JP2988129B2 - Digital magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital magnetic recording / reproducing apparatus for converting a video signal and an audio signal into a digital signal and recording the digital signal on a magnetic tape in a time-division manner. The present invention provides a digital magnetic recording / reproducing apparatus which enables an insert for recording only a video signal.

[0002]

2. Description of the Related Art Conventional video tape recorders for home use (hereinafter referred to as VTRs) do not record video signals and audio signals in a time-division manner because of analog recording. A method has been introduced in which recording is performed by frequency modulation in a deep part of a magnetic tape. Therefore, it has been impossible to perform post-recording of only audio signals or insert recording of only video signals.

In recent years, with the development of digital technology, there has been known a technology of converting a video signal and an audio signal into a digital signal and recording the video signal and the audio signal on a magnetic tape in a time-division manner by helical scanning. With such a recording method, since the video signal and the audio signal are divided,
Dubbing and inserts are possible.

[0004] However, digital magnetic recording / reproducing apparatuses capable of such a function are a stationary type magnetic recording / reproducing apparatus which does not require much power concerns and a magnetic recording / reproducing apparatus integrated with a camera for broadcasting which emphasizes performance. In a home camera-integrated magnetic recording / reproducing apparatus, there is no known recording / reproducing amplifier capable of inserting and dubbing digitally recorded video and audio signals with small size and low power consumption.

[0005] In a low power consumption configuration used in a conventional home camera-integrated magnetic recording / reproducing apparatus, a video signal and an audio signal are digitally converted and recorded after time-division recording on a magnetic tape. The problem at the time of insertion will be described with reference to the drawings.

FIG. 4 is a diagram showing a basic configuration of a recording / reproducing amplifier used in a conventional camera-integrated magnetic recording / reproducing apparatus. FIG. 5 is a diagram showing a video signal and a time-division-converted video signal and a digital signal. FIG. 6 is a diagram showing a track pattern of a sound signal on a magnetic tape, and FIG. 6 is a diagram showing a waveform of a main part of FIG. 4 at the time of insertion.

In FIG. 4, reference numeral 53 denotes normal recording or
This is an input terminal of a signal to be recorded at the time of insert or after-recording, and is input to the recording amplifiers 60 and 61.

The outputs of the recording amplifiers 60 and 61 are connected to rotary transformers 74 and 7 via coupling capacitors 66 and 69, respectively.
5 is connected.

Reference numeral 55 denotes a power supply terminal, which is connected to output terminals of the recording amplifiers 60 and 61 via inductances 67 and 68.

Thus, the amplitude of the recording waveform centering on the power supply voltage can be obtained from the outputs of the recording amplifiers 60 and 61.

A current corresponding to the recording waveform amplitude flows through the coils of the rotary transformers 74 and 75, and the recording current flows through the rotary magnetic heads 76 and 77 via the rotary transformers 74 and 75. The track pattern shown in FIG.

In FIG. 5, reference numeral 80 denotes a rotating magnetic head 76.
Is a video signal recorded by the rotary magnetic head 7.
6 is an audio signal recorded. Similarly, 82 and 83
Are video and audio signals recorded by the rotating magnetic head 77.

In the case of helical scan recording, the recorded track patterns are arranged vertically, but FIG. 5 is arranged horizontally for convenience of explanation. No signals are recorded at 84 and 85 at the end of the magnetic tape or at the gap between the video signal and the audio signal.

In the case of digitally converted signals, such time division recording is possible. Switches 70 and 78 are connected to the rotary transformer side of the coupling capacitors 66 and 69, and input / output terminals 52 and 5 for recording / reproduction control signals.
7, the switches 70 and 78 are turned on during recording.
FF is turned on during playback and grounded.

Numerals 54 and 56 are input terminals for signals for controlling whether or not the recording current is supplied by the recording amplifiers 60 and 61.

Reference numerals 59 and 62 denote regenerative amplifiers, which are connected to one coil side of the rotary transformers 74 and 75 via coupling capacitors 63 and 72, respectively.

The outputs of the reproduction amplifiers 59 and 62 are output to a reproduction signal output terminal 51 via a switch 58. The switch 58 is switched to take out a reproduction signal by an input signal of an input terminal 50 of a switching signal synchronized with a rotating cylinder (not shown).

Switches 64 and 73 are connected to the rotary transformer side of the coupling capacitors 63 and 72, and control signals of input terminals 52 and 57 for recording / reproduction control signals are inverted by inversion circuits 65 and 71, respectively. It is turned on during recording and grounded by a signal, and turned off during reproduction.

The operation of the conventional example shown in FIG. 4 when only the video signal of the recording track pattern shown in FIG. 5 is rewritten, that is, when the insert is performed, will be described with reference to the waveforms shown in FIG.

The insert and the after-recording are basically in a reproducing state, and it is sufficient to switch to the recording only during the period in which the recording is desired.

In the case of an insert in FIG. 5, the video signal portions 80 and 82 may be recorded as new video signals.

In FIG. 6, (a) is a switching signal synchronized with the rotating cylinder. The switch 58 is operated so as to extract the reproduction signal of the reproduction amplifier 59 during the High period and to extract the reproduction signal of the reproduction amplifier 62 during the Low period. Control. (B) is an input signal of a new video signal to be recorded by the insert, and (c) is a control signal for controlling the recording amplifier 60, and operates the recording amplifier 60 during a High period.

(D) Recording / reproduction control signal input terminal 5
2, the switch 64 is turned on and the regenerative amplifier 59 is turned off during a Low period. During the High period, the switch 70 is turned on and the regeneration amplifier 59 is turned on.
Let it.

(E) is a control signal for controlling the recording amplifier 61, and operates the recording / reproducing amplifier 61 during the High period. (F) is an input signal of the recording / reproduction control signal input terminal 57. During the Low period, the switch 73 is turned on and the reproduction amplifier 62 is turned off. During the High period, the switch 78 is turned on, and the regeneration amplifier 62 is turned on.

The video signal (b) input for the insert in this manner is amplified by the recording amplifiers 60 and 61, and is connected to the rotating magnetic heads 76 and 77 via the coupling capacitors 66 and 69 and the rotary transformers 74 and 75. so,
It is recorded during the period of the track patterns 80 and 82 in FIG.

At the time of insert recording, the power of the power supply terminal 55 is kept on, and no DC fluctuation occurs due to switching between recording and reproduction. Also, since the DC voltage is cut by the coupling capacitors 63, 66, 69, 72,
The ON / OFF switching of the switches 64, 70, 78, 73 is also performed around the ground potential, so that no whisker current is generated.

[0027]

However, in the above configuration, when the insert is turned off, that is, at the time of switching from recording to reproduction, the inductances 67 and 6 are not changed.
8 and a ringing waveform determined by the time constant of the coupling capacitors 66 and 69 is generated. At this time, switches 70 and 7
8 is turned on to attenuate the ringing waveform. However, since the ON resistance of the switch is about 1Ω and then the regenerative amplifiers 59 and 62 amplify about 60 dB, as shown in FIG. The first part of the signal cannot be reproduced sufficiently due to the ringing waveform.

Therefore, when performing post-recording insertion, the sound quality becomes very poor during insertion,
At the time of post-recording, there is a problem that image quality is reduced.

The present invention solves the above conventional problems.
It is an object of the present invention to provide a digital magnetic recording / reproducing apparatus which has a low power consumption, can accurately perform an after-recording insert, and can faithfully reproduce other signals during the insert-recording.

[0030]

In order to achieve the above object, a digital magnetic recording / reproducing apparatus according to the present invention converts an information signal into a digital signal, and converts the digital signal by a plurality of rotating magnetic heads in a time-division manner. A digital magnetic recording and reproducing apparatus for recording and reproducing, corresponding to a plurality of rotating magnetic heads,
A plurality of recording amplifying means, comprising a plurality of reproducing amplifying means and a plurality of rotary transformers, the plurality of recording amplifying means and the plurality of reproducing amplifying means are connected to respective terminals of the rotary transformer via respective coupling capacitors, First switch means and second switch means for grounding are provided on the rotary transformer side of the coupling capacitor, and an inductance is provided to a power supply as a load impedance of the recording amplification means.
And a third switch means for short-circuiting the inductance.

[0031]

According to the present invention, there is provided a digital magnetic recording / reproducing apparatus for converting a video signal and an audio signal into digital signals and recording in a time-division manner with the above-mentioned configuration. It is possible to provide a digital magnetic recording / reproducing apparatus in which the switching of the reproduction is quick and the reproduction signal during the dubbing / insertion can be reproduced faithfully.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction and operation of an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a diagram of a track pattern recorded on a magnetic tape in this embodiment, and FIG. 3 is a main waveform diagram in FIG.

In FIG. 1, reference numeral 4 denotes an input terminal of a signal to be recorded, which is input to the recording amplifiers 13 and 14. Outputs of the recording amplifiers 13 and 14 are connected to coupling capacitors 17 and 2 respectively.
5 are connected to the rotary transformers 30 and 31. Reference numeral 7 denotes a power supply terminal, and inductances 18 and 19 are provided.
Are connected to the output terminals of the recording amplifiers 13, 14.

Thus, the amplitude of the recording waveform centering on the power supply voltage can be obtained from the outputs of the recording amplifiers 13 and 14.

A current corresponding to the recording waveform amplitude flows through the coils of the rotary transformers 30 and 31, and the recording current flows through the rotary magnetic heads 32 and 33 via the rotary transformers 30 and 31. The track pattern shown in FIG.

Switches 22 and 26 are connected to the rotary transformer side of the coupling capacitors 17 and 25. The switches 22 and 26 are turned off during recording by the control signals of the input terminals 3 and 10 of the recording / reproduction control signal. Is turned on at the time of reproduction and grounded.

Reference numerals 5 and 9 denote input terminals of signals for controlling whether or not the recording current flows in the recording amplifiers 13 and 14.

On the recording amplifier side of the coupling capacitors 17 and 25, short switches 23 and 24 are connected to the power supply, and 6 and 8 are connected to the short switches 23.
And 24 are input terminals for control signals.

Regeneration amplifiers 12 and 15 are connected to one coil side of the rotary transformers 30 and 31 via coupling capacitors 16 and 28, respectively.

The outputs of the reproduction amplifiers 12 and 15 are output to the reproduction signal output terminal 2 via the switch 11. The switch 11 is switched to take out a reproduction signal by an input signal of an input terminal 1 of a switching signal synchronized with a rotating cylinder (not shown).

Switches 21 and 29 are connected to the rotary transformer side of the coupling capacitors 16 and 28, and control signals of input terminals 3 and 10 for recording / reproduction control signals are inverted by inversion circuits 20 and 27, respectively. By
It is turned on during recording and grounded, and turned off during reproduction.

Input terminals 3 and 1 for recording / reproduction control signal
The 0 control signal is also input as a control signal for the regenerative amplifiers 12 and 15.

In the embodiment of the present invention shown in FIG. 1, the operation when only the video signal of the recording track pattern as shown in FIG. 2 is rewritten, that is, when the insert is performed, will be described with reference to the waveforms of FIG.

In FIG. 2, reference numeral 34 denotes a rotating magnetic head 32.
Is a video signal recorded by the rotary magnetic head 3
2 is an audio signal recorded. Similarly 36 and 37
Are video and audio signals recorded by the rotating magnetic head 33.

In the case of helical scan recording, the recorded track patterns are arranged vertically, but FIG. 2 is arranged horizontally for convenience of explanation. Reference numerals 38 and 39 denote the end of the magnetic tape and the gap between the video signal and the audio signal, where no signal is recorded.

In the case of a digitally converted signal, such time division recording is possible. Inserts and dubbing are basically in a correct state, and it is sufficient to switch to recording only during the period in which recording is desired.

In the case of an insert in FIG. 2, the video signal portions 34 and 36 may be recorded as new video signals.

In FIG. 3, (a) is a switching signal synchronized with the rotating cylinder. The switch 11 is set so as to take out the reproduction signal of the reproduction amplifier 12 during the High period and to take out the reproduction signal of the reproduction amplifier 15 during the Low period. Control. (B) is an input signal of a new video signal to be recorded by the insert, and (c) is a control signal for controlling the recording amplifier 13, and operates the recording amplifier 13 during a High period.

(D) is an input signal of the input terminal 3 of the recording / reproducing control signal. In the Low period, the switch 21 is turned on and the reproducing amplifier 12 is turned off. During the High period, the switch 22 is turned on and the regenerative amplifier 12 is turned off.
N.

(E) is a control signal for the short switch 23. The short switch 23 is turned off during the High period.
F, and the short switch 23 is turned ON during the Low period.

(F) is a control signal for controlling the recording amplifier 14, and operates the recording / reproducing amplifier 14 during a High period. (G) is an input signal of the recording / reproduction control signal input terminal 10, in which the switch 29 is turned on and the reproduction amplifier 15 is turned off during a Low period. During the High period, the switch 26 is turned on and the regenerative amplifier 15 is turned on.

In this manner, the video signal (b) input for the insert is amplified by the recording amplifiers 13 and 14, and is passed through the coupling capacitors 17 and 25 and the rotary transformers 30 and 31 to the rotating magnetic head 32. And 33
At the time of the track patterns 34 and 36 in FIG.

At the time of insert recording, the power supply of the power supply terminal 7 is kept on, and no DC fluctuation occurs due to switching between recording and reproduction. In addition, since the DC voltage is cut by the coupling capacitors 16, 17, 25, and 28, the ON / OFF switching of the switches 21, 22, 26, and 29 is performed centering on the ground potential, so that there is no generation of mustache current.

When the insert is turned off, that is, when switching from recording to reproduction, a ringing waveform is generated by the inductances 18 and 19 and the coupling capacitors 17 and 25, and a reproduction signal cannot be sufficiently extracted. For example, when insert is OFF, short switch 2
By turning on 3 and 24 and shorting the inductances 18 and 19, no ringing occurs.

FIG. 3 (i) shows a reproduced signal at the time of insertion obtained at the reproduced signal output terminal 2.

Note that a ringing waveform is also generated when the short switch is released, so that the short switch O
FF is preferably a period during which the rotating magnetic head does not contact the magnetic tape.

Similarly, in the case of post-recording, only the audio signal portions of the track patterns 35 and 37 in FIG.
It can be easily realized by changing the timing of each control signal.

[0059]

As described above, when a video signal and an audio signal are converted into digital signals and dubbing and insertion of a signal recorded on a magnetic tape in a time-division manner are performed, recording / recording with a low power consumption configuration is performed. Conventionally, in the case of a reproduction amplifier, there has been a problem that ringing occurs when switching from recording to reproduction, and a signal to be reproduced cannot be reproduced sufficiently. Ringing does not occur even at the time of switching, and a reproduced signal can be sufficiently taken out, and its industrial value is large.

[Brief description of the drawings]

FIG. 1 is a block diagram of a recording / reproducing amplifier according to an embodiment of the present invention.

FIG. 2 is a track pattern diagram of a video signal and an audio signal recorded on a magnetic tape in the embodiment.

FIG. 3 is a main waveform diagram of FIG. 1 at the time of insertion in the embodiment.

FIG. 4 is a block diagram of a conventional recording / reproducing amplifier.

FIG. 5 is a track pattern diagram of a video signal and an audio signal recorded on a conventional magnetic tape.

FIG. 6 is a main waveform diagram of FIG. 4 at the time of a conventional insert.

[Explanation of symbols]

 Reference Signs List 12 reproduction amplifier 13 recording amplifier 14 recording amplifier 15 reproduction amplifier 18 inductance 19 inductance 21 switch 22 switch 23 switch 24 switch 26 switch 29 switch 30 rotary transformer 31 rotary transformer 32 rotating magnetic head 33 rotating magnetic head

Claims (3)

(57) [Claims] 1. A digital magnetic recording / reproducing apparatus which converts an information signal into a digital signal and records / reproduces the digital signal in a time-division manner with a plurality of rotating magnetic heads. A plurality of recording / amplifying means, a plurality of reproducing / amplifying means, and a plurality of rotary transformers, wherein the plurality of recording / amplifying means and the plurality of reproducing / amplifying means are respectively connected to respective terminals of a rotary transformer via coupling capacitors. It is, in the rotary transformer side of the coupling capacitor is provided with a first switch means and second switch means for grounding the load of the recording amplifier means
Inductance is connected to the power supply as impedance
And a third switch means for short-circuiting the inductance. A first switch means for turning on at the time of reproduction and turning off at the time of recording; a second switch means for turning on at the time of recording and turning off at the time of reproduction; 2. The digital magnetic recording / reproducing apparatus according to claim 1, wherein the means controls to turn on during reproduction and to turn off during recording. 3. The digital magnetic recording / reproducing apparatus according to claim 1, wherein the third switch means controls to be turned off during a period when the rotating magnetic head is not in contact with the magnetic tape.