JPH0685772A - High-vision audio signal receiving and reproducing device - Google Patents

Abstract

PURPOSE:To output an audio signal with high quality at 4th and 2nd channels corresponding to the diversified broadcast modes of the high-vision broadcast system. CONSTITUTION:Ch1, ch2, ch3 and ch4 signals from an audio decoder 3 are. fed to a signal selection control circuit 9, the ch1, ch3, ch4 signals and the ch2, ch3, ch4 signals are added by mixers 7, 8 respectively at a ratio represented by a control signal S1 and ch1',ch2' signals are respectively formed and fed to a signal selection control circuit 9. The signal selection control circuit 9 is controlled by a control signal S2 and a mute ON/OFF control signal MT, any of selected audio signals L2, R2, L1, R1, C, S is outputted from any of the ch1, ch2, ch3, ch4, ch1', ch2' and any of the signals is muted, the selected audio signals L2, R2 are outputted as 2-channel signals and selected audio signals L1, R1, C, S are outputted as 4-channel signals respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-definition audio receiving / reproducing apparatus compatible with various audio broadcasting modes in a high-definition broadcasting system.

[0002]

2. Description of the Related Art In recent years, with the development of satellite broadcasting and EDTV broadcasting, television receivers have become larger in screen size and higher in image quality. Furthermore, the practical application of high-definition broadcasting, which is the next-generation media, will be close to practical use. The development of new audio systems that complement such large-screen, high-quality television receivers is becoming an important issue.

On the other hand, in the current satellite broadcasting, the PCM system which can obtain high sound quality has been put into practical use as an audio system. Also, in the next-generation high-definition broadcasting, the PCM system is adopted as an audio system, and a new acoustic system is proposed which is suitable for a large screen and high image quality of a television receiver.

The audio system of the high-definition broadcasting system is A
4 channels can be used in mode and 2 channels can be used in B mode, and many audio systems combining these are BT.
Proposed by A (Broadcasting Technology Council). For example, there are 2-channel stereo, monaural 1 and 2 system broadcasting, stereo 2 system broadcasting, and 3-1 stereo broadcasting. In particular, 4-channel stereo 2 system and 3-1 stereo broadcasting are new broadcasting systems that are not in the current broadcasting, and are a major feature of the next high-definition broadcasting. Furthermore, in 3-1 stereo broadcasting, for example, "Journal of Television Society", Vol. Four
2 No. 6 (1988), p.579-p587, entitled "Stereo Audio System for Hi-Vision". A method that enhances the presence of people has been developed and proposed.

However, as a conventional high-definition audio reproducing apparatus, a 3-1 stereo system is considered, and audio signals for four channels from an audio decoder are directly connected to an audio output apparatus, and four audio signals are supplied to each audio output apparatus. -It just connects to the power source and outputs it.

[0006]

SUMMARY OF THE INVENTION In the above conventional technique,
No consideration has been given to the various audio broadcasting modes in future high-definition broadcasting. For example, when stereo 2 system broadcasting mode, one stereo broadcast is selected and played back by the left and right speakers, or when bilingual multiplex broadcasting, one channel audio is monaural and all the sounds are reproduced.
There was a problem that operations such as playing with a mosquito could not be performed.

In addition, a stereo two-system broadcasting mode and 3-1
In 4-channel broadcasting such as stereo broadcasting mode, the speed is
You may need four or more mosquitoes. However, when this is played back by a home receiver, it may be forced to be played back by two left and right speakers, and no consideration has been given to this. Therefore, in the stereo 2 system broadcasting mode, the sub stereo cannot be reproduced, and in the 3-1 stereo broadcasting mode, only the left and right 2 channels can be reproduced.
There was a problem that the quality of the stereo playback was degraded.

An object of the present invention is to solve the above problems and to provide a high-definition audio receiving / reproducing apparatus capable of outputting high-quality audio signals of 4 channels and 2 channels in response to various high-definition broadcasting modes. To provide.

[0009]

In order to achieve the above-mentioned object, the present invention has a plurality of audio broadcasting modes, and the first to fourth channels of four channels are transmitted as digital data. In a high-definition audio receiving and reproducing apparatus that receives an audio signal, demodulates and reproduces it, first to fourth audio output terminals as output terminals of a 4-channel audio signal and 2
Audio output means having fifth and sixth audio output terminals as output terminals for channel audio signals, and detecting the received audio broadcast mode, and detecting a mode corresponding to the audio broadcast mode A mode detecting means for generating a signal and the demodulated audio signals of the first, third, and fourth channels are added at a predetermined addition ratio to form a first added audio signal, which is demodulated. Signal conversion means for adding the audio signals of the second, third, and fourth channels at a predetermined addition ratio to form a second added audio signal, and an addition ratio adjustment for adjusting the addition ratio in the signal conversion means Means, a silent state generating means for generating a silent signal, and the first to sixth controlled means controlled according to the mode detection signal.
1 to 4 audio signals demodulated to the output terminals of the
A signal switching means for selecting and outputting either the second added voice signal or the silent signal is provided.

[0010]

The first to fourth output terminals are output terminals for four channels, and the fifth and sixth output terminals are output terminals for two channels. Therefore, these first to fourth output terminals can be connected to the front left, front right, front center, and rear speakers of a 4-channel audio system or the like.
The output terminal of can be connected to a 2-channel audio terminal of a television receiver or the like or a 2-channel audio terminal of a VTR.

The signal switching means appropriately selects the audio signals of the first to fourth channels, the first and second added audio signals, and the silent signal according to the audio broadcasting mode, and outputs them to the first to fourth output terminals. And also to the fifth and sixth output terminals. As a result, 4-channel audio signals corresponding to the audio broadcasting mode are output from the first to fourth output terminals, and 2-channel audio signals corresponding to the audio broadcasting mode are output from the fifth and sixth output terminals. As a result, the high-quality audio reproduction that is optimum for the above-mentioned devices connected to the respective terminals becomes possible.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a high-definition audio receiving / reproducing apparatus according to the present invention, in which 1 is an input terminal for high-definition signals, 2 is a high-definition audio separation circuit, 3
Is an audio decoder, 4 is an audio reproduction block, 5 is an audio control block, 6 is an addition ratio adjusting circuit, 7 and 8 are mixers, 9 is a signal selection control circuit, 10 is a broadcast mode detection circuit, and 11 is a control signal generation circuit. Circuit, 12 is a mute control circuit, 13 to 1
8 is an amplifier, 19 is a two-channel system HDTV receiver, 20 is a left speaker, 21 is a right speaker, 2
Reference numeral 2 is an audio system, 23 is a left speaker, 24 is a right speaker, 25 is a central speaker, 26 is a rear speaker, and 27 is an audio reproduction mode selector.

In FIG. 1, a high-definition signal input from an input terminal 1 is supplied to a high-definition audio demultiplexing circuit 2, and a digital audio data signal time-division-base-band-multiplexed with the video signal is extracted. This digital voice data signal is supplied to the voice decoder 3 and is subjected to processes such as voice sync signal detection, bit / word deinterleave, error correction / interpolation, PCM demodulation and the like, and a 4-channel digital voice signal. Is output and voice playback block 4
Is supplied to. However, the audio signals of these channels may be analog signals, and in this case, the output section of the audio decoder 3 is provided with a D / A (digital / analog) converter. Below, the digital audio signals of the respective channels are ch1, ch2, ch in order from the first channel.
It is called 3, ch4 signal.

The audio reproduction block 4 is composed of mixers 7 and 8, a mute control circuit 12, a signal selection control circuit 9 and the like. In the audio reproduction block 4, all of the ch1 to ch4 signals are supplied to the signal selection control circuit 9 and the ch1, ch3 and ch4 signals are supplied to the mixer 7 from the addition ratio adjusting circuit 6 of the audio control block 5. Ch is added at a ratio according to the output control signal S1,
The 2, ch3 and ch4 signals are also supplied to the mixer 8 and added at a ratio according to the control signal S1. The output signals of the mixers 7 and 8 are supplied to the signal selection control circuit 9 as ch1 ′ and ch2 ′ signals, respectively. The signal selection control circuit 9 is controlled by the control signal S2 from the voice control block 5.

On the other hand, the audio control block 5 includes an addition ratio adjusting circuit 6, a broadcast mode detecting circuit 10, and a control signal generating circuit 1.
1, a voice reproduction mode selector 27 and the like. As described above, the addition ratio adjusting circuit 6 includes the mixer 7,
A control signal S1 for setting the addition ratio of the ch3 and ch4 signals to the ch1 and ch2 signals at 8 is generated. Broadcast mode
The mode detection circuit 10 will be described later, for example, a 2-channel T
Various broadcast modes such as V voice, bilingual broadcast, and 3-1 stereo broadcast are detected from the code data CD output from the voice decoder 3. The sound reproduction mode selector 27 is used for TV / additional sound and TV sound (main / sub / main +
Sub), main / sub stereo, multiple monaural audio, 4 channel to 2 channel conversion, switching between through mode,
Upon receiving the mode detection signal MD output from the broadcast mode detection circuit 10, the selector mode signal SM corresponding to the state of the audio reproduction mode selector 27 is generated. The control signal generation circuit 11 generates a control signal S2 according to the mode detection signal MD from the broadcast mode detection circuit 10 and the selector mode signal SM from the audio reproduction mode selector 27, and supplies it to the audio reproduction block 4.

Therefore, in the voice reproduction block 4,
The control signal S2 from the control signal generation circuit 11 is supplied to the signal selection control circuit 9 and the mute control circuit 12.
The signal selection control circuit 9 responds to various broadcasting modes by the control signal S2 to input audio sources, ch1 to ch.
A more optimal audio signal is selected from among h4, ch1 ′, ch2 ′, etc., and selected audio signals L1, R1, C, S, L2.
Output as R2. These selected voice signals are amplified by the amplifiers 13, 14, ..., 18 and then output from the voice output terminals 53, 54 ,. When the control signal S2 indicates that it should be muted,
The mute control circuit 12 detects this and controls the signal selection control circuit 9 so that the signal selection control circuit 9 does not selectively output any input signal. This mutes.

When the input signal of the signal selection control circuit 9 is a digital signal, a D / A converter is provided at the output of the signal selection control circuit 9 for each selected audio signal.
These selected audio signals can be output as analog audio signals.

The above 6 output from the audio reproduction block 4
Of the two selected audio signals, the two-channel selected audio signals L2 and R2 output from the audio output terminals 53 and 54 are 2
The channel system is for a high-definition television receiver 19 and is supplied to the left and right speakers 20 and 21, respectively. The remaining four channels of selected audio signal outputs L1, R1, C and S are left speaker 23, right speaker 24, center speaker 25, rear speaker 26.
For an audio system 22 with a selected audio signal L1 to the left speaker 23, a selected audio signal R1 to the right speaker 24 and a selected audio signal C to the central speaker. The speaker 25 and the selected audio signal S are supplied to the rear speaker 26, respectively.

Next, the functions and operations characterizing the high-definition audio receiving and reproducing apparatus of the present invention will be described with reference to FIGS. 1 and 2. FIG. 2 is a diagram showing the form of each audio broadcasting mode in the high-definition broadcasting system, the audio channel source corresponding to each audio output, and the selection system by the signal selection control circuit 9.

As shown in FIG. 2, the audio modes in the high-definition broadcasting system include a 2-channel mode using a 2-channel audio signal and a 4-channel mode using a 4-channel audio signal. . The 2-channel mode includes TV audio broadcasting and additional audio broadcasting. TV audio broadcasting includes bilingual multiplex broadcasting of main and sub audio, monaural broadcasting and 2-channel stereo broadcasting, and additional audio broadcasting includes 2 channels. There is only stereo broadcasting. In 4-channel mode, in addition to 3-1 stereo broadcast, main stereo, sub stereo multiple stereo broadcast, and main audio, sub 1, sub 2, sub 3
It is also conceivable to use a 4-multiplex audio broadcast of audio. In addition, there are some through modes that are not related to the broadcast mode.

Channels 1 to 4 in the "audio output" column of FIG. 2 are output from the audio decoder 3 of FIG. 1, respectively.
The four signals are abbreviated and shown. Also, 1 + 3 '+ 4', 2
As will be described later, + 3 ′ + 4 ′ are ch1 and ch1 added at the addition ratio determined by the control signal S1 in the mixer 7 of FIG.
Addition signals of 3 and ch4 signals, ch2 and ch added by the addition ratio determined by the control signal S1 in the mixer 8 of FIG.
The addition signals of the 3 and ch4 signals are shown respectively. M indicates that the selected voice signal is muted.

Further, as the audio output form of the receiver, a four-output form for outputting four kinds of sounds and a two-output form for outputting two kinds of sounds are possible. In FIG. 2, these two audio output forms are collectively shown, and the selected audio signal is
When outputting for a channel system, the signal source names for the selected audio signals L1, R1, C, S of the signal selection control circuit 9 are shown. When the selected audio signal is output for the 2-channel system, the selected audio signals are shown as L2 and R2. Here, the 2-channel selection audio signals L2 and R2 are mainly used for a TV receiver with a built-in 2-speaker or a VTR for 2-channel audio recording. Hereinafter, these audio output forms will be described.

As a control system for selecting the audio channel,
As shown in the rightmost column of FIG. 2, there are 10 types of A to J. The method of selecting the source channel for each broadcasting mode is based on the following ideas.

(1) In the case of 2-channel stereo broadcasting, L1 and R for both TV audio and additional audio
Allocate to 1 channel and mute C and S channels. Only TV audio is always assigned to the L2 and R2 channels. (2) In the case of bilingual or monaural 4 multiplex broadcasting, L
1, R1, C, S channels, playback of only one channel of main / sub audio, or main + sub audio, main / sub 1
~ Simultaneous playback of all three voices can be selected. Also, for both the L2 and R2 channels, it is possible to select the reproduction of only one channel of the main / sub audio of the TV audio, or the simultaneous reproduction of all of the main + sub audio and the main / sub 1 to 3 audio. (3) In the case of multiple stereo broadcasting, main stereo (ch
1, ch2) or sub-stereo (ch3, ch4) can be selected, and these signals are assigned to the L1 and R1 channels and the L2 and R2 channels, and the C and S channels are muted. (4) In the case of 3-1 stereo broadcasting, 4-channel audio is assigned to L1, R1, C and S channels. Also,
As described above, it is possible to switch to the 4-channel-2 channel conversion signal. Further, since the L2 and R2 channels are used for a TV receiver for exclusive use of 2 channels, VTR recording, etc., in the 3-1 stereo broadcast, the 4 channel-2 channel conversion signal is always assigned. (5) In the case of the through mode, regardless of the broadcasting mode, 4-channel audio is always provided for the L1, R1, C and S channels, and L1 and R are provided for the L2 and R2 channels, respectively.
Assign the same audio as channel 1.

FIG. 3 is a block diagram showing a specific example of the audio reproduction block 4 in FIG. 1, in which 28 is an input terminal.
29 and 30 are input terminals for digital audio data from the decoder 3 in FIG. 1, 31 and 32 are switch circuits, 33 and
34 is a digital filter, 35-38 are terminals, 39,
40 is a switch circuit, 41-44 are D / A converters, 45
48 are LPFs (low-pass filters), 49-52 are amplifiers, 53-58 are output terminals, 59-64 are switch circuits, 65 and 66 are mute circuits, and 82 and 92-97 are input terminals. The same reference numerals are attached to the portions corresponding to 1.

In the figure, in the audio reproduction block 4,
Ch1 from the audio decoder 3 of FIG. 1 from the input terminal 29
The digital audio data D1 including the ch2 signal is also input from the input terminal 30 to the digital audio data D2 including the ch3 and ch4 signals, respectively. These digital audio data D1 and D2 may be serial data or parallel data, but here they are serial data. An example of the data format in this case is shown in FIG. In the audio control block 5, the code data CD indicating the broadcast mode from the audio decoder 3 is input from the input terminal 82, and the control signal S2 corresponding to this is input to the input terminal 92 of the audio reproduction block 4.
To 97, and the control signal S1 generated by the addition ratio adjusting circuit 6 (FIG. 1) is supplied to the input terminal 28 of the audio reproduction block 4. The control signal S2 is composed of switch switching control signals SW1, SW2, SW3, SW4 and SW5 and a mute on / off control signal MT, and the switch switching control signals SW1, SW2, SW3, SW4 and SW5 are input terminals 92, 93 ,. From 95, 96 and 97, the mute on / off control signal MT is input to the audio reproduction block 4 from the input terminal 94, respectively.

Input digital voice data D1, D
Reference numeral 2 denotes terminals a and b of the switch circuit 31 which is switch-controlled by the switch switch control signal SW1 and switch circuit 3 which is switch-controlled by the same switch switch control signal SW1.
2 terminals b and a, respectively. Switch circuit 3
As will be described later, the states of 1 and 32 differ depending on the switch switching control signal SW1 and both switch circuits 31 and 32 may close to the terminal a side or the terminal b side. In some cases, the switch circuit 32 is closed to the terminal a side, and the switch circuit 31 is closed to the terminal a side and the switch circuit 32 is closed to the terminal b side.

The output digital audio data of the switch circuit 31 is supplied to a digital filter 33, is subjected to a filter process for removing aliasing components, etc., and is divided into digital audio data of different channels, each of which is connected to a terminal 3.
It is output to 5, 36 and supplied to the terminals a and b of the switch circuit 39. Similarly, the output digital audio data of the switch circuit 32 is also supplied to the digital filter 34, is subjected to a filtering process for removing the aliasing component, etc., and is divided into digital audio data of different channels, which are respectively applied to the terminals 37 and 38. Switch circuit 40 is output
Are supplied to the terminals a and b.

The switch circuits 39 and 40 have two systems of switching circuits, and have two common terminals c1 and c2 on the output side, which are common to the terminals a and b on the input side, respectively. As will be described later, the states of the switch circuits 39 and 40 differ according to the switch switching control signal SW2, and the common terminals c1 and c2 may select different terminals a and b, respectively, but the same terminals. In some cases, a or b may be selected.

Common terminals c1 and c2 of the switch circuit 39
The digital audio data output from each of them is supplied to D / A converters 41 and 42 and converted into analog audio signals, noises outside the audio band are removed by LPFs 45 and 46, and amplified by amplifiers 49 and 50. After that, the audio signals L and R are supplied to the mixers 7 and 8, respectively, and are also supplied to the terminals a of the switch circuits 63 and 64. These audio signals L and R are further supplied to the terminals a of the switch circuits 59 and 60. Similarly, the digital audio data output from the common terminals c1 and c2 of the switch circuit 40 are supplied to the D / A converters 43 and 44, respectively, and converted into analog audio signals, and the LPFs 47 and 48 generate noise outside the audio band. Etc. are removed and amplified by the amplifiers 51 and 52. The audio signals C and S output from these amplifiers 51 and 52 are removed.
Are both supplied to the mixers 7 and 8, and the audio signal C
To the terminal b of the switch circuit 61 and the mute circuit 65,
The audio signal S is supplied to the terminal b of the switch circuit 62 and the mute circuit 66, respectively.

In the mixer 7, the three-channel analog audio signals L, C and S from the amplifiers 49, 51 and 52 are added at a predetermined addition ratio determined by the control signal S1 from the audio control block 5, and in the mixer 8 as well, Similarly, the amplifiers 50, 5
3 channel analog audio signal R from 1, 52,
C and S are added at a predetermined addition ratio determined by the control signal S1. The audio signal L ′ output from the mixer 7 is supplied to the terminals b of the switch circuits 59 and 63, and the audio signal R ′ output from the mixer 8 is output to the switch circuits 60 and 6.
It is supplied to each of the four terminals b. Switch circuits 59, 60
The output audio signals of are supplied to the terminals a of the switch circuits 61 and 62, respectively.

Here, the switch circuits 63 and 64 are switch-controlled by the switch switch control signal SW3 from the input terminal 95, and the switch circuits 61 and 62 are input terminals 9.
The switch circuits 59 and 60 are controlled to be switched by the switch switching control signal SW4 from the input terminal 97, respectively. The mute circuits 65 and 66 are on / off controlled by a mute on / off control signal MT from the input terminal 94. Here, turning on the mute circuits 65 and 66 means that mute is applied. The switch circuits 59 and 60, the switch circuits 61 and 62, and the switch circuits 63 and 64 are respectively
When one selects the terminal a, the other also selects the terminal a, and when one selects the terminal b, the other also selects the terminal b.

The output audio signals from the switch circuits 63 and 64 are the selected audio signals L1 and R1 output from the output terminals 55 and 56 described above, and hereinafter, the output audio signals from the switch circuits 61 and 62. Are output terminals 53 and 54
The selected audio signals L2 and R2 output from the mute circuits 65 and 66 are the selected audio signals C and S output from the output terminals 57 and 58.

FIG. 4 shows each switch circuit 3 in FIG. 3 in the control systems A to J corresponding to each broadcast mode shown in FIG.
1, 32, 39, 40, 63, 64, 59, 60, 6
FIG. 3 is a diagram showing the states of mute circuits 65, 66 and 1, 62. In addition, "-" in the drawing indicates that the state of the switch circuit to which this is attached is not related to the operation of this embodiment. For example, regarding the control method B, since the mute circuits 65 and 66 are in the mute state and the switch circuits 61 and 62 are closed to the terminal a side, the amplifier 5
The audio signals C and S output from 1, 52 are not output from any output terminal of the audio reproduction block 4. Therefore, in the control method B, the states of the switch circuits 32 and 40 are not involved in the operation at all.

In order to realize the control methods A to J shown in FIG. 2, each switch circuit and mute circuit 65 shown in FIG.
The state of 66 is set by the control signal S2 as shown in FIG.

For example, in the case of the through mode shown in FIG. 2, the control system is A, and according to FIG.
1, 32, 63, 64, 59, 60, 61 and 62 are all closed to the terminal a side, and the common terminal c1 of the switch circuits 39 and 40 selects the terminal a and the common terminal c2 selects the terminal b. Further, the mute circuits 65 and 66 are in the mute off state, and the audio signal is allowed to pass through without being muted.

In this state, the digital audio data D1 shown in FIG. 6 is supplied to the digital filter 33 through the switch circuit 31 and divided into the ch1 signal and the ch2 signal, and the ch1 signal is supplied to the terminal 35 and the ch2 signal is supplied. It is output to the terminal 36, respectively. ch1 signal is switch circuit 3
9, the D / A converter 41, the LPF 45, and the amplifier 49 to become the audio signal L, which is output as the selected audio signal L1 from the output terminal 55 through the switch circuit 63 and the switch circuit 59. , 61 and is output from the output terminal 53 as the selected audio signal L2.
The ch2 signal is sent to the switch circuit 39 and the D / A converter 4
2, the LPF 46 and the amplifier 50 to become the audio signal R, which is output as the selected audio signal R1 from the output terminal 56 through the switch circuit 64 and the output terminal through the switch circuits 60 and 62. The selected audio signal R2 is output from 54.

In the case of the digital voice data D2 shown in FIG. 6 input from the input terminal 30, the switch circuit 3
The ch3 signal is output to the terminal 37 and the ch4 signal is output to the terminal 38 by the digital filter 34 through 2 respectively. The ch3 signal is supplied to the switch circuit 40 and the D / A converter 4
3, the audio signal C is passed through the LPF 47 and the amplifier 51, and the audio signal C is output from the output terminal 57 as the selected audio signal C through the mute circuit 65. Also, c
The h4 signal is supplied to the switch circuit 40, D / A converter 44, LP
The audio signal S is passed through F48 and the amplifier 52, and this audio signal S is output as the selected audio signal S from the output terminal 58 through the mute circuit 66.

Therefore, as shown in FIG. 2, in the through mode, the selected audio signals L1 and L2 are ch1 signals, the selected audio signals R1 and R2 are ch2 signals, and the selected audio signal C is the ch3 signal. The selected audio signal S is a ch4 signal.

In the case of the TV 2-channel stereo broadcast mode, the control method is B. This is the selected audio signal L
1 and L2 are ch1 signals, and selected audio signals R1 and R2 are ch
There are two signals, and the selected audio signals C and S are muted. The control method B is the same control when the bilingual main + sub audio is reproduced, the TV audio is selected in the additional audio broadcasting mode, and the main stereo is selected in the multiple stereo. In order to realize this, according to FIG.
6 is turned on so that the selected audio signals C and S are muted, and the switch circuits 31, 32, 39 and 4 are turned on.
The states of 0, 59 to 64 are the same as those of the control method A. However, the states of the switch circuits 32 and 40 depend on this control method B.
Regardless of

When the sub stereo of the multiple stereo broadcast is selected, the control method is C. This is the selected audio signal L
1 and L2 are ch3 signals, and selected audio signals R1 and R2 are ch
There are four signals, and the selected audio signals C and S are muted. In order to realize this, according to FIG. 4, except that the switch circuit 31 is closed on the terminal b side, the control method B is the same, and the digital audio data D2 shown in FIG. ch
Divide into 4 signals.

Next, the case of monaural audio reproduction will be described. First, in the case of main sound reproduction of TV sound, the control method is D. In this, as shown in FIG. 2, all the selected audio signals L1, R1, C, S, L2 and R2 are ch1 signals. This control method D is the same control when reproducing TV monaural audio and reproducing main audio of four-channel multiplex broadcasting. In order to realize this, according to FIG. 4, the switch circuit 31 selects the terminal a side, the switch circuit 32 selects the terminal b side, and all other switch circuits select the terminal a side. According to this, the switch circuits 31, 3
2 selects the same digital audio data D1 shown in FIG. Common terminals c1 and c2 of the switch circuits 39 and 40
Selects the terminal a side, the digital filter 3
The ch2 signal output from the terminals 3 and 34 to the terminals 36 and 38 is cut off by the switch circuits 39 and 40, and the amplifiers 49 to 52 are connected.
The audio signals L, R, C and S output from are all ch1 signals. Then, the switch circuits 59 to 64 are closed to the side of the terminal a, and the mute circuits 65 and 66 are both turned off to prevent muting. Therefore, the selected audio signals L1, R1, C, S, L2 obtained at the output terminals 53 to 58 are obtained. All R2s are ch1 signals.

As another monaural audio reproduction mode,
As shown in FIG. 2, the selected audio signals L1, R1, C, S,
TV audio sub-audio reproduction in which L2 and R2 are all ch2 signals only, 4-channel multiplexed sub-1 audio reproduction (control method E),
Similarly, there are 4-channel multiplexed sub 2 audio reproduction (control method F) in which only ch 3 signals are used, and 4 channel multiplexed sub 3 audio reproduction (control method G) in which only ch 4 signals are also included. These can also be realized by setting the states of the switch circuits and the mute circuits 65 and 66 as shown in FIG. 4, as in the case of the control method D described above.

In the case of 3-1 stereo mode selection in the 3-1 stereo broadcast mode, the control system is H. As shown in FIG. 2, this is because the selected audio signals L1, R1, C,
S is the ch1, ch2, ch3, and ch4 signals, respectively, and the selected audio signal L2 is a signal obtained by adding the ch1, ch3, and ch4 signals at a predetermined ratio with the mixer 7, that is, the ch1 ′ signal and the selected audio signal R2 are ch2 and ch3. , Ch4 signal added by the mixer 8 at a predetermined ratio, that is, ch
2'signal. For this addition ratio,
This will be explained later.

To realize this, the switch circuit 3
1, 32, 39, 40, 61-64 and mute circuit 6
The states of Nos. 5 and 66 are similar to those in the case of the control method A, but the switch circuits 59 and 60 select the terminal b side. In this state, similarly to the control method A, the audio signals L, R, C, S output from the amplifiers 49, 50, 51, 52 are ch1, ch2, ch3, ch4, respectively.
The selected audio signals L1, R1, C and S obtained at the output terminals 55, 56, 57 and 58 are ch1 and ch, respectively.
2, ch3 and ch4 signals. However, the added audio signal L ′ from the mixer 7 is output from the output terminal 53 through the switch circuits 59 and 61, and the added audio signal R ′ from the mixer 8 is output through the switch circuits 60 and 62. It is output from the terminal 54. Therefore, the selected audio signal L2
Is an addition audio signal L ', that is, an addition signal ch1' having a predetermined ratio of ch1, ch3 and ch4 signals, and a selection audio signal R
2 is an added voice signal R ', that is, an added signal ch2' having a predetermined ratio of ch2, ch3 and ch4 signals.

In the case of selecting the 4-channel / 2-channel conversion mode in the 3-1 stereo broadcast mode, the control system is I. As shown in FIG. 2, the selected audio signals L1 and L2 are ch1 'signals by the mixer 7,
The selected audio signals R1 and R2 are channeled by the above mixer 8.
The 2'signal is used to mute the selected audio signals C and S. In order to realize this, as shown in FIG. 4, switch circuits 31, 32, 39, 40, 59, 6 are provided.
0, 61, and 62 are the same as in the case of the control method H, but the switch circuits 63 and 64 select the terminal b side, and the mute circuits 65 and 66 are turned on to output the selected audio signals C and S. Try to mute.

According to this, the added audio signal L ', that is, the ch1' signal output from the mixer 7 is the switch circuit 6.
3, the added audio signal R ′ output from the output terminal 55 and output from the mixer 8, that is, the ch2 ′ signal is output from the output terminal 56 via the switch circuit 64, and the selected audio signals C and S. Is different from the control method H only in that it is muted. Therefore, as described above, the selected audio signals L1 and L2 become ch1 ′ signals, the selected audio signals R1 and R2 become ch2 ′ signals, and the selected audio signals C and
S cannot be obtained.

In the case of additional voice selection in the additional voice broadcasting mode, the control method is J. The selected audio signals L1 and R1 are ch3 and ch4 signals, respectively, the selected audio signals C and S are muted, and the selected audio signals L2 and R2 are also muted.
Always outputs only TV sound, so ch1 and c respectively
This is the h2 signal.

In order to realize this, as shown in FIG. 4, the switch circuits 31 and 32 are both closed to the terminal b side.
The common terminal c1 of the switch circuits 39 and 40 selects the terminal a side, and the common terminal c2 selects the terminal b side. Also, the switch circuits 63 and 64 are closed to the terminal a side,
The switch circuits 61 and 62 are closed on the terminal b side, and the mute circuits 65 and 66 are turned on to mute the selected audio signals C and S. When the mute circuits 65 and 66 are turned on, the states of the switch circuits 59 and 60 become irrelevant.

In such a state, the switch circuit 31 selects the digital audio data D2 and the switch circuit 32 selects the digital audio data D1, respectively, so that the ch3 signal and the ch4 are supplied from the digital filter 33 to the terminals 35 and 36, respectively.
A signal is output and the digital filter 34 outputs the signal to the terminal 3
The ch1 signal and ch2 signal are output to 7 and 38, respectively.
Then, the ch3 signal and the ch4 signal pass through the switch circuit 39, and the D / A converters 41 and 42 and the LPFs 45 and 4 respectively.
6, output from the output terminals 55 and 56 as the selected audio signals L1 and R1 via the amplifiers 49 and 50 and the switch circuits 63 and 64. Further, the ch1 signal and the ch2 signal pass through the switch circuit 40, and the D / A converters 43, 44 and L respectively.
PFs 47, 48, amplifiers 51, 52, switch circuit 6
The selected audio signals L2 and R2 are output from the output terminals 53 and 54 via the terminals 1 and 62. In this case, since the mute circuits 65 and 66 are on, the selected audio signals C and S
Is muted and is not output.

As described above, since the output terminals 53 and 54 for outputting the selected audio signals L2 and R2 are dedicated output terminals for TV audio 2 channels, they are automatically detected in the 3-1 stereo broadcasting mode. Even if the 4 channel-2 channel converted addition signal, that is, the ch1 'and ch2' signals described above, or the additional audio mode is selected in the additional audio broadcasting mode, ch1, which is always the TV audio signal, is selected. ch2
Only the signal will be output.

FIG. 5 is a block diagram showing a specific example of the voice control block 5 in FIGS. 1 and 3, and 71 is a TV.
/ Additional audio changeover switch circuit, 83 for 3-1 stereo broadcast mode detection circuit, 84 for additional audio broadcast mode detection circuit, 85 for 2-channel TV audio broadcast mode detection circuit,
86 is a 4-channel multiplex stereo broadcast mode detection circuit,
87 is a 4-channel multiplex voice broadcasting mode detection circuit, 88
Is a 4 channel-2 channel conversion changeover switch circuit,
Reference numeral 89 is a main / sub / main + sub audio switching switch circuit, 90 is a main / sub stereo switching switch circuit, 91 is a monaural audio switching switch circuit, and 120 is a through-mode switching switch circuit. The same symbols are attached to the portions corresponding to.

In FIG. 5, the broadcast mode detection circuit 10 includes a 3-1 stereo broadcast mode detection circuit 83, an additional audio broadcast mode detection circuit 84, a 2-channel TV audio broadcast mode detection circuit 85, and a 4-channel multiplexing. It is composed of a stereo broadcast mode detection circuit 86 and a 4-channel multiplex audio broadcast mode detection circuit 87, and one of these detection circuits 83 to 87 detects the broadcast mode by the code data CD from the input terminal 82 and the broadcast mode. Output the detection signal.

Here, the 3-1 stereo broadcast mode detection circuit 83 detects the 4-channel stereo broadcast mode in FIG. 2 based on the code data CD, and the additional audio broadcast mode detection circuit 84 detects the 2-channel additional audio broadcast mode. To 2
The channel TV audio broadcast mode detection circuit 85 is for the 2-channel TV audio broadcast mode, the 4-channel multiplex stereo broadcast mode detection circuit 86 is for the 4-channel multiplex stereo broadcast mode, and the 4-channel multiplex audio broadcast mode detection circuit 87 is used. Detects the 4-channel monaural multiplex audio broadcasting mode, respectively.

The audio reproduction mode selector 27 is a TV.
/ Additional audio changeover switch circuit 71, 4 channel-2 channel conversion changeover switch circuit 88, main / sub / main / sub audio changeover switch circuit 89, main / sub stereo changeover switch circuit 90, monaural sound changeover switch circuit 91 and through- The mode changeover switch circuit 120 includes a 4-channel / 2-channel conversion changeover switch circuit 88, a TV / additional voice changeover switch circuit 71, a main / sub / main + sub voice changeover switch circuit 89, and a main / sub stereo changeover switch circuit. 9
0 and the monaural audio changeover switch circuit 91 are respectively a 3-1 stereo broadcast mode detection circuit 83, an additional audio broadcast mode detection circuit 84 and a 2-channel TV audio broadcast mode detection circuit 85 of the broadcast mode detection circuit 10. When receiving a broadcast mode detection signal from the 4-channel multiplex stereo broadcast mode detection circuit 86 and the 4-channel multiplex audio broadcast mode detection circuit 87, it outputs a control code according to a user's instruction operation. The through-mode changeover switch circuit 120 outputs a control code therefor in the through mode.

The control signal generation circuit 11 includes changeover switch circuits 71, 88 to 91, 1 of the audio reproduction mode selector 27.
20 receives the control code output from any one of 20 and the broadcast mode detection signal output from the 2-channel TV audio broadcast mode detection circuit 85 of the broadcast mode detection circuit 10, and the switch switching control signals SW1 and SW2 corresponding thereto , SW3
SW4, SW5 and mute on / off control signal MT are output.

Next, the operation of this specific example in each broadcast mode will be described. In the case of 2-channel TV audio broadcasting mode:
In this case, the code data CD from the input terminal 82 represents a two-channel TV audio broadcast mode of multiple audio, monaural or stereo mode, and the two-channel TV audio broadcast in the broadcast mode detection circuit 10. Mode
The broadcast mode signal indicating one of these modes is generated by the detection by the mode detection circuit 85. This broadcast mode detection signal is the main / sub / main + in the audio reproduction mode selector 27.
It is supplied to either the sub audio changeover switch circuit 89 or the control signal generation circuit 11. When receiving the broadcast mode detection signal, the main / sub / main / sub audio changeover switch circuit 89 is set to a state in accordance with a user's instruction operation, and supplies a control code determined in this state to the control signal generation circuit 11.

Here, in the multiple voice mode, a multiple voice broadcast mode detection signal indicating the multiple voice mode is supplied to the main / sub / main + sub voice changeover switch circuit 89, and the main / sub / main / sub switch is supplied. In the + sub-audio changeover switch circuit 89, a state is set according to the user's instruction operation. And this Lord /
The sub / main + sub audio switch circuit 89 generates a control code determined by the state and supplies the control code to the control signal generation circuit 11.
Switch switch control signals SW1, SW2, S corresponding to this
W3, SW4, SW5 and mute on / off control signal M
T is generated so that the control method D, E or B shown in FIG. 2 can be executed.

That is, when the main / secondary / main + secondary voice changeover switch circuit 89 is in the state of indicating the main voice selection, each switch circuit and mute circuit in FIG. 3 are set to the state as in the control method D shown in FIG. Then, as shown in FIG. 2, the selected audio signals L1, R1, C, S, L2, R2 are all ch1 audio signals. Further, when the main / sub / main / sub audio changeover switch circuit 89 is in a state of indicating the sub audio selection, FIG.
4, each switch circuit and mute circuit are set to the state as in the control method E shown in FIG. 4, and as shown in FIG. 2, all the selected audio signals L1, R1, C, S, L2 and R2 are ch2.
Audio signal. Further, when the main / sub / main / sub audio changeover switch circuit 89 is in a state of (main + sub) audio selection, each switch circuit and mute circuit in FIG. 3 are in the same state as the control method B shown in FIG. 2, the selected audio signals L1 and L2 are ch1 signals, the selected audio signals R1 and R2 are ch2 signals, and the selected audio signals C and S are muted.

In addition, monaural or stereo broadcasting mode
When the mode is OFF, the control code corresponding to each mode is supplied from the 2-channel TV audio broadcast mode detection circuit 85 to the control signal generation circuit 11, and the switch switching control signals SW1, SW2, SW3, SW4 and SW5 corresponding thereto are supplied. The mute on / off control signal MT is generated to generate the mute on / off control signal MT regardless of the state of the main / sub / main / sub audio changeover switch circuit 89.
The control method D or B shown in FIG. Therefore, in the monaural broadcasting mode, each switch circuit and mute circuit in FIG. 3 are set in the state as in the control system D shown in FIG. 4, and the selected audio signals L1, R1, C, S,
Let L2 and R2 be ch1 audio signals. In the stereo broadcasting mode, the switch circuits and the mute circuit in FIG. 3 are set in the state as in the control system B shown in FIG. 4, the selected audio signals L1 and L2 are ch1 signals, and the selected audio signals R1 and R1 are selected. Select audio signal C with R2 as ch2 signal,
Mute S.

In case of 2-channel additional audio broadcasting mode:
In this case, the code data CD from the input terminal 82 is 2
The channel-added audio broadcasting mode is shown, and the additional audio broadcasting mode detection circuit 84 in the broadcasting mode detection circuit 10 is shown.
And a broadcast mode detection signal indicating the 2-channel additional audio broadcast mode is generated. This broadcast mode detection signal is supplied to the TV / additional sound changeover switch circuit 71 in the sound reproduction mode selector 27, and the TV / additional sound changeover switch circuit 71 is set to a state according to the user's instruction operation. Then, the TV / additional voice changeover switch circuit 7
1 generates a control code according to the state and supplies it to the control signal generation circuit 11. Therefore, the control signal generation circuit 11 causes the switch switching control signals SW1, S corresponding to this control code.
W2, SW3, SW4 and SW5 and a mute on / off control signal MT are generated to appropriately set the states of the switch circuit and the mute circuit in FIG.

Here, when TV audio is selected, the same control as that of each of the two-channel TV audio broadcasting modes is performed as shown in FIG.

When the TV / additional voice changeover switch circuit 71 is in the state of indicating the additional voice selection, the state of each switch circuit and the mute circuit in FIG. 3 is set as in the control method J shown in FIG. 4 and shown in FIG. So that the selected audio signal L
1 and R1 are used as ch3 and ch4 signals, respectively, and selected audio signals L2 and R2 are used as ch1 and ch2 signals, respectively, and the selected audio signals C and S are muted.

In the case of 4-channel stereo broadcasting mode:
In this case, the code data CD supplied from the input terminal 82 represents the 3-1 stereo broadcast mode of the 4-channel stereo broadcast mode, and the broadcast mode detection circuit 10
The 3-1 stereo broadcast mode detection circuit 83 therein detects the 3-1 stereo broadcast mode, and outputs a broadcast mode detection signal indicating the 3-1 stereo broadcast mode. When the broadcast mode detection signal is received, the state of the 4-channel / 2-channel conversion changeover switch circuit 88 in the audio reproduction mode selector 27 is set according to the user's instruction operation, and the control code determined by the state is controlled. It is supplied to the signal generation circuit 11. The control signal generation circuit 11 generates the switch switching control signals SW1, SW2, SW3, SW4, SW5 and the mute on / off control signal MT according to the control code so that the control method H or I shown in FIG. 2 can be executed. To

That is, when the 4-channel / 2-channel conversion changeover switch circuit 88 is in the state indicating the 3-1 stereo selection, each switch circuit and the mute circuit in FIG. 3 are set to the state as in the control method H shown in FIG. And then Figure 2
3, the selected audio signals L1, R1, C and S are ch1, ch2, ch3 and ch4 signals, and the selected audio signals L2 and R2 are added audio signals from the mixers 7 and 8 of FIG. The signal is ', ch2'.

When the 4-channel / 2-channel conversion changeover switch circuit 88 is in the state of indicating 4-channel / 2-channel conversion selection, each switch circuit and mute circuit in FIG. 3 are set to the states as in the control method I in FIG. Then, as shown in FIG. 2, the selected audio signals L1 and L2 are ch
1'signal, selected voice signals R1 and R2 are ch2 'signals, and selected voice signals C and Sch are muted.

In the case of 4-channel multiplex stereo broadcast mode: In this case, the code data CD from the input terminal 82 represents the 4-channel multiplex stereo broadcast mode,
The 4-channel multiplex stereo broadcast mode detection circuit 86 in the broadcast mode detection circuit 10 detects this and supplies a broadcast mode detection signal indicating the 4-channel multiplex sub stereo broadcast mode to the main / sub stereo changeover switch circuit 90. To do. This main / sub stereo switch circuit 90 is used for this broadcast mode.
When receiving the command detection signal, the state is set according to the user's instruction operation, and the control code according to this state is supplied to the control signal generation circuit 11. The control signal generation circuit 11 uses the switch switching control signals SW1, SW2, S corresponding to the control code.
W3, SW4, SW5 and mute on / off control signal M
T is generated so that the control method B or C shown in FIG. 2 can be executed.

That is, the main / sub stereo changeover switch circuit 9
When 0 indicates the main stereo selection, each switch circuit and mute circuit in FIG. 3 are set to the state as in the control method B shown in FIG. 4, and the selected audio signals L1 and L2 are set as shown in FIG. ch1 signal, selected audio signal R
The selected audio signals C and S are muted with 1 and R2 as ch2 signals.

When the main / sub stereo switching switch circuit 90 is in the state of indicating the sub stereo selection, each switch circuit and mute circuit in FIG. 3 are controlled by the control method C shown in FIG.
2, the selected audio signals L1 and L2 are ch3 signals, and the selected audio signals R1 and R2 are set as shown in FIG.
Is used as a ch4 signal to mute the selected audio signals C and S.

In the case of 4-channel monaural multiplex audio broadcasting mode: the code data CD from the input terminal 82 indicates any of the 4 channels, and the broadcast mode detecting circuit 10
A 4-mode multiplex audio broadcast mode detection circuit 87 detects the broadcast mode detection signal indicating the 4-channel multiplex audio broadcast mode. Upon receiving this broadcast mode detection signal, the monaural audio changeover switch circuit 91 is set to a state according to the user's instruction operation, and supplies the control code determined in this state to the control signal generation circuit 11. The control signal generation circuit 11 generates the switch switching control signals SW1, SW2, SW3, SW4, SW5 and the mute on / off control signal MT according to the control code, and the control method D, E, F or G shown in FIG. To be able to execute.

That is, the monaural voice changeover switch circuit 91
Is in the state of indicating channel 1, the respective switch circuits and mute circuit in FIG. 3 are set in the state as in the control method D shown in FIG. 4, and as shown in FIG. 2, the selected audio signals L1, L2, C, S, R1 and R2 are all ch1 signals. When the monaural audio changeover switch circuit 91 is in the state showing the channel 2, the respective switch circuits and the mute circuit in FIG. 3 are set in the state as in the control method E shown in FIG. 4, and the selected audio signal is outputted as shown in FIG. L1, L
2, C, S, R1 and R2 are all ch2 signals. When the monaural audio changeover switch circuit 91 is in the state showing the channel 3, the state of each switch circuit and the mute circuit in FIG. 3 is set as in the control method F shown in FIG.
As shown in FIG. 2, the selected audio signals L1, L2, C, S,
R1 and R2 are all ch3 signals. When the monaural audio changeover switch circuit 91 is in the state indicating the channel 4, the respective switch circuits and the mute circuit in FIG. 3 are set in the state like the control method G shown in FIG. 4, and the selected voice signal is set as shown in FIG. L1, L2, C, S, R1 and R2 are all ch4 signals. In this way, the sound of either channel can be reproduced by the 2-channel system HDTV receiver 19 or the audio system 22 (FIG. 1).

In the case of the through mode (output as it is) which is not related to the broadcast mode: In this case, the through mode changeover switch circuit 120 is brought into the through mode by the user's instruction operation. A control code indicating a through mode that is set and is determined by this state is generated, and the control signal generation circuit 11 is generated.
Is supplied to. The control signal generation circuit 11 takes in this control code with priority over the control code from the other changeover switch circuits 88, 71, 89, 90, 91 and the broadcast mode detection signal from the broadcast mode detection circuit 10, and assigns this control code to this control code. Switch switch control signals SW1, SW2, SW3, SW according to
4, SW5 and the mute on / off control signal MT are generated so that the control method A shown in FIG. 2 can be executed.

That is, the control signal generation circuit 11 has the switch switching control signals SW1, SW2, SW3, SW4.
By the SW5 and the mute on / off control signal MT, FIG.
4, each switch circuit and mute circuit are set in the state as in the control method A shown in FIG. 4, and as shown in FIG. 2, the selected audio signals L1, L2, C and S are respectively set to ch1, ch2 and c.
h3 and ch4 signals, and the selected audio signals L2 and R2 are ch1 and ch2 signals, respectively.

FIGS. 7 (a) and 7 (b) are circuit diagrams showing a concrete example of the mixers 7 and 8 of FIG. 3 used in the 4-channel / 2-channel conversion mode, respectively. )
, 67 is an input terminal, 68 to 70 are coefficient multipliers,
72 and 73 are input terminals, 74 is an adder, and 75 is an output terminal. Further, in FIG. 7B, 76 is an input terminal,
77 to 79 are coefficient multipliers, 72 and 73 are input terminals, 80
Is an adder, and 81 is an output terminal. Incidentally, 28 is an input terminal for the control signal S1 shown in FIG.

In FIG. 7A, the audio signal L output from the amplifier 49 (FIG. 3) is input to the input terminal 67, multiplied by the coefficient α in the coefficient multiplier 68, and then supplied to the adder 74. It The audio signals C and S output from the amplifiers 51 and 52 (FIG. 3) are input to the input terminals 72 and 73, respectively.
Is input, multiplied by coefficient β1 and coefficient β2 by coefficient multipliers 69 and 70, and then supplied to adder 74. Adder 74
Then, the output signals of the coefficient multipliers 68, 69 and 70 are added, and the output signal is supplied from the output terminal 75 to the terminal b of the switch circuits 59 and 63 of FIG. 3 as the added audio signal L ′. The coefficients β1 and β of the coefficient multipliers 69 and 70 are
2 corresponds to the control signal S1 from the input terminal 28.

The same applies to the mixer 8 shown in FIG. 7 (b).
That is, the audio signal R output from the amplifier 50 (FIG. 3) is input to the input terminal 76, multiplied by the coefficient α by the coefficient multiplier 77, and then supplied to the adder 80. Also, input terminal 7
Audio signals C and S output from amplifiers 51 and 52 (FIG. 3) are input to 2 and 73, respectively, and coefficient multipliers 78 and 7 are input.
It is supplied to the adder 80 after being multiplied by the coefficient β1 and the coefficient β2 by 9. In the adder 80, these coefficient multipliers 77, 7
The output signals of 8 and 79 are added, and the output signal is supplied from the output terminal 81 to the terminal b of the switch circuits 60 and 64 of FIG. 3 as the added audio signal R ′. The coefficients β1 and β2 of the coefficient multipliers 78 and 79 correspond to the control signal S1 from the input terminal 28.

The value of the coefficient α of the coefficient multipliers 68 and 77 is normally set to 1, and the coefficient β of the coefficient multipliers 69 and 78 is set.
The values of ₁ and β ₂ of the coefficient multipliers 70 and 79 are respectively set by the control signal S1 supplied from the addition ratio adjusting circuit 6 (FIG. 1).
Although it can be varied in the range of 0 to 1, it is usually set to a value of 0.7.

FIG. 8 is a circuit diagram showing a specific example of the mute circuits 65 and 66 shown in FIG. 3, in which 94 is an input terminal for the mute on / off control signal MT, and 98 is an audio signal C or S.
Input terminal, a switch circuit 99, and an output terminal 101 for the selected audio signal C or S.

In the figure, the switch circuit 99 is on / off controlled by a mute on / off control signal MT input from the mute control circuit 12 of FIG. 1 to the input terminal 94. When mute is on, the b terminal side is muted off. Then, it closes to the terminal a side, respectively. Therefore, when the mute is on, the audio signal C input from the amplifier 51 of FIG. 3 to the input terminal 98, or the input of the audio signal C from the amplifier 52 of FIG.
The audio signal S input to is cut off (muted) by the switch circuit 99, and the selected audio signal C or S cannot be obtained at the output terminal 101. When mute is off, the audio signal C or S input to the input terminal 98 is input.
Passes through the switch circuit 99, and the selected audio signal C or S is obtained at the output terminal 101. The output terminal 101
Corresponds to the output terminal 57 or 58 in FIG.

As described above, in this embodiment, 6
Optimal audio signals corresponding to the respective broadcasting modes can be obtained at the one output terminals 53 to 58. That is, the output terminal 5
3, 54 are output terminals for 2 channel TV sound,
Further, the output terminals 55 to 58 are used for additional audio, for 4-channel stereo broadcasting, etc., and can reproduce a high-quality audio signal with no discomfort even in 4-channel broadcasting. Also, the 2 channel output terminals 53 and 54 can be used as audio recording terminals for VTRs or the like, and can also be used as TV audio monitors, corresponding to both 2 channel / 4 channel broadcasting modes. You can

FIG. 9 is a block diagram showing another specific example of the audio reproduction block 4 in FIG.
Is a demultiplexer, 104 is an input terminal, and 105 is a selector. The parts corresponding to those in FIG.

In this specific example, all the audio channel switch switching operation and the audio signal adding operation are intensively performed by the analog audio processing unit after D / A conversion. Next, the configuration and operation of this specific example will be described.

In FIG. 9, digital audio data D as shown in FIG. 6 input from the input terminals 29 and 30.
1, 1 and 2 are filtered by digital filters 33 and 34, respectively, and then supplied to demultiplexers 102 and 103 to be divided into ch1, ch2 signals, ch3 and ch4 signals. These signals are respectively D / A converters 41 to 4
4, processed by the LPFs 45 to 48 and the amplifiers 49 to 52, and converted into analog audio signals L, R, C and S, and supplied to the terminals I ₁ , I ₂ , I ₃ and I ₄ of the selector 105.

Further, the audio signals L, C and S from the amplifiers 49, 51 and 52 are supplied to the mixer 7 and added at a ratio according to the control signal S1 from the addition ratio adjusting circuit 6 to obtain the added audio signal L '. Is generated. Similarly, the amplifiers 50, 51,
The audio signals R, C, S from 52 are supplied to the mixer 8,
Addition is performed at a ratio according to the control signal S1 from the addition ratio adjusting circuit 6 to generate an added voice signal R '. These added audio signals L ′ and R ′ are supplied to the terminals I ₅ and I ₆ of the selector 105. In the mixers 7 and 8, as shown in FIG.
The C, S signals and the R, C, S signals are added.

The selector 105 has a terminal I ₇ as an input terminal in addition to the terminals I _{1 to} I ₆ , and this terminal I ₇
Has an input level of zero potential for mute. Also,
As output terminals, terminals O ₁ , O ₂ , O ₃ , O ₄ , O ₅ , and O ₆ are provided, and as shown in FIG. 1, output terminals 53, 54, 55, to which external devices are connected, respectively. 56, 57 and 58 are connected. The selector 105 is switching control by the control signal S1 input to the input terminal 104 from the control signal generating circuit 11 of FIG. 1, terminal O _1, O _2, O ₃ in accordance with the control signal S2, O _4, O _5, O ₆ is connected to one of respective terminals I ₁ ~I _7. As a result, these output terminals 5
3, 54, 55, 56, 57 and 58 are audio signals L, R,
C, S, L ', R'are selected voice signals L2, R2, L1,
It will be obtained as any one of R1, C and S.

FIG. 11 is a diagram showing a control system for each broadcast mode and a signal selection operation in the selector 105.
Here, the relationship between the broadcast mode and the control methods A to J is as shown in FIG. 2, in which the output side terminals O _{1 to} O ₆ and the input side terminal I are connected.
The connection relation with _{1 to} I ₇ is selected in each broadcasting mode. Audio signal L
1, R1, C, S, L2 and R2 are the signals shown in FIG. Therefore, also in the specific example shown in FIG. 9, the audio signals similar to those in the specific example shown in FIG. 3 are obtained at the output terminals 53 to 58 in each broadcast mode.

FIG. 10 shows the audio reproduction block 4 in FIG.
FIG. 105 is a block diagram showing still another specific example of
˜110 are D / A converters, 118 and 119 are digital mixers, and 121 is a data selector. The parts corresponding to those in FIG.

This specific example has basically the same configuration as the specific example shown in FIG. 9, but a mixer and a selector are arranged in front of the D / A converter, and a digital format audio signal is provided. 9 is different from the specific example shown in FIG. 9 in that the selected audio signal is obtained in a digital format and then converted into an analog format.

Digital voice data D1 and D2 as shown in FIG. 6 inputted from the input terminals 29 and 30 are filtered by the digital filters 33 and 34, respectively, and then,
It is supplied to the demultiplexers 102 and 103, respectively c
It is divided into an h1 signal and a ch2 signal, and a ch3 signal and a ch4 signal. Then, the ch1, ch3, and ch4 signals are supplied to the digital mixer 118, and are digitally added at a ratio determined by the control signal S1 from the addition ratio adjusting circuit 6 to form a digital addition audio signal DL ′.
The ch2, ch3 and ch4 signals are supplied to the digital mixer 119 and digitally added at a ratio determined by the control signal S1 from the addition ratio adjusting circuit 6 to form a digital added voice signal DR '.

The digital added voice signals DL ', D
R'is represented by the following equation. DL ′ = ch1 + β ₁ ch3 + β ₂ ch4 DR ′ = ch2 + β ₁ ch3 + β ₂ ch4 where β ₁ and β ₂ are control signals S1 from the addition ratio adjusting circuit 6.
It is an addition coefficient determined by the above and is a value in the range of 0 to 1.

The ch1, ch2, ch3 and ch4 signals output from the demultiplexers 102 and 103 are demultiplexed respectively.
Terminals I ₁ , I ₂ , and I as input terminals of the data selector 121.
₃ , I ₄ , and digital mixers 118, 1
Digital added voice signals DL ', D output from 19
R'is a terminal I as an input terminal of the data selector 121.
₅ and I ₆ are supplied. The data selector 121 is
It also has a terminal I ₇ for mute which uses the zero potential as an input signal. Further, the data selector 121 has terminals O _{1 to} O ₆ as output terminals, and in response to the control signal S2 from the input terminal 104, the terminal I ₁ according to the broadcast mode is output in the same manner as shown in FIG. The connection relationship between ~ I ₇ and terminals O _{1 to} O ₆ is set. Therefore, the terminals O _{1 to} O ₆ are respectively connected to ch1,
Any of ch2, ch3, ch4 signals, digital added audio signals DL 'and DR', and a zero potential signal can be obtained.

The signals obtained at the terminals O _{1 to} O ₆ of the data selector 121 are converted into analog audio signals by the D / A converters 105 to 110, processed by the LPFs 111 to 116 and the amplifiers 13 to 18, respectively. Output terminals 53, 54, 5
5, 56, 57 and 58 select audio signals L2, R2 and L
It is output as 1, R1, C, S.

As described above, in this embodiment, in audio broadcasting using four channels of high-definition broadcasting, 4
Since a dedicated TV 2 channel audio terminal is provided separately from the channel audio output terminal, it is a new broadcasting mode not only for 2 channel stereo broadcasting and bilingual broadcasting, but for a speaker with a built-in television receiver.
It is possible to switch and select each channel audio signal from the optimum audio decoder for each broadcasting mode corresponding to -1 stereo, multiple stereo, multiple monaural broadcasting, and the like. Also, by connecting the above-mentioned 2 channel output terminal to the 2 channel audio input terminal of the current VTR,
It is also possible to record one stereo 4-channel broadcast without any discomfort. Therefore, in both the 2-channel / 4-channel system, it is possible to perform reproduction by making the most of various high-definition audio broadcasts, from highly realistic high-definition music broadcasts to multiple audio information programs.

[0094]

As described above, according to the present invention,
In both 2-channel and 4-channel systems, it is possible to optimally select and reproduce a high-quality audio signal corresponding to various audio modes of high-definition broadcasting 4-channel, and recording to a VTR or the like. It is possible by connecting the output terminals for 2 channels. Further, since muting is applied to the unused output terminals, unnecessary noise is not generated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a high-definition audio receiving / reproducing apparatus according to the present invention.

FIG. 2 is a diagram showing output audio channels for each broadcast mode in the embodiment shown in FIG.

3 is a block diagram showing a specific example of an audio reproduction block in FIG.

FIG. 4 is a diagram showing a state of each switch circuit for each control method in the specific example shown in FIG.

5 is a block diagram showing a specific example of an audio reproduction mode selector and a broadcast mode detection circuit in FIG.

FIG. 6 is a diagram showing a format of input digital voice data in FIG.

7 is a configuration diagram showing a specific example of the mixer shown in FIGS. 1 and 3. FIG.

8 is a configuration diagram showing a specific example of the mute circuit in FIG.

9 is a block diagram showing another specific example of the audio reproduction block in FIG. 1. FIG.

10 is a block diagram showing still another specific example of the audio reproduction block in FIG. 1. FIG.

FIG. 11 is a diagram showing an operation of the selector in FIGS. 9 and 10.

[Explanation of symbols]

 3 audio decoder 4 audio reproduction block 5 audio control block 6 addition ratio adjusting circuit 7, 8 mixer 9 signal selection control circuit 10 broadcast mode detection circuit 11 control signal generation circuit 12 mute control circuit 27 audio reproduction mode Deselector 31, 32, 39, 40, 59 to 64 Switch circuit 65, 66 Mute circuit 105 Selector 118, 119 Digital mixer 121 Data selector

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiro Umisaki 4-6, Surugadai Kanda, Chiyoda-ku, Tokyo Inside Hitachi, Ltd.

Claims (4)

[Claims] 1. A high-definition audio receiving / reproducing apparatus which has a plurality of audio broadcasting modes and receives, demodulates and reproduces audio signals of first to fourth channels transmitted as 4-channel digital data. In the above, the audio output means has first to fourth audio output terminals as output terminals for 4-channel audio signals and fifth and sixth audio output terminals as output terminals for 2-channel audio signals. And a mode detecting means for detecting the voice broadcasting mode and generating a mode detection signal corresponding to the voice broadcasting mode, and demodulated voice signals of the first, third and fourth channels. Are added at a predetermined addition ratio to form a first added audio signal, and the demodulated audio signals of the second, third, and fourth channels are added at a specified addition ratio to form a second added audio signal. And a signal converting means for Means for adjusting the addition ratio in the means, a silent state generating means for generating a silent signal, and the audio output means when the audio broadcasting mode is a predetermined 4-channel broadcasting mode. To the first to fourth output terminals of each of the first to fourth channels, the audio signal of the first to fourth channels, the first and second added audio signals, and the silent signal are selected and supplied. To the signal switching means and the fifth and sixth output terminals of the audio output means.
A high-definition audio receiving / reproducing apparatus, comprising: a second signal switching means for outputting the first and second added audio signals based on the detection signal. 2. A high-definition audio receiving / reproducing apparatus which has a plurality of audio broadcasting modes and receives, demodulates and reproduces audio signals of channels 1 to 4 transmitted as 4-channel digital data. In the above, the audio output means has first to fourth audio output terminals as output terminals for 4-channel audio signals and fifth and sixth audio output terminals as output terminals for 2-channel audio signals. And a mode detecting means for detecting the voice broadcasting mode and generating a mode detection signal corresponding to the voice broadcasting mode, a silent state generating means for generating a silent signal, and the voice broadcasting mode. When the mode is an additional audio broadcasting mode in which the audio signals of the third and fourth channels include an additional audio signal independent of the TV audio signal, the first and the first audio output means are provided.
The second audio output terminal selectively outputs the demodulated TV audio signals of the first and second channels or the additional audio signals of the demodulated third and fourth channels, and outputs the audio output means. To the 3rd and 4th output terminals,
The first signal switching means for outputting the silent signal and the fifth and sixth output terminals of the audio output means are connected to the mode.
A high-definition audio receiving / reproducing apparatus comprising: second signal switching means for selecting and outputting the demodulated TV audio signals of the first and second channels based on the detection signal. 3. A high-definition audio receiving / reproducing apparatus which has a plurality of audio broadcasting modes and receives, demodulates and reproduces the audio signals of the first to fourth channels transmitted as 4-channel digital data. In the above, the audio output means has first to fourth audio output terminals as output terminals for 4-channel audio signals and fifth and sixth audio output terminals as output terminals for 2-channel audio signals. And a mode detecting means for detecting the voice broadcasting mode and generating a mode detection signal corresponding to the voice broadcasting mode, a silent state generating means for generating a silent signal, and a predetermined four-channel broadcasting Each of the first to fourth of the audio output means when the mode or the audio signal of the third and fourth channels is other than the additional audio broadcasting mode including the additional audio signal independent of the TV audio signal. Output terminal A first signal switching means for selecting and outputting any one of the demodulated audio signals of the first to fourth channels and the silent signal according to a mode detection signal, and the audio output means. Corresponding to the mode detection signal, and second signal switching means for selecting and outputting to the fifth and sixth output terminals the same audio signal as the audio signal output to the first and second output terminals. A voice control means for generating a control signal, wherein the first and second control signals are generated by the control signal.
A high-definition audio receiving and reproducing apparatus characterized in that switching control of the signal switching means is performed. 4. A high-definition audio receiving / reproducing apparatus which has a plurality of audio broadcasting modes and receives, demodulates and reproduces audio signals of first to fourth channels transmitted as 4-channel digital data. In the audio output means, the audio output means has first to fourth audio output terminals as output terminals for 4-channel audio signals, and fifth and sixth audio output terminals as output terminals for 2-channel audio signals. First signal switching means for selecting and outputting the demodulated first to fourth channel audio signals to the first to fourth output terminals of the output means, and fifth and sixth audio output means. And a second signal switching means for selecting and outputting the demodulated first and second channel audio signals at its output terminal, and the first and second audio signals are always output regardless of the audio broadcasting mode. Audio signal by signal switching means A high-definition audio receiving and reproducing apparatus characterized by performing a selection operation of.