JPH04249484A - Audio circuit for television receiver - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an audio circuit for a television receiver. This invention relates to an audio circuit for a television receiver having a three-speaker system in which a center speaker is placed at the upper or lower part of the center.

0002

[Prior Art] In recent television receivers, in order to reproduce the sound field, the frequency characteristics of the audio circuit are adjusted according to the content of the audio signal (for example, voice-based software, music software, movie software, etc.). There are some that use a multi-speaker system with two or more speakers.

[0003]One of them is Japanese Patent Application No. 2-3161.
There are audio circuits for 8 television receivers.

FIG. 5 is a block diagram showing the circuit configuration of a conventional embodiment. In the figure, 1 is the left speaker, 2
is the right speaker, 3 is the center speaker, 4 is the volume control circuit, 5 is the addition circuit, 6 is the band pass filter (BPF), 7 is the mode switching circuit, 8 and 9 are the subtraction circuits, respectively, 10, 11, 12 , 13 are amplifier circuits, respectively.

[0005] This system has left and right speakers on the left and right sides of the screen, and a center speaker at the top or bottom of the center, and only the frequency component corresponding to the human voice is output from the center speaker. The speakers output signals obtained by subtracting the center signal from the original left and right signals,
Furthermore, a mode switching circuit for switching the magnitude of the center signal is provided, and by switching the switching circuit according to the various software, the optimum sound field for the software can be obtained.

[0006]

[Problem to be Solved by the Invention] In the conventional system as described above, various modes with different center signal sizes are set, and the optimum sound field can be obtained by switching the mode using various software. It has the disadvantage that it requires manual manipulation.

SUMMARY OF THE INVENTION An object of the present invention is to provide an audio circuit for a television receiver that can eliminate the above-mentioned problems and improve audio effects without artificially switching according to screen software.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides left and right speakers on the left and right sides of the screen.
A center speaker is provided at the top or bottom of the center, and the center speaker outputs only the frequency component corresponding to the human voice, and the left and right speakers output signals obtained by subtracting the center signal from the original left and right signals. In the audio circuit for the television receiver that outputs, a new circuit is installed to control the gain of the center signal.
Furthermore, band-pass filter circuits are provided for the left and right signals that pass frequency components corresponding to the human voice, and a subtraction circuit is provided to obtain the difference between the signals that have passed through this circuit, and the difference between the two signals is detected. to control the control circuit.

[0009]

[Function] A new circuit is installed to control the gain of the center signal, and band-pass filter circuits are installed for the left and right signals to pass frequency components corresponding to the human voice. A subtraction circuit is provided to detect the difference between the two signals to control the control circuit. You can control the output from the speakers.

0010

[Embodiment] An embodiment of the present invention will be described below.

FIG. 1 is a block diagram showing the circuit configuration of an embodiment of the present invention. In the figure, 14 and 15 are band pass filters (BPF), 16 is an addition circuit, 17 is a subtraction circuit, 18 is a gain control circuit for the center signal, and 19 is a DC conversion circuit for converting the difference signal into a DC voltage. , is.

Next, the circuit operation will be explained.

The left signal L and right signal R are input to band pass filters (BPF) 14 and 15 having the same performance, respectively, and the frequency components of the voice (approximately 400 Hz to 5 kHz) are
Extracted only. Now, to explain the frequency range of a bandpass filter, if you allow the high range to pass through, the sound will be hard, and if you let the low range pass, the sound will be muffled, so take these points into account when deciding on the band.

Note that it does not matter whether the left signal L and the right signal R are stereo signals or monaural signals.

The voice frequency components of the extracted left and right signals are respectively input to the adder circuit 16 and then to the amplifier circuit 1.
After the signal is amplified by 0 and the amplitude is controlled by the gain control circuit 18, it is outputted to the center speaker 3 via the volume control circuit 4 and further via the amplifier circuit 11.

On the other hand, band pass filter (BPF) 1
The voice frequency components of the left and right signals extracted by 4 and 15 are respectively input to a subtraction circuit 17 to obtain the difference, which is converted to direct current by a DC conversion circuit 19, and this direct current is used to control the gain control circuit. 18. As shown in FIG. 3, the DC conversion circuit 19 and gain control circuit 18 are configured to reduce the gain when the difference obtained by the subtraction circuit 17 becomes large, and to increase the gain when the difference becomes small. It is something that exists.

[0017] In addition to the above, the left signal L and right signal R are processed in subtraction circuits 8 and 9, respectively, to obtain frequency components (approximately 400 Hz to 5 kHz) of the voice output to the center speaker.
After subtracting z), via the volume control circuit 4,
Further, the signal is outputted to the left speaker 1 and the right speaker 2 via the amplifier circuits 12 and 13.

FIG. 2 is a characteristic diagram showing the frequency characteristics of each part of the signal in the circuit of FIG.

That is, the left signal L and right signal R are respectively shown in FIG.
It has almost flat frequency characteristics as seen in (b).

FIG. 2(b) shows a bandpass filter (B
The frequency characteristics of PF) 14 and 15 are shown. That is, it will be understood that the frequency components of the voice (approximately 400 Hz to 5 kHz) are extracted in the band pass filters (BPF) 14 and 15.

The signals output from the subtraction circuits 8 and 9 to the left speaker 1 and right speaker 2 via the amplifier circuits 12 and 13 have frequency characteristics as shown in FIG. 2(C).

[0022] In this way, the difference in the frequency components of the human voice between the left signal and the right signal is detected, and depending on the magnitude, the voice component output from the center speaker can be adjusted from the left and right speakers. Since the output voice components are automatically increased or decreased, it is possible to create a sound field that matches the software.

FIG. 4 is a block diagram showing the circuit configuration of another embodiment of the present invention. In the figure, 20 and 21 are variable attenuation trap circuits.

Next, the circuit operation will be explained.

The left signal L and the right signal R are input to band pass filters (BPF) 14 and 15 having the same performance, respectively, and the frequency components of the voice (approximately 400 Hz to 5 kHz) are
Extracted only.

Note that it does not matter whether the left signal L and the right signal R are stereo signals or monaural signals.

The voice frequency components of the extracted left and right signals are input to the adder circuit 16, respectively, and are then input to the amplifier circuit 1.
After the signal is amplified by 0 and the amplitude is controlled by the gain control circuit 18, it is outputted to the center speaker 3 via the volume control circuit 4 and further via the amplifier circuit 11.

On the other hand, band pass filter (BPF) 1
The voice frequency components of the left and right signals extracted by 4 and 15 are respectively input to a subtraction circuit 17 to obtain the difference, which is converted to direct current by a DC conversion circuit 19, and this direct current is used to control the gain control circuit. 18. As shown in FIG. 3, the DC conversion circuit 19 and gain control circuit 18 are configured to reduce the gain when the difference obtained by the subtraction circuit 17 becomes large, and to increase the gain when the difference becomes small. It is something that exists.

In addition to the above, the left signal L and right signal R are transmitted through variable attenuation trap circuits 20 and 21, respectively.
Further, through the volume control circuit 4, the amplifier circuits 12 and 1
3 to the left speaker 1 and the right speaker 2. Note that the variable attenuation trap circuits 20 and 21 are
Voice frequency components centered around approximately 1kHz (approximately 400Hz
~5kHz), and is controlled by the output of the DC conversion circuit 19, and is configured to reduce the amount of attenuation when the difference obtained by the subtraction circuit 17 becomes large, and increase the amount of attenuation when the difference becomes small. It is set to .

In this way, the difference in the frequency components of the human voice between the left signal and the right signal is detected, and depending on the magnitude, the voice component output from the center speaker and the left and right speakers are adjusted. Since the output voice components are automatically increased or decreased, it is possible to create a sound field that matches the software.

[0031]

According to the present invention, depending on the content of the audio signal, if the difference between the frequency components of the human voice in the left and right signals is small, the voice component is output from the center speaker, and the voice component is output from the left and right speakers. If a sound with missing components is output, and the difference between the frequency components of the human voice in the left and right signals is large, the output of the center speaker will be small, and the output of the left and right speakers will have fewer missing voice components. During this time, it can be changed continuously, so the output of each speaker can be automatically controlled without human intervention.
This has the effect that the voice can be heard from the center of the screen.

Therefore, in the case of a source such as a talk program, the speaker is placed in the center of the screen, so the sound (voice) is also output from the center speaker. Further, in the case of a stereo music source, the left and right signals are completely different, so they are not output from the center speaker, but are output from the left and right speakers as in normal stereo. Furthermore, in the case of sources such as movies and dramas where dialogue and sound effects are mixed, the person speaking is placed in the center of the screen and the sound emphasizes the dialogue, so there are few sound effects and the human voice is Since the left and right signals often contain the same level, the voice is heard from the center of the screen, that is, from the center speaker, and when sound effects are used, the left and right signals become completely different signals to create a stereo effect. , the output is not output from the center speaker, but sufficient effects can be obtained from the left and right speakers, and the voice output is automatically optimized depending on the content of the image, making it particularly effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a circuit configuration of an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing frequency characteristics of signals of various parts in the circuit of FIG. 1;

FIG. 3 is a characteristic diagram showing the gain of the gain control circuit depending on the amplitude difference between left and right signals necessary in one embodiment and another embodiment of the present invention.

FIG. 4 is a block diagram showing a circuit configuration of another embodiment of the present invention.

FIG. 5 is a block diagram showing a circuit configuration of a conventional example.

[Explanation of symbols]

1. Left speaker, 2. Right speaker, 3. Center speaker, 4. Volume control circuit, 5, 16. Addition circuit, 6, 14, 15. Bandpass filter, 7. Mode switching circuit, 8, 9, 17. Subtraction circuit, 10, 11, 1
2,13. Amplification circuit, 18. gain control circuit,
19. DC conversion circuit, 20, 21. variable attenuation trap circuit,

Claims (3)

[Claims] Claim 1: A left speaker is placed on the left side of the screen of a television receiver, a right speaker is placed on the right side, and a center speaker is placed at the top or bottom of the center of the screen, and audio signals accompanying images are transmitted to each speaker. An audio circuit for a television receiver that outputs audio by inputting an image to the image is equipped with a frequency component extraction circuit that extracts a predetermined frequency component corresponding to a human voice from an audio signal accompanying an image, and The signals obtained by passing the left and right signals through the respective extraction circuits are input to an addition circuit and a first subtraction circuit, and the output of the addition circuit is outputted from the center speaker through a gain control circuit, and the first subtraction circuit is performed. An audio circuit for a television receiver, characterized in that the gain control circuit is controlled by the output of the circuit. [Claim 2] A left speaker is placed on the left side of the screen of the television receiver, a right speaker is placed on the right side, and a center speaker is placed on the top or bottom of the center of the screen, so that the audio signal accompanying the image is transmitted to each speaker. An audio circuit for a television receiver that outputs audio by inputting an image to the image is equipped with a frequency component extraction circuit that extracts a predetermined frequency component corresponding to a human voice from an audio signal accompanying an image, and The signals obtained by passing the left and right signals through the respective extraction circuits are input to an addition circuit and a first subtraction circuit, and the output of the addition circuit is outputted from the center speaker through a gain control circuit, and the first subtraction circuit is performed. The gain control circuit is controlled by the output of the circuit, and the signal input to the center speaker through the gain control circuit, which is a frequency component equivalent to a human voice, is subtracted from the left and right audio signals. A television receiver comprising second and third subtraction circuits input to the left and right speakers, and outputting the outputs of the second and third subtraction circuits from the left and right speakers. audio circuit. [Claim 3] A left speaker is placed on the left side of the screen of the television receiver, a right speaker is placed on the right side, and a center speaker is placed on the top or bottom of the center of the screen, so that audio signals accompanying images are transmitted to each speaker. An audio circuit for a television receiver that outputs audio by inputting an image to the image is equipped with a frequency component extraction circuit that extracts a predetermined frequency component corresponding to a human voice from an audio signal accompanying an image, and The signals obtained by passing the left and right signals through the respective extraction circuits are input to an addition circuit and a first subtraction circuit, and the output of the addition circuit is outputted from the center speaker through a gain control circuit, and the first subtraction circuit is performed. The gain control circuit is controlled by the output of the circuit, and the left and right audio signal paths are further provided with a variable attenuation trap circuit that covers a predetermined frequency corresponding to a human voice centered around about 1 kHz. An audio circuit for a television receiver, characterized in that the amount of attenuation of the variable attenuation trap is changed by the output of the first subtraction circuit.