JPH0670271A - Magnetic recording device - Google Patents

Abstract

PURPOSE:To provide a compact and light-weight magnetic recording device which can attain the high speed recording at the low cost. CONSTITUTION:A video tape VT runs at a speed three time as fast as the tape speed at the time of reproduction, i.e., a long time mode. This speed of the VT is equal to the tape speed of a standard mode. A 270 deg.-wind drum DA is provided with four heads HA-HD, and the video signals are successively supplied to the heads in the order of HA, HB, HC, HD, HA... at every 90 deg. rotational angle of the drum DA. The rotational frequency of the DA is equal to 1.5 times as much as the rotational frequency at the time of the reproduction, i.e., the long time mode. In such a way, the signals can be recorded at a speed three times as fast as the speed attained by a track mode of the long time mode by taking the number of heads and the drum rotational frequency into consideration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording apparatus for video signals, and more specifically, it analyzes the movement of an image by performing high-speed recording at a speed three times as fast as that at the time of reproduction and reproducing. The present invention relates to a magnetic recording device suitable for a high-speed video system.

[0002]

2. Description of the Related Art A video signal is recorded at a speed of 3 times and reproduced by a commercially available VTR such as the widely used VHS (registered trademark) so that the movement of an image is reduced to 1 /.
A commercial video system for high-speed shooting that has been reduced to 3 speeds for analysis has been put to practical use. As a conventional example of such a magnetic recording device for high-speed imaging, there is one shown in FIG. 5 (B) or (C). In the figure, the size of the arrow corresponds to the magnitude of the speed. First, a generally popular magnetic recording device is
Two heads HA and HB are provided symmetrically on a drum D of 0 ° winding. Then, with respect to the video tape VT sent in the direction of arrow F1, a head HA that rotates in the direction of arrow F2,
Video signals are recorded alternately by switching HB every 180 °.

Next, in the prior art shown in FIG. 3B, the video tape VT is indicated by arrow 3 in FIG.
It is fed at double speed, and the drum D also rotates at triple speed as shown in FIG. That is, the operation shown in FIG. 9D is performed at a triple speed, and high-speed recording at a triple speed is performed. Next, in the conventional technique shown in FIG. 1C, six heads HA to HF are arranged on the drum D at equal intervals. The video tape VT is sent at a speed three times as fast as that shown in FIG. However, the drum D rotates at a normal speed as shown by the arrow F2, and the heads HA to HF are driven every 60 ° to perform high-speed recording at triple speed. In this conventional example, the rotation number of the drum D is normal, but the number of heads is tripled.

[0004]

However, such a conventional technique has the following disadvantages. (1) In the conventional example of FIG. 5 (B), since the triple speed recording is performed only by the high speed rotation of the drum D, it is necessary to improve the rigidity and processing accuracy of the bearing and to prevent vibration, and at a low price. It is not preferable in terms of weight reduction and weight reduction. (2) In the conventional example shown in FIG. 2C, since the triple speed recording is performed only by increasing the number of heads, it is difficult to reduce the price. (3) In all cases, since the drum D of the normal size is used, it is unsuitable for reduction in size and weight.

On the other hand, in order to realize such a high-speed shooting system with a consumer movie (video camera),
Small size, light weight, and low price are absolutely necessary. The present invention focuses on these points, and an object thereof is to provide a magnetic recording apparatus that can realize high-speed recording at a small size, a light weight, and a low price.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a magnetic recording apparatus for recording a signal on a video tape at a speed three times as high as that at the time of reproduction, and an image signal for taking in an image signal from a source at a speed three times as high as that at the time of reproduction. A take-in means, a tape running means for running the video tape at a speed three times as fast as the reproduction, and a drum having a diameter corresponding to 270 ° winding of the video tape and having four heads arranged symmetrically at equal intervals. , A drum rotating means for rotating this drum at a rotational speed 1.5 times as high as that at the time of reproduction, and a desired processing for the image signal taken in by the image signal taking-in means, and the head in order corresponding to the rotation angle. A recording signal processing means for outputting is provided.

[0007]

According to the present invention, desired high speed recording is performed by changing both the number of heads and the number of rotations of the drum from that during reproduction. Therefore, the inconvenience that occurs when high-speed recording is realized by only one of them is reduced. Also, as a drum 27
Since the one wound at 0 ° is used, the size and weight can be further reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the magnetic recording apparatus according to the present invention will be described below with reference to the accompanying drawings. The same reference numerals are used for the same components as those of the above-described conventional example or components corresponding to those of the conventional example.

FIG. 1A shows the arrangement of heads on the rotary drum in this embodiment. In addition, the same figure (B)
In the figure, the arrangement of the heads is shown expanded. In these drawings, the diameter of the drum DA is ⅔ of the diameter of a commonly used drum (see FIG. 5D, 2 heads, 180 ° winding), which is 62 mm, which is 41.3 mm. . The video tape VT is wound around the drum DA by 270 ° by the tape guide TG. In addition,
This wrapping angle is an effective wrapping angle necessary for recording a signal, and it is the same as in the conventional art that an outside overlap of about 5 to 10 ° is taken. The size of the drum DA is relatively shown in FIG. 5A, and FIG.
The diameter is 2/3 that of the conventional drum D shown in (D).

Next, on the drum DA, HA, HB, H
Four heads of C and HD are symmetrically arranged at intervals of 90 °. Two of them facing each other at 180 °, that is, the heads HA and HC, and HB and HD respectively have the same azimuth angle (FIG. 1).
(See (B)). The track widths of the heads HA to HD are the same as those in the so-called long-time mode (EP mode).
It is set to μm to 26 μm. Further, the rotation number of the drum DA is set to 45 r / s (= 2700 rpm, NTSC), which is 1.5 times the normal case shown in FIG. 5D. Note that the above-described configuration is basically the same as the configuration of the small-diameter drum with 4 heads and 270 ° winding, which is practically used in video movies.

Next, the circuit block of the magnetic recording apparatus according to the present embodiment will be described with reference to FIG. In the figure, in the camera section 10, the image formed by the image pickup optical system 12 is picked up by the image pickup device 14, and the image signal is outputted from the image pickup device 14. The image signal output side of the image pickup device 14 is connected to the signal capturing circuit 16, and the output side of the signal capturing circuit 16 is connected to the changeover switch 18. The four switching outputs of the change-over switch 18 are connected to the recording signal processing circuits 20A ...
20D, and the output sides of these recording signal processing circuits 20A to 20D are connected to the above-described heads HA to HD via switches 22A to 22D via rotary transformers (not shown) or the like. There is.

Next, the drum DA provided with the heads HA to HD is provided with the auto-tracking drive unit 24, the drum rotation drive unit 26 and the tape running drive unit 2.
8 are provided respectively. Further, the signal capturing circuit 16, the changeover switch 18, and the switches 22A to 22D described above.
A switching circuit 30 is connected to. Furthermore,
Signal acquisition circuit 16, auto-tracking drive unit 2
4, a drive control unit 32 is connected to the drum rotation drive unit 26, the tape running drive unit 28, and the switching circuit 30.

Of the above parts, the signal acquisition circuit 16
Is for capturing an image signal from the image sensor 14. In this embodiment, an image signal for one screen (one field) is taken in every three times the normal time, that is, every 1/180 second. Recording signal processing circuits 20A to 20D
Is a circuit for performing well-known general signal processing such as time extension of an input image signal, color signal processing such as low frequency conversion, luminance signal processing such as FM modulation, and amplification of each signal.

Next, the changeover switch 18 and the switch 22A
22D are sequentially switched by the switching circuit 30, and this switching is configured to be performed in synchronization with the signal capturing in the signal capturing circuit 16. FIG. 3 shows the timing of signal supply to each of the heads HA to HD, and the image signal taken in during a period of 1/180 seconds (corresponding to 90 ° in drum rotation angle) indicated by OFF is indicated by ON. Video tape VT in a period of 1/60 seconds (equivalent to 270 ° in drum rotation angle)
The data is output to a head that scans above and the recording is performed. The switching circuit 30 includes switches 18 and 22A to 2A so that the recording operation is performed.
It is for switching between 2D.

Next, the auto-tracking drive unit 24
This is for making the track angle of the signal recorded on the video tape VT coincide with the head scanning direction at the time of reproduction, which is known as so-called AST technology. For example, a piezoelectric element such as a bimorph displaces the heads HA to HD in a direction perpendicular to the head traveling direction to change the track angle, and a moving coil displaces the heads HA to HD similarly to change the track angle. By changing the mounting inclination of the DA, the angle of the tape guide lead is shifted to change the track angle,
Such methods are known, and any method may be used.

Next, the drum rotation drive unit 26 is a head HA.
~ HD is for rotational driving, and the tape running drive unit 28 is for running and transporting the video tape VT. In either case, the head or tape V is formed by a well-known method.
It is configured to drive T. However, in the present embodiment, the head DA is rotationally driven at a speed 1.5 times faster than during playback (long-time mode), and the tape running is 3 times faster than during playback. It is supposed to be done. Further, the drive control section 32 is for performing operation control of the entire magnetic recording apparatus and servo control in the drive sections 24, 26, 28.

Next, the operation of the embodiment configured as described above will be described. In the present embodiment, by the action of the tape running drive unit 28, the video tape VT runs at the time of reproduction, that is, at a tape speed of 33.35 mm / s which is three times as high as the tape speed of 11.12 mm / s in the long time mode. This speed is equal to the so-called standard mode (SP mode) tape speed. On the other hand, the four heads HA to HD are shown in FIG.
As shown in the timing chart of FIG.
HA → HB → HC → H every ° (1/180 seconds)
It turns on in the order of D → HA → ... and each head has a rotation angle of 2
Video tape V over 70 ° (corresponding to 1/60 second)
Record the signal at T.

In this case, in the camera unit 10, 1/18
An image signal for one screen is taken from the image pickup device 14 by the signal taking-in circuit 16 every 0 seconds, and the changeover switch 18
Recording signal processing circuits 20A to 20D that are switched and connected by
Sent to any of. The change-over switch 18 is operated by the switching circuit 30 so that the recording signal processing circuits 20A, 20B, 20C, 20D, 20A, ...
It can be switched in the order of. For example, if an image signal for one screen is input to the recording signal processing circuit 20A,
The image signal for the next one screen is input to 20B.

In the recording signal processing circuits 20A to 20D, the input image signal for one screen is time-expanded three times from 1/180 seconds to 1/60 seconds, and band conversion and amplification are performed. The switch 22 is subjected to the normal signal processing of
A to 22D, respectively. Here, switch 22A
22D are opened and closed in synchronization with the rotation angle of the drum DA by the action of the switching circuit 30. That is, as shown in FIG. 3, the drum DA is sequentially turned on for each rotation angle of 90 ° (corresponding to 1/180 second), and a video signal is supplied to each head.

For example, if the switch 22A is first turned on (time T1 in FIG. 7A), the head HA is driven for 1/60 seconds (T1 to T4 in FIG. 7A), and the recording signal processing circuit 20A is operated. The output video signal expanded for 1/60 seconds is recorded on the video tape VT. continue,
When the switch 22B is turned on 1/180 seconds after the switch 22A is turned on (T2 in the same figure), 1/60
The head HB is driven for a second (T2 to T5 in the same figure),
The video signal output from the recording signal processing circuit 20B is recorded on the video tape VT. Similarly, the switches 22C, 22D, 22A, ... Are sequentially turned on every 1/180 second.
N, and the heads HC, HD, HA, ...
After being driven for 60 seconds, signal recording is performed as described above.

By the way, in this embodiment, the heads HA to H are
The rotation speed of D is 1.5 times higher than that during reproduction by the drum rotation drive unit 26 (see arrow F5 in FIG. 5A). That is, the number of heads is twice as high as that of the conventional example shown in FIG. 1B, but the speed is 1/2 times that of the conventional example shown in FIG. It is 3 times, but the speed is 3/2 times. Therefore, the number of recording tracks during the same time is the same. As described above, according to the present embodiment, signal recording is performed at a speed lower than that of the conventional example shown in FIG. 1B and using a smaller number of heads than that of the conventional example shown in FIG.

Further, in this embodiment, the auto-tracking drive unit 24 adjusts the angle of the recording track to match the head traveling angle during reproduction. First, assuming that the track angle is not adjusted by the auto-tracking drive unit 24, the track angle is the one when signal recording is performed in the standard mode. In FIG. 4 (B),
The state of the track pattern in this case is shown. In the figure, a, b, c and d are heads HA, HB. HC,
These are tracks recorded in HD. In this recording state, the track angle θ _S is the standard mode angle of 5 ° 5
8'10 ".

On the other hand, the reproduction is performed in a long time mode in which the tape running speed is ⅓, as will be described later. However, the track angle θ _E in this long time mode is 5 ° 56′48 ″ as shown in FIG. 7A, and the two do not match. Therefore, the track angle θ _S at the time of recording is set to that in the long time mode. It becomes necessary to match the track angle θ _{E. In the} present embodiment, the track angle is adjusted by the auto-tracking drive unit 24.

The tape running speed is in the standard mode (three times that in the long time mode) as described above, but the head HA
~ HD is switched and driven at a speed three times faster than the standard mode. Therefore, the track pitch is ⅓ of the standard mode track pitch of 58 μm, that is, 19.3 μm. This corresponds to the track pitch in the long time mode.
As described above, according to the present embodiment, the video signal is recorded on the video tape VT running at three times the speed of the long-time mode at the same track pitch and the same track angle as in the long-time mode.

Next, since the video tape VT on which the signal is recorded in this manner matches the track pattern of the long time mode, reproduction can be performed by the long time mode of all VHS type VTRs. it can. In long-time mode, tape running speed is 1/3 compared to standard mode
Therefore, as a result, the data is reproduced at a speed of 1/3 of the recording speed. For example, what was recorded in 10 minutes will be reproduced in 30 minutes. As a result, a fast moving screen can be observed as a slow screen, and various motion analyzes can be easily performed.

As described above, the present embodiment has the following effects. By using the structure of the small-diameter drum used in the consumer video movie as it is, a high-speed image pickup device with a triple speed can be easily realized. Since a small diameter drum is used, it can be made smaller and lighter than a standard drum. Compared with the prior art, the number of rotations of the drum is 1.5 times and the number of heads is 2/3 times, and it is not necessary to improve the accuracy of processing / assembly. Therefore, the conventional production equipment can be used as it is, which is advantageous in terms of cost. It is possible to perform reproduction by using a VTR that is generally popular as it is.

The present invention is not limited to the above embodiments, and includes the following, for example. Although the present invention is applied to the VHS type magnetic recording apparatus in the above-described embodiment, the present invention is also applicable to other types of magnetic recording apparatuses, such as 8 mm video. Further, the video signal system is not limited to NTSC, but can be similarly applied to systems such as PAL and SECAM.

Further, in the above-mentioned embodiment, auto-tracking is performed so that the track angle coincides with the head traveling angle at the time of reproduction. However, in the dedicated machine for triple speed recording, the signal recording is performed at the standard mode tape speed. If the lead angle of the drum is set in advance so that the track angle of the long time mode is obtained, it is not necessary to perform the auto tracking. That is, the lead angle of the VHS type drum is 5 ° 56'7.4 ".
On the other hand, the drum lead angle may be set to 5 ° 54′46.5 ″. By doing so, a track pattern with a good angle can be realized without using the AST technique described above.

The same applies to the audio signal, and it may be recorded and reproduced at a triple speed together with the video signal.
In this case, the sound becomes slow just as the screen moves slowly. In the above-mentioned embodiment, the video movie is used as the source, but any image source can be used as long as the image signal can be taken in at a speed three times as high as that at the time of reproduction (1/3 time). In addition, the circuit configuration can be modified in various ways so as to achieve the same effect, and these configurations are also included in the present invention.

[0030]

As described above, according to the magnetic recording apparatus of the present invention, a drum of 270 ° winding is used, and a desired high speed recording is performed in consideration of both the number of heads and the number of rotations of the drum. Since it is decided to do so, there is an effect that high-speed recording can be realized while achieving downsizing, weight reduction, and price reduction.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a drum portion in an embodiment of a magnetic recording apparatus according to the present invention.

FIG. 2 is a circuit block diagram showing a circuit configuration in the embodiment.

FIG. 3 is a time chart showing how the head is driven in the embodiment.

FIG. 4 is an explanatory diagram showing a relationship between track angles in the embodiment.

FIG. 5 is an explanatory diagram showing the relationship between the tape speed, the number of heads, and the number of drum rotations between the embodiment and the conventional example.

[Explanation of symbols]

10 ... Camera section, 12 ... Imaging optical system, 14 ... Imaging element,
16 ... Signal capturing circuit (image signal capturing means), 1
8 ... Changeover switch, 20A, 20B, 20C, 20D ...
Recording signal processing circuit (recording signal processing means), 22A, 22
B, 22C, 22D ... Switch, 24 ... Auto-tracking drive section, 26 ... Drum rotation drive section (drum rotation means), 28 ... Tape running drive section (tape running means), 3
0 ... Switching circuit, 32 ... Drive control unit, DA ... Drum, HA, HB, HC, HD ... Head, TG ... Tape guide, VT ... Video tape, θ _E , θ _S ... Track angle.

Claims (1)

[Claims] 1. A magnetic recording device for recording a signal on a video tape at a speed three times faster than that at the time of reproduction, and an image signal fetching means for fetching an image signal from a source at a speed three times as fast as that at the time of playback, and three at the time of playback A tape running means for running a video tape at a double speed, a drum having a diameter corresponding to 270 ° winding of the video tape and having four heads arranged symmetrically at equal intervals, and a drum for playing this drum. A drum rotating means for rotating at a rotational speed of 5 times, and a recording signal processing means for performing desired processing on the image signal captured by the image signal capturing means and outputting the image signal to the head in order corresponding to the rotation angle. A magnetic recording device characterized by being provided.