JPS6394404A - Information signal recording reproducing method and its compound magnetic head - Google Patents

Abstract

PURPOSE:To attain the rewriting without eliminating to a guard band by executing alternately the reproducing and recording between first and second heads with the size of a signal level by the signal attenuation due to re-writing and the azimuth loss at the time of reproduction. CONSTITUTION:A compound thin film magnetic head 60 has heads 20 and 30 for a picture signal and heads 40 and 50 for a sound signal. To the guard band of a magnetic disk, the sound signal by the head 40 and the sound signal by the head 50 are recorded. Since the head 40 and the head 50 mutually have an azimuth angle, the sound signal recorded at other head is hard to be reproduced by said head due to the azimuth loss and the old sound signal recorded by other head is generally eliminated by the signal overwritten newly by said head, the newest sound signal recorded by either of the heads can be reproduced.

Description

[Detailed Description of the Invention] <Industrial Application Field> When recording and reproducing image signals on a rotating magnetic disk, the present invention provides information signals other than the above-mentioned image signals, such as audio, music, or other image signals. a method for recording and reproducing;
The present invention relates to a composite magnetic head used therein.

<Prior art and problems> Still image playback devices that rotate a magnetic disk and reproduce the 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.

An integrated three-channel composite magnetic head is used to record image signals on such tracks and record and reproduce information signals on guard bands. In the case of field recording, image signals for each field are recorded, and in the center channel, an information signal is recorded located on the guard band.

In addition, the image signal heads constituting the two channels are arranged parallel to each other, but the information signal head is arranged at an azimuth angle with respect to the image signal head, and is placed on the image track. Even if there is a duplicate recorded portion of information, only one of the information signal or the image signal is extracted due to azimuth loss.

FIG. 6 shows a circuit block for recording and reproducing image signals and information signals (here, audio signals). In this FIG. 6, the color signal of the still image obtained from the imaging system O is F
After being modulated and added by the M modulators IA and IB, the signals pass through the gate 2 and are recorded on the magnetic disk 6 by the image signal heads 4 and 5 in the three-track composite magnetic head 3. On the other hand, the audio signal obtained from the microphone M is amplified by the amplifier 8, and then compressed into 60 seconds by the time axis compression circuit 9, and this compressed audio signal is FM modulated by the M10.
Then, the audio signal head 7 in the composite magnetic head 3 records the audio signal on the aforementioned audio signal track of the magnetic disk 6. Also, when reproducing audio signals, the magnetic disk 6
The audio signal recorded on the FM
time axis expansion circuit 1
3, the original audio signal is restored. 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 4 and 5 and displayed as a still image on a display device such as a television receiver by a well-known reproduction system (not shown).

In this way, in a method in which information signals are recorded and played back azimuthally in a guard band, and when the information signal is an audio signal, the time axis is compressed and expanded for recording and playback, the image In addition to recording and reproducing signals, a head is required to record and reproduce information signals such as audio signals, but recording of information signals using guard bands should be done without using an erasing head or using an erasing circuit or an erasing circuit. There is a strong demand for a solution that does not require large currents to flow.

SUMMARY OF THE INVENTION In response to the above-mentioned demands, the present invention aims to provide an information signal recording and reproducing method that enables rewriting without erasing when recording an information signal on a guard band, and a composite magnetic head thereof.

Means for Solving the Problems> The present invention achieves the above object in a method for recording and reproducing information signals on guard bands formed between adjacent tracks on which image signals are recorded. A first information signal is reproduced by a first head having an azimuth angle with respect to the image signal head forming the image signal, and a second head having an azimuth angle with respect to each of the image signal head and the first head. In the reproduction mode, the information signal reproduced by the first head or the second head, whichever outputs the first and second information signal amplifiers from the first and second heads, is larger. is the playback output, and in the recording mode, the information signal is recorded by the first head or the second head, whichever is the smaller of the first and second information signal amplifier outputs of the first and second heads, Furthermore, an image signal head that forms an image signal track while forming a guard band on the magnetic disk, and an image signal head that is located on the guard band and shifted in the track width direction with respect to the image signal head and that is located on the guard band and that is located on the guard band. A first head having an azimuth angle with respect to the head and recording/reproducing a first information signal with a track width narrower than the width of the guard band, and a first head located on the same guard band as the first head. Moreover, it has an azimuth angle with respect to each of the image signal head and the first head, and furthermore, the second information signal is recorded with a track width narrower than the width of the guard band.
The present invention is characterized by a composite magnetic head that is integrally configured with a second head for reproduction.

Function> Information No. 48 The head has a first head and a second head that have an azimuth angle to each other, and reproduction and recording are performed depending on the signal level due to signal attenuation due to rewriting and azimuth loss during reproduction. and 1st. By alternately performing erasing between the second heads, there is no need to specifically perform erasing.

EMBODIMENTS> The present invention will now be described in detail with reference to FIGS. 1 to 3. FIG. 1 shows the structure of a thin film head among composite magnetic heads. The structure of the head will be explained based on FIG. 1.

This composite thin film magnetic head 60 includes two image signal heads 20 and 30 separated by a guard band, and two image signal heads 20 and 30 separated by a guard band.
For audio signals, the head 20.30 for audio signals is located adjacent to the head 20.30 for image signals and on the guard band in the track direction of the head 20.30 for audio signals, which has an azimuth angle of θ with the head 20.30 for image signals. The first head 40 and the two image signal heads 20 and 30 have an azimuth of angle θ', and the first head 40 also has no azimuth, and like the first head 40, the image signal head 20 and the two image signal heads 20 and 30 have an azimuth of an angle θ'. .30 and a second audio signal head 50 located adjacent to the guard band.

Moreover, the first head 40 and the second head 5 for audio signals
The first head 40 and the second head 50 are arranged such that the audio track width formed by 0 is shorter than the guard band width.
is located. That is, when the track width T,' of the first head 40 and the track width T,' of the second head 50 are formed to have the same length, T'C for the first head 40 is
&Dθ〈Guard band width, T1 per second head 50.
The track widths of each of the first head 40 and the second head 50 are determined, and the azimuth is set with respect to the image signal head 20.30 so that the following relationship holds: 1' x θ' - guard band width.

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 have upper magnetic layers 21, 31, 41, 51 and lower magnetic layers F122, 32, 42, 52, respectively. A gap portion 23a, which is a nonmagnetic layer, is sandwiched between.

By bringing the magnetic disks 33a, 43a, and 53m into sliding contact with the magnetic disk, recording and reproduction of image or audio signals is performed.

This composite thin film magnetic head 60 is a 3-track composite thin film magnetic head that can record and reproduce image signals in frames.
As shown in FIG. 2, the two image signal heads 20, 30 of the present magnetic head 60 create two image tracks 71, 72 of one field each on the magnetic disk 70.
An image signal is recorded between these two image tracks.
Audio signals are recorded by the first audio signal head 40 and the second audio signal head 50 in a portion that was conventionally a guard band. Therefore, according to this composite thin film magnetic head 60, the audio track 73 is formed without reducing the number of image tracks, and audio No. 41 can be recorded and reproduced. Moreover, the first head 40 and the second head 50 are on the same track.
Since they form an azimuth, the first head 40 can record and reproduce only the first audio signal, and the second head 50 can record and reproduce only the second audio signal. This is because only the corresponding audio signal can be recorded and reproduced at a high level due to the attenuation of the old signal due to rewriting and the azimuth loss during reproduction.

Here, the manufacturing process of the composite thin film magnetic head 60 shown in FIG. 1 will be briefly explained. First, m 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, an Si02 layer is formed on top of that, non-magnetic layers 23a and 33a are formed by etching, and upper magnetic layers 21 and 31 are formed on top of that. is formed by sputtering, and then an i-retaining layer 25 is formed by sputtering 5iO1. 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 23 m and 33 a corresponds to the track width.

On the other hand, another thin film magnetic head formed similarly to the image signal head 20.30 is cut obliquely as shown in FIGS. 3A and 3B, and this cut surface is used as the image signal head 20.30.
30 and is bonded to the substrate 24. in this case,
The magnetic head 40 on the right side of the cut plane A is bonded to the substrate 1pJ25 of the image signal head, and the magnetic head 50 on the left side of the cut plane B is bonded to the lower 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. Furthermore, since the first head 40 and the second head 50 have their cut planes AB obliquely in different directions, when they are joined to the image signal head, not only the image signal head 20.30 but also the first head 40 , second
There is also an azimuth between the heads 50.

Next, an image signal reproducing circuit and an audio signal recording/reproducing circuit related to the thin film magnetic head shown in FIG. 1 will be explained with reference to FIG. 4. In FIG. 4, two image signal heads 20 and 30 of the thin film magnetic head 60 each have a video amplifier circuit 2? , 37. Next, a second switch 28 is provided which alternately selects the video amplifier circuit 27 or 37, that is, alternately selects and reproduces one field corresponding to one image track. This switch 28
A common terminal of is connected to a video playback circuit 29 connected to a video output terminal, and is also connected to the system controller 100 via an envelope detection circuit 38 and an A/D converter 39 that detect a signal level for use in tracking the image signal. connected to.

Further, the two audio signal heads 40 and 50 of the thin film magnetic head 60 are connected to the audio amplification circuit 4 through recording/reproduction switching switches 46 and 56, respectively.
Connected to 7.57. Audio amplifier circuit 47.57
The output ends of the first
It is connected to the system controller 100 via an envelope detection circuit 58 and an A/D converter 59 for detecting reproduction output levels by the head 40 and the second head 50. In addition, switches 46 and 56 are for system control.
The audio recording circuit 49 is controlled by the system controller 100 and connected to the audio recording circuit 49.
0 controls the changeover switches 46 and 56 and the audio amplification circuit 47 or 57.

The system controller 100 further controls the head movement mechanism 102 via the head movement control circuit 101 to perform tracking based on the image signal described above.

Recording and reproduction of audio signals will be explained based on the configuration shown in FIG. 4. Image signal head 20 shown in FIG.
．． By switching the switch 28 shown in FIG. 4, the image signal already recorded on the image track 71 or 73 shown in FIG. The video (image signal) reaches the reproduction circuit 29 and the envelope detection circuit 38.
As soon as the output is obtained, the signal level is detected, tracking is performed, and the head is moved! ! It controls the tII mechanism 102.

In the reproduction state by the image signal head 20.30, the guard band shown in FIG.
Alternatively, an audio signal is recorded by the second head 50 and then reproduced. Regarding recording and reproduction in this case, as described above, compression and expansion of the time axis shown in FIG. 6 are performed. Recording and reproduction of audio signals by the first head 40 and the second head 50 are performed according to the flowchart shown in FIG.

In FIG. 5, when the flow starts, muting is first applied, and then, in judgment block A, it is judged whether the playback output of the audio amplification circuit 47 or 57 of the first head 40 or the second head 50 is above a certain value. be done. That is, the switches 46 and 56 shown in FIG. The determination is made by the system controller 100. If a reproduction signal of a certain value or higher is not obtained from any head, it means that no audio signal is recorded in the guard band of the magnetic disk, so the process moves to block B and it is determined whether or not a recording command is issued. Then, due to the presence of the recording command, the switch 46 shown in FIG. 4 is connected to the audio amplifier circuit 49, and the first head 40 records the first audio signal on the guard band (block C).

If a reproduction signal of a certain value or more is obtained from either the first head 4o or the second head 50 in block A, an audio track has already been formed in the guard band and audio No. 41 has been recorded. become. Therefore, in this case, the process moves to block D, where it is determined whether or not there is a recording command, and the magnitude of the reproduction signal of the first head 40 and the second head 50 is compared depending on the existence of the recording command.Block E) If the signal is large, a switch 56 shown in FIG. 4 is connected to the audio recording circuit 49, and the audio signal is recorded by the second head 50 (block F). Also, conversely, the second head 5
0 is large, the switch 46 shown in FIG. 4 is connected to the audio recording circuit 49, and the first head 4
Record the audio signal at 0 (block G). thus,
Audio recording is performed using the head 40 or 50 on the side where the reproduction signal is small. Visual perception is very sensitive to video beats, but hearing is not very sensitive to audio beats, so the old Iko issue (small playback 474
It is okay to rewrite the same azimuth on top of the same azimuth and generate a slight beat.

Returning to block D, if there is no recording command even if the first head 40 or the second head 50 obtains a reproduction signal of a certain value or more, the process moves to block H. In block H, it is determined whether or not there is a regeneration command, and if there is a regeneration command, the first head 4
If the reproduction signal of the first head 40 is large, the switch 46 shown in FIG.
The audio signal reproduced by the first head 40 is output as a reproduction output (block J). Conversely, when the reproduction signal of the second head is large, the switch 56 shown in FIG. 4 is connected to the audio amplifier circuit 47 to output the audio signal reproduced by the second head 50 (block K ).

In this way, the audio is played back by the head 4 on the side with the larger playback signal.
By using 9 or 0 or 50, the signal with the newest signal (with the highest signal level) will be reproduced.

There are two types of guard bands for magnetic disks:
An audio signal by the head 40 and an audio signal by the second head 50 will be recorded, but the first head 40 and the second head 50 have an azimuth angle with each other, and the audio signal is recorded by the other head. The audio signal is unlikely to be reproduced by the head due to azimuth loss, and the old audio signal recorded by the other head will be largely erased by the newly overwritten signal by the head, so if either head This means that the latest recorded audio signal cannot be played back.

In the above description, an example has been described in which an audio signal is recorded in a guard band and reproduced, but many other information signals including image signals can be handled as signals to be recorded and reproduced in a guard band. However, in the case of a reimage signal, operations such as pressure inspection and expansion of the time axis are not necessary.

In addition, in the explanation of FIG. 4, it was described that tracking servo is performed on the image number of one track, but there are various methods for tracking, and in the 3-channel head shown in FIG. Recording information signals by tracking image signals of channels,
When reproducing an information signal, tracking can also be performed using the signal. That is, tracking servo can be applied by the output of the envelope detection circuit 58 shown in FIG. 4 itself.

Although FIG. 1 shows an example of a composite thin film magnetic head, it is also possible to integrate a bulk type head into a composite head.

<Effects of the Invention> As explained above, according to the present invention, there is no need for erasing, and information signals can be recorded and reproduced simply by rewriting on the track.

[Brief explanation of the drawing]

1 to 5 show one embodiment of the present invention, in which FIG. 1 is a front view showing the sliding surface of a composite thin-film magnetic head, FIG. 2 is a schematic plan view of a magnetic disk, and FIG. 3 is a first embodiment of the present invention. Fig. 4 is a block diagram of the signal system related to the head, Fig. 5 is a diagram for recording and reproducing audio signals, and Fig. 6 is a diagram showing the conventional recording and reproducing process for audio signals. It is a block diagram. In the figure, 20.30 is the image signal head, 40 is the first head, 50 is the second head, T,,T,' is the gap length, 7 is the magnetic disk, 46.56 is the switch, 47.57 is the 48 is an audio reproduction circuit; 49 is an audio recording circuit; 58 is an envelope detection circuit; 59 is an A/D converter; 100 is a system controller. Figure 1 4゜ Figure 2 Figure 4 Figure 5

Claims (2)

[Claims] (1) In a method for recording and reproducing information signals on a guard band formed between adjacent tracks on which image signals are recorded, a first head having an azimuth angle with respect to the image signal head forming the track. The image signal head and the first information signal are reproduced by the first information signal.
The second information signal is reproduced by a second head having an azimuth angle with respect to each head, and in the reproduction mode, the second information signal is reproduced by the second head, which has a larger first and second information signal amplifier output from the first and second heads. The information signal reproduced by the first head or the second head is the reproduction output, and in the recording mode, the first head or the second head, whichever is the smaller of the first and second information signal amplifier outputs by the first and second heads, is used as the reproduction output. 1. An information signal recording and reproducing method characterized by recording an information signal. (2) an image signal head that forms an image signal track while forming a guard band on a magnetic disk; A first head that has an azimuth angle with respect to the signal head and records and reproduces a first information signal with a track width narrower than the width of the guard band, and a first head that is on the same guard band as the first head. , and the image signal head and the first
A composite magnetic head integrally configured with a second head that has an azimuth angle with respect to each head and further records and reproduces a second information signal with a track width narrower than the width of the guard band.