JPH02166612A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To eliminate the need of an exclusive rotary erasing head and to reduce a cost by erasing rotatively a track to be recorded with a 1st rotary head using preceding 2nd and 3rd rotary heads and erasing rotatively a track to be recorded with the 2nd rotary head using the preceding 3rd rotary head. CONSTITUTION:Under a standard time (SP) mode, a track to be recorded by a standard time mode video head 1 is rotatively erased by using precedent HiFi sound head 6 and long time (EP) mode video head 4. And, under a long time mode, a track to be recorded by a long time mode video head 4 is rotatively erased by using the precedent HiFi sound head 6. By this method, the need of the exclusive rotary erasing head is eliminated, and the cost can be reduced, and in addition, the contact state between a tape and the heads can be improved, while the picture quality is hence improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a magnetic recording/reproducing device, and particularly to a VTR that aims to reduce the cost and improve the image quality.

[Conventional technology]

FIG. 7 shows, for example, AV (Audiov1sual)
This is a sectional view of a rotary drum of a conventional VTR with a rotation erasing function described in the magazine "Video Salon" (Genkosha), February 1986 issue, page 22, showing the arrangement of each head.

In FIG. 7, 1 is an Rch standard time mode video head (hereinafter referred to as 5P-R head), 2 is an Lch standard time mode video head (hereinafter referred to as 5P-L head), 3
4 is an Lch long-time mode video head (hereinafter referred to as EP-L head); 5 is an Rch Hi-Fi audio head (hereinafter referred to as HiFi-R head). (referred to as 7d), 6 is L
chHiFi audio head (hereinafter referred to as HiFi-L head); 7 is a rotating erasing head; 8 is a balancer for the rotating erasing head 7;

Here, 5P-R head 1, EP-L, head 4.5P
- The L head 2 and the BP-R head 3 form a composite head as described in "Video Salon" June 1986 issue, pages 100-101, in order to improve the quality of special playback images. There is. Furthermore, each head is separated by an angle of 60'' in the direction of drum rotation (indicated by an arrow in the figure) with respect to the combined head of the 5P-R head 1 and the EP-L head 4. head 6.5p
- A composite head of the L head 2 and the EP-R head 3, the balancer 8, and the HiFi-R head 5 are arranged in this order. Also,
The long time mode (hereinafter referred to as EP mode) can record three times as long as the standard time mode (hereinafter referred to as SP mode).

Next, the state of rotation cancellation in the conventional rotation cancellation method during sp momo will be explained using FIG. 8.

As shown in FIG. 8(a), the already recorded video signal is erased one frame (two fields) at a time by the rotary erasing head 7, and immediately after that, the image signal is erased one frame at a time (in the same figure).

As shown in (C), by performing recording in the order of 5P-R head 1 and 5P-L head 2, image quality deterioration during splicing, follow-up recording, and insertion was prevented.

The BP mode is the same as the SP mode except that three frames are erased using a rotating erasing head, so a description thereof will be omitted.

[Problem to be solved by the invention]

Conventional rotational erasure methods are configured to perform rotational erasure using a rotating head dedicated to rotational erasure.
In addition to the recording/playback head, a new rotary erasing head must be added to the rotary drum, which increases the cost due to the increased number of heads, and deteriorates the image quality due to poor contact between the tape and the head. There was a problem.

The present invention has been made to solve the problems of the conventional devices as described above, and its object is to provide a magnetic recording/reproducing device that can perform rotational erasing without using a dedicated head for rotational erasing.

[Means to solve the problem]

In the magnetic recording/reproducing apparatus according to the present invention, in the standard time mode, the track recorded by the standard time mode video head is rotated and erased using the preceding HiFi audio head and the long time mode video head, and the track recorded by the standard time mode video head is erased by rotation. In the time mode, the track recorded by the long time mode video head is rotated and erased using the preceding HiFi audio head.

[Effect]

The magnetic recording/reproducing apparatus according to the present invention connects the trunk on which the standard time mode video head records to the preceding HiF1
Rotation erasure is performed using the head and long-time mode video head, and the track recorded by the long-time mode video head is rotated and erased using the preceding HiFi audio head. No longer needed,
In addition to reducing costs, it is possible to improve the contact state between the tape and the head, thereby improving image quality.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a drum of a VH3-VTR according to an embodiment of the present invention, in which each head is mounted on the rotating drum, as viewed from the direction of rotation of the drum (indicated by an arrow in the figure). In the figure, the same symbols as in FIG. 7 indicate the same parts, and the 5P-R head 1 and the BP-L head 4.5P-L head 2 and the EP-R head 3 are used to improve the quality of special reproduction images. A composite head is formed. Also, HiF
i-L head 6 is 5P-R head l and EP-L head 4
The HiFi-R head 5 is arranged at an angle of 120 degrees in the drum rotation direction from the composite head of the 5P-L head 2 and the EP-R head 3, and the HiFi-R head 5 is arranged at an angle of 120 degrees in the drum rotation direction from the composite head of the 5P-L head 2 and the EP-R head 3. It is located.

FIG. 2 is a diagram showing an example of the relationship between steps in the rotation direction of each head when the viewpoint is placed on the head rotation surface. In FIG. 2, the 5P-R head 1 has a track width of 48 μm and is positioned with its lower end aligned with the BP-L head 4 having a track width of 32 μm.

The HlFi-L head 6 has a track width of 35 μm, which is slightly longer than usual for rotational erasing, and the 5P-R head 1
The 5P-L head 2 having a track width of 48 μm and the EP-R head 3 having a track width of 32 μm are located 51.5 μm above the lower end of the 5P-R head 1 with their lower ends aligned with the 5P-R head 1. The HiFL-R head 5 is HIF
It has the same track width of 35 μm as the i-L head 6,
It is positioned with its lower end aligned with the HiFi-L head 6.

Next, the operation will be explained. Note that since the explanation is redundant, only one channel (Rch in SP mode, Lch in EP mode) will be described.

FIG. 3 is a diagram showing how rotation of the rotating drum according to this embodiment is erased in SP mode. In the SP mode, the track advances 58 μm every time the drum rotates 180°.Here, the Hi Fi-L head 6 is 120° ahead of the 5P-R head 1, so the 5P-R head 1 is magnetically X -58X (120°/180°) s before contacting the tape and starting recording 38.
A track deviation of 6 t μm] occurs.

Therefore, as shown in FIG. 3, the HiFi-L head 6 will lead with its upper end aligned with the track traced by the 5P-R head 1.

Here, "Video Salon J April 1984 issue, P14
5, HiFi audio signals are recorded deeper than video signals using saturation magnetic recording, so by recording the original HiFi audio signals,
The video signal from the previous work will be erased.

Therefore, with the HiFL-L head 6, the width of 35 μm from the top of the track traced by the 5p-R head 1 is
This means that the rotation has been erased. Furthermore, since the EP-L head 4 is in the lead with its lower ends aligned, the 5P-R head 4 can be
It is possible to rotate and erase the entire trunk width to be traced.

Next, the state of rotation cancellation in the EP mode will be explained using FIG. 4. In EP mode, the track advances 58/3 μm for every 180 rotations of the drum.

Here, the HiFi-L head 6 is 120° ahead of the EP-L head 4, so x = (5B/3)X (120°7180°)
A track deviation of [μm] will occur.

Therefore, the track traced by the HIFi-L head 6 before one rotation (two fields ago) is 1 rotation in addition to the above-mentioned X with respect to the track traced by the EP-L head 4.
This results in a track deviation of 80°×2 rotations. Therefore, the total track deviation X is: X= (5B/3) X2+x −51,5(un
).

Here, since the HiFi-L head 6 is placed 51.5 μm above the lower end of the EP-L head 4, as shown in FIG.
The EP-L head 4 will trace the same track with its lower end aligned with the trunk traced by the -L Hendro.

Furthermore, since the HiFi-L head 6 has a wider track width than the BP-L head 4, rotation erasure in the EP mode can be performed.

FIG. 5 shows a block diagram of a rotary erasing method according to an embodiment of the present invention. In FIG. 0, the same reference numerals as in FIG.
34 is a recording amplifier for the head, 35 is an EP mode recording signal processing circuit, 36 is an sp mode recording signal processing circuit, 37 is an audio signal recording signal processing circuit, 38 is a video signal input, 39 is an audio signal 40 is a video signal erasure signal oscillator, and 31 and 51 are switches.

For SP mode recording, the switch 31 is closed to the SP mode side, and the video signal erasure signal outputted by the video signal erasure signal oscillator 40 to the EP heads 3 and 4 (for example, a single frequency with the same frequency and output as the carrier wave of the video signal) signals, etc.) are supplied via a recording amplifier 32 for the EP head. The switch 51 is also closed to the SP mode side, and the video signal output from the SP mode recording signal processing circuit 36 is supplied to the SP heads 1 and 2 via the recording amplifier 33 for the SP head.

For EP mode recording, the switch 31 is closed to the EP mode side, and the EP mode recording signal processing circuit 3 is placed in the EP head.
The video signal outputted by the EP head 5 is supplied to the recording amplifier 32 for the EP head. At this time, the switch 51 is turned off to prevent the video signal from being input to the recording amplifier 33 for the SP head.

In addition, when recording in any mode, the HiFi head 5
and 6, the audio signal recording signal processing circuit 37 outputs Hi.
Needless to say, the Fi audio signal is supplied via the recording amplifier 34 for the HiFl head.

FIG. 6 is a block diagram of a rotational cancellation method according to another embodiment of the invention. In the figure, the same symbols as in FIG. 5 indicate the same parts, and 41 is the carrier wave frequency of the video signal ±200.
It is a band pass filter of about kHz.

In this second embodiment, when recording in SP mode, switch 3
1 is closed to the SP mode side, and a bandpass filter 41 extracts a signal having a frequency of about ±200 kHz of the carrier wave of the video signal from the video signal input to the recording amplifier 33 for the SP head, and supplies it to the recording amplifier 32 for the EP head. The switch 51 is also closed to the SP mode side, and the SP heads 1 and 2
The video signal output from the SP mode recording signal processing circuit 36 is supplied to the recording amplifier 33 for the SP head.

Further, during EP mode recording, the switch 31 is closed to the EP mode side, and the video signal outputted by the EP mode recording signal processing circuit 35 to the EP heads 3 and 4 is supplied to the recording amplifier 32 for the EP head. At this time, the switch 51 is turned off,
To prevent a video signal from being input to a recording amplifier 33 for an SP head.

In this way, in this embodiment, when recording in SP mode, 5P-
The HiFi-L head 6 and the EP-L head 4 that precede the R head 1 rotate and erase the track on which the R head 1 attempts to record.
The track on which you are trying to record is
Since the Fi-L head 6 performs rotational erasing, a head dedicated to rotational erasing is not required, reducing costs and improving the contact state between the tape and the head. Furthermore, since the space where the rotary erasing head was mounted becomes vacant, it is also possible to mount a new head.

Note that in the above embodiment, only the VTR was explained, but
A magnetic recording/reproducing device that records only audio signals or a device that records PCM signals or the like may be used, and the same effects as those of the above embodiments can be obtained.

Further, the level difference relationship of the heads in the above embodiment is merely an example, and it goes without saying that other level difference relationships may be used.

〔Effect of the invention〕

As described above, according to the magnetic recording and reproducing apparatus according to the present invention, the first rotary head records on the track recorded on the second track preceding it. The third rotating head is used to perform rotational erasing, and the track recorded by the second rotating head is rotated and erased using the preceding third rotating head. This eliminates the need for a head, which not only reduces costs, but also improves the contact between the tape and the head.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a rotating drum of a VH5-VTR according to an embodiment of the present invention, and FIG. 2 is a sectional view of the rotating direction of each head when the viewpoint is placed on the head rotation surface of the rotating drum of FIG. 1. FIG. 3 is a diagram showing the relationship between steps, FIG. 3 is a diagram showing rotation cancellation in SP mode according to an embodiment of the present invention, and FIG. 4 is a diagram showing rotation cancellation in EP mode according to an embodiment of the present invention. FIG. 5 is a block diagram of a rotational cancellation method according to an embodiment of the present invention, FIG. 6 is a block diagram of a rotational cancellation method according to another embodiment of the invention, and FIG. 7 is a block diagram of a conventional rotational cancellation method. FIG. 8, which is a sectional view of the drum of a VTR with functions, is a diagram showing how rotation erasing is performed in a conventional rotation erasing method. In the figure, 1 is the Rch standard time mode video head; 2 is the Rch standard time mode video head;
is Lch standard time mode video head, 3 is Rch long time mode video head, 4 is Lch long time mode video head, 5 is RchHi F i audio head, 6 is LchHi
F i audio head, 7 is a rotating erase head, 8 is a balancer, 9 is an old recording track, 10 is a new recording track, 32
is a recording amplifier for EP heads, 33 is a recording amplifier for SP heads, 34 is a recording amplifier for HiFi heads, 35 is an EP head recording amplifier.
mode recording signal processing circuit, 36 is an SP mode recording signal processing circuit, 7 is an audio signal recording signal processing circuit, 38 is a video signal input, 9 is an audio signal input, 40 is an erasure signal oscillator, 1 is a bandpass filter, 31° 1 is a switch. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) In a magnetic recording/reproducing device having a rotating drum on which a pair of first, second, and third rotating heads are mounted at a predetermined angle, when the first rotating head records, The preceding second and third rotary heads rotate and erase the track on which the first rotary head attempts to record, and when the second rotary head records, the second rotary head A magnetic recording/reproducing apparatus characterized in that the preceding third rotary head rotates and erases a track on which recording is to be performed.