JPS63197003A - Recording method for information signal - Google Patents

Abstract

PURPOSE:To execute recording extending over many hours by recording a second information signal in a guard band by a second head having a prescribed azimuth angle at which no crosstalk occurs against a first head. CONSTITUTION:Two image signal use heads 20, 30 separated by a guard band portion, and the first head 40 for a sound signal which is positioned on the guard band at an azimuth of an angle theta to said head, and also, adjacently in the track width Tw direction are provided. Also, the second head 50 for a sound signal which is positioned on the guard band at an azimuth of an angle theta' to the two image signal use heads 20, 30, and also, at an azimuth to the first head 40, as well, and adjacently to the image signal use heads 20, 30 in the track width Tw direction is provided. Only the first sound signal can be recorded by the first head 40, and also, only the second sound signal can be recorded by the second head 50, therefore, a voice of many hours and an image of many frames can be recorded and reproduced, and the recording density is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for recording information signals such as audio, music, or other image signals when recording image signals on a rotating magnetic disk.

<Prior art and problems> There are still image playback devices that rotate a magnetic disk and reproduce image signals recorded thereon as still images on a display device such as a television receiver, and magnetic disks that convert a subject image into an electrical signal. In electronic still camera devices that record still images on a magnetic disk and reproduce the still images on a display device such as a television receiver, image signals are not only recorded on multiple tracks of a magnetic disk, but also on the gaps separating each track. A method has been proposed in which an information signal such as voice or music is recorded in a so-called guard band, and the image signal and this information signal are recorded so as to be azimuthal to each other.

To record image signals on such tracks and record information signals on guard bands, an integrated three-channel composite magnetic head 3 is used, as shown in FIG. 8, and a video signal head 20. In the two channels at both ends, image signals for the first and second fields in the case of frame recording or for each field in the case of field recording are recorded, and in the center channel by the information signal head 40, the image signals are recorded on the guard band. Information signals such as audio are recorded.

Further, an image signal head 20 constituting two channels,
30 are structures arranged parallel to each other, and the information signal head 40 is similar to the image signal heads 20 and 30.
They are arranged at an azimuth angle θ with respect to the image track, so that even if there is an overlapped recording portion of information on the image track, only one of the information signal or the image signal is extracted due to azimuth loss.

FIG. 9 shows a circuit block for recording an image signal and an information signal (in this case, an audio signal). In FIG. 9, the still image color signal obtained from the imaging system 0 is sent to the FM modulator IA.

After being modulated by IB and added, it passes through gate 2 and then 3.
Image signal head 20 in the composite magnetic head 3 of the truck
．． 30 is recorded on the magnetic disk 6. On the other hand, the audio signal obtained from the microphone M is amplified by the amplifier 8, and then compressed to 1/60 second by the time axis compression circuit 9.
This compressed audio signal passes through the FM modulator 10 and is recorded on the aforementioned audio signal track of the magnetic disk 6 by the audio signal head 40 in the composite magnetic head 3. When reproducing an audio signal, the audio signal recorded on the magnetic disk 6 is also detected by the information signal head 40, amplified by the amplifier 11, and then sent to the FM demodulator 1.
2, and is restored to the original audio signal by the time axis expansion circuit 13. This restored audio signal is outputted as an audio signal through an amplifier 14. The image signal recorded on the magnetic disk 6 is similarly detected by the image signal heads 20 and 30 and displayed as a still image on a display device such as a television receiver by a well-known reproduction system (not shown).

Information signals such as audio signals recorded by compressing the time axis in this way are recorded on the guard band in an azimuth with respect to the image signal by the head arrangement shown in Figure 8, and the density is correspondingly higher. However, due to the actual demand that recording of this information signal that effectively utilizes guard bands often requires recording of audio information for a longer time than images, for example, 1. In order to satisfy cases such as cases in which explanations on a single screen are provided by voice over a long period of time, even higher density recording of information signals is desired.

SUMMARY OF THE INVENTION In response to the above-mentioned demands, the present invention aims to provide an information signal recording method that enables recording of information signals on a guard band for a longer time than the current method.

Means for Solving the Problems> The configuration of the present invention for achieving the above-mentioned object includes the above-mentioned method for recording information signals in guard bands formed between adjacent tracks on which image signals are recorded. A first information signal is recorded on the guard band by a first head having an azimuth angle with respect to the image signal head forming a track, and the first information signal having an azimuth angle with respect to the image signal head forming a track A second information signal is recorded on the guard band by a second head having a predetermined azimuth angle that does not cause crosstalk with respect to the head.

<Function> By recording the first information signal and the second information signal on the guard band at a predetermined azimuth angle that does not cause crosstalk, both the first information signal and the second information signal are suitable for the guard band. At the same time, during reproduction, only one information signal can be reproduced due to azimuth loss.

Here, we will describe the principle by which both the first information signal and the second information signal can be distinguished and recorded on the magnetic recording medium.

FIGS. 7(a) and 7(b) are explanatory diagrams schematically showing the orientation state of magnetic particles together with a magnetic head.

The magnetic heads 40.50 shown in both figures are magnetic heads 40.50.
50 and magnetic recording medium 6 (Fig. 7 is explained using tape)
It has an azimuth of approximately 45 degrees in the clockwise and counterclockwise directions with respect to a line perpendicular to the direction of relative movement A. The magnetic recording medium 6 is formed by coating acicular magnetic particles (hereinafter referred to as magnetic particles), and the magnetic surface thereof is preferably a collection of magnetic particles with completely random orientation. Among the magnetic particles, as shown in FIG. 7(a), the magnetization direction B due to the gap between the longitudinal direction and the magnetic head 40
4a is the one in which these are parallel, 4b is the one that intersects at 45 degrees, and 40 is the one that is orthogonal to each other.

In this case, as shown in FIG. 7(a), when information is written on the magnetic recording medium 6 by the magnetic head 40, there is a phenomenon in which the information by the magnetic head 40 is mainly recorded on the magnetic particles 4a.

On the other hand, as shown in FIG. 7(b), the magnetic recording medium 6
When information is written using the magnetic head 50, the magnetic head 50
There is a phenomenon in which information is mainly recorded on the magnetic particles 4C.

Therefore, when the magnetic head 50 records second information over the first track on which the first information is recorded by the magnetic head 40 to form a second track, the magnetic recording medium 6 is The magnetic particles 4a recording the first information and the magnetic particles 4C mainly recording the second information coexist without much interference with each other. That is, it is possible to record twice on the same track.

On the other hand, when the magnetic head 40 performs reproducing scanning on the same track formed as described above, the first information recorded on the magnetic particles 4a parallel to the magnetization direction B is mainly reproduced, and the first information recorded on the magnetic particles 4a parallel to the magnetization direction B is
The second information recorded on the magnetic grains 4C orthogonal to the second information is hardly reproduced because it involves a large azimuth loss. Also,
When the magnetic head 50 similarly performs reproduction scanning, the second information recorded on the magnetic particles 4c parallel to the magnetization direction C is mainly reproduced, and the first information recorded on the magnetic particles 4a perpendicular to the magnetization direction C is reproduced with a large azimuth. It is rarely played because it involves losses. That is, the first and second information can be reproduced separately without causing crosstalk.

At this time, the orientation directions of the magnetic particles in the actual magnetic recording medium 6 are, of course, not three types as mentioned above, but are randomly distributed in all orientation directions, so some crosstalk occurs, but it is sufficient. It was confirmed that a reproduced signal with a S/N ratio suitable for practical use could be obtained. The present invention was completed based on the above phenomenon.

Embodiments Here, an embodiment method of the present invention will be described regarding a magnetic disk with reference to the structures shown in FIGS. 1 to 6. First, the structure of a thin film head among composite magnetic heads is shown in FIG.

The structure of the head will be explained based on FIG. 1. This composite thin film magnetic head 60 has two image signal heads 20 and 30 separated by a guard band, and an azimuth angle θ with these two image signal heads 20 and 30. A first audio signal head 40 located on the guard band adjacent to the image signal head 20°30 in the track width direction of .30, and an azimuth angle θ' with the two image signal heads 20 and 30. In addition, the second head 50 for audio signals has no azimuth with the first head 40, and is located adjacent to the image signal heads 20, 30 in one track width direction like the first head 40 and on the guard band. are doing. Moreover, the first head 40 and the second head 50 are arranged so that the audio track width formed by the first audio signal head 40 and the second head 50 is shorter than the guard band width. That is, the track width T of the first head 40
When u′ and the track width T1, 1′ of the second head 50 are formed to have the same length, T′(1)θ for the first head 40
Guard band width, 2nd head 50mm
The track width of each of the first head 40 and the second head 50 is determined, and the azimuth is applied to the image signal heads 20 and 30 so that the relationship of oθ′ and guard band width is established. Therefore, the audio track width formed by the first head 40 and the second head 50 is formed with a margin in the width direction within the guard band, and is based on expansion and contraction based on changes in temperature and humidity of the magnetic disk and tracking accuracy. The influence of tracking deviation due to positioning error can be alleviated, and the overlap of the audio track with the image track is also prevented from becoming too large unless extreme tracking deviation occurs.

two heads 20.30 for image signals and a first for audio signals;
．． A total of four magnetic heads including the second head 40 and 50 are integrated thin film magnetic heads formed of thin films, and include upper magnetic layers 21, 31, 41, 51 and lower magnetic layers 22, 32, 42, respectively. held by 52,
Gap portion 23a is a nonmagnetic layer.

By bringing the magnetic disks 33a, 43a, and 53a into sliding contact with the magnetic disk, images or audio signals are recorded.

This composite thin-film magnetic head 60 is a three-track composite thin-film magnetic head that can record image signals in frames.
As shown in the figure, the magnetic head 6 is attached to the magnetic disk 70.
Image signals are recorded by the two image signal heads 20 and 30 of 0 on two image tracks 71 and 72 of one field each, and a guard band portion between these two image tracks is used for audio signals. The first head 40 and the second head
An audio signal is recorded by the head 50. therefore,
According to this composite thin film magnetic head 60, the audio track 73 is formed and audio signals can be recorded without reducing the number of image tracks. Moreover, since the first head 40 and the second head 50 are on the same track and have an azimuth of θ+θ', the above-mentioned double recording of the audio signal is possible, and the first head 40 records the first This means that only the second audio signal can be recorded, and only the second audio signal can be recorded by the second head 50.

Here, the manufacturing process of the composite thin film magnetic head 60 shown in FIG. 1 will be briefly explained. First, the image signal head 20.30
For example, the lower magnetic layers 22, 32 (2
2 and 32 are the same layer) are formed by sputtering, SiO, ii is formed on top of that, and non-magnetic layers 23a and 33a are formed by etching, and an upper magnetic layer 21 and 31 is formed on top of that by sputtering. A protective layer 25 is then formed by sputtering SiO2. Next, the lower and upper portions of the substrate 24 and the protective layer 25 are cut, polished, and planarized. In this case, the length of the nonmagnetic layers 23a, 33a becomes the track width -.

On the other hand, another thin film magnetic head formed similarly to the image signal heads 20 and 30 is cut obliquely as shown in FIGS. 3A and 3B, and this cut surface is used as the image signal head 20.
The protective layer 25 of 30 is bonded to the substrate 24. in this case,
The magnetic head 40 on the right side of cut plane A is bonded onto the protective layer 25 of the image signal head, and the magnetic head 5 on the left side of cut plane B is bonded to the protective layer 25 of the image signal head.
0 is bonded to the bottom surface of the substrate 24 of the image signal head. The bonding is performed by positioning the magnetic heads 40, 50 so that the audio track width defined by the track width T' is located on the guard band width. In addition, the first head 40 and the second head
Since the cut plane AB of the head 50 is oblique in a different direction, when it is joined to the image signal head, there is an azimuth difference not only between the image signal head 20 and 30 but also between the first head 40 and the second head 50. will have the following.

FIG. 4 shows a vertical example of the composite thin film magnetic head 60, in which the first head 4o for audio signals and the second head 50 for audio signals are arranged together on the same side with respect to the head 20.30 for image signals. It is.

When recording an audio signal using the composite thin film magnetic head 60 shown in FIGS. 1 and 4, the time-axis compressed audio signal is
While being recorded on the guard band by the head 40,
Still another time-base compressed audio signal is recorded on the guard band by the second head 5°. And these first
The separate audio signals from the head 40 and the second head 5o are 2
Since a channel is formed and the audio signal is recorded in duplicate, the recording capacity of the audio signal can be doubled.

The examples in FIGS. 1 and 4 are based on the 2-channel image signal head 20.30, but the 1-channel image signal head 20 or 3° and the 2-channel audio signal magnetic head 40.50. Dual recording of audio signals is also possible using a composite magnetic head with a total of three channels.

In the above embodiment, an example was described in which an audio signal is recorded on a guard band, but this is not limited to a side audio signal, and of course, information signals such as image signals may also be used.

In addition, the azimuth angles θ and θ' formed by the first head 40 and the second head 50 on the guard band are 3 in FIG. 1 and 4.
Although the angle is described as approximately 5", if you consider that double recording will be performed on the same track and only one of the double recorded signals will be reproduced due to azimuth loss, θ and θ' will be approximately 45". Since the azimuth is the largest, an azimuth angle in this vicinity is preferable. This also applies to FIGS. 5 and 6, which will be described later.

In the examples shown in Figures 1 and 4, when recording an audio signal on a guard band, double recording of the audio signal was achieved by adjusting the azimuth angle of the head. From the viewpoint of increasing capacity, the head structure is formed as shown in Fig. 5. For example, the A and B heads play a frame image, and the C head and/or the D head record an audio signal. You can also play A, D
It is also possible to record or reproduce an audio signal using the B head and/or the C head while reproducing a frame image using the head. Furthermore, if all heads A, B, C, and D are used for the audio channel, or all heads are used for the video channel,
Capable of recording and playing back long periods of audio and multiple frames of images.

Thus, the channel head significantly increases recording density.

Fig. 6 shows a modification of the channel head structure shown in Fig. 5, and shows that a 4-channel head can be obtained by joining 3 blocks of heads instead of joining 4 blocks as shown in Fig. 5. It shows.

<Effects of the Invention> As explained in the embodiments above, according to the present invention, the recording density of information signals can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the manufacturing process of a composite thin film magnetic head using a guard band, Fig. 4 is a front view showing a modification of the sliding surface of a composite thin film magnetic head using a guard band, and Fig. 5 is a 4-channel FIG. 6 is a front view showing an example of the sliding surface of the head. FIG. 6 is a front view showing a modification of the sliding surface of a 4-channel head. FIGS. FIG. 8 is an explanatory diagram showing a sliding surface of a conventional three-channel head using a guard band, and FIG. 9 is a block diagram of audio signal recording and reproduction. In the figure, 20.30 is the magnetic head for image signals, and 40.50 is the first magnetic head for audio signals. This is the second head. Kasa; 3: Figure 4 "廿-一--←] LO(,Q

Claims (1)

[Claims] In a method for recording an information signal on a guard band formed between adjacent tracks on which image signals are recorded, the guard band is recorded with a first head having an azimuth angle with respect to the image signal head forming the track. While recording the first information signal, a second head having an azimuth angle with respect to the image signal head and a predetermined azimuth angle that does not cause crosstalk with respect to the first head is used to record the first information signal on the guard band. A method for recording an information signal, comprising recording a second information signal.