JPH05199600A - Audio circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] To realize an audio circuit that can obtain a vocal cancel effect as well as a surround effect at the same time not only during playback but also during recording. [Structure] A circuit 11 for separating stereo audio signals (L + R) and (LR) into left and right audio signals L and R, and a circuit 12 for generating a surround signal from output signals L and R of the audio signal separation circuit 11. And a circuit 13 for generating a vocal cancel signal by removing the vocal sound band from the surround signal.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to audio circuits for portable video devices and the like.

[0002]

2. Description of the Related Art FIG. 2 is a diagram showing a configuration example of an audio circuit in a conventional portable video device, for example, Video Walkman (trade name), in which 1 is a first frequency modulation (hereinafter referred to as FM modulation). ) Circuit, 2 is a second FM modulation circuit, 3 is a vocal cancellation signal generation circuit, 4 is an audio signal separation circuit (matrix circuit), 5 is a surround signal generation circuit, 6 is an audio output circuit, 7 is audio such as a speaker The generating parts are shown respectively. The first FM modulation circuit 1
The first stereo audio signal (L + R) in the RF frequency band is FM-modulated into a signal in the baseband. The second FM modulation circuit 2 FM-modulates the second stereo audio signal (LR) in the RF frequency band into a signal in the baseband.

The vocal cancellation signal generating circuit 3 amplifies only the low frequency component of the output signal (L + R) of the first FM modulating circuit 1 and the output signal (L- of the second FM modulating circuit 2). The low-frequency component of (L + R), which is the output of the amplifier 3b, is added to R) to obtain the vocal cancellation signal [(L-R) + {low-frequency component of (L + R)}] (hereinafter, indicated by symbol S3c). To generate.

When the operation mode is set to the surround mode, the audio signal separation circuit 4 outputs the left audio signal L and the left audio signal L based on the output signal (L + R) of the vocal cancellation signal generation circuit 3 and the vocal Kinsel signal S3c. When the operation mode is set to the vocal cancel mode, the vocal cancel signal S3c from the vocal cancel signal generation circuit 3 is subjected to a predetermined process such as amplification when the separation analysis process for the right audio signal R is performed. Output.

The surround signal generating circuit 5 outputs the output signals L and R of the audio signal separating circuit 4 in the surround mode.
To surround signal [L + {(LR) mid-range component}]
(Hereinafter, indicated by reference numeral S5A) and [R-{(LR)
Mid-range component}] (hereinafter referred to as symbol S5B),
Signal [(LR) + in vocal cancel mode
The {(L + R) low-frequency component}] is subjected to a predetermined process such as amplification and output.

The voice output circuit 6 is a DBB (Dynamic Bass).
Boost), headphone amplifier, etc., and selectively generate a sound according to the surround mode or the vocal cancel mode based on the output signals S5A, S5B of the surround signal generation circuit 5 through the sound generation unit 7 including a speaker and headphones. Let

In such a configuration, the first stereo audio signal (L + R) in the RF signal reproduced from a recording medium such as a tape is input to the first FM modulation circuit 1 and the second stereo audio signal ( L-R) is the second F
It is input to the M modulation circuit 2. The stereo audio signals (L + R) and (LR) input to the FM modulation circuits 1 and 2 are respectively subjected to the modulation action and output to the vocal cancellation signal generation circuit 3.

In the vocal cancel signal generation circuit 3,
The output signal (L + R) of the first FM modulation circuit 1 is the amplifier 3
Only the low frequency component is amplified by a and output to the audio signal separation circuit 4. In parallel with this, the signal (L +
After the low frequency component of R) further passes through the amplifier 3b, the output signal of the second FM modulation circuit 2 (L-
R) and the vocal cancellation signal S3 is added.
c is generated and output to the audio signal separation circuit 4.

At this time, if the operation mode is the surround mode, the audio signal separation circuit 4 performs a predetermined analysis process on the basis of the output signal (L + R) of the vocal cancellation signal generation circuit 3 and S3c to input the input signal. The audio signals L and R are separated and output to the surround signal generation circuit 5.

In the surround signal generation circuit 5, the surround signals S5A and S5 are converted from the input audio signals L and R.
5B is generated and output to the audio output circuit 6. As a result, the sound generating unit 7 is driven, a surround system is established, and a powerful surround effect is obtained.

On the other hand, when the operation mode is the vocal cancel mode, in the audio signal separating circuit 4, the vocal cancel signal S3c generated in the vocal cancel signal generating circuit 3 is subjected to a predetermined amplifying action, etc. It is output to the generation circuit 5. [(L-
R) + {(L + R) low-frequency component}] is output to the audio output circuit 6 after being subjected to predetermined processing by the surround signal generation circuit 5. As a result, the sound from which the mid-range vocal sound band has been removed is expressed through the sound generation unit 7, and a vocal cancellation effect is obtained.

[0012]

However, in the above-mentioned conventional circuit, the vocal cancellation signal generation circuit 3 is arranged in the preceding stage of the audio signal separation circuit 4, and the low frequency component of (L + R) is converted into the signal (LR). Since the vocal cancellation signal [(L−R) + {(L + R) low-frequency component}} is generated by addition and then input to the audio signal separation circuit 4, its output is so-called monaural. It became a signal and I could not get the surround effect in addition to the vocal cancellation effect.

Further, the conventional circuit can obtain the vocal canceling effect only at the time of reproduction, and at the time of recording or so-called E
At the time of E, the effect could not be obtained. further,
Since the first and second FM modulation circuits 1 and 2 and the audio signal separation circuit 4 are respectively configured by separate ICs, they are one of the factors that complicate the arrangement configuration of each element and increase the cost of the circuit. It was

The present invention has been made in view of such circumstances, and an object thereof is to obtain a vocal canceling effect not only at the time of reproduction but also at the time of recording, and in addition to that effect, simultaneously obtain a surround effect. Another object of the present invention is to provide an audio circuit capable of simplifying the arrangement of each element and reducing the cost of the circuit.

[0015]

In order to achieve the above object, in the present invention, stereo audio signals (L + R) and (L-
R) for separating the left and right audio signals L and R, a circuit for generating a surround signal from the output signals L and R of the audio signal separating circuit, and a vocal sound band from the surround signal generated by the surround signal generating circuit. And a circuit for generating a vocal cancellation signal from which is removed. In addition to the above configuration, a circuit which selectively receives a surround signal or a surround signal and a vocal cancel signal and outputs an audio signal corresponding to the surround mode or the vocal cancel mode may be provided.

[0016]

According to the present invention, for example, the stereo audio signals (L + R) and (LR) reproduced from the recording medium are input to the audio signal separation circuit. In the audio signal separation circuit, separation analysis processing is performed based on the input stereo audio signals (L + R) and (LR), and the stereo audio signal is separated into a left audio signal L and a right audio signal R. These audio signals L
And R are output to the surround signal generation circuit, and the surround signal is generated from the input signals L and R in the surround signal generation circuit. The surround signal generated by the surround signal generation circuit is input to the vocal cancellation signal generation circuit. The vocal cancel signal generation circuit generates a vocal cancel signal by removing the vocal sound band from the input surround signal. As a result, a surround system is established based on the surround signal, a powerful surround effect is obtained, and a sound in which the mid-range vocal sound band is removed based on the vocal cancel signal is expressed, resulting in a vocal cancel effect. can get.

Further, according to the configuration provided with a circuit for selectively receiving the surround signal or the surround signal and the vocal cancel signal and outputting the sound corresponding to the surround mode or the vocal cancel mode, for example, the operation mode is set to the surround mode. If set, only the surround signal is input to the audio output circuit. Thereby, a surround system is established based on the surround signal, and a powerful surround effect is obtained. On the other hand, when the operation mode is set to the vocal cancel mode, the surround signal generated by the surround signal generating circuit is input to the vocal cancel signal generating circuit. The vocal cancel signal generation circuit generates a vocal cancel signal by removing the vocal sound band from the input surround signal. The generated vocal cancel signal and surround signal are input to the audio output circuit. As a result, a surround effect is obtained, and a sound in which the mid-range vocal sound band is removed is expressed based on the vocal cancel signal, so that the vocal cancel effect is obtained.

[0018]

1 is a block diagram showing a first embodiment of an audio circuit in a portable video device according to the present invention. In the figure, 11 is an audio signal modulation / separation circuit, 12 is a surround circuit, and 13 is a vocal. A cancel signal generation circuit, 14 is an audio output circuit, and 15 is an audio generation unit including a speaker and headphones.

The audio signal modulation / separation circuit 11 is a single IC.
The first stereo audio signal (L + R) and the second stereo audio signal (L-R) having a predetermined frequency are FM-modulated, and predetermined analysis processing is performed based on these signals to obtain a stereo audio signal. Is separated into a left audio signal L and a right audio signal R.

The surround signal generation circuit 12 uses the output signals L and R of the audio signal modulation / separation circuit 11 to output a surround signal [L + {(L−R) mid-range component}] (hereinafter referred to as symbol S).
12A) and [R-{(LR) mid-range component}] (hereinafter indicated by reference numeral S12B). Specifically, a BP that takes the difference (LR) between the output signal L and the signal R of the audio signal modulation / separation circuit 11 and extracts the mid-range component thereof.
An amplifier 12a having an F function and an amplifier 12a for the signal L
The surround is obtained by taking the difference between the amplifier 12b that generates the surround signal S12A by adding the (LR) mid-range component obtained in step S6 and the mid-range component (LR) obtained by the signal R and the amplifier 12a. It is composed of an amplifier 12c that generates a signal S12B.

The vocal cancel signal generation circuit 13 has
A vocal cancel signal [(LR) + {(L +) in which the vocal sound band is removed from the surround signals S12A and S12B generated by the surround signal generation circuit 12
R) low-frequency component}] (hereinafter denoted by reference sign S13c) is generated. Specifically, the amplifier 13a that extracts the signal (LR) by taking the difference between the surround signal S12A and the surround signal S12B and the sum of the surround signal S12A and the surround signal S12B takes the low frequency component of (L + R). An amplifier 13b having an LPF function for extracting, and an amplifier 1
3a output (LR) output of amplifier 13b {(L +
R) low-frequency component} to generate a vocal cancellation signal [(LR) + {(L + R) low-frequency component}].

The voice output circuit 14 has a DBB, a headphone amplifier, etc., and outputs a voice based on the surround signals S12A and S12B by the surround signal generation circuit 12 and the vocal cancel signal S13c by the vocal cancel signal generation circuit 13 to the voice generation section 15. To generate selectively.

Next, the operation of the above configuration will be described. For example, the first stereo audio signal (L + R) and the second stereo audio signal (LR) in the RF frequency band reproduced from the recording medium are input to the audio signal modulation / separation circuit 11. In the audio signal modulation / separation circuit 11, the input audio signals (L + R) and (LR) are FM-modulated, and separation analysis processing is performed on the basis of these signals to convert the stereo audio signal into the left audio signal L and the right audio. Separated into signal R,
These signals L and R are output to the surround signal generation circuit 12.

In the surround signal generating circuit 12, first, the difference between the input signals L and R is taken in the amplifier 12a, and the (PF) middle band component is extracted by the BPF function. Next, in the amplifier 12b, the left audio signal L and the output (LR) midrange component of the amplifier 12a are summed to generate a surround signal S12A, and in the amplifier 12c, the right audio signal R and Amplifier 12a
The difference with the mid-range component (LR) which is the output of
The surround signal S12B is generated.

The surround signals S12A and S12B generated by the surround signal generation circuit 12 are next input to the vocal cancellation signal generation circuit 13. In the vocal cancellation signal generation circuit 13, the difference between the surround signals S12A and S12B is taken in the amplifier 13a to extract the signal (LR), and the amplifier 13a
In b, the surround signals S12A and S12B are summed, and the LPF function thereof extracts the low-frequency component of (L + R). Further, in the adder 13c, the output (LR) of the amplifier 13a and the output {low-frequency component of (L + R)} of the amplifier 13b are added to generate a vocal cancel signal S13c. The vocal cancel signal S13c is input to the audio output circuit 14. As a result, the sound from which the mid-range vocal sound band has been removed is expressed through the sound generation unit 15, and the vocal cancellation effect and the surround effect are obtained at the same time. In addition, the vocal cancel signal generation circuit 13
The output of is also output as so-called Line Out, and is configured so that the vocal cancellation effect can be obtained even during recording.

As described above, according to this embodiment,
The FM modulation processing for the first stereo audio signal (L + R) and the second stereo audio signal (LR) and the separation processing for the left audio signal L and the right audio signal R are performed in one IC.
Since it is configured to be performed by the audio signal modulation / separation circuit 11 including, it is possible to simplify the arrangement configuration of each element and reduce the cost of the circuit. In addition, this circuit can obtain a vocal cancel effect not only during reproduction but also during recording, and can also obtain a surround effect at the same time.

FIG. 3 is a block diagram showing a second embodiment of the audio circuit according to the present invention. The second embodiment is different from the first embodiment in that the surround signal S12 generated by the surround signal generation circuit 12 in two operation modes, that is, a surround mode and a cancel mode.
This is because the routes to the audio output circuits 14 of A and S12B are different. Therefore, in this embodiment, the connection switching circuit 16a is arranged between the output side of the surround signal generation circuit 12 and the input side of the vocal cancellation signal generation circuit 13, and the connection switching circuit 16b is connected to the vocal cancellation signal generation circuit 13. Output side and audio output circuit 14
It is placed between the input side of and the Line Out.

The connection changeover circuits 16a and 16b connect the terminal A to the terminal B when the mode changeover switch (not shown) is set to the surround mode, and the surround signal S12 generated by the surround signal generation circuit 12 is connected.
Input A and S12B to the audio output circuit 14. On the other hand, when the mode changeover switch (not shown) is set to the vocal cancel mode, the connection changeover circuit 16
a inputs the surround signals S12A and S12B generated by the surround signal generation circuit 12 to the vocal casel signal generation circuit 13, and the connection switching circuit 16b.
Outputs the vocal cancel signal S13c generated by the vocal casse signal generation circuit 13 to the audio output circuit 14
To enter.

In such a configuration, if the mode setting switch (not shown) is set to the surround mode,
Each connection terminal A of the connection switching circuits 16a and 16b is connected to the terminal B. Therefore, the surround signals S12A and S12B generated by the surround signal generation circuit 12 are directly input to the audio output circuit 14. As a result, the sound generating unit 15 is driven, the surround system is established, and a powerful surround effect is obtained.

On the other hand, when the mode setting switch (not shown) is set to the vocal cancel mode, the connection terminals A of the connection switching circuits 16a and 16b are connected to the terminal C.
It is connected to the. Therefore, the surround signals S12A and S12B generated by the surround signal generation circuit 12 are input to the vocal cancellation signal generation circuit 13 via the connection switching circuit 16a.

In the vocal cancellation signal generating circuit 13, the amplifier 13 is used as in the case of the first embodiment.
The signal (LR) is extracted at a, and the low frequency component of (L + R) is extracted at the amplifier 13b.
These are added by the adder 13c to generate the vocal cancel signal S13c. The vocal cancel signal S13c is input to the audio output circuit 14 via the connection switching circuit 16b and is also output as Line Out. As a result, the sound from which the mid-range vocal sound band has been removed is expressed through the sound generation unit 15, and the vocal cancellation effect is obtained.

According to the second embodiment, it is possible to obtain an appropriate audio output depending on the use. Therefore, in addition to the effect of the first embodiment, there is an advantage that it is easy to use and excellent in versatility.

[0033]

As described above, according to the present invention,
It is possible to realize a highly versatile audio circuit that can obtain a vocal canceling effect not only during playback but also during recording, and can also obtain a surround effect at the same time. Further, there are advantages that the arrangement configuration of each element can be simplified and the cost of the circuit can be reduced. Furthermore, by providing a circuit that selectively receives the surround signal or the surround signal and the vocal cancel signal and outputs the sound according to the surround mode or the vocal cancel mode, a circuit that is easy to use and excellent in versatility can be realized.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an audio circuit in a portable video device according to the present invention.

FIG. 2 is a block diagram of an audio circuit in a conventional portable video device.

FIG. 3 is a configuration diagram showing a second embodiment of the audio circuit in the portable video device according to the present invention.

[Explanation of symbols]

11 ... Audio signal modulation / separation circuit, 12 ... Surround signal generation circuit, 13 ... Vocal cancellation signal generation circuit, 14 ... Audio output circuit, 15 ... Audio generation unit, 16a, 16b ... Connection switching circuit, S12A ... Surround signal [L + { (LR) mid-range component}] S12B ... Surround signal [R-{(LR) mid-range component}] S13c ... Vocal cancel signal [(LR) +
{Low-pass component of (L + R)}].

Claims (2)

[Claims] 1. Stereo audio signals (L + R), (L-
R) for separating the left and right audio signals L, R, a circuit for generating a surround signal from the output signals L, R of the audio signal separating circuit, and a vocal sound band from the surround signal generated by the surround signal generating circuit. And a circuit for generating a vocal cancellation signal from which the audio signal has been removed. 2. The audio circuit according to claim 1, further comprising a circuit which selectively receives a surround signal or a surround signal and a vocal cancel signal and outputs an audio signal corresponding to the surround mode or the vocal cancel mode.