JPS6394402A - Reproducing system for magnetic recording - Google Patents

Abstract

PURPOSE:To perform the satisfactory reproduction even when other information generates a track dislocation by reproducing other information while a tracking servo is loaded based on the reproducing output and reading the information which is stored in a storing means beforehand. CONSTITUTION:To the main track of a floppy disk I, a picture signal is recorded and to a guard band, a time compressed sound signal is recorded. A system controller 44 selects a contact 41a, rotates and drives the disk I, reproduces an FM sound signal by an audio head 7 of a magnetic head II and loads a tracking servo to a head 7 by the output. A reproducing sound signal at this time is stores into a memory 38b. Next, a contact 41b is selected, a tracking servo is loaded to a video head 5 and a picture signal is outputted to a video output terminal 35. Simultaneously, the sound signal stored in the memory 38b is read and outputted to an audio output terminal 40. Thus, even when a track dislocation is generated, the output can be executed in the optimum condition.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for reproducing magnetic recording, and in particular, the present invention relates to a method for reproducing magnetic recording, and in particular, an audio signal is transmitted to a guard band of a magnetic disk on which main information such as an image signal is recorded via a guard band. This tracking method is devised when reproducing information from a magnetic disk on which other information such as the following information is recorded.

<Prior Art> When recording information on a magnetic disk, such as a floppy disk, the floppy disk is rotated and information is recorded on annular tracks.

Also, generally, a guard band is provided between two adjacent tracks. The guard band is provided to absorb tracking deviations due to expansion and contraction of the floppy disk due to changes in temperature and humidity and positioning errors due to accuracy of the head tracking mechanism.

There are various types of magnetic recording devices that use floppy disks as recording media, but still image recording devices such as so-called electronic still cameras convert the image of a subject obtained through a lens into an electrical signal and record it on a floppy disk. It has been known. A floppy disk for this purpose is called a video floppy. As a playback device, a device is known that rotates a floppy disk and plays back an image signal recorded on a track as a still image on a display device such as a television receiver.

In these devices, one field of the image signal is recorded in one round of the track. This method of reproducing one still image using image signals for one field is called field recording and reproducing. In addition, a method of recording one field of the same frame on two tracks each, constructing one frame using the image signals from the two tracks, and playing back one still image is called frame recording and playback. .

According to the standards for electronic still cameras, the floppy disk is rotated at 3600 rpm, and tracks 60 μm wide are formed concentrically at a pitch of 100 μm. The width of the guard band is nominally 40 μm, and the allowable width of the track radius due to expansion and contraction of the floppy disk is ±14 μm.・On the other hand, when displaying still images on a television receiver, etc.
In response to the strong demand for simultaneously outputting audio, music, etc. that correspond to image signals, a method for recording this information on a guard band was proposed in Japanese Patent Laid-Open Nos. 61-129701 and 6
No. 1-153803, respectively. In other words, the conventional track is used as the main track to record image signals, and the guard band between the main tracks is used to temporally compress and record information signals such as audio. Record the signal as desired. The information signal recorded in a temporally compressed manner is expanded into light during reproduction. The magnetic head for recording image signals on the main track and the magnetic head for recording information signals on the guard band may be provided independently, or they may be integrated as proposed in JP-A-61-129701. Sometimes it is done.

Generally, an information signal such as audio is recorded azimuthally on a guard band adjacent to the main track after a corresponding image signal is recorded on the main track.

Regarding the recording current, assuming that the characteristics of the main track magnetic head and the guard band magnetic head are the same, the same value of recording current is caused to flow through both heads. This is because the image signal and the time-compressed information signal have substantially the same frequency band, so the optimal current value for each recording is the same. Note that when the characteristics of the magnetic heads, such as the number of coil windings, are different, the optimum recording current values for the main track and guard band magnetic heads generally differ, but their respective magnetomotive forces are approximately the same.

The above is the same when recording image signals on the main track and the guard band, respectively, and also when arbitrary signals in substantially the same frequency band are recorded on the main track and the guard band, respectively.

<Problems to be Solved by the Invention> By the way, as mentioned above, tracking deviation is unavoidable. Therefore, when other information is recorded on the guard band, the information is recorded so as to overlap part 3 of the main track 1 of the floppy disk I, as shown in FIG. At this time, if main information has already been recorded on the main track 1, the information in the overlap portion 3 of the main information on the main track 1 will deteriorate. Third
In the figure, 2 is a guard band, and 4 is a recording area for other information recorded by the guard band recording magnetic head.

By the way, when reproducing information recorded in an electronic still camera system, the tracking servo of the magnetic head is of course applied, but the tracking servo in this case is designed to maximize the level of the reproduction output based on the reproduction output of the main information. It is used for tracking. Therefore, this tracking method is used when reproducing both image and audio information on the floppy disk shown in FIG. If this is used for reproduction with a magnetic head, the audio information will be off-track. Since the other information recorded in the guard band 2 is azimuth recorded, the tracking deviation causes a fatal attenuation of the reproduction output.

In view of the above-mentioned prior art, the present invention makes it possible to obtain good reproduction output with tracking servo control when reproducing both information on a magnetic disk in which other information is later recorded in the guard band between the main tracks. The purpose of the present invention is to provide a method for reproducing magnetic recording that is possible.

Means for Solving the Problems The present invention achieves the above object by recording main information between adjacent main tracks of a magnetic disk via a guard band using a head with an azimuth angle of substantially zero. Then, when reproducing information from a magnetic disk on which other information is azimuthally recorded on the guard band, first, the other information is reproduced while applying a tracking servo based on the reproduction output of the other information, and this is stored in the storage means. After that, the main information is reproduced and outputted while applying tracking servo based on the reproduced output of the main information, and other information stored in the storage means is also outputted.

Note that the information recorded on the main track is mainly an image signal, but basically any signal. In addition, the information recorded in the guard band is basically an arbitrary signal, but
When an image signal is recorded on the main track, it is mainly a time-compressed audio domain signal.

According to the present invention having the above configuration, the main information is reproduced while applying the tracking servo based on the reproduction output, while other information is reproduced while applying the tracking servo based on the reproduction output, and is stored in advance in the storage means. The main information is reproduced by reading out the information stored in the main information.

Example of implementation Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1(a) is a block diagram showing an apparatus for realizing an embodiment of the present invention, and FIG. 1(b) is a front view showing the sliding surface of the magnetic head.

The apparatus shown in FIG. 1(a) uses a three-channel magnetic head to send an image signal from a floppy disk I, on which an audio signal has been dubbed, to a guard band 2 between main tracks 1 and 1 on which the image signal is recorded, along with the audio signal. This is a device that simultaneously reproduces images using

As shown in FIG. 1(b), the magnetic head (2) integrally includes first and second video heads 5, 6 for the main track and one audio head 7 for the guard band. be.

Specifically, each head 5, 6.7 is a thin film magnetic head in which a magnetic layer, a conductor layer, and an insulating layer are formed of thin films, and sendust alloy is sputtered on a magnetic ferrite substrate 8 to form an R4 film head. 5 and 6 lower magnetic layers 9.13 are formed. An insulating layer 10.14 is formed on the lower magnetic layer 9.13, and a coil conductor (
(not shown) is formed. Sendust alloy is sputtered onto these laminates to form the upper magnetic layer 11.1.
5 is formed into a film, and a protective lI layer 12 is formed thereon. On top of these video heads 5 and 6, a substrate 16, a lower magnetic layer 17, an insulating layer 18, and a coil conductor (
A thin film magnetic head 7 consisting of an upper magnetic layer 19 and a protective layer 20 (not shown) is bonded with a low melting point glass 19.

20 is a non-magnetic protective plate, which is made of low melting point glass 21 and placed on the protective layer 19.

The video heads 5 and 6 for the main track each have a magnetic gap portion Sm having an azimuth angle of zero and forming a track with a width of 60 μm.

It has 6a. Also, the two video heads 5°6 are 40μ
The magnetic gap portion 5 is arranged so as to form a guard band of m.
a, 6 m and 40 μm al in the track width direction. On the other hand, audio head 7 for guard band
has a magnetic gap portion 7a forming a track with an azimuth angle of 45 degrees and a width of 40 μm.

This audio head 7 has a track formed by the main track 1 formed by the two video heads 5 and 6.
, 1 are arranged exactly adjacent to each other.

The apparatus shown in FIG. 1(a) uses the magnetic head (2) described above. In the figure, ``■'' is a floppy disk that is rotationally driven by a motor 31, on which a main track 1 records an image signal, and a guard band 2 records a time-base compressed audio signal. ■ is the first. A magnetic head that integrally combines the second video heads 5, 6 and the audio head 7, 32 is the first or second video head 5,
6, a switch for selecting one of the output signals; 33, a video amplifier circuit; 34, a video playback circuit; and 35, a video output terminal.

Further, 36 is an audio amplification circuit, 37 is a demodulation/de-emphasis circuit, 38 is a time axis expansion value @38 that returns the reproduced time axis compressed audio signal to the original time, and A/D converter 38 a) Memory 38b , and a D/A converter 38c, the audio signal stored in the memory 38b is read out at a cycle rate of the reciprocal of the reading clock at the time of compression. 39 is an amplifier circuit, and 40 is an audio output terminal.

41 is a switch for selecting either an image signal or an audio signal, 42 is an envelope detection circuit, and 43a is an A/D
44 is a system controller, 45 is a head transfer 1!111 control circuit, 46 is a head transfer mechanism, and 47 is a helad carriage.

In the method of this embodiment using such a device, first, the system controller 44 controls the switch 41 to select the contact 41a on the audio side. In this state, the motor 31
The 7q tsupi disk I is rotated by the magnetic head■
The audio head 7 reproduces the FM audio signal.

This FM audio signal is supplied to the envelope detection circuit 42 via the audio amplification circuit 36, and after the envelope detection circuit 42 detects the level of the FM audio signal,
The information is supplied to the system controller 44 via the A/D converter 43. As a result, the system controller 44 moves the head carriage 47 via the head transfer control circuit 45 and head transfer mechanism 46 so that the level of the FM audio signal is maximized. That is, the magnetic head (2) is moved by the FM audio signal which is the reproduction signal at this time, and tracking servo is applied to the audio head 7.

On the other hand, the FM signal amplified by the audio amplification circuit 36 is stored in the memo 1J38b of the time axis expansion device 38 via the demodulation/de-emphasis circuit 37.

After storing the audio signal in the memory 38b in this way, the switch 329! The system controller 44 controls the switch 41 and selects the contact 41b by operating the contact 32a to select the playback signal for the first video head 5.
Let them choose. As a result, the system controller 44
Move the head carriage 47 so that the level of the FM image signal is maximized. As a result, the magnetic head (2) is now moved by the FM reproduction signal, and tracking servo is applied to the first video head 5.

Therefore, an image signal tracked based on the image signal of the main track 1 is obtained at the video output terminal 35. At the same time, the audio signal stored in the memo 'J38b is read out by a four-stroke pulse from the system controller 44, and an audio signal corresponding to the image signal is output to the audio output terminal 40.

After that, if the switch 32 is operated to select the contact point 32b, the video output terminal 35 receives an image signal from the second video head 6 which is subjected to tracking servo by the playback signal based on the second video head 6. Let it go.

Thus, both the image signal output from the video output terminal 35 and the audio signal output from the audio output terminal imitate the regular track.

FIG. 2(a) conceptually shows a floppy disk I in which an audio signal is recorded with a depth of 10 μm in the first main track reproduced by the first video head 5, and FIG. (di is the emp a-p detection circuit 4 when the tracking servo according to this embodiment is applied at this time)
The output levels of No. 2 are shown in correspondence with the track positions. More specifically, FIG. 2(b) corresponds to the first video head 5, FIG. 2(0) corresponds to the audio head 7, and FIG. 2(d) corresponds to the second video head 6.

Referring to FIG. 2(a) and FIG. 2(b), it can be seen that both the image signal and the audio signal are tracked to the maximum level position. factorζζ, second video head 6
When an audio signal is reproduced by tracking, the center of the audio head 7 should be tracked to a position indicated by L in the figure, that is, a position shifted by 10 μm from the position where the maximum level audio signal is obtained.〈Effect of the invention〉 As specifically explained above in conjunction with the embodiments, according to the present invention, even if other information recorded on the guard band causes track deviation, it is possible to reproduce each piece of information with optimal tracking. Therefore, good playback output can be obtained.

[Brief explanation of the drawing]

FIG. 1(1) is a block diagram showing an apparatus for realizing an embodiment of the present invention, FIG. 1(b) is a front view showing the sliding surface of the magnetic head, and FIG. 2(a) is a floppy disk recording device. Explanatory diagrams conceptually showing the state, Fig. 2 (bl is a graph showing the output level of the first video head, Fig. 2 (C1 is a graph showing the output level of the audio head, Fig. 2 (d) is a graph showing the output level of the first video head, Figure 2 is a graph showing the output level of the video head, and Figure 3 is an explanatory diagram conceptually showing the recording state of a floppy disk. In the drawings, ■ indicates a floppy disk, ■ indicates a magnetic head, 1 indicates a main track, and 2 indicates a 5 is a first video head, 6 is a second video head, and 7 is an audio head. Patent applicant: Fuji Photo Film Co., Ltd. Agent

Claims (1)

[Claims] When reproducing information from a magnetic disk in which main information is recorded via a guard band between adjacent main tracks of a magnetic disk by a head with an azimuth angle of substantially zero, and other information is then azimuthally recorded in the guard band. First, the other information is reproduced while applying the tracking servo based on the reproduction output of the other information and stored in the storage means, and then the main information is reproduced while applying the tracking servo based on the reproduction output of the main information. 1. A reproducing method for magnetic recording, characterized in that, at the same time as outputting, other information stored in the storage means is also outputted.