JP2002300061A - Broadcast receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a broadcast receiver that adjusts a reproduced sound volume depending on a degree of deterioration in the reception state so as to reduce a sense of incongruity caused on a user. SOLUTION: The broadcast receiver detects a reception state of a broadcast wave and controls an output level of an audio signal received in response to the detected reception state. When the reception state is deteriorated from an excellent state, the output level is decreased to a mute level and when the reception state is restored to the excellent state after that, the output level is gradually recovered up to the original level so as to relieve a sense of incongruity caused on the user.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a broadcast receiving apparatus, and more particularly, to volume control in a broadcast receiving apparatus.

[0002]

2. Description of the Related Art Currently, DAB (Digital Audio Broadcast)
ing) Digital audio broadcasting based on the standard is performed. D
The AB can provide a high-quality digital audio program and data service to a receiving device on a mobile object.

[0003] In DAB, audio data is M
It is encoded according to a compression encoding method such as PEG audio, and furthermore, COFDM (Coded Orthogonal Frequen
Modulation by cy Division Multiplex (coded orthogonal frequency division multiplexing) is performed and the broadcast wave is obtained. COFDM
Includes processes such as error correction coding and interleaving, which is rearrangement of audio data in a frequency / time plane, to reduce the influence of fading in a wireless transmission path. As a result, the reception quality of audio broadcasting in a mobile object is improved in DAB.

The DAB receiver demodulates a broadcast wave modulated by the COFDM method, decodes encoded data, and reproduces original audio data.
In the DAB receiving apparatus, the deterioration of the receiving state due to the influence of fading or the like is caused by the BER when decoding the received data.
(Bit Error Rate).

[0005]

In the DAB reception, the degree of deterioration of the reception state due to the effects of fading or the like can be determined based on the BER. Therefore, it is also possible to judge that the noise of the sound has increased based on the BER and mute the reproduced sound. This not only reduces the discomfort to the user, but also eliminates the burden of the user himself operating the receiving device to mute the sound when noise enters the sound.

On the other hand, the reception state in the DAB changes in a complicated manner depending on the passage of time and the place. Therefore, BE
Just muting the sound when R decreases may not always reduce the discomfort to the user.

[0007] The present invention has been made in view of such circumstances. That is, an object of the present invention is to provide a broadcast receiving apparatus capable of appropriately adjusting a reproduction volume in accordance with a degree of deterioration of a reception state and appropriately reducing a sense of discomfort to a user.

[0008]

SUMMARY OF THE INVENTION Therefore, the invention according to claim 1 is a broadcast receiving apparatus for receiving a broadcast wave and reproducing an audio signal, wherein the detecting means detects a reception state of the broadcast wave, and the detecting means. Control means for changing the output level of the reproduced audio signal in accordance with the reception state detected by the control unit. According to the reception state, it is possible to perform control to lower the output level of the audio signal as the reception state deteriorates and to increase the output level of the audio signal as the reception state recovers. Therefore, it is possible to reduce a sense of incongruity given to the user due to mixing of noise into the reproduced sound.

[0009] In the broadcast receiving apparatus according to claim 2,
The control means reduces the output level of the audio signal to the first level when the deterioration of the reception state is detected.

Here, if the control means is configured to gradually increase the output level of the audio signal from the first level when the recovery of the reception state is detected after the deterioration of the reception state, the audio output Since the level gradually increases after the decrease, the user does not feel uncomfortable (claim 3).

Alternatively, the control means may be configured to increase the output level of the audio signal stepwise from the first level when the recovery of the reception state is detected after the deterioration of the reception state. Item 4).

In this case, it is preferable that the control means performs the stepwise increase at predetermined time intervals.

Preferably, the first level is a mute level. In this case, the user does not hear annoying noise sound.

[0014] In the broadcast receiving apparatus according to claim 7,
The control means gradually reduces the output level of the audio signal when the deterioration of the reception state is detected. In this case, when noise is mixed in the reproduced audio, the output level of the audio signal is gradually reduced, so that it is possible to maintain a state where the user can hear the broadcast content.

Alternatively, the control means may be configured to gradually decrease the output level of the audio signal when the deterioration of the reception state is detected (claim 8).

In this case, it is preferable that the control means performs the stepwise reduction at predetermined time intervals.

According to a tenth aspect of the present invention, there is provided a broadcast receiving apparatus for receiving a broadcast wave of encoded audio data and reproducing the audio data, wherein the detecting means detects a reception state of the broadcast wave, and the detecting means. Depending on the reception status detected by
Control means for changing the output level of the audio data to be reproduced. According to the reception state, it is possible to perform control to lower the output level of audio data as the reception state deteriorates or to increase the output level of audio data as the reception state recovers. Therefore, it is possible to reduce a sense of incongruity given to the user due to mixing of noise into the reproduced sound.

[0018] In the broadcast receiving apparatus according to the eleventh aspect, the detecting means includes a BER detecting means for detecting a bit error rate of the received audio data.

[0019] In the broadcast receiving apparatus according to the twelfth aspect, the control means may determine that the detected bit error rate is the first bit error rate.
When rising to a predetermined value, the output level of the audio signal is reduced to the first level.

Here, the control means gradually increases the output level of the audio data from the first level when a decrease in the bit error rate is detected after the bit error rate has increased to a first predetermined value. With this configuration, since the output level of the sound gradually increases after the decrease, the user does not feel uncomfortable (claim 13).

Alternatively, the control means increases the output level of the audio data stepwise from the first level when a decrease in the bit error rate is detected after the bit error rate has risen to the first predetermined value. (Claim 14).

In this case, the control means preferably performs the stepwise increase at predetermined time intervals.
5).

Preferably, the first level is a mute level. In this case, the user does not hear annoying noise sound.

According to a seventeenth aspect of the present invention, when the increase in the bit error rate is detected, the control means gradually reduces the output level of the audio data. In this case, when noise is mixed in the reproduced audio, the output level of the audio data is gradually reduced,
It is possible to maintain a state where the user can hear the broadcast contents.

Alternatively, the control means may be configured to gradually decrease the output level of the audio data when an increase in the bit error rate is detected.
8).

In this case, it is preferable that the control means performs stepwise reduction at predetermined time intervals.

[0027]

FIG. 1 is a block diagram showing the overall configuration of a DAB receiving apparatus 100 according to an embodiment of the present invention. A DAB signal, which is a DAB broadcast wave, is first input to the tuner unit 10 via the antenna 3. The tuner section 10 tunes with a DAB signal of a desired frequency in accordance with a control signal 31 from the microcomputer 30, demodulates the DAB signal of the desired frequency, and sends the demodulated DAB signal to the A / D converter 15.
Note that the tuner unit 10 includes generally known components such as an amplifier circuit, a mixing circuit, a local oscillator, and a PLL circuit. The oscillation frequency of the local oscillator is changed from the microcomputer 30 via the control signal 31 in accordance with the frequency division ratio set in the PLL circuit.

The signal from the tuner section 10 is converted into a digital signal by the A / D converter 15 and input to the DAB decoder 20. The DAB decoder 20 has an A / D
An FFT (Fast Fou) is performed on the data string from the converter 15.
rier Transform (fast Fourier transform), de-interleaving, error correction and the like. In this case, the memory 27 is used. DAB decoder 2
0 detects a BER (bit error rate) of the data sequence from the A / D converter 15 using an error correction code or the like.

Further, the MPEG decoding unit 21 outputs
For the data decrypted by the AB decoder 20, M
A decoding process based on the PEG audio system is performed. Thereby, the original audio data is decoded. The decoded audio data is sent to a D / A converter 22, converted into an analog signal, and amplified by an amplifier 24.
Sent to speaker 25. The amplifier 24 is connected to the microcomputer 30, and the amplification degree of the amplifier 24 can be controlled by the microcomputer 30. The MPEG decoding unit 21 is connected to the microcomputer 30. MPEG
The decoding unit 21 controls the output level (ie, amplitude value) of the audio data to be decoded under the control of the microcomputer 30.
Is controlled to increase or decrease.

The microcomputer 30 is a general microcomputer having a ROM, a RAM and the like inside. Also, the microcomputer 30
Is connected to an operation panel 35 which controls a user interface. The microcomputer 30 includes the DAB decoder 20
The BER value detected by is monitored periodically. Then, the microcomputer 30 determines the output level of the audio data to be decoded by the MPEG decoding unit 21 according to the BER according to Table 1 below.
"MPEG output" which is a parameter to be set to 1 is determined.

[0031]

[Table 1]

In Table 1, the MPEG output is a numerical value in hexadecimal notation, and the smaller the value is, the lower the output level of the audio data output from the MPEG decoding unit 21 is. Here, it is assumed that when the MPEG output 0xF0 is set in the MPEG decoding unit 21, the output level of the audio data output from the MPEG decoding unit 21 becomes the mute level. Also, the MPEG decoding unit 21 outputs the MPEG output 0xFF.
Is set, the audio data output from the MPEG decoding unit 21 has the amplitude value (that is, the normal level) of the data to be decoded itself. The MPEG output is assigned at equal intervals from 0xF0 to 0xFF, and each value corresponds to each level obtained by equally dividing the range from the mute level to the normal level of the audio data output by the MPEG decoding unit 21. .

The BER is 2.0 × E-2 (2.0 × 10 ⁻² ).
The above indicates that the reception state is considerably degraded, and that the BER is less than 1.2 × E−2 indicates that the reception state is good. In Table 1, BER
Is divided into six stages by dividing a range between 1.2 × E-2 and 2.0 × E-2 by a range of 0.2 × E-2.

FIG. 2 is a flowchart showing the control of the output level of audio data by the microcomputer 30.
The microcomputer 30 controls the DAB decoder 20 at predetermined time intervals.
, The MPEG output is determined according to Table 1, and the MPEG output to the MPEG decoding unit 21 is set. Here, the predetermined time interval is 1 second.

In step S1, it is determined whether the BER is equal to or greater than 2.0 × E-2. If the reception state is deteriorated and the BER is 2.0 × E−2 or more (S1: YES),
The MPEG output is set to the minimum value 0xF0, that is, the mute level (S2). In step S2, a wait of one second is performed, and a new BER is sent from the DAB decoder 20.
Is obtained, and the process returns to step S1. And BE
When R is smaller than 2.0 × E-2 (S1: N
O) For the first time, the process proceeds to step S3, where the MPEG output is raised by one step to 0xF3 (S3). Then, a wait of one second is performed in step S3, and B
An ER is obtained. When the BER is obtained, the process proceeds to step S4.

The BER obtained in step S3 is 1.
If it is smaller than 8 × E-2 (S4: YES), the process proceeds to step S5, and the MPEG output is further raised by one step to 0xF6. On the other hand, in step S4, BE
If R is 1.8 × E−2 or more (S4: NO), MP
The process proceeds to step S6 with the EG output kept at 0xF3,
It is determined whether the BER is not less than 1.8 × E-2 and less than 2.0 × E-2, that is, whether or not the current MPEG output 0 × F3 can be used as it is. If BER is equal to or more than 1.8 × E-2 and less than 2.0 × E-2 (S6: YES), the process proceeds to step S3.
And the MPEG output is set to 0xF3. In step S6, if the BER is not less than 1.8 × E-2 and less than 2.0 × E-2, that is, if the BER is degraded to 2.0 × E-2 or more (S6: NO), the process returns to step S2. , MPEG output is set to the minimum value 0xF0.

In step S5, the MPEG output is 0xF
6, a wait of 1 second is performed, and BER is obtained. Then, the process proceeds to step S7. If the BER obtained in step S5 is smaller than 1.6 × E-2 (S7: YES), the process proceeds to step S9, and the MPEG
The output is further raised by one step to 0xF9. On the other hand, if the BER is 1.6 × E−2 or more in step S7 (S7: NO), the process proceeds to step S8 with the MPEG output being 0 × F6, and the BER is 1.6 × E−2 or more.
It is determined whether it is less than 1.8 × E−2, that is, whether it is appropriate to use the current MPEG output 0 × F6 as it is. If the BER is not less than 1.6 × E−2 and less than 1.8 × E−2 (S8: YES), the process returns to step S5, and the MPEG output is continuously set to 0 × F6. In step S8, if the BER is not less than 1.6 × E-2 and less than 1.8 × E-2, that is, if the BER is deteriorated to 1.8 × E-2 or more (S8: NO), the process returns to step S2. , MPEG output is set to the minimum value 0xF0.

In step S9, the MPEG output is 0xF
9, a waiting time of one second is performed, and further, a BER is obtained. Then, the process proceeds to step S10.
If the BER obtained in step S9 is smaller than 1.4 × E-2 (S10: YES), the process proceeds to step S12, where the MPEG output is further raised by one step and 0xFC
It is said. On the other hand, in step S10, BER is 1.
If 4 × E−2 or more (S10: NO), MPEG
The process proceeds to step S11 with the output being 0xF9, and B
It is determined whether the ER is equal to or greater than 1.4 × E-2 and less than 1.6 × E-2, that is, whether it is appropriate to use the current MPEG output 0 × F9 as it is. If the BER is greater than or equal to 1.4 × E-2 and less than 1.6 × E-2 (S11: YES), the process returns to step S9, and the MPEG output continues to be 0 × F9.
It is said. In step S11, BER is 1.4 × E-2
If not less than 1.6 × E-2, that is, BER is 1.6 × E
If it has deteriorated to -2 or more (S11: NO), the process returns to step S2, and the MPEG output becomes the minimum value 0xF
It is set to 0.

In step S12, the MPEG output is set to 0x
The FC is set, and a waiting time of 1 second is performed. Further, the BER is obtained. Then, the process proceeds to step S13. If the BER obtained in step S12 is smaller than 1.2 × E-2 (S13: YES), the process proceeds to step S15, and the MPEG output is further raised by one step to the maximum value of 0xFF. On the other hand, in step S13, B
If ER is equal to or greater than 1.2 × E-2 (S13: NO),
The process proceeds to step S14 with the MPEG output kept at 0xFC, and determines whether the BER is equal to or more than 1.2 × E-2 and less than 1.4 × E-2, that is, whether it is appropriate to use the current MPEG output 0xFC as it is Is determined. BER
If it is not less than 1.2 × E-2 and less than 1.4 × E-2 (S14: YE
S), the process returns to step S12, and the MPEG output is set to 0xFC. In step S14, BE
When R is not less than 1.2 × E-2 and less than 1.4 × E-2, ie, B
If the ER has deteriorated to 1.4 × E-2 or more (S14:
NO), the process returns to step S2, and the MPEG output is set to the minimum value 0xF0.

In step S15, the MPEG output is set to 0x
It is set to FF, a waiting time of 1 second is performed, and BER is obtained. Then, the process proceeds to step S16. If the BER obtained in step S15 is smaller than 1.2 × E-2, that is, if it is appropriate that the MPEG output remains at 0xFF (S16: YES), the process proceeds to step S17. On the other hand, in step S16, BE
When R is 1.2 × E−2 or more, that is, when the BER is worse than the case where the MPEG output can be set to 0xFF, the process returns to step S2, and the MPEG output is set to the minimum value 0xF0. You.

In step S17, it is determined whether the operation can be continued. If the operation can be continued (S17: YES),
The process returns to step S15, and the operation is continued while the MPEG output remains at 0xFF. If the operation cannot be continued in step S17 (S17: NO), the process ends.

According to the control described above and shown in FIG.
When an AB broadcast is being received in a good reception state (S1
When the BER decreases to a state where steps S5 to S17 are repeated), the MPEG output is reduced to the mute level 0xF0 (the process proceeds to step S2 according to the determination in step S16). MPEG output is set.

Immediately after the MPEG output is dropped to 0xF0 in step S2, even if the BER is 1.2
It should be noted that even if the level recovers to a good level of less than × E−2, steps S2, S3, S5, S9, and S12 wait for one second at a time, and the MPEG output is increased stepwise. Must. That is, since the volume of the reproduced sound gradually recovers when returning to the original volume from the time of muting, the user does not feel uncomfortable because the volume suddenly increases.

FIG. 3 is a flowchart showing a second embodiment of the control of the output level of the audio data by the microcomputer 30 shown in FIG. The flowchart in FIG. 3 corresponds to a flowchart in which the BER level used in the determination in step S16 in the flowchart in FIG. 2 is changed, and the other parts are the same as those in the flowchart in FIG. Therefore, in the flowchart of FIG. 3, the same reference numerals are used for the same steps as those in the flowchart of FIG.

That is, in the process of FIG. 3, when the good reception state continues (when S15 to S17 are repeatedly executed), the BER is set in step S16a.
Becomes worse for the first time when it becomes 2.0 × E-2 or more (S
16a: YES), the process proceeds to step S2, and the MPEG
The output is dropped to 0xF0. That is, according to the control of FIG. 3, the sound is muted only when the reception state is considerably deteriorated, and thereafter, the sound volume gradually recovers to the volume corresponding to the BER.

FIG. 4 is a flowchart showing a third embodiment of the control of the output level of the audio data by the microcomputer 30 shown in FIG. The control of FIG.
As compared with the control of FIG. 2, S6, S8, S
11, when the determination is NO in S14, this control is not to reduce the MPEG output to 0xF0, but to make a further BER determination to reduce the MPEG output to the BER equivalent MPEG output. Hereinafter, the flowchart of FIG. 4 will be described in detail.

When the control of FIG. 4 is started, step S3
At 1, it is determined whether the BER is equal to or greater than 2.0 × E−2. If the reception state is deteriorated and the BER is 2.0 × E−2 or more (S31: YES), the MPEG output is 0 × F
0, that is, the mute level (S32). In step S32, a wait of one second is performed, a BER is newly acquired from the DAB decoder 20, and the process returns to step S31. When the BER is smaller than 2.0 × E−2 (S31: NO), the process first proceeds to step S33, and the MPEG output is raised by one step to 0xF3 (S33). Then, step S33
Waits for one second and obtains the BER. When the BER is obtained, the process proceeds to step S34.

The BER obtained in step S33 is 1.8 × E
If it is smaller than -2 (S34: YES), the process proceeds to step S35, and the MPEG output is further raised by one step to 0xF6. On the other hand, in step S34, B
If ER is 1.8 × E-2 or more (S34: NO),
The process proceeds to step S36 with the MPEG output being 0xF3, and it is determined whether the BER is not less than 1.8 × E-2 and less than 2.0 × E-2, that is, whether or not the current MPEG output 0xF3 can be used as it is. . BER is 1.8 × E-2 or more 2.
If it is less than 0xE-2 (S36: YES), the process returns to step S33, and the MPEG output is continuously set to 0xF3. In step S36, if the BER is not less than 1.8 × E-2 and less than 2.0 × E-2, that is, the BER is 2.0 × E-2
If it has deteriorated (S36: NO), the process returns to step S32, and the MPEG output is set to 0xF0.

In step S35, the MPEG output is set to 0x
The state is set to F6, a waiting time of one second is performed, and further, a BER is obtained. Then, the process proceeds to step S37. If the BER obtained in step S35 is smaller than 1.6 × E-2 (S37: YES), the process proceeds to step S39, where the MPEG output is further raised by one step to 0xF9.
It is said. On the other hand, in step S37, BER is 1.
If it is 6 × E−2 or more (S37: NO), the MPEG
The process proceeds to step S38 with the output being 0xF6, and B
It is determined whether or not ER is equal to or greater than 1.6 × E−2 and less than 1.8 × E−2, that is, whether or not it is appropriate to use the current MPEG output 0 × F6 as it is. If the BER is not less than 1.6 × E-2 and less than 1.8 × E-2 (S38: YES), the processing returns to step S35, and the MPEG output continues to be 0 × F.
6 is assumed. On the other hand, in step S38, the BER is
1.6 × E-2 or more and less than 1.8 × E-2, that is, BER
Is worse than 1.8 × E-2 (S38: N
O), the process returns to step S36, and the BER is 1.8 × E-2.
It is determined whether the above is less than 2.0 × E−2, that is, whether or not the MPEG output should be set to 0xF3 which is one step lower.

In step S39, the MPEG output is set to 0x
In step F9, a waiting time of one second is performed, and a BER is obtained. Then, the process proceeds to step S40. The BER obtained in step S39 is 1.4 × E-2
If smaller (S40: YES), the process proceeds to step S
Proceeding to step 42, the MPEG output is further raised by one step to 0
xFC. On the other hand, in step S40, BE
If R is equal to or greater than 1.4 × E-2 (S40: NO), M
The process proceeds to step S41 with the PEG output kept at 0xF9, and determines whether or not the BER is equal to or more than 1.4 × E-2 and less than 1.6 × E-2.
That is, it is determined whether it is appropriate to use the current MPEG output 0xF9 as it is. BER 1.4
If not less than × E-2 and less than 1.6 × E-2 (S41: YE
S), the process returns to step S39, and the MPEG output is set to 0xF9. In step S41, BE
When R is not less than 1.4 × E-2 and less than 1.6 × E-2, ie, B
If the ER is worse than 1.6 × E-2 (S41:
NO), the process returns to step S38, and step S39
Is determined to be not less than 1.6 × E−2 and less than 1.8 × E−2, that is, whether or not the MPEG output should be set to 0 × F6, one step lower. BER 1.6 × E-2 or more 1.8 × E
If it is less than -2 (S38: YES), the MPEG output is
The value is set to 0xF6, which is one step lower (S35). BER 1.8
If it is not less than × E-2 (S38: NO), the process returns to S36, and the BER obtained in step S39 is 1.8 × E-2.
Is less than 2.0 × E−2, that is, whether the MPEG output should be 0xF3 two steps lower or 0xF3 three steps lower
It is determined whether F0 should be set.

In step S42, the MPEG output is set to 0x
The FC is set, and a waiting time of 1 second is performed. Further, the BER is obtained. Then, the process proceeds to step S43. If the BER obtained in step S42 is smaller than 1.2 × E-2 (S43: YES), the process proceeds to step S45, where the MPEG output is further raised by one step to 0xFF.
It is said. On the other hand, in step S43, BER is 1.
If it is 2 × E-2 or more (S43: NO), MPEG
The process proceeds to step S44 with the output being 0xFC, and B
It is determined whether or not the ER is not less than 1.2 × E−2 and less than 1.4 × E−2, that is, whether or not it is appropriate to use the current MPEG output 0 × FC as it is. If the BER is greater than or equal to 1.2 × E-2 and less than 1.4 × E-2 (S44: YES), the process returns to step S42, and the MPEG output continues to be 0 × F
C. In step S44, the BER is 1.2 × E
-2 or more and not less than 1.4 × E-2, that is, BER is 1.4
If it is worse than × E-2 (S44: NO),
The process returns to step S41, and it is determined whether the BER obtained in step S42 is equal to or more than 1.4 × E-2 and less than 1.6 × E-2, that is, whether or not the MPEG output should be reduced by one step to 0xF9. . If the BER is equal to or greater than 1.4 × E-2 and less than 1.6 × E-2 (S41: YES), the MPEG output is set to 0xF9, which is one step lower (S39). If the BER is 1.6 × E-2 or more (S41: NO), the process returns to S38, and the BER obtained in step S42 is 1.6 × E-2 or more and 1.8 × E-2.
Is determined, ie, whether the MPEG output should be set to 0xF6 two steps lower.

If the BER is not less than 1.6 × E-2 and less than 1.8 × E-2 (S38: YES), the MPEG output is set to 0 which is two steps lower.
xF6 (S35). If the BER is equal to or greater than 1.8 × E-2 (S38: NO), the process returns to S36, and determines whether the BER obtained in step S42 is equal to or greater than 1.8 × E-2 and less than 2.0 × E-2, ie, MPEG output is reduced by 3 steps to 0
It is determined whether it should be xF3 or 0xF0, which is four steps lower.

In step S45, the MPEG output is set to 0x
It is set to FF, a waiting time of 1 second is performed, and BER is obtained. Then, the process proceeds to step S46. In step S46, it is determined whether the operation of the MPEG output control can be continued. If the operation can be continued (S4
6: YES), the process returns to step S43. When the operation cannot be continued in step S46 (S46: N
O), the process ends.

According to the control of FIG. 4 described above, when it is not possible to maintain a value equal to or higher than the current MPEG output due to deterioration of BER (S36, S38, S41, and S44).
If it is determined as NO), instead of unconditionally lowering the MPEG output to the minimum value of 0xF0, the MPEG output corresponding to the deteriorated BER can be obtained. That is, as the BER increases, the noise of the reproduced sound also increases. However, since the volume gradually decreases as the BER increases, the noise gradually becomes inconspicuous. Although the noise decreases as the BER decreases, the sound volume is gradually restored to a level corresponding to the BER.

Therefore, according to the control shown in FIG. 4, even if the receiving condition is deteriorated when the user is listening to information that he does not want to miss, even if noise is mixed in the reproduced sound, the information can be heard. The volume can be reduced as much as possible. That is, even when the reception state is deteriorated, the sound is reproduced in a state where the user does not mind the noise, and therefore, the user does not miss the information.

FIG. 5 is a flowchart showing a fourth embodiment of the control of the output level of the audio data by the microcomputer 30 shown in FIG. Note that the flowchart of FIG. 5 corresponds to step S4 of the flowchart of FIG.
BER determination process between steps 5 and S46 (step S66)
, And if the determination in S46 is YES, the destination is set to S.
This corresponds to 45.

That is, according to the control of FIG. 5, when the good reception state continues (when S65 to S67 are repeated), the BER is equal to or more than the predetermined value (in the case of FIG. 5,
If it becomes worse (1.2 × E−2 or more) (S66: NO), the process returns to step S52, and the MPEG output is set to 0 × F0. That is, when the BER deteriorates from the state in which the good reception state continues, the sound is always muted, and the BE is only restored during the process of restoring the MPEG output.
Control is performed to gradually increase or decrease the MPEG output according to R. The BER 1.2 × E-2 used for the determination in step S66 is not limited to this value, and other values, for example, 2.0 × E-2, may be used. May be reduced to 0xF0.

Various substitutions for the embodiments described above,
Deformations can be made. For example, referring to Table 1, the setting of the range of each step of the BER, the number of steps of 6 steps, and the numerical value of the MPEG output are merely examples, and the range of the BER is different from that shown in the embodiment. ,
It goes without saying that the number of steps and the numerical value of the MPEG output can be used.

In the above-described embodiment, the change in the reception state is detected by the change in the BER. However, the change in the reception state can be detected by other means. For example, the reception state may be detected using a multipath noise level or the like that is detected using the property of the reflected wave due to multipath.

Although the above embodiment relates to a DAB receiving apparatus, the present invention is similarly applicable to digital broadcast receiving apparatuses other than DAB.

Further, if the reception state is determined based on the multipath noise level or the like, the present invention can be applied to an analog broadcast receiving apparatus. In this case, a change in the reception state may be detected based on the multipath level, and the volume may be adjusted.

[0062]

As described above, according to the present invention, B
Muting the sound when the ER deteriorates, then gradually increasing the volume to the original volume, gradually decreasing the volume according to the BER, and further reducing the volume with less noise and content It can be adjusted to a level that can be heard. That is, a broadcast receiving apparatus that can control the volume so that the user does not feel uncomfortable when the reception state is deteriorated is realized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of a broadcast receiving device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating control of an output level of audio data in the broadcast receiving device of FIG. 1;

FIG. 3 is a flowchart illustrating a second embodiment of control of an output level of audio data in the broadcast receiving device of FIG. 1;

FIG. 4 is a flowchart illustrating a third embodiment of control of an output level of audio data in the broadcast receiving device of FIG. 1;

FIG. 5 is a flowchart illustrating a fourth embodiment of control of an output level of audio data in the broadcast receiving device of FIG. 1;

[Explanation of symbols]

 Reference Signs List 10 Tuner unit 20 DAB decoder 21 MPEG decoding unit 22 D / A converter 24 Amplifier 25 Speaker 30 Microcomputer

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tomonori Tanaka 5-35-2 Hakusan, Bunkyo-ku, Tokyo Clarion Co., Ltd. F-term (reference) 5C025 BA09 DA10 5C026 DA05 DA09 5C059 MA00 RF02 SS30 UA05 5K014 AA01 BA01 BA06 FA08 FA11 GA02 HA05 5K061 AA03 AA10 AA11 BB06 BB17 CC39 CC42 CC51 CD04 CD05

Claims (19)

[Claims] 1. A broadcast receiving apparatus that receives a broadcast wave and reproduces an audio signal, comprising: a detecting unit that detects a receiving state of the broadcast wave; and a reproducing unit that reproduces an audio signal according to the receiving state detected by the detecting unit. Control means for changing the output level of the audio signal. 2. The broadcast receiving apparatus according to claim 1, wherein the control unit reduces the output level of the audio signal to a first level when the deterioration of the reception state is detected. apparatus. 3. The control unit according to claim 2, wherein, when the recovery of the reception state is detected after the deterioration of the reception state, the output level of the audio signal is gradually increased from the first level. The broadcast receiving apparatus according to claim 2, wherein 4. The method according to claim 1, wherein the control unit increases the output level of the audio signal stepwise from the first level when the recovery of the reception state is detected after the deterioration of the reception state. The broadcast receiving apparatus according to claim 2 or 3, wherein 5. The broadcast receiving apparatus according to claim 4, wherein said control means performs said stepwise increase at predetermined time intervals. 6. The broadcast receiving apparatus according to claim 2, wherein the first level is a mute level. 7. The broadcast receiving apparatus according to claim 1, wherein the control unit gradually reduces the output level of the audio signal when the deterioration of the reception state is detected. 8. The control unit according to claim 1, wherein the control unit decreases the output level of the audio signal in a stepwise manner when the deterioration of the reception state is detected.
A broadcast receiving apparatus according to claim 1. 9. The broadcast receiving apparatus according to claim 8, wherein said control means performs said stepwise reduction at predetermined time intervals. 10. A broadcast receiving apparatus that receives a broadcast wave of encoded audio data and reproduces the audio data, wherein the detection unit detects a reception state of the broadcast wave, and is detected by the detection unit. Control means for changing an output level of the reproduced audio data according to a reception state. 11. The broadcast receiving apparatus according to claim 10, wherein said detecting means includes a BER detecting means for detecting a bit error rate of the received audio data. 12. The control means decreases the output level of the audio signal to a first level when the detected bit error rate rises to a first predetermined value.
The broadcast receiving apparatus according to claim 11, wherein: 13. The control means, when increasing the bit error rate to the first predetermined value and detecting a decrease in the bit error rate, adjusts the output level of the audio data to the first level. 13. The broadcast receiving apparatus according to claim 12, wherein the level is gradually increased from a level. 14. The control means, when increasing the bit error rate to the first predetermined value and detecting a decrease in the bit error rate, adjusts the output level of the audio data to the first level. 14. The broadcast receiving device according to claim 12, wherein the broadcast receiving device increases the level in a stepwise manner. 15. The broadcast receiving apparatus according to claim 14, wherein said control means performs said stepwise increase at predetermined time intervals. 16. The broadcast receiving apparatus according to claim 12, wherein the first level is a mute level. 17. The apparatus according to claim 1, wherein the control unit gradually reduces the output level of the audio data when the increase in the bit error rate is detected.
2. The broadcast receiving device according to 1. 18. The apparatus according to claim 11, wherein said control means decreases the output level of said audio data stepwise when an increase in said bit error rate is detected. Broadcast receiving device. 19. The broadcast receiving apparatus according to claim 18, wherein said control means performs said stepwise reduction at predetermined time intervals.