JPH0983905A - Signal processor for multiplex sound broadcast - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute low-pass signal processing corresponding to a broadcast mode. SOLUTION: A television receiver 1 is capable of receiving mutiplex sound broadcast and executes the processing of a low-pass boost (low-pass emphasis) corresponding to the structure and constitution of a cabinet main body and speakers 13L and 13R. In the case of setting an automatic sound quality adjusting mode by operating a key operation part 19 or a transmitter 21, when an audio signal SA is a stereo broadcast, filter circuits 11L and 11R do not respectively execute low-pass attenuation processing to the audio signal SA so that a low band is emphasized in the sound outputs of the speakers 13L and 13R by low-pass boost processing. When an audio signal SA is not the stereo broadcast, the filter circuits 11L and 11R respectively execute low-pass attenuation processing to the audio signal SA to cancell low-pass boost processing so that the low band is emphasized in the sound outputs of the speakers 13L and 13R as the result. Consequently, low-pass signal processing is properly executed corresponding to the broadcast mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio multiplex broadcast signal processing device. Specifically, the frequency characteristic of a filter circuit inserted between the signal processing means and the speaker is controlled to emphasize the low frequency range of the audio output from the speaker in the stereo mode, The present invention relates to an audio multiplex broadcast signal processing device that performs low-frequency signal processing according to a broadcast mode by not emphasizing the low frequency range of audio output from a speaker in the mode.

[0002]

2. Description of the Related Art Recently, television receivers are used not only for watching broadcast programs but also for watching movie / music software. Therefore, in television receivers, various measures are taken to improve the sound quality in order to obtain a powerful sound when watching movie / music software.

[0003] In intermediate and higher level television receivers, for example, the following method is adopted for the purpose of improving the bass range by raising the level of the bass range, which is apt to be insufficient with a commonly used small-diameter speaker. ing. The response in the low frequency range is electrically increased by using a sound quality adjustment circuit. By devising the structure of the television receiver cabinet, a horn speaker and a resonance box using a small-diameter speaker are constructed. A speaker for enhancing the low range is added to the speaker of the television receiver body.

By the above-mentioned methods (1) to (10) Hz,
The response in the low frequency range up to about 200 Hz is improved by about 10 dB or more in terms of hearing. Therefore, in terms of frequency characteristics, as shown in FIG. 8, there are many cases where the level rises from 800 Hz or less.

[0005]

As described above, when the low-frequency boost (low-frequency emphasis) process is applied to the television receiver, it is very powerful when receiving music and movie programs and listening to them. It is preferable because the sound quality has a certain level or is almost flat in hearing. However, when listening to a news program, for example, the level of the voice is also increased by enhancing the response in the frequency range corresponding to the band of the voice uttered by the male announcer. It will reduce the clarity.

In the worst case, the level in the low frequency range exceeds the allowable value of the circuit, causing voice distortion, and even worsening the clarity of the voice.

In view of this, the present invention provides an audio multiplex broadcast signal processing device which performs appropriate low-frequency signal processing according to the broadcast mode (monaural, two-voice or stereo broadcast modes).

[0008]

SUMMARY OF THE INVENTION An audio multiplex broadcast signal processing device according to the present invention comprises a signal processing means for processing an audio multiplex broadcast signal to obtain an output audio signal, and an output audio signal output from the signal processing means. A speaker to be supplied, a filter circuit inserted between the signal processing means and the speaker, a control means for controlling the frequency characteristic of the filter circuit, and a mode determination means for determining the mode of the audio multiplex broadcast signal,
When the mode determining means determines that the audio multiplex broadcast signal is in the stereo mode, the control means controls the frequency characteristic of the filter circuit so that the low frequency range of the audio output from the speaker is emphasized. When the discrimination unit discriminates a mode other than the stereo mode, the control unit controls the frequency characteristic of the filter circuit so that the low frequency range of the audio output from the speaker is not emphasized.

When it is determined that the mode is the stereo mode, the frequency characteristic of the filter circuit is controlled to emphasize the low frequency range of the sound output from the speaker. When it is determined to be a mode other than the stereo mode, the frequency characteristic of the filter circuit is controlled and the low frequency range of the sound output from the speaker is not emphasized.

[0010]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a television receiver as an embodiment. The television receiver 1 is capable of receiving audio multiplex broadcasting, and performs low-frequency boost processing (low-frequency emphasis) as shown in FIG. 8 by the structure and configuration of the cabinet body and the speaker.

The television receiver 1 shown in FIG. 1 has a tuner 2, a video intermediate frequency amplification circuit 3, a video detection circuit 4, a video processing circuit 5 and a color picture tube 6.

The tuner 2 is supplied with the television signal SVS captured by the antenna AT. In the tuner 2, the television signal SVS supplied from the antenna AT
The signal of the desired channel is selected from among these and the frequency is converted. An intermediate frequency signal (58.75 MHz image intermediate frequency signal and 54.2 MHz audio first intermediate frequency signal) SIF is supplied from the tuner 2 to the image intermediate frequency amplifier circuit 3 and amplified. The video intermediate frequency signal SVIF is supplied from the video intermediate frequency amplifier circuit 3 to the video detection circuit 4 to perform detection processing. The video signal SV is supplied from the video detection circuit 4 to the video processing circuit 5, and is subjected to amplification processing, separation processing of luminance signal and color signal, demodulation processing of color signal, matrix processing of luminance signal and color difference signal, and the like. , A red signal R, a green signal G, and a blue signal B are formed. Then, the color picture tube 6 receives color signals R, G, B from the video processing circuit 5.
Is supplied, and a color image based on the color signals R, G, B is displayed on the screen.

Further, the television receiver 1 shown in FIG.
Has an audio intermediate frequency amplification circuit 7 and an audio detection circuit 8.

The audio intermediate frequency amplifier circuit 7 has a 4.5 MHz audio second intermediate frequency signal S2IF obtained by amplitude-detecting the intermediate frequency signal SIF described above in the video intermediate frequency amplifier circuit 3.
(58.75MHz video intermediate frequency signal and 54.25M
The difference signal of the audio first intermediate frequency signal of Hz) is provided.
In the audio intermediate frequency amplifier circuit 7, the video intermediate frequency amplifier circuit 3
The audio second intermediate frequency signal S2IF supplied from the amplifier is amplified and amplitude-limited. The voice detection circuit 8 is supplied with the voice second intermediate frequency signal from the voice intermediate frequency amplifier circuit 7 to perform detection processing. As a result, the voice detection circuit 8
Outputs an audio signal SA.

Further, the television receiver 1 shown in FIG.
Is a low pass filter 9 and a band pass filter 14
And a sub voice detection circuit (FM detection circuit) 15, a multiplex control detection circuit (AM detection circuit) 16, a band pass filter 17D, a band pass filter 17S, a voice switching matrix circuit 10, and a system controller. Microcomputer (hereinafter referred to as "microcomputer") 1
8 is provided.

The low-pass filter 9 is for removing the main channel signal SMCH by removing the frequency component of 15 kHz or more. The low-pass filter 9 is supplied with the audio signal SA output from the audio detection circuit 8. The bandpass filter 14 is for individually extracting the carrier sub-audio signal SCSA existing in the band of 16 to 47 kHz and the carrier multiplex control signal SCMC existing in the vicinity of 55.125 kHz. The audio signal SA output from the detection circuit 8 is supplied. Here, when the audio signal SA is related to stereo broadcasting or dual audio broadcasting, the band-pass filter 14 outputs the carrier sub-audio signal SCSA and the carrier multiplexing control signal SCMC. On the other hand, when the audio signal SA relates to monaural broadcasting, the bandpass filter 14 does not output the carrier sub-audio signal SCSA and the carrier multiplexing control signal SCMC.

The carrier sub-audio signal SCSA output from the band pass filter 14 is supplied to the sub-audio detection circuit 15 for FM detection processing. Voice switching matrix circuit 10
Is supplied with the main channel signal SMCH extracted by the low-pass filter 9 and the sub-channel signal SSCH output from the sub-audio detection circuit 15. Multiple control detection circuit 16
Is supplied with the carrier multiplexing control signal SCMC extracted by the bandpass filter 14 and subjected to AM detection processing. The bandpass filters 17D and 17S have center frequencies of 922.5 Hz and 982.5 Hz, respectively, and the output signal SPL of the multiplex control detection circuit 16 is supplied to these bandpass filters 17D and 17S.

Here, when the audio signal SA is related to dual audio broadcasting, the output signal S of the multiplex control detection circuit 16 is output.
A 922.5 Hz pilot signal is obtained as PL, and this pilot signal is output from the bandpass filter 17D. When the audio signal SA is for stereo broadcasting, a pilot signal of 982.5 Hz is obtained as the output signal SPL of the multiplex control detection circuit 16, and this pilot signal is output from the bandpass filter 17S.

The microcomputer 18 includes a bandpass filter 17
The output signals of D and 17S are supplied. The operation of the voice switching matrix circuit 10 described above is performed by the bandpass filter 1
It is controlled by the microcomputer 18 based on the output signals of 7D and 17S. In this case, when the audio signal SA relates to monaural broadcasting, the band pass filter 17D, 1
Since the pilot signal is not output from any of 7D, the left audio output terminal 1 of the audio switching matrix circuit 10
Switch control is performed so that the main channel signal SMCH is output to each of the 0L and the right audio output terminal 10R.

When the audio signal SA is related to dual audio broadcasting, the pilot signal is output from the bandpass filter 17D, so that the left audio output terminal 10L and the right audio output terminal 10R of the audio switching matrix circuit 10 are output.
The switch control is performed so that either the main channel signal SMCH (main audio signal) or the sub channel signal SSCH (sub audio signal) is output to each of the above. Whether the main audio signal or the sub audio signal is selected is determined by the user operating the key operation unit 19 connected to the microcomputer 18. A remote control signal (hereinafter referred to as "remote control signal") receiving unit 20 is connected to the microcomputer 18, and even if the remote control signal transmitter 21 is used, the same operation as the operation by the key operation unit 19 is performed. Is possible.

When the audio signal SA is related to stereo broadcasting, a pilot signal is output from the bandpass filter 17S, so that the audio switching matrix circuit 10 outputs the main channel signal SMCH (sum signal L + R) and the sub channel. The signal SSCH (difference signal LR) is matrix-processed, and the left audio signal L and the right audio signal R are respectively supplied to the left audio output terminal 10L and the right audio output terminal 10R.
Is switch-controlled so that is output.

Further, the television receiver 1 shown in FIG.
Is a filter circuit 11L, 11R and an audio amplifier circuit 12
It has L, 12R and speakers 13L, 13R.
The speakers 13L and 13R have output signals S from the output terminals 10L and 10R of the audio switching matrix circuit 10, respectively.
LA and SRA are supplied via the filter circuits 11L and 11R and the audio amplifier circuits 12L and 12R, respectively. A control signal S is sent from the microcomputer 18 to the filter circuits 11L and 11R.
CF is supplied to control its operation.

When the automatic sound quality adjustment mode is set by the operation of the key operation unit 19 or the transmitter 21, when the audio signal SA relates to stereo broadcasting, the filter circuits 11L and 11R output the output signals SLA and SRA. On the other hand, when no processing is performed and the audio signal SA is related to other than stereo broadcasting, the filter circuits 11L and 11R are used.
The low-frequency attenuation processing is performed on the output signals SLA and SRA. When the automatic sound quality adjustment mode is not set, no processing is performed on the output signals SLA and SRA in the filter circuits 11L and 11R regardless of whether or not the audio signal SA relates to stereo broadcasting. I don't know.

FIG. 2 shows a specific configuration of the filter circuits 11L and 11R. The filter circuit 11L includes a low-pass attenuation filter 111L and a changeover switch 112L. The audio signal SLA is directly supplied to the fixed terminal on the a side of the changeover switch 112L, and is also supplied to the fixed terminal on the b side of the changeover switch 112L via the low-pass attenuation filter 111L. Then, an output signal is derived from the movable terminal c of the changeover switch 112L.

The changeover of the changeover switch 112L is controlled by the control signal SCF. When the automatic sound quality adjustment mode is set, the changeover switch 112L is connected to the side a when the audio signal SA is related to stereo broadcasting, while the changeover switch 112L is connected when the audio signal SA is not related to stereo broadcasting. Is connected to the b side. When the automatic sound quality adjustment mode is not set, the changeover switch 112L is always connected to the a side.

The filter circuit 11R is a low-pass attenuation filter 1.
11R and changeover switch 112R.
The audio signal SRA is directly supplied to the fixed terminal on the side a of the changeover switch 112R, and the low-pass attenuation filter 111R is also provided.
Is supplied to the fixed terminal on the b side of the changeover switch 112R via. Then, an output signal is derived from the movable terminal c of the changeover switch 112R.

The changeover of the changeover switch 112R is controlled by the control signal SCF. When the automatic sound quality adjustment mode is set, the changeover switch 112R is connected to the side a when the audio signal SA is related to stereo broadcasting, while the changeover switch 112R is connected when the audio signal SA is not related to stereo broadcasting. Is connected to the b side. When the automatic sound quality adjustment mode is not set, the changeover switch 112R is always connected to the a side.

FIG. 3 shows the low-pass attenuation filter 111 described above.
The frequency characteristics of L and 111R are shown.

In the above configuration, the video signal SV relating to the television broadcast received by the tuner 2 from the video detection circuit 4.
Is output to the color picture tube 6 and the video signal S
A V color image is displayed. Further, the audio signal SA related to the television broadcast received by the tuner 2 is output from the audio detection circuit 8.

When the audio signal SA relates to monaural broadcasting, the main channel signal SMCH (monaural audio signal) extracted by the low-pass filter 9 is output to each of the output terminals 10L and 10R of the audio switching matrix circuit 10.
Is output and supplied to the speakers 13L and 13R via the filter circuits 11L and 11R and the audio amplifier circuits 12L and 12R. As a result, the speakers 13L and 13R each output a sound based on a monaural sound signal.

Here, when the automatic sound quality adjustment mode is set by the operation of the key operation unit 19 or the transmitter 21, the filter circuits 11L and 11R respectively perform low-frequency attenuation processing on the monaural audio signals. . in this case,
As described above, in the television receiver 1 of FIG. 1, the low frequency boost processing is performed by the structure and configuration of the cabinet body and the speaker, but the low frequency boost processing is performed by the low frequency attenuation processing in the filter circuits 11L and 11R. Since they cancel each other out, the low frequencies are not emphasized in the audio outputs of the speakers 13L and 13R. On the other hand, when the automatic sound quality adjustment mode is not set, the low-frequency attenuation processing is not performed on the monaural audio signal by the filter circuits 11L and 11R. Therefore, with the low range boost processing by the structure and configuration of the cabinet body and the speaker,
The sound output from the speakers 13L and 13R is emphasized in the low frequency range.

When the audio signal SA is related to two-audio broadcasting, the low-pass filter 9 is provided at each of the output terminals 10L and 10R of the audio switching matrix circuit 10.
The main channel signal SMCH (main audio signal) extracted by the sub-channel signal S output from the sub-audio detection circuit 15
SCH (sub audio signal) is output and the filter circuit 11L, 1
Speaker 1 via 1R and audio amplifier circuits 12L and 12R
It is supplied to 3L and 13R. As a result, the speaker 13
From L and 13R, the audio by the main audio signal or the sub audio signal is output, respectively.

Here, when the automatic sound quality adjustment mode is set by the operation of the key operation unit 19 or the transmitter 21, the filter circuits 11L and 11R attenuate the main audio signal or the sub audio signal in the low frequency range. Processing is performed. Therefore, as in the case where the audio signal SA relates to monaural broadcasting, the low frequencies are not emphasized in the audio outputs of the speakers 13L and 13R. On the other hand, when the automatic sound quality adjustment mode is not set, the filter circuit 11
In L and 11R, the low frequency attenuation processing is not performed on the main audio signal or the sub audio signal. Therefore, as in the case where the audio signal SA relates to monaural broadcasting, the speaker 13
The low and high frequencies are emphasized in the L and 13R audio outputs.

When the audio signal SA is related to stereo broadcasting, the main channel signal SMCH (sum signal L +) extracted by the low-pass filter 9 is provided to each of the output terminals 10L and 10R of the audio switching matrix circuit 10.
R) and the sub-channel signal SSCH (difference signal L-R) output from the sub-audio detection circuit 15 are matrix-processed to output a left audio signal L and a right audio signal R. Then, these audio signals L and R are respectively supplied to the filter circuit 1
It is supplied to the speakers 13L and 13R via 1L and 11R and the audio amplifier circuits 12L and 12R. As a result, the speakers 13L and 13R output the sounds of the audio signals L and R, respectively.

Here, when the automatic sound quality adjustment mode is set by the operation of the key operation unit 19 or the transmitter 21, the low-frequency attenuation processing is performed on the audio signals L and R by the filter circuits 11L and 11R, respectively. Not done for that reason,
Due to the low-frequency boost processing by the structure and configuration of the cabinet body and the speaker, the low-frequency is emphasized in the audio output of the speakers 13L and 13R. On the other hand, when the automatic sound quality adjustment mode is not set, similarly, since the low-frequency attenuation processing is not performed on the audio signals L and R by the filter circuits 11L and 11R, respectively, depending on the structure and configuration of the cabinet body and the speaker. With the low frequency boost processing, the low frequency is emphasized in the audio output of the speakers 13L and 13R.

FIG. 4 is a flowchart showing the control operation of the filter circuits 11L and 11R by the microcomputer 18.

In the figure, when the reception of a television broadcast is started, it is first determined in step ST1 whether or not the automatic sound quality adjustment mode is set. When the automatic sound quality adjustment mode is set, it is determined in step ST2 whether or not the audio signal SA relates to stereo broadcasting.

When it is determined in step ST2 that the broadcast is related to stereo broadcasting, the process proceeds to step ST3 to perform low-frequency boost (low-frequency emphasis). That is, the control signal SC is sent from the microcomputer 18 so that the changeover switches 112L and 112R of the filter circuits 11L and 11R are connected to the a side.
Output F. On the other hand, when it is determined in step ST2 that the audio signal SA does not relate to stereo broadcasting, the process proceeds to step ST4 and low frequency flat processing is performed. That is, the changeover switch 112 of the filter circuits 11L and 11R
The control signal SCF is output from the microcomputer 18 so that the L and 112R are connected to the b side.

If the automatic sound quality adjustment mode is not set in step ST1, the process proceeds to step ST3 to perform low frequency boost processing.

As described above, according to the present embodiment, when the audio signal SA is related to stereo broadcasting by setting the automatic sound quality adjustment mode by operating the key operation unit 19 or the transmitter 21. Indicates that the sound output from the speakers 13L and 13R is emphasized in the low frequency range, and the sound signal S
Speaker A when A is not related to stereo broadcasting
The audio outputs of L and 13R are controlled so that low frequencies are not emphasized. Therefore, when watching a news program or the like, it is possible to avoid the inconvenience that the voice of the male announcer becomes a “stalk” and impairs the clarity.

Further, according to the present embodiment, unless the automatic sound quality adjustment mode is set, the low frequencies are emphasized in the audio outputs of the speakers 13L and 13R even when the audio signal SA does not relate to stereo broadcasting. Become. Therefore, for example, when receiving a television broadcast of a foreign movie that is performed in two audio broadcasting (bilingual broadcasting), the audio output from the speakers 13L and 13R is emphasized in the low frequency range by setting the automatic sound quality adjustment mode. Can also be

Although the sound quality adjustment by the filter circuits 11L and 11R is performed by switching the changeover switches 112L and 112R, the configuration is such that the frequency characteristic of the low frequency range of a single filter circuit is changed by the control signal SCF. May be.

Next, a television receiver 30 as another embodiment of the present invention will be described with reference to FIG. 5, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, the television receiver 3
In No. 0, the low range boost process is not performed due to the structure and configuration of the cabinet body and the speaker. Then, instead of the filter circuits 11L and 11R in the example of FIG. 1, filter circuits 31L and 31R are connected. Others are shown in Fig. 1.
The configuration is similar to the example.

A control signal SCF 'is supplied from the microcomputer 18 to the filter circuits 31L and 31R to control the operation thereof. When the automatic sound quality adjustment mode is set by operating the key operation unit 19 or the transmitter 21, the audio signal S
When A is related to stereo broadcasting, low-frequency emphasis processing is performed on the output signals SLA and SRA by the filter circuits 11L and 11R, while when the audio signal SA is related to other than stereo broadcasting, the filter circuit is processed. No processing is performed on the output signals SLA and SRA in 11L and 11R. When the automatic sound quality adjustment mode is not set, the low-frequency emphasis processing is performed on the output signals SLA and SRA in the filter circuits 11L and 11R regardless of whether or not the audio signal SA relates to stereo broadcasting. Done.

FIG. 6 shows a specific configuration of the filter circuits 31L and 31R. The filter circuit 31L includes a low-frequency emphasis filter 311L and a changeover switch 312L. The audio signal SLA is supplied to the a-side fixed terminal of the changeover switch 312L via the low-frequency emphasis filter 311L and directly to the b-side fixed terminal of the changeover switch 312L. Then, an output signal is derived from the movable terminal c of the changeover switch 312L.

The changeover of the changeover switch 312L is controlled by the control signal SCF '. When the automatic sound quality adjustment mode is set, the changeover switch 312L is connected to the a side when the audio signal SA is related to stereo broadcasting, while the changeover switch 312L is connected when the audio signal SA is not related to stereo broadcasting. Is connected to the b side. When the automatic sound quality adjustment mode is not set, the changeover switch 312L is always connected to the a side.

The filter circuit 31R is a low-frequency emphasis filter 3
11R and a changeover switch 312R.
The audio signal SRA is supplied to the a-side fixed terminal of the changeover switch 312R via the low-frequency emphasis filter 311R and directly to the b-side fixed terminal of the changeover switch 312R. Then, an output signal is derived from the movable terminal c of the changeover switch 312R.

The switching of the changeover switch 312R is controlled by the control signal SCF '. When the automatic sound quality adjustment mode is set, the changeover switch 312R is connected to the side a when the audio signal SA is related to stereo broadcasting, while the changeover switch 312R is connected when the audio signal SA is not related to stereo broadcasting. Is connected to the b side. When the automatic sound quality adjustment mode is not set, the changeover switch 312R is always connected to the a side.

FIG. 7 shows the low-frequency emphasis filter 311 described above.
The frequency characteristics of L and 311R are shown.

In the above configuration, when the audio signal SA relates to monaural broadcasting, the monaural audio signals obtained at the output terminals 10L and 10R of the audio switching matrix circuit 10 are respectively filtered.
It is supplied to the speakers 13L and 13R via the L and 31R and the audio amplification circuits 12L and 12R. As a result, the speakers 13L and 13R each output a sound based on a monaural sound signal. Further, when the audio signal SA is related to two audio broadcasting, the audio switching matrix circuit 10
The main audio signal or the sub audio signal obtained at each of the output terminals 10L and 10R of the
It is supplied to the speakers 13L and 13R via 31R and the audio amplifier circuits 12L and 12R. As a result, the speaker 1
The 3L and 13R outputs the audio by the main audio signal or the sub audio signal, respectively.

In this way, when the audio signal SA is related to monaural broadcasting or dual audio broadcasting, when the automatic sound quality adjustment mode is set by the operation of the key operation unit 19 or the transmitter 21, the filter circuit 31L. , 31
In R, no processing is performed on the monaural audio signal and the main audio signal (sub audio signal). Therefore, the speaker 13
The low and high frequencies are not emphasized in the audio outputs of L and 13R. On the other hand, when the automatic sound quality adjustment mode is not set, low-frequency emphasis processing is performed on the monaural audio signal and the main audio signal (sub audio signal) by the filter circuits 31L and 31R. Therefore, the sound output from the speakers 13L and 13R is emphasized in the low frequency range.

When the audio signal SA is related to stereo broadcasting, the left audio signal L and the right audio signal R obtained at the output terminals 10L and 10R of the audio switching matrix circuit 10 are the filter circuits 31L and 31R, respectively. , Speaker 13L, 13R through the audio amplifier circuit 12L, 12R
Is supplied to. As a result, the speakers 13L and 13R output the sounds of the audio signals L and R, respectively.

Here, when the automatic sound quality adjustment mode is set by the operation of the key operation unit 19 or the transmitter 21, the low-frequency emphasis processing is performed on the audio signals L and R by the filter circuits 31L and 31R, respectively. Done. Therefore, the sound output from the speakers 13L and 13R is emphasized in the low frequency range. On the other hand, even when the automatic sound quality adjustment mode is not set, similarly, since the low-frequency emphasis processing is performed on the audio signals L and R by the filter circuits 31L and 31R, the audio output of the speakers 13L and 13R is low-frequency. Is emphasized.

As described above, according to the second embodiment, the automatic sound quality adjustment mode is set by operating the key operation unit 19 or the transmitter 21 as in the first embodiment. With this setting, when the audio signal SA is related to stereo broadcasting, the audio outputs of the speakers 13L and 13R are emphasized in the low frequency range, and when the audio signal SA is not related to stereo broadcasting, the speaker 13L is , 1
The 3R audio output is controlled so that the low frequency band is not emphasized. Therefore, when watching a news program or the like, it is possible to avoid the inconvenience that the voice of the male announcer becomes a “stalk” and impairs the clarity.

Further, according to the second embodiment, as in the case of the above-described first embodiment, unless the automatic sound quality adjustment mode is set, even when the audio signal SA does not relate to stereo broadcasting, The sound output from the speakers 13L and 13R is emphasized in the low frequency range. Therefore, for example, when receiving a television broadcast of a foreign movie that is performed in two audio broadcasting (bilingual broadcasting), by setting the automatic sound quality adjustment mode, the audio output from the speakers 13L and 13R is emphasized in the low frequency range. It can also be made.

The sound quality adjustment by the filter circuits 31L, 31R is performed by switching the changeover switches 312L, 312R (see FIG. 6). However, the frequency characteristic of the low frequency range of a single filter circuit is changed by the control signal SCF. It may be configured so as to allow it.

Further, although the above-described first and second embodiments have been described as being applied to the television receiver, the present invention is also applied to other receivers such as FM radio and AM radio. It goes without saying that you can do it.

[0059]

According to the present invention, when the audio signal is related to stereo broadcasting, the audio output of the speaker is such that the low range is emphasized, and when the audio signal is not related to stereo broadcasting. The audio output of the speaker is controlled so that low frequencies are not emphasized. for that reason,
Appropriate low frequency signal processing can be performed according to the broadcast mode.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a television receiver as a first embodiment of the present invention.

FIG. 2 is a block diagram showing a specific configuration of the filter circuit of the previous figure.

FIG. 3 is a diagram showing frequency characteristics of a low-pass attenuation filter.

FIG. 4 is a flowchart showing a control main routine of the microcomputer.

FIG. 5 is a block diagram showing a configuration of a television receiver according to a second embodiment.

FIG. 6 is a block diagram showing a specific configuration of the filter circuit of the previous figure.

FIG. 7 is a diagram showing frequency characteristics of a low-frequency emphasis filter.

FIG. 8 is a diagram showing frequency characteristics during low-frequency boost processing.

[Explanation of symbols]

 1 Television receiver 2 Tuner 3 Video intermediate frequency amplification circuit 4 Video detection circuit 5 Video processing circuit 6 Color picture tube 7 Audio intermediate frequency amplification circuit 8 Audio detection circuit 9 Low-pass filter 10 Audio switching marix circuit 10L, 10R Output terminal 11L, 11R filter circuit 12L, 12R audio amplification circuit 13L, 13R speaker 14 bandpass filter 15 sub-audio detection circuit 16 multiplex control detection circuit 17D, 17S bandpass filter 18 microcomputer 19 key operation unit 20 remote control signal reception unit 21 remote control Signal transmitter 30 Television receiver 31L, 31R Filter circuit 111L, 111R Low-pass attenuation filter 112L, 112R selector switch 311L, 311R Low-pass emphasis filter 312L, 312R selector switch Pitch AT antenna

Claims (3)

[Claims] 1. A signal processing means for processing an audio multiplex broadcast signal to obtain an output audio signal, a speaker to which an output audio signal output from the signal processing means is supplied, and a space between the signal processing means and the speaker. A filter circuit to be inserted into the audio circuit, control means for controlling the frequency characteristic of the filter circuit, and mode discriminating means for discriminating the mode of the audio multiplex broadcast signal. When it is determined that the mode is the mode, the control means controls the frequency characteristic of the filter circuit so that the low frequency range of the sound output from the speaker is emphasized, and the mode determination means determines other than the stereo mode. When it is determined to be the mode, the control unit controls the frequency characteristic of the filter circuit to output the sound output from the speaker. An audio multiplex broadcast signal processing device, characterized in that the low frequencies of the above are not emphasized. 2. A mechanical low-frequency emphasizing means for mechanically emphasizing a low frequency band of a sound output from the speaker, wherein the filter circuit has a low frequency band attenuating filter for attenuating the low frequency band. When the discriminating means discriminates the audio multiplex broadcast signal in the stereo mode, the output audio signal output from the signal processing means is supplied to the speaker without passing through the low-pass attenuation filter, and the mode discriminating means operates. 2. The audio multiplex broadcast signal according to claim 1, wherein the output audio signal output from the signal processing means is supplied to the speaker through the low-pass attenuation filter when it is determined to be a mode other than the stereo mode. Processing equipment. 3. The filter circuit has a low-frequency emphasis filter for emphasizing low frequencies, and when the mode determining means determines that the audio multiplex broadcast signal is in the stereo mode, it is output from the signal processing means. When the output audio signal is supplied to the speaker through the low-frequency emphasis filter and the mode discrimination means discriminates a mode other than the stereo mode, the output audio signal output from the signal processing means is the low-frequency emphasis filter. The audio multiplex broadcast signal processing device according to claim 1, wherein the audio multiplex broadcast signal processing device is supplied to the speaker without passing through.