JPH0366066A - Sound signal reproducing device - Google Patents

Abstract

PURPOSE:To lighten the operator's burden by discriminating whether 1st and 2nd sound signals are stereo sound signals or main- and sub- sound signals and selectively outputting sound signals via a matrix circuit or the 1st and 2nd sound signals. CONSTITUTION:The 1st sound signal extracted by a BPF 6 from a signal regenerated by a head 2 is supplied to a processing circuit 7 where a sum signal or a main-sound signal is restored. On the other hand, the 2nd sound signal extracted by a BPF 12 is supplied to a processing circuit 13 where a difference signal or a sub-sound signal is restored. The 1st and 2nd sound signals are supplied to a matrix circuit 8 where the two channel sound signals are outputted, and whether or not 1st and 2nd sound signals are outputted via the circuit 8 is discriminated by a switch circuit 9. Then, the 1st and 2nd sound signals are directly outputted irrespective of a discriminated result at the time of dubbing. By this method, the operator's burden is lightened while the sound signals are prevented from deteriorating at the time of dubbing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an audio signal reproducing device, and particularly to an audio signal reproducing device capable of reproducing two-channel audio signals.

[Prior Art] Conventionally, it is known that a video tape recorder (VTR) records and reproduces a video signal by frequency multiplexing an FM-modulated monaural audio signal. In recent years, in this type of device, in addition to the conventionally used FM modulated carrier wave for monaural audio signals, a second FMf modulated carrier wave has been added, and this second carrier wave is used to record stereo audio signals. A reproducing type of device has been announced. That is, the second
The purpose is to perform FM modulation on this stereo audio signal and the R difference signal (L-R) using a carrier wave, and record the signal.

In addition, the conventional monaural audio signal is used as the main audio signal,
By recording the sub-audio signal using the second carrier wave, it is possible to record the main-sub-audio signal such as bilingual audio in the same way.

Now, considering the reproduction of the stereo audio signal or the main and sub audio signals as described above, the conventional audio signal using a carrier wave (hereinafter simply referred to as the first audio signal) is the sum signal of the stereo audio signals or the main audio signal. The signal is recorded, and the second one! As the audio signal (hereinafter simply referred to as the second audio signal) transmitted by the Il wave, a difference signal of the stereo audio signal or a sub audio signal is recorded. Therefore, when outputting a stereo audio signal, the first and second audio signals must be supplied to a matrix circuit, and left and right audio signals must be output from the matrix circuit, and when outputting a main and sub audio signal, the left and right audio signals must be output. It is necessary to output the first and second audio signals as they are as main and sub audio signals.

Manually switching the output as described above increases complexity and causes confusion. Moreover, if the switching is done incorrectly, the playback quality will be significantly impaired.
It is desirable that the above output switching be performed automatically. Such automatic switching of outputs can be realized by recording identification information for identifying the type of audio signal on the recording medium in some form, and performing the above switching in accordance with this identification information.

[Problems to be Solved by the Invention] However, when dubbing audio signals in such a VTR, the following problems arise.

First, if the sum-difference signal of stereo audio signals is recorded on the playback VTR, it is first converted into left and right signals by a matrix circuit and output, and then the left and right signals are converted to a sum signal and a difference signal by the matrix circuit again. It will be converted and recorded.

In this way, if dubbing is performed twice through the matrix circuit, it is not preferable because it causes deterioration of the S/N ratio and incomplete separation of left and right signals.

In addition, in order to reproduce the dubbed audio signal, it is necessary to record identification information for identifying whether the audio signal recorded by dubbing is a stereo audio signal or a main/sub audio signal. It is necessary for the operator to always recognize the type of audio signal inside and to record the identification information by switching a switch or the like.

The task of recording identification information during dubbing is extremely troublesome for the operator.

Furthermore, if the audio signal to be dubbed is a monaural signal, it is desirable not to record the second audio signal. This is because the FMW tone signal resulting from the second audio signal leaks into the first audio signal or into the video signal band. That is, this leakage (crosstalk) adversely affects other signals. However, even in this case, the operator always recognizes whether the audio signal being dubbed is a monaural audio signal and decides whether or not to record the second audio signal by switching a switch or the like. There must be.

[Means and actions for solving the problem] Under the above-mentioned background, the tree W! In the first invention, a first audio signal consisting of a left and right sum signal of a stereo audio signal or a main audio signal, and a second audio signal consisting of a left and right difference signal of a stereo audio signal or a sub audio signal. In the apparatus for reproducing from a recording medium, a discriminating means for discriminating whether the first and second audio signals are the stereo audio signal or the main and sub audio signals, and a discriminating result of the discriminating means. The configuration includes a terminal for outputting to the outside of the device.

By applying W in this way, even if the operator does not recognize whether the reproduced audio signal is a stereo audio signal or a main/sub audio signal, the above discrimination result can be used together with the audio signal recorded during dubbing. By using this feature, information indicating whether this audio signal is a stereo audio signal or a main/sub audio signal can be automatically recorded.

Further, in the second invention of the present application, the first audio signal consisting of the left and right sum signal of the stereo audio signal or the main audio signal, and the NS2 consisting of the left and right difference signal of the stereo audio signal or the sub audio signal. In the apparatus for reproducing audio signals from a recording medium, the matrix circuit is supplied with the reproduced first and second audio signals, and the first and second audio signals are the stereo audio signals. a determining means for determining whether the audio signal is the main/sub audio signal; and selectively outputting the two-channel audio signal output from the matrix circuit and the first and second audio signals according to the determination result of the determining means. and a switching circuit for outputting the first and second audio signals at the time of a dubbing command, regardless of the determination result of the determining means.

By configuring as described above, the sum-difference signal of the stereo audio can be output as is when dubbing, and the two
There is no need to use a frequency matrix circuit, and deterioration of the stereo audio signal during dubbing can be minimized.

Furthermore, in the third invention of the present application, a first audio signal consisting of a left and right sum signal of the stereo audio signal or a main audio signal, and a second audio signal consisting of a left and right difference signal of the stereo audio signal or a sub audio signal. A device capable of reproducing a second audio signal from a recording medium includes a determining means for determining whether or not the second audio signal is recorded on the recording medium, and transmitting a determination result of the determining device to the outside of the device. The configuration includes an output terminal.

By configuring as described above, even if the operator does not recognize whether or not the reproduced audio signal is only the first audio signal, this audio signal can be processed using the determination result outputted to the outside of the device. It is possible to automatically prohibit the recording of the second audio signal when the signal is a monorough 14 signal, and it is possible to prevent the occurrence of an adverse effect on the first audio signal without bothering the operator. can.

[Example J Hereinafter, the present invention will be explained according to examples.

FIG. 1 is a diagram showing the configuration of a reproduction system P of a VTR as an embodiment of the present invention, and the configuration of a recording system R of the VTR that records a reproduction signal from the reproduction system during dubbing.

Here, first, we will briefly explain the frequency allocation of the signals recorded on the magnetic tape l using Fig. 2. The pilot signal, C is the low frequency converted chroma signal, Y is the recording band of the FM modulated luminance signal, AI is the FM modulated first audio signal, and A2 is the FM modulated second audio signal. Indicates the recording band of audio signals. The frequency of the FM modulated carrier wave of the first audio signal is 1.5 MH2, and the frequency of the FM modulated carrier wave of the second audio signal is 1.7 MH2.

Hereinafter, the operation of the reproduction system shown in FIG. 1 will be explained step by step.

A signal recorded on the magnetic tape 1 is reproduced by a magnetic head 2, and then amplified by a reproduction amplifier 3 to a predetermined level. The video signal in the reproduced signal is subjected to well-known processing in a video signal reproduction processing circuit 4, and is outputted from a video output terminal 5 in the form of a television signal. The first F extracted from the reproduced signal by a bandpass filter (BPF) 6
The M-modulated audio signal is supplied to the first audio signal reproduction processing circuit 7, and the sum signal (L+R) signal or main audio signal is restored. On the other hand, the second FM modulated audio signal extracted by the BPF 12 is supplied to the second audio signal reproduction processing circuit 13, and the difference signal (LR) or sub-audio signal is restored.

8 is a matrix circuit for converting the sum signal (L+R) and difference signal (L-R) from the processing circuits 7 and 13 into a left signal and a right signal R. Further, the analog switch circuit 9 is a circuit that selects whether or not to output the reproduced 1.5G2 audio signal via the matrix circuit, and in this embodiment, the control terminal is set to a logical high level (rHJ). is input, matrix circuit 8
The logic is such that the signals that are not passed through the circuits, that is, the signals output from the circuits 7 and 13 are output as they are.

The monaural detection circuit 14 outputs rHJ when the carrier wave of the second audio signal is not present. Also.

The identification signal detection circuit 15 outputs rHJ when it is detected by an identification signal to be described later that a main and sub audio signal is recorded. The gate 17 is a circuit for controlling the analog switch circuit 9 other than during dubbing, which will be described later. That is, the outputs of the OR gate 17 and the OR gate 18 are:
When the carrier wave of the second audio signal does not exist or when the main and sub audio signals are recorded, rHJ occurs, and the first and second audio signals output from the processing circuits 7 and 13, respectively, are output from the output terminal 10.11. It will be output as is. On the other hand, when the recorded signal is a stereo audio signal, the output of the AND gate 17 is at a logical low level (rLJ
), and since the output of the OR gate 18 also becomes rLJ except during dubbing, the left and right audio signals output from the matrix circuit 8 are output from the terminals 10 and 11.

During dubbing, the video output terminal 5 is connected to the video input terminal 51 of the recording system, and the audio output terminal 10.11 is connected to the audio input terminal 52.53. Further, the dubbing control terminal 19 is connected to the dubbing control terminal 54, the monaural detection information output terminal 20 is connected to the detection information input terminal 55, and the identification information output terminal 21 is connected to the identification information input terminal.

In both the recording system, the video signal input to the terminal 51 is subjected to well-known processing in a video signal recording processing circuit 57, and the video signal output from the circuit 57 is combined with the FM modulated audio signal in the mixer 7.
5, the signals are mixed at a constant current by a recording amplifier 66, and recorded on a magnetic tape 68 by a magnetic head 67.

In the recording system R, numeral 69 is an operation switch for instructing dubbing, and 70 is an operation switch for instructing whether the input audio signal other than dubbing is a stereo audio signal or a main/sub audio signal.

When the user instructs dubbing by turning on the switch 69, the output of the OR gate 71 becomes rHJ. Also, since the terminal 54 of the recording system and the terminal 19 of the reproducing system P are connected, the output of the OR game)-18 also becomes rHJ. Therefore, switch circuit 9. Both switch circuits 59 output signals that do not go through the matrix circuits 8 and 58,
Regardless of whether the audio signal to be dubbed is a main/sub audio signal or a stereo audio signal, the processing circuit 7.13 outputs the first. The second audio signal is processed by the processing circuit 60.6 as it is.
1 is input. That is, when the audio signal to be dubbed is a stereo audio signal, the sum signal (L+R) and the difference signal (L-R) are input and output as they are.

The first audio signal recording processing circuit 60 and the second audio signal recording processing circuit 61 are connected to the first audio signal recording processing circuit 60 and the second audio signal recording processing circuit 61. 1.5 MHz for the second audio signal
, performs processing such as FM modulation using a 1.7 MHz carrier wave, and outputs the signal. The output of the inverter 63 is r
HJ and the switch 65 is on, so the two-channel FM modulated waves output from the circuits 60 and 61 are frequency-multiplexed by the mixing circuit 72. Furthermore, when the second carrier wave exists in the reproduction system P and the main and sub audio signals are being reproduced, the outputs of the detection circuits 14 and 15 are rLJ, rH
J, the output of the AND gate 64 becomes rHJ, and the identification signal recording circuit 62 further mixes the identification signal with the output of the mixing circuit 72. That is, the identification signal is mixed only when the main and sub audio signals are recorded.

The output of this identification signal recording circuit 62 is mixed with the above-mentioned video signal in a mixer 75. If the second carrier wave is not detected in the reproduction system P, that is, the monaural detection circuit 14
When the output is rHJ, the second audio signal recording processing circuit 61
Since the output of is meaningless, the switch 65 is turned off in response to the output of the inverter 63 becoming rLJ, and recording of the second audio signal is prohibited. Further, when the output of the inverter 63 is rLJ, the video signal recording processing circuit 57 described above expands the exclusive band of the FM modulated luminance signal to the extent that there is no second audio signal (the band is indicated by the dotted line in FIG. 2). This improves the resolution of the luminance signal accordingly.

By dubbing as described above, the operator can perform appropriate processing depending on the type of the reproduced audio signal, no matter what audio signal is being reproduced, simply by connecting the reproduction system P and the recording system R. In other words, during dubbing, the stereo audio signal is sent from the playback system to the recording system in the form of a sum-difference signal.
Dubbing can be performed without going through a matrix circuit, and it is possible to prevent deterioration of the S/N of the stereo audio signal after dubbing and incomplete separation of left and right signals.

Furthermore, when dubbing the main and sub audio signals, the playback system P automatically detects that the audio signal to be dubbed is the main and sub audio signal, and outputs the detection result as identification information. Using the identification information, the recording system R can record an identification signal indicating that the recording signal is a main/sub audio signal. Therefore, it is possible to automatically reproduce the dubbed audio signal without bothering the operator.

Furthermore, when dubbing only one channel of audio signal, the playback system P automatically detects this and outputs the detection result, so the recording system is prohibited from recording unnecessary second audio signals. This made it possible to suppress the adverse effects on the first audio signal and the video signal without bothering the operator.

Furthermore, since the recording system was able to widen the band of the video signal, the resolution of the video signal could be made as high as possible.

Finally, the operation of the recording system R of the VTR shown in FIG. 1 when performing normal recording other than during dubbing will be briefly described. In this case, since switch 69 is off, the output of OR gate 71 is r
It becomes HJ, and when it is off, it becomes rLJ. That is, when the switch 70 is turned on by the user when recording the main and sub audio signals, the switch 59 inputs the main and sub audio signals input to the terminals 52.53 as they are to the recording processing circuit 60.61. Further, the output of the OR game)-71 becomes rHJ and the above-mentioned identification signal is recorded.

In the above embodiment, the dubbing command switch 69 is provided on the recording side R, but the same operation can be performed even if it is provided on the reproducing side P and supplied to the OR gate 71 via the terminal 19.54.

Furthermore, by connecting the recording side R and the reproducing side P, it is possible to automatically set the output of the OR gate 18.71 to rHJ, further reducing the burden on the operator.

[Effects of the Invention] As explained above, according to the present invention, it is possible to obtain an audio signal reproducing device that can reduce the burden on the operator when dubbing, and an audio signal reproducing device that can prevent deterioration of the audio signal to be dubbed. I can do it.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a reproduction system of a VTR as an embodiment of the present invention and the configuration of a recording system of a VTR connected to this reproduction system during dubbing. FIG. FIG. 3 is a diagram for explaining frequency allocation of recorded signals. In the figure, 1 is a magnetic tape as a recording medium, 2 is a playback head, and 6.12 is a bandpass filter. 7 is a first audio signal reproduction processing circuit, 8 is a matrix circuit, 9 is a switching circuit, 10° 11 is an audio output terminal, 13 is a second audio signal reproduction processing circuit, and 14 is a monaural detection circuit. 15 is an identification signal detection circuit, 20.21 is an output terminal, 69
is a dubbing command switch.

Claims (5)

[Claims] (1) Reproducing a first audio signal consisting of a left and right sum signal of a stereo audio signal or a main audio signal, and a second audio signal consisting of a left and right difference signal of a stereo audio signal or a sub audio signal from a recording medium. The apparatus includes a determining means for determining whether the first and second audio signals are the stereo audio signal or the main and sub audio signals, and a terminal for outputting the determination result of the determining means to the outside of the apparatus. An audio signal reproducing device comprising: (2) The apparatus according to claim (1), including a matrix circuit to which the reproduced first and second audio signals are supplied, and two channels output from the matrix circuit according to the determination result of the determination means. of the audio signal and the first
and a switching circuit for selectively outputting a second audio signal. (3) Reproducing the first audio signal consisting of the left and right sum signal of the stereo audio signal or the main audio signal, and the second audio signal consisting of the left and right difference signal of the stereo audio signal or the sub audio signal from the recording medium. A matrix circuit to which the reproduced first and second audio signals are supplied, and whether the first and second audio signals are the stereo audio signal or the main/sub audio signal. and a switching circuit for selectively outputting the two-channel audio signal output from the matrix circuit and the first and second audio signals according to the determination result of the determining means, An audio signal reproducing device characterized in that, during dubbing, the switching circuit outputs the first and second audio signals regardless of the determination result of the determining means. (4) The audio signal reproducing device according to claim (3), further comprising an output terminal for outputting a dubbing command from the dubbing operation section to the outside of the device. (5) A first audio signal consisting of the left and right sum signal of the stereo audio signal or the main audio signal, and a second audio signal consisting of the left and right difference signal of the stereo audio signal or the sub audio signal can be reproduced from the recording medium. an audio signal reproducing device comprising: a determining means for determining whether or not the second audio signal is recorded on the recording medium; and a terminal for outputting the determination result of the determining means to the outside of the device. .