JPH0969260A - Magnetic recording/reproducing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a two-series stereo recording compatible with the conventional technique, by superimposing and recording a difference signal of right and left components of a second audio signal with a frequency multiplex modulation signal of a first audio signal. SOLUTION: A left component signal L1 and a right component signal R1 of a first audio signal are turned at an addition circuit, 7 to frequency multiplex modulation signals through LPFs 1, 2, noise reduction circuits 3, 4 and FM modulation circuits 5, 6, respectively. The multiplex FM modulation signal is recorded as HiFi stereo sound at a rotary magnetic head 10 through a recording amplifier 8 and a rotary transformer 9. A left component, signal L2 and a right component signal, R2 of a second audio signal are added at an addition circuit, 11 to be a sum signal L2 +R2 which is overlapped with an alternating current bias from a bias oscillation circuit 13 through a recording amplifier 12 and recorded at a fixed head 14 as normal monaural sound. A difference signal L2 -R2 of the left and right components is generated at an addition circuit 32 via an inverting circuit 31 and overlapped with the FM modulation signal via an addition circuit 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus capable of recording / reproducing two stereo audio signals.

[0002]

2. Description of the Related Art A conventional magnetic recording / reproducing apparatus will be described below with reference to FIGS. Here, FIG. 5 is a block diagram showing a recording system in the conventional magnetic recording / reproducing apparatus, and FIG. 6 is a block diagram showing a reproducing system in the conventional magnetic recording / reproducing apparatus.

As shown in FIG. 5, the recording system in the conventional magnetic recording / reproducing apparatus is a HiFi stereo audio recording circuit, which removes unnecessary high frequency noise components from the left and right component signals L and R of the input audio signal. Low-pass filters (hereinafter referred to as LPF) 1 and 2,
Further, noise reduction circuits 3 and 4 for suppressing noise, FM modulation circuits 5 and 6 for FM modulation,
An adder circuit 7 for frequency-multiplexing the left and right component signals L and R;
The recording amplifier 8, the rotary transformer 9, and the rotary magnetic head 10 are provided.

On the other hand, as a normal voice recording circuit, an adding circuit 11 for adding the left and right component signals L and R of the input voice signal to obtain a monaural signal L + R, a recording amplifier 12 for performing a predetermined correction, and an alternating current Bias oscillation circuit 13 for superimposing bias and monaural signal L
And a fixed head 14 that records + R with an AC bias.

As shown in FIG. 6, the reproducing system in the conventional magnetic recording / reproducing apparatus is a HiFi stereo sound reproducing circuit, which is reproduced by the rotary magnetic head 10 and is amplified by the head amplifier 15 after passing through the rotary transformer 9. Band pass filter (hereinafter, referred to as BPF) that separates the reproduced FM signal into left and right components L and R, respectively.
16, 17 and an FM demodulation circuit 18 for FM demodulation,
19 and noise reduction circuits 20 and 21.

On the other hand, as a normal audio reproduction circuit, a reproduction equalizer amplifier 22 for correcting the reproduction signal from the fixed head 14 and an amplifier 23 for amplifying to a predetermined level are provided.

In the conventional magnetic recording / reproducing apparatus configured as described above, for one system of audio signals L and R, HiFi stereo audio by the rotary magnetic head 10 and monaural normal audio by the fixed head 14 are used. It is possible to record and reproduce.

[0008]

In recent years, a magnetic recording / reproducing apparatus capable of recording / reproducing two programs on the same tape at the same time has been proposed. In such a magnetic recording / reproducing apparatus, two systems of stereo audio are used. It is desired to record / reproduce signals.

However, in the above-mentioned conventional magnetic recording / reproducing apparatus, while maintaining compatibility with the conventional technique in which the fixed head 14 is capable of recording / reproducing normal (monaural) audio, the HiFi stereo audio by the rotary magnetic head 10 is maintained. Besides, there is a problem that it is extremely difficult to newly record and reproduce another stereo sound.

The present invention has been made in view of the above circumstances, and magnetic recording / reproducing which can easily and inexpensively realize recording / reproducing of stereo audio of two systems while maintaining compatibility with the prior art. The purpose is to provide a device.

[0011]

In the magnetic recording / reproducing apparatus of the present invention, the first audio signal is FM-modulated to perform stereo recording / reproduction by a rotary magnetic head, and at the same time, the sum of the left and right components of the second audio signal is added. A magnetic recording / reproducing apparatus for recording / reproducing a signal with an AC bias by a fixed head, which superimposes a difference signal of left and right components in the second audio signal onto the FM-modulated first audio signal during recording. During reproduction, a filter means for extracting the difference signal between the left and right components of the superimposed second audio signal, the difference signal between the left and right components of the second audio signal from the filter means, and the fixed head are reproduced. Matrix means for independently obtaining the left and right components of the second audio signal based on the sum signal of the left and right components of the second audio signal. Than it is.

In the magnetic recording / reproducing apparatus of the present invention, at the time of recording, the fixed head records the sum signal of the left and right components of the second audio signal, and the difference signal of the left and right components of the second audio signal is FM. The superimposed first audio signal is recorded by the rotary magnetic head, and at the time of reproduction, the difference signal between the left and right components in the superimposed second audio signal is taken out to output the second audio signal from the fixed head. The left and right components of the second audio signal can be independently obtained by using the sum signal of the left and right components of. As a result, while maintaining compatibility with the conventional technology that enables recording / playback of normal (monaural) audio with a fixed head, stereo audio recording / recording of not only the first audio signal but also the second audio signal is possible. Reproduction is possible, and recording / reproduction of two systems of stereo sound can be realized easily and inexpensively.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a magnetic recording / reproducing apparatus of the present invention will be described below with reference to FIGS. 1 to 4. The same parts as those in the conventional example described above are designated by the same reference numerals, and the description thereof will be omitted. To do.

Here, FIG. 1 is a block diagram showing a recording system in the magnetic recording / reproducing apparatus of this embodiment, FIG. 2 is a block diagram showing a reproducing system in the magnetic recording / reproducing apparatus of this embodiment, and FIG. 3 is in FIG. It is a schematic waveform diagram which shows the waveform of each part output.

As shown in FIG. 1, the recording system in the magnetic recording / reproducing apparatus of the present embodiment has an L that removes unnecessary high frequency noise components from the left and right component signals L ₁ and R _{1 of} the first audio signal. ． P. F. 1 and 2, noise reduction circuits 3 and 4 for further suppressing noise, FM modulation circuits 5 and 6 for FM modulation, and a left and right component signal L
An adding circuit 7 for frequency-multiplexing ₁ and R ₁ , a recording amplifier 8, a rotary transformer 9, and a rotary magnetic head 10 are provided.

On the other hand, the addition circuit 11 for adding the left and right component signals L ₂ and R ₂ of the second audio signal to obtain a monaural signal (sum signal of the left and right components) L ₂ + R ₂ and a predetermined correction are performed. A recording amplifier 12, a bias oscillation circuit 13 for superimposing an AC bias, and a fixed head 14 for AC bias recording the monaural signal L ₂ + R ₂ .

Further, an inverting circuit 31 for inverting the right component signal R ₂ of the second audio signal, and the inverting circuit 31.
Right component signal R in the second audio signal inverted by
₂ and the left component signal L ₁ of the second audio signal are added to obtain a left / right component difference signal L ₂ −R ₂
And an adder circuit 33 for superposing the difference signal L ₂ -R ₂ of the left and right components in the second audio signal from the adder circuit 32 on the first audio signal (FM modulated signal) frequency-multiplexed by the adder circuit 7. And are provided.

Further, as shown in FIG. 2, the reproducing system in the magnetic recording / reproducing apparatus of the present embodiment has a rotary magnetic head 10 as shown in FIG.
The reproduced signal reproduced by the head amplifier 15 after being reproduced by the rotary transformer 9 is separated into left and right components L ₁ and R _{1 of} the first audio signal (FM modulated signal). P. F. 16 and 17, FM demodulation circuits 18 and 19 for FM demodulation, and noise reduction circuits 20 and 21.

On the other hand, a reproduction equalizer amplifier 22 for correcting the reproduction monaural signal L ₂ + R ₂ from the fixed head 14 and an amplifier 23 for amplifying it to a predetermined level.
And

Further, the FM signal is removed from the reproduced signal reproduced by the rotary magnetic head 10, passed through the rotary transformer 9, and then amplified by the head amplifier 15 to remove a difference signal L ₂ − between the left and right components of the second audio signal. A filter circuit 34 for extracting R ₂ and an amplifier 35 for amplifying the output signal L ₂ -R ₂ of the filter circuit 34 to a predetermined level.
And the output signal L ₂ −R ₂ from the amplifier 35 and the output signal L ₂ + R ₂ from the amplifier 23 are subjected to matrix processing to produce left and right component signals L ₂ and L ₂ in the second audio signal.
A matrix circuit 36 for independently obtaining R ₂ is provided.

In the above structure, the matrix circuit 36 has an L ₂ -R ₂ signal and an L ₂ + R ₂ signal as shown in FIG.
Add ₂ signals and (L ₂ −R ₂ ) + (L ₂ + R ₂ ).
= 2L ₂ , an adding circuit 36a, an inverting circuit 36b that inverts the L ₂ −R ₂ signal, and − (L ₂ −R ₂ ) and L ₂ + R signal inverted by the inverting circuit 36b are added. hand,
− (L ₂ −R ₂ ) + (L ₂ + R ₂ ) = 2R ₂ is obtained by the addition circuit 36c and addition circuits 36a and 36c.
1/2 for L ₂ and 2R ₂ signals for level adjustment
Attenuating circuits 36d and 36e for obtaining L ₂ and R ₂
Is provided.

In the magnetic recording / reproducing apparatus configured as described above, at the time of recording, the sum signal (monaural signal) L ₂ + R ₂ of the left and right components of the second audio signal is recorded by the fixed head 14 and inverted. A first audio signal (FM modulation signal) L obtained by frequency-multiplexing the difference signal L ₂ -R ₂ (see FIG. 4B) of the left and right components in the second audio signal obtained by the circuit 31 and the addition circuit 32. ₁ , R ₁ (Fig. 4
(See FIG. 4 (c)).
See) Recording with a rotating magnetic head.

At the time of reproduction, the first audio signals L ₁ and R ₁ are stereophonically output based on the reproduction signal from the rotary magnetic head 10, and the left and right of the superimposed second audio signal are outputted by the filter circuit 34. Component difference signal L ₂
-R ₂ is taken out, and the difference signal L ₂ −R ₂ of the left and right components in the second audio signal and the sum signal L ₂ + R ₂ of the left and right components in the second audio signal from the fixed head 14 are extracted by the matrix circuit 36. By performing the matrix processing, it is possible to independently obtain the left and right component signals L ₂ and R ₂ in the second audio signal and output the stereo audio.

As described above, in the magnetic recording / reproducing apparatus of this embodiment, the fixed head 14 records / reproduces the difference signal L ₂ + R ₂ of the left and right components of the second audio signal. While maintaining compatibility with the conventional technology that enables recording / reproduction of the normal audio signal, the stereo audio is applied not only to the first audio signals L ₁ and R ₁ but also to the second audio signals L ₂ and R _2. It is possible to record / reproduce, and it is possible to easily and inexpensively record / reproduce two systems of stereo sound.

In the magnetic recording / reproducing apparatus of this embodiment, in order to simplify the configuration, the difference signal L ₂ -R ₂ of the left and right components in the second audio signal is frequency-changed in the state of the AM signal. Although it is configured to be superimposed on the multiplexed first audio signals (FM modulated signals) L ₁ and R ₁ , the difference signal L ₂ -R ₂ of the left and right components in the second audio signal is FM-modulated to obtain the first signal. It is also possible to frequency-multiplex _one audio signal (FM modulated signal) L ₁ and R ₁ .

[0026]

Since the magnetic recording / reproducing apparatus of the present invention is configured as described above, at the time of recording, the fixed head records the sum signal of the left and right components of the second audio signal and the second audio signal. The difference signal of the left and right components at
A rotary magnetic head is used to superimpose on the M-modulated first audio signal for recording, and at the time of reproduction, a difference signal between the left and right components of the superimposed second audio signal is taken out to output the second audio from the fixed head. The left and right components of the second audio signal can be independently obtained using the sum signal of the left and right components of the signal. As a result, it is possible to record not only the first audio signal but also the second audio signal while maintaining compatibility with the conventional technology that enables recording / playback of normal (monaural) audio by the fixed head.
It is also possible to record / reproduce stereo audio with respect to the audio signal of, and it is possible to easily and inexpensively realize recording / reproduction of two systems of stereo audio.

[Brief description of drawings]

FIG. 1 is a block diagram showing a recording system in an embodiment of a magnetic recording / reproducing apparatus of the present invention.

FIG. 2 is a block diagram showing a reproducing system in an embodiment of the magnetic recording / reproducing apparatus of the present invention.

FIG. 3 is a block diagram showing a matrix circuit in an embodiment of the magnetic recording / reproducing apparatus of the present invention.

FIG. 4 is a schematic waveform diagram showing a waveform of an output of each part in FIG.

FIG. 5 is a block diagram showing a recording system in a conventional magnetic recording / reproducing apparatus.

FIG. 6 is a block diagram showing a reproducing system in a conventional magnetic recording / reproducing apparatus.

[Explanation of symbols]

 1 L. P. F. 2 L. P. F. 3 noise reduction circuit 4 noise reduction circuit 5 FM modulation circuit 6 FM modulation circuit 7 addition circuit 8 recording amplifier 9 rotary transformer 10 rotary magnetic head 11 addition circuit 12 recording amplifier 13 bias oscillation circuit 14 fixed head 15 head amplifier 16 B. P. F. 17 B. P. F. 18 FM demodulation circuit 19 FM demodulation circuit 20 Noise reduction circuit 21 Noise reduction circuit 22 Reproduction equalizer amplifier 23 Amplifier 31 Inversion circuit 32 Addition circuit 33 Addition circuit 34 Filter circuit 35 Amplifier 36 Matrix circuit

Claims (1)

[Claims] 1. A magnetic recording in which the first audio signal is FM-modulated and stereo recording / reproduction is performed by a rotary magnetic head, and the sum signal of the left and right components of the second audio signal is AC bias recording / reproduction by a fixed head. A reproducing apparatus, which superimposes a difference signal of left and right components of the second audio signal on the FM-modulated first audio signal at the time of recording; and a superimposing second audio at the time of reproduction. Filter means for extracting a difference signal of left and right components of the signal, a difference signal of left and right components of the second audio signal from the filter means, and a sum signal of left and right components of the second audio signal reproduced by the fixed head. And a matrix means for independently obtaining the left and right components of the second audio signal based on the above.