JPH08111856A - MUSE voice processing circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the circuit scale, improve reliability, and realize cost reduction. [Structure] The input MUSE digital signal is a MUSE audio digital signal processing circuit 1a which outputs 4-channel digital pre-selection audio, and a D / A converter DA.
1 to DA4 and low-pass filters LPF1 to LPF4, analog pre-selection voice signals CH1 to CH4 are taken, and digital pre-selection voice is calculated by the voice selection circuit 1b, and D
/ A converter DA5, DA6, low-pass filter LPF
After analog selection via 5 and 6, audio signals L-CH, R-
CH, and the analog pre-selection audio signals CH3 and CH4 are used as the post-analog selection audio outputs C-CH and S-CH by the switch circuits 1h and 1i and the audio output control circuit 1c.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a MUSE voice processing circuit.

[0002]

2. Description of the Related Art In recent years, MUSE voice processing has been mainly used in high-definition receivers and MUSE-NTSC system converters. The MUSE audio processing circuit in the conventional high-definition receiver will be described below.

FIG. 2 shows a conventional MUSE voice processing circuit. In FIG. 2, reference numeral 2 is a MUSE voice processing circuit. 2a is a digital signalized MUSE
A MUSE digital audio signal that receives a signal as an input, and outputs an audio signal CH1 ', CH2', CH3 ', CH4' before selection of four channels and an internal audio selection signal 2c obtained by decoding the audio mode information in the MUSE signal. It is a processing circuit. 2b receives the pre-digital selection voice signals CH1 'to CH4' as input, and based on the internal voice selection signal 2c, pre-digital selection voice signal CH1 '.
To CH4 'are calculated, and after digital selection, audio signals L-CH', R-CH ', C-CH',
It is a voice selection circuit that synthesizes and outputs S-CH '. DA
1 to DA8 are the audio signals CH1 'before digital selection
-CH4 'and digitally selected voice signals L-CH', R-CH ', C-CH', S output from the voice selection circuit.
It is a D / A converter that converts -CH 'into an analog audio signal. Since the LPF1 to LPF8 have quantization noise in the output of the D / A converter, the LPF1 to LPF8 are low-pass filters that remove the quantization noise.
H1-CH4 and audio signals L-CH, R after analog selection
Outputs -CH, C-CH, S-CH.

The operation of the MUSE voice processing circuit configured as described above will be described below. First,
The MUSE signal converted into a digital signal is input to the MUSE digital audio signal processing circuit 2a, which decodes the audio data in the MUSE signal and outputs 4-channel digital pre-selection audio signals CH1 'to CH4'. Next, the four-channel digital pre-selection audio signal CH
1 ′ to CH4 ′ are converted into analog signals by the D / A converters DA1 to DA4, and then the low pass filter LP.
After passing through F1 to LPF4 to remove quantization noise, M
Voice signal CH1 before analog selection of USE voice processing circuit 2
~ Output as CH4.

On the other hand, digital pre-selection voice signal C
H1 'to CH4' are input to the voice selection circuit 2b.
The voice selection circuit 2b is based on the internal voice selection signal 2c,
The calculation processing between the channels shown in (Table 1) is performed, and after the digital selection, the audio signals L-CH ', R-CH', CC are selected.
It outputs H'and S-CH '. After this, digitally selected audio output L-CH ', R-CH, C-CH', S-C
H'is converted into an analog signal by D / A converters DA5-DA8, and then low-pass filters LPF5-LPF
After passing through 8 to remove the quantization noise, it is output as an audio signal L-CH, R-CH, C-CH, S-CH after analog selection.

[0006]

However, in the above-mentioned conventional configuration, the post-selection audio signal C-C is selected as shown below.
D / A converter DA for creating H, S-CH
7, DA8 and low-pass filter LPF7, LP
There is a case where F8 becomes unnecessary, and there is a problem that the circuit scale increases.

That is, calculation between audio channels (Table 1)
As shown in, the audio signal C-CH ′ after digital selection,
S-CH 'is a digital audio signal CH3', CH4 '
It can be seen that there is a voice selection mode equal to In this voice selection mode, the analog pre-selection voice signal CH obtained by converting these digital voice signals into analog signals
3, CH4 and voice signals C-CH, S- after analog selection
CH becomes equal to each other. That is, the D / A converter and the low-pass filter for obtaining the audio signals C-CH and S-CH after analog selection are connected to the audio signal C before analog selection.
It can be used in common with the D / A converter and the low-pass filter for obtaining H3 and CH4.

On the contrary, in Table 1), in the voice selection mode in which the voice signals L-CH 'and R-CH' after digital selection are not output, the voice signals C-CH and S after analog selection are selected.
The D / A converter and low pass filter to obtain -CH are not needed.

The present invention solves the above-mentioned problems of the prior art. The pre-selection voice outputs CH3 and CH4 are the post-selection voice outputs C.
A switch circuit for switching the pre-selection voice outputs CH3 and CH4 so that they can be used as -CH and S-CH,
An audio output control circuit for controlling this switch circuit is provided,
By deleting the D / A converter and the low-pass filter for the post-selection voice output C-CH and S-CH, which are conventionally required, the circuit scale is reduced and the reliability is improved.
The purpose is to achieve low prices.

[0010]

[Table 1]

[0011]

In the MUSE audio processing circuit of the present invention, the C channel and S of the audio output after selecting the third and fourth channels of the pre-selection audio signal, respectively.
A switch circuit for use as a channel, a voice output control circuit for controlling the switch circuit based on voice selection information contained in the input MUSE signal, and voice selection information from the outside are provided.

[0012]

With the above structure, the D / A for obtaining the post-selection audio signal conventionally required by using the third and fourth channels of the pre-selection audio signal as the C channel and the S channel of the post-selection audio output, respectively. Half of the A converter and half of the low-pass filter can be removed, the circuit scale can be reduced, and the cost of the MUSE audio processing circuit can be reduced.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A MUSE voice processing circuit according to an embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram showing the configuration of the MUSE voice processing circuit according to the present invention. In FIG. 1, reference numeral 1
Is a MUSE voice processing circuit. 1a receives the MUSE signal converted into a digital signal as input, and the four-channel digital pre-selection audio signals CH1 ', CH2', CH
3 ', CH4', and MU which outputs the internal voice selection signal 1d obtained by decoding the voice mode information in the MUSE signal
SE digital audio signal processing circuit. 1b receives the pre-digital selection voice signals CH1 'to CH4' as input, performs an operation between the digital pre-selection voice signals CH1 'to CH4' based on the internal voice selection signal 2c, and outputs the post-digital selection voice signal. L-CH ', RC
A voice selection circuit for synthesizing and outputting H '. DA1-D
A6 is the pre-selection digital audio signals CH1 'to CH
4'and a D / A converter for converting the digitally selected voice signals L-CH 'and R-CH' output from the voice selection circuit into analog voice signals. LPF1 to LPF6
Since there is quantization noise in the output of the D / A converter, it is a low-pass filter that removes the quantization noise. Is output. The analog pre-selection audio signals CH3 and CH4 are output as the pre-analog selection audio signals, and the analog pre-selection audio signals C-CH and S-CH are input to the switch circuits 1h and 1i described later, respectively. Branched into things. Switch circuits 1h and 1i are controlled by audio output control signals 1f and 1g, respectively, which will be described later, and open / close the analog pre-selection audio signals CH3 and CH4 and output post-analog selection audio signals C-CH and S-CH. Reference numeral 1d is an internal voice selection signal obtained by decoding the voice mode in the MUSE signal by the MUSE voice digital signal processing circuit 1a. Reference numeral 1e is an external voice selection signal sent from an external microcomputer. An audio output control circuit 1c outputs audio output control signals 1f and 1g for controlling the switch circuits 1h and 1i based on both information of the internal audio selection signal 1d and the external audio selection signal 1e.

The operation of the MUSE voice processing circuit configured as described above will be described below. First,
The MUSE signal converted into a digital signal is input to the MUSE digital audio signal processing circuit 1a, which decodes the audio data in the MUSE signal and outputs 4-channel digital pre-selection audio signals CH1 'to CH4'. Next, the four-channel digital pre-selection audio signal CH
1 ′ to CH4 ′ are converted into analog signals by the D / A converters DA1 to DA4, and then the low pass filter LP.
After passing through F1 to LPF4 to remove quantization noise, M
Voice signal CH1 before analog selection of USE voice processing circuit 1
~ Output as CH4.

On the other hand, the digital pre-selection voice signal C
H1 'to CH4' are input to the voice selection circuit 1b.
The voice selection circuit 1b performs arithmetic processing between channels shown in Table 1 based on the internal voice selection signal 1d or the external voice selection signal 1e, and after digital selection the voice signal L-CH ',
R-CH 'is output. After this, after digital selection, the audio outputs L-CH 'and R-CH' are the D / A converter DA.
5, after being converted into an analog signal by DA6, after passing through the low-pass filters LPF5 and LPF6 to remove quantization noise, the analog-selected audio signals L-CH and R-CH
Is output as On the other hand, the internal voice selection signal 1d and the external voice selection signal 1e are input to the voice output control circuit 1c,
The audio output control signals 1f and 1 are compared with the contents of Table 1.
Determine the behavior of g. In addition, in Table 1, C-CH '
In the voice selection mode where CH3 'is described in the column of
The audio output control signal 1f turns on the switch 1h, and S-
In the voice selection mode in which CH4 'is described in the CH' column, the voice output control signal 1g means a signal for turning on the switch 1i. This audio output control signal 1f, 1g
Are input to the control inputs of the switch circuits 1h and 1i respectively to open and close the signals branched from the pre-analog selection audio signals CH3 and CH4, and the analog selection audio signal C-CH,
Outputs S-CH. The internal audio selection signal 1d and the external audio selection signal 1e input to the audio output control circuit 1c.
If there is a contradiction, or if the user wants to freely control the output of the audio signals C-CH and S-CH after analog selection, ignore the contents of the internal audio selection signal 1d,
Voice signal C-CH, S after user freely selects analog
-CH output can be controlled.

[0017]

As described above, according to the present invention, the C channel and the S channel of the audio signal after selection are set to the third audio signal before selection.
And an audio output control circuit and an audio output switch circuit that enable replacement with the fourth channel, thereby providing D for obtaining an audio signal after selection, which has been conventionally required.
By reducing the half of the / A converter and the low-pass filter, the circuit scale can be reduced, the reliability can be improved, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a MUSE voice processing circuit according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional MUSE voice processing circuit.

[Explanation of symbols]

 1d Internal voice selection signal 1e External voice selection signal 1f C-CH voice output control signal 1g S-CH voice output control signal 1h C-CH voice switch circuit 1i S-CH voice switch circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidefumi Otsuka 1-1 Sachimachi, Takatsuki-shi, Osaka Matsushita Electronics Industrial Co., Ltd.

Claims (1)

[Claims] 1. A MUSE digital signal is input and 4
MUSE that outputs digital audio before channel selection
A voice selection in which a voice digital signal processing circuit and the digital voice output before selection of the four channels are input, calculation is performed between the pre-selection digital voice channels, and digital voice is output after selecting two channels of L channel and R channel. A circuit, the 4 channel pre-selection digital voice and the L channel and R channel post-selection digital voice are respectively converted into a 4 channel analog pre-selection voice signal and an L channel and R channel analog pre-selection voice signal. A D / A converter and six low-pass filters are provided, and the third and fourth channels of the four-channel pre-selection analog audio output are branched and the branched third- and fourth-channel pre-selection analog audio outputs are output. After opening and closing, select C channel and S channel, then analog voice Switch circuit based on the audio control signal from the external microcomputer and the audio mode output obtained by decoding the audio mode information in the digital MUSE signal by the MUSE audio digital signal processing circuit. A MUSE voice processing circuit, comprising: a voice output control circuit that outputs a control signal for controlling each of two circuits.