of the information. .

  In the service reception operation described above, the service set as the DAB reception service among the services broadcasting on the DAB reception channel corresponds to the service targeted for the reception operation.

Further, the FM receiver 2 performs the following station reception operation.
That is, in the reception operation of the station, the FM front end 21 of the FM receiver 2 receives the frequency channel set as the FM reception channel and sends the received signal to the FM demodulator 22. The FM demodulator 22 receives the received signal from the received signal. The audio signal is demodulated and sent to the AD converter 24. The AD converter 24 converts the sent audio signal into audio data and sends it to the audio adjusting unit 25. The audio adjustment unit 25 performs predetermined audio adjustment processing on the audio data sent from the FM demodulation unit 22 and sends the audio data to the switching processing unit 3. Further, the FM demodulator 22 sends the data signal multiplexed and transmitted by the RDS (Radio Data System) to the RDS decoder 23, and the RDS decoder 23 decodes the data from the data signal and sends it to the controller 6. . Here, the data sent from the RDS decoder 23 to the control unit 6 includes a program identifier PI that becomes an identifier of a program (program) broadcasted from a station of a frequency channel set as an FM reception channel, an AF list, and the like. It is. Further, the FM front end 21 detects information related to the reception quality of the FM broadcast of the FM reception channel, such as the received electric field strength and the SN ratio of the FM reception channel, and notifies the control unit 6 of the information.

  Here, the sound adjustment processing performed by the sound adjustment unit 25 described above is such that the reception electric field strength is small when the reception electric field strength of the FM reception channel detected by the FM front end 21 is equal to or lower than a predetermined threshold value. The high cut processing that greatly attenuates the high frequency component of the audio data, and when the reception electric field strength of the FM reception channel detected by the FM front end 21 is equal to or lower than a predetermined threshold value, the audio signal decreases as the reception electric field strength decreases. This is a soft mute process for reducing the volume level of data.

In the reception operation of the above stations, the station that is broadcasting on the FM reception channel corresponds to the target station of the reception operation.
Here, the control unit 6 calculates the reception quality of the DAB service for which the digital broadcast reception unit performs the reception operation from the information related to the reception quality of the service notified from the DAB reception unit 1, and receives the FM signal. From the information regarding the FM broadcast reception quality notified from the FM front end 21 of the unit 2, the reception quality of the FM broadcast station in which the FM reception unit 2 is performing the reception operation is calculated.

  Now, an FM broadcast station that broadcasts the content broadcast by the DAB service and the PI program that matches the SID of the service broadcasts the program (program) having the same content. Also, the AF list received by FM broadcast indicates an alternative frequency that is the frequency of another FM broadcast that broadcasts the program of the same PI. The service linking information received by the DAB service indicates, for each program (program), the identification of the DAB service broadcasting the program and the FM broadcast station.

  Therefore, the control unit 6 broadcasts the program having the same content for each program based on the SID of the DAB service, the PI of the FM broadcast, the AF list received by the FM broadcast, and the service linking information received by the DAB. That is, it is possible to know DAB services and FM broadcast stations related to simulcast.

Next, FIG. 2 shows a configuration of the switching processing unit 3.
As shown in the figure, the switching processing unit 3 includes a first buffer 31 that stores audio data sent from the DAB receiving unit 1, a second buffer 32 that stores audio data sent from the FM receiving unit 2, and a synchronization processing unit. 33, a first volume level detector 34, a second volume level detector 35, a first digital amplifier 36, a second digital amplifier 37, a selector 38, and a DA converter 39 (D / A 39).

  In such a configuration, the synchronization processing unit 33 compares the audio data stored in the first buffer 31 and the second buffer 32, and the DAB audio data and the FM broadcast audio data that are in a simulcast relationship are the same. A synchronization process for setting a delay time of each audio data by the first buffer 31 and the second buffer 32 so that a portion corresponding to the sound is simultaneously output from the first buffer 31 and the second buffer 32; 31 and the second buffer 32 perform processing to delay and output the delay time audio data set in the buffer.

  The first volume level detector 34 detects the volume level of DAB audio data output from the first buffer 31 and notifies the controller 6 of the volume level, and the second volume level detector 35 detects the volume level of the second buffer 32. Is detected and notified to the control unit 6.

  The first digital amplifier 36 amplifies the DAB audio data output from the first buffer 31 with the gain set by the control unit 6 and sends it to the selector 38, and the second digital amplifier 37 is set by the control unit 6. The FM broadcast audio data output from the second buffer 32 is amplified with the obtained gain and sent to the selector 38.

  The selector 38 controls one of the two audio data, DAB audio data output from the first digital amplifier 36 and FM broadcast audio data output from the second digital amplifier 37, under the control of the control unit 6. The DA converter 39 converts the audio data sent from the selector 38 into an analog audio signal and outputs it to the amplifier 4.

  In such a configuration of the radio receiver, if the control unit 6 receives a request for receiving a specific DAB service from the user via the operation unit 8 with an appropriate user interface using the display unit 7, For example, the reception target broadcast is switched to the service requested to be received.

  When the reception target broadcast is switched to the DAB service in response to a user request, the control unit 6 sets the frequency channel of the ensemble including the service as the DAB reception channel in the DAB front end 11, Setting the service as a DAB reception service in the DAB decoder 12 causes the DAB reception unit 1 to perform the reception operation of the service.

Further, the control unit 6 causes the selector 38 of the switching processing unit 3 to output the DAB audio data output from the first buffer 31 to the DA converter 39.
Here, as a result, the sound broadcast on the DAB service requested by the user, which is the target broadcast, is output from the speaker 5 to the user.
In the initial state, the delay times of the first buffer 31 and the second buffer 32 and the gains of the first digital amplifier 36 and the second digital amplifier 37 are set to predetermined initial values.
When the reception target broadcast is switched to the DAB service from the FM broadcast station or another DAB service, the control unit 6 starts the FM broadcast switching preparation process shown in FIG. 3 and the DAB service is the reception target. The execution of the FM broadcast switching preparation process is continued during the period in which the broadcast is continued.

  As shown in the figure, in this FM broadcast switching preparation process, the control unit 6 first sets the sound adjustment function of the sound adjustment unit 25 of the FM reception unit 2 to OFF, and the sound adjustment unit 25 of the FM reception unit 2 described above. The audio adjustment processing such as the high cut processing and soft mute processing is not performed (step 302). Note that the audio adjusting unit 25 of the FM receiving unit 2 sends the audio data sent from the FM demodulating unit 22 to the switching processing unit 3 as it is during the period when the audio adjusting function is set to OFF.

  Then, the control unit 6 next sets the response time characteristic of the sound adjustment unit 25 of the FM reception unit 2 to a long time setting (step 304). Here, in the high cut processing, when the received electric field strength changes, the attenuation rate of the high frequency component of the audio data is gradually changed, and the attenuation rate of the high frequency component of the audio data is attenuated according to the received electric field strength. Process to change rate. In the soft mute process, when the received electric field strength changes, the volume level of the audio data is gradually changed to change the volume level of the audio data to the volume level corresponding to the received electric field strength. Further, the response time characteristic of the audio adjustment unit 25 is the high cut processing, from when the received electric field strength changes until the attenuation rate of the high frequency component of the audio data changes to the attenuation rate according to the received electric field strength. In the case of soft mute processing, the response time is the time from when the received electric field strength changes until the volume level of the audio data changes to the volume level corresponding to the received electric field strength. It prescribes.

  Here, as the response time characteristic of the sound adjusting unit 25 of the FM receiving unit 2, the above-described long time setting and normal time setting can be selectively set, and the response time of the sound adjusting unit 25 of the FM receiving unit 2 is set. When the characteristic is set to the long time setting, the response time of the high cut processing and the soft mute processing is relatively longer than when the normal time setting is set. In other words, when the response time characteristic of the sound adjusting unit 25 of the FM receiving unit 2 is set to a long time setting, the normal time setting is set for the change in the attenuation rate of the high frequency component of the audio data in the high cut processing. The volume level of the audio data in the soft mute process changes more gradually than when the normal time setting is set.

  Next, the control unit 6 determines whether or not there is a receivable FM broadcast station in the relationship between the DAB being received by the DAB receiving unit 1 and the simulcast, and whether the DAB receiving unit 1 is receiving the DAB and the simulcast. The reception of each station of the FM broadcast that is related to the broadcast is sequentially performed by the FM receiver 2 and the reception quality of each station is calculated to investigate (step 306). If there is no FM broadcast station that can be received and has a relationship of simultaneous broadcasting with the DAB being received, the process of step 306 is repeated.

  On the other hand, if there is a receivable FM broadcast station that is in a relationship between the DAB being received and the simulcast, the FM reception of the best FM broadcast station among the existing FM broadcast stations is received by FM. Start part 2 (step 308).

Further, the synchronization processing unit 33 of the switching processing unit 3 starts the above-described synchronization processing (step 310).
Next, the synchronization processing of the synchronization processing unit 33 is completed, and the portion corresponding to the same sound of the DAB audio data received by the DAB receiving unit 1 and the FM broadcast audio data received by the FM receiving unit 2 is the first buffer 31. Are output simultaneously from the second buffer 32 (step 312), the volume level of the DAB audio data from the first volume level detection unit 34 and the second volume level detection unit 35 of the switching processing unit 3 And the volume level of the FM broadcast audio data is acquired (step 314).

  Then, based on the acquired FM broadcast audio data and volume level, the acquired DAB audio data volume level, and the gain set in the first digital amplifier 36, the FM broadcast audio input to the selector 38 is input. The gain of the second digital amplifier 37 that matches the volume level of the data with the volume level of the DAB audio data input to the selector 38 is calculated and set in the second digital amplifier 37 (step 316).

  Then, a timer having a predetermined timeout time (for example, several minutes) is started (step 318). When the timer times out (step 320), the processing returns to step 306.

In the above, the FM broadcast switching preparation process performed by the control unit 6 during a period in which the reception target broadcast is a DAB service has been described.
According to the FM broadcast switching preparation process as described above, during the period when the reception target broadcast is a DAB service, that is, during the period when the DAB audio received by the DAB receiving unit 1 is output from the speaker 5, the DAB concerned. Of the FM broadcast station that can be received by the FM broadcast station, and the DAB audio data received by the DAB receiver 1 of the switching processing unit 3 and the FM broadcast received by the FM receiver 2. The synchronization with the audio data is performed in the background, and the detection of the volume level of the FM broadcast audio data received by the FM receiver 2 and the adjustment of the gain of the second digital amplifier 37 are periodically performed.

  Next, if the reception quality of the DAB of the DAB receiving unit 1 deteriorates during the period in which the reception target broadcast is a DAB service, the control unit 6 causes the FM receiving unit 2 to have an FM relationship between the DAB service and the simulcast. It is checked whether or not a broadcast station is received, and if it is received, FM broadcast switching processing is performed to switch the reception symmetric broadcast to the FM broadcast station received by the FM receiver 2.

FIG. 4 shows the procedure of this FM broadcast switching process.
As shown in the figure, in the FM broadcast switching process, the control unit 6 first switches on the sound adjustment function of the sound adjustment unit 25 of the FM reception unit 2 (step 402).
Then, the reception target broadcast is switched to the FM broadcast station received by the FM receiver 2, and the audio data output from the selector 38 to the DA converter 39 is converted into the FM broadcast audio data output from the second digital amplifier 37. Switching (step 404).

Here, the sound output from the speaker 5 is switched to the sound of FM broadcasting.
Up to this point, the DAB audio data before switching and the FM broadcasting audio data after switching have been synchronized and at the same volume level by the above-described FM broadcast switching preparation process, so that they are output from the speaker 5. The voice is seamlessly switched from the voice of the DAB service to the voice of the FM broadcast station. In other words, the FM broadcast switching preparation process synchronizes the audio data of the DAB before switching with the audio data of the FM broadcasting after switching, so that the volume level is the same. If the reception quality of this service deteriorates, the reception target broadcast can be immediately switched to the FM broadcast.

  Next, a timer is started (step 406), and a timer timeout is awaited. Here, the time-out time of the timer is a time corresponding to the maximum response time of the high cut processing and soft mute processing of the audio adjusting unit 25 of the FM receiving unit 2 when the response time characteristic is set to a long time.

  If the timer has timed out (step 408), the response time characteristic of the audio adjusting unit 25 of the FM receiving unit 2 is set to the normal time setting described above (step 410), and the FM broadcast switching process is terminated.

The FM broadcast switching process performed by the control unit 6 has been described above.
FIG. 5a shows an operation example of such FM broadcast switching preparation processing and FM broadcast switching processing.
In the illustrated example, when the reception target broadcast is a DAB service and DAB audio is output from the speaker 5, the FM broadcast switching preparation process at time t0 performs the volume level and FM of the DAB audio data at that time. When the gain G of the FM broadcast audio data switches the sound output from the speaker 5 to the sound of the FM broadcast according to the difference in the volume level of the broadcast audio data, the sound of the FM broadcast is output from the current speaker. It is adjusted so that it is output at the same volume level as the sound of the DAB being played.

  After that, when the reception quality of the DAB service that is the reception target broadcast deteriorates at time t1, the sound output from the speaker 5 is switched to the sound of the FM broadcast by the FM broadcast switching process. Here, during the period when the reception target broadcast is a DAB service, the voice adjustment function of the voice adjustment unit 25 of the FM reception unit 2 is set to OFF, so that the FM reception unit is between time t0 and time t1. It can be expected that the volume level of the FM broadcast sound output from No. 2 has not changed significantly.

  Therefore, when the sound output from the speaker 5 at time t1 is switched from DAB sound to FM broadcast sound, there is no significant difference in the volume level output from the speaker 5 before and after switching, and the output sound is seamlessly DAB. It can be expected to switch from the sound of FM to the sound of FM broadcast.

  At time t1, the sound adjustment function of the sound adjustment unit 25 of the FM reception unit 2 is switched from OFF to ON. At this time, the response time characteristic of the sound adjustment function of the sound adjustment unit 25 of the FM reception unit 2 is FM. Since the setting has been set for a long time by the broadcast switching preparation process, a sudden change in the output volume level due to switching of the sound adjustment function from OFF to ON is also suppressed.

  After that, at time t2 when a predetermined period has elapsed, the response time characteristic of the voice adjustment function of the voice adjustment unit 25 of the FM reception unit 2 is set to the normal time characteristic, and thereafter the voice adjustment function of the voice adjustment unit 25 , The discomfort due to the output of noise when the received electric field strength of FM broadcasting is reduced is effectively suppressed.

  Next, FIG. 5b shows a change in the output volume level when the sound adjustment function of the sound adjustment unit 25 of the FM receiver 2 having the response time characteristic as the normal time characteristic is always turned on as a comparative example to the present embodiment. Show.

  In this example, when the reception target broadcast is a DAB service and the DAB audio is output from the speaker 5, at the time t0, the volume level of the audio data of the DAB at that time and the volume level of the audio data of the FM broadcast When the gain G of the FM broadcast audio data is switched from the sound output from the speaker 5 to the sound of the FM broadcast according to the difference between the sound of the FM broadcast and the sound of the DAB currently output from the speaker. It is adjusted to output at the same volume level.

After that, when the reception quality of the DAB service that is the reception target broadcast deteriorates at time t1, the sound output from the speaker 5 is switched to the sound of the FM broadcast.
Here, even during the period when the reception target broadcast is a DAB service, the audio adjustment function of the audio adjustment unit 25 of the FM reception unit 2 is set to ON. Due to the change, the volume level of the sound of the FM broadcast output from the FM receiver 2 may change greatly between time t0 and time t1. That is, at time t0, the FM broadcast reception electric field strength is good and high cut or soft mute is not performed by the audio adjustment function of the audio adjustment unit 25, but the FM broadcast reception electric field strength deteriorates by time t1. When high cut or soft mute is performed by the sound adjustment function of the sound adjustment unit 25 at time t1, the volume level of the FM broadcast sound is lower than time t0 at time t1, as shown in FIG. 5b. Conversely, at time t0, the FM broadcast reception field strength is degraded, and high cut and soft mute are performed by the voice adjustment function of the voice adjustment unit 25. On the other hand, FM broadcast reception field strength is reached by time t1. If the high cut or soft mute is not performed by the audio adjustment function of the audio adjustment unit 25 at time t1, the volume level of the FM broadcast audio becomes higher than time t0 at time t1.

  When the volume level changes greatly, the difference in volume level between the FM broadcast sound output by the FM receiver 2 and the DAB sound output by the DAB receiver 1 at time t1 is significantly different from the difference at time t0. Therefore, the volume level of the FM broadcast sound at time t1 with the gain G adjusted according to the difference at time t0 is significantly different from the volume level of DAB sound at time t1, and the speaker at time t1. When the sound output from 5 is switched from DAB sound to FM broadcast sound, a large difference occurs in the volume level output from the speaker 5 before and after switching.

  Next, the control unit 6 causes the DAB receiving unit 1 to sequentially receive the frequency channels of the DAB stations related to the simulcast during the period in which the target broadcast is an FM broadcast station. Then, by calculating the reception quality of each frequency channel, the process of searching for whether or not the DAB service that is in the relationship with the FM broadcast station that is the broadcast to be received and the simulcast is receivable is repeated.

  When the DAB service that is in the relationship with the FM broadcast station that is the reception target broadcast can be received, the DAB receiving unit 1 starts to receive the DAB service and the reception target broadcast is transmitted. Then, DAB switching processing for switching from the FM broadcast station to the searched DAB service is performed.

FIG. 6 shows the procedure of this DAB switching process.
As shown in the figure, in this DAB switching process, the control unit 6 first causes the synchronization processing unit 33 of the switching processing unit 3 to start the above-described synchronization processing (step 602). Then, the synchronization processing of the synchronization processing unit 33 is completed, and the portion corresponding to the same sound of the DAB audio data received by the DAB receiving unit 1 and the FM broadcast audio data received by the FM receiving unit 2 is the first buffer 31. If they are simultaneously output from the second buffer 32 (step 604), the volume level of the DAB audio data is detected from the first volume level detector 34 and the second volume level detector 35 of the switching processor 3. The volume level of the FM broadcast audio data is acquired (step 606).

  Then, based on the acquired FM broadcast audio data and volume level, the acquired DAB audio data volume level, and the gain set in the second digital amplifier 37, the DAB audio data input to the selector 38 is input. The gain of the first digital amplifier 36 that matches the volume level of the first digital amplifier 36 with the volume level of the FM broadcast audio data input to the selector 38 is calculated and set in the first digital amplifier 36 (step 608).

  Then, the reception target broadcast is switched to the DAB service received by the DAB receiver 1, and the audio data output from the selector 38 to the DA converter 39 is switched to the DAB audio data output from the first digital amplifier 36 ( Step 610). Here, the sound output from the speaker 5 is switched to the DAB sound.

  Further, when the reception target broadcast is switched to the DAB service, the FM broadcast switching preparation process is started as described above, and the execution of the FM broadcast switching preparation process is continued during the period in which the DAB service is the reception target broadcast. Is done.

The DAB switching process performed by the control unit 6 has been described above.
Here, when the reception target broadcast is switched from the FM broadcast station to the DAB station in this way, the volume level of the DAB audio data and the volume level of the FM broadcast audio data are acquired, and the first digital amplifier 36 Immediately after adjusting the gain, the sound output from the speaker 5 is switched from the sound of the FM broadcast station to the sound of the DAB service, so that even if the sound adjustment function of the sound adjustment unit 25 of the FM reception unit 2 is on. The difference in volume level output from the speaker 5 before and after switching does not increase.

The embodiment of the present invention has been described above.
In the above embodiment, the radio receiver that receives FM broadcast and DAB has been described. However, in the present embodiment, audio is output between an arbitrary analog broadcast and an arbitrary digital broadcast that are related to a simulcast. The present invention can be similarly applied to a broadcast receiving apparatus that performs broadcast switching.

  DESCRIPTION OF SYMBOLS 1 ... DAB receiving part, 2 ... FM receiving part, 3 ... Switching processing part, 4 ... Amplifier, 5 ... Speaker, 6 ... Control part, 7 ... Display part, 8 ... Operation part, 11 ... DAB front end, 12 ... DAB Decoder, 13 ... Audio decoder, 21 ... FM front end, 22 ... FM demodulator, 23 ... RDS decoder, 24 ... AD converter, 25 ... Audio adjuster, 31 ... First buffer, 32 ... Second buffer, 33 ... Synchronization Processing unit 34... First volume level detector 35. Second volume level detector 36. First digital amplifier 37. Second digital amplifier 38. Selector 39.

Claims (7)

A radio receiver for receiving digital broadcast and analog broadcast,
A digital broadcast receiver that receives the digital broadcast and outputs a digital broadcast sound that is the sound received in the digital broadcast;
An analog broadcast receiving unit having an audio adjustment function for adjusting the analog broadcast sound to be output according to the reception state of the analog broadcast; ,
Volume level adjustment means for adjusting the volume level of the analog broadcast audio with a set gain;
An output means for selectively outputting to the user one of the digital broadcast sound and the analog broadcast sound whose volume level adjusting means has adjusted the volume level;
Control means,
The control means includes
During the period when the output means is outputting the digital broadcast audio, the analog broadcast receiving unit with the audio adjustment function disabled, the same broadcast as the digital broadcast received by the digital broadcast receiving unit. And the volume level adjusting means outputs the sound output by the output means from the digital broadcast sound based on the volume level of the digital broadcast sound and the volume level of the analog broadcast sound. Switching preparation means for setting a gain in the volume level adjusting means so that the volume level does not change even when switching to the analog broadcast sound whose volume level is adjusted;
When the output means is outputting the digital broadcast sound, when the reception quality of the digital broadcast of the digital broadcast receiver is deteriorated, the sound output by the output means is changed from the digital broadcast sound to the volume level. A broadcast receiving apparatus comprising: an output switching means for enabling the audio adjustment function of the analog broadcast receiving apparatus while the adjusting means switches to the analog broadcast sound whose volume level is adjusted. The broadcast receiving device according to claim 1,
The audio adjustment function of the analog broadcast receiving unit adjusts the analog broadcast audio in response to a change in the reception state of the analog broadcast with a set response time characteristic,
The control means sets the first response time characteristic to the sound adjustment function of the analog broadcast receiver during the period in which the output means is outputting the digital broadcast sound, and the sound output by the output means When the predetermined time elapses after the digital broadcast sound is switched to the analog broadcast sound whose volume level is adjusted by the volume level adjusting means, the response time of the sound adjustment function of the analog broadcast receiving unit is the first response. A broadcast receiving apparatus, wherein a second response time characteristic that is shorter than a time characteristic is set in an audio adjustment function of the analog broadcast receiving unit. The broadcast receiving apparatus according to claim 1 or 2,
The audio adjusting function of the analog broadcast receiving unit includes a high cut function for attenuating a high frequency component of the analog broadcast audio when the reception electric field strength of the analog broadcast decreases. The broadcast receiving device according to claim 1, 2, or 3,
The audio receiving function of the analog broadcast receiving unit includes a soft mute function for reducing the volume level of the analog broadcast audio when the reception electric field strength of the analog broadcast is reduced. The broadcast receiving device according to claim 1, 2, 3 or 4,
The broadcast receiving apparatus, wherein the analog broadcasting is FM broadcasting. The broadcast receiving device according to claim 1, 2, 3, 4 or 5,
The broadcast receiving apparatus is characterized in that the digital broadcasting is DAB (Digital Audio Broadcasting). The broadcast receiving device according to claim 1, 2, 3, 4, 5 or 6,
The broadcast receiving apparatus is mounted on a mobile body.