JPH0789424B2 - Rotating magnetic recording device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording device, in particular, an electronic still camera, a magnetic disk video recording device for receiving a video signal from a video signal source and recording the video signal on a magnetic disk. The present invention relates to a rotary magnetic recording medium recording device for recording a signal on a rotary magnetic recording medium such as a magnetic disk.

2. Description of the Related Art For example, when recording a signal on a magnetic disk, signal dropout may occur depending on the contact state between the magnetic recording head and the recording surface of the magnetic disk. As is well known, the dropout may be caused by a defect of the magnetic material on the recording surface of the magnetic disk or the like, and may be caused by the inclusion of foreign matter at the tip of the recording surface of the magnetic head. The former occurs on the fixed body at the same position on the recording surface, but the latter often occurs temporarily and generally has low reproducibility.

For example, a so-called video floppy used in an electronic still camera has 50 tracks recorded according to a certain standard. In general, some dropout may occur on those tracks. A slight dropout usually allows the image to be properly corrected by interpolating the missing scanlines of the image with other scanlines. However, if the degree of dropout is large, it is difficult to restore the image by interpolation of scanning lines.

Therefore, in the conventional video signal magnetic recording apparatus, normally, the dropout track is not used and recording is performed on another new track. However, this reduces the capacity that can be recorded in one video floppy. this is,
The same applies not only to the electronic still camera but also to a video signal magnetic recording device for recording a video signal from another video signal source, for example.

It is an object of the present invention to solve the above-mentioned drawbacks of the prior art and to provide a rotary magnetic recording device capable of recording a signal with a small amount of dropout.

DISCLOSURE OF THE INVENTION According to the present invention, there is provided a rotary magnetic recording medium recording apparatus for recording a recorded signal on a track of the rotary magnetic recording medium by a magnetic head that is in sliding contact with the rotary magnetic recording medium. Is supplied to the magnetic head to record a signal to be recorded on the rotary magnetic recording medium, head moving means for moving the magnetic head along the recording surface of the rotary magnetic recording medium, and recording on the rotary magnetic recording medium. Erasing means for erasing a signal via a magnetic head, dropout detecting means for detecting a dropout of a signal read by a magnetic head from a rotating magnetic recording medium, and control for controlling the recording means, head transfer means and erasing means. The control means controls the recording means in response to the recording instruction signal to record the recorded signal on the track of the rotating magnetic recording medium.
When the signal recorded on the track is read from the magnetic head to the dropout detection means and the dropout detection means detects the dropout in the read signal,
The erasing means is controlled to erase the signal recorded on the track, and the head moving means is controlled to vibrate the magnetic head, and then the magnetic head is turned back on the original track to control the recording means. Then, the recorded signal is recorded on the track.

Description of Embodiments Next, embodiments of a rotary magnetic recording medium recording apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, there is shown an embodiment in which the present invention is applied to a magnetic disk recording apparatus for recording a video signal representing a still image on a magnetic disk. Specifically, this is, for example, an electronic still camera, a magnetic disk video recording device for receiving a video signal from a video signal source and recording the video signal on a magnetic disk, or a magnetic disk used as a file storage device in a data processing system. It is advantageously applied to devices and the like.

In the present embodiment, a recorded signal, for example, a baseband video signal obtained from a video signal source such as a solid-state imaging device is input to the input terminal 10. The input terminal 10 is connected to the input 18 of the recording circuit 16 via the switch 12. Recording circuit 16
Is a circuit that frequency-modulates and amplifies the video signal and outputs the amplified signal to the output 20. The modulated video signal output 20 is a switch 22
And 14 are connected to the magnetic head 24 through a connecting line 42.

The magnetic head 24 is in sliding contact with the recording surface of the magnetic disk 28 and is supported by a head transfer mechanism 29 so as to be movable on the recording surface, as conceptually shown by a dotted line 26. The magnetic head 24 is an electromagnetic conversion element that records a video signal on the magnetic disk 28 and reads a video signal from the video signal. The head transfer mechanism 29 is controlled by the system control unit 40 to transfer the magnetic head 24 and place it on the track at a desired track position on the magnetic disk 28.

The magnetic disk 28 is removably mounted on a rotary shaft 32 driven by a spindle motor 30. The spindle motor 30 receives servo control from the motor control circuit 34 and rotates in a predetermined direction at a predetermined speed.

As the magnetic disk 28, for example, a floppy disk having a diameter of about 50 mm used in an electronic still camera is advantageously used. It has a capacity of recording 50 tracks. The magnetic disk 28 has a core 34 that engages with the tip of the rotating shaft 32. A phase detector 36 is arranged near the core 34, and a phase detection signal PG corresponding to a predetermined rotation phase angle of the magnetic disk 28 is generated thereby. It has a period that is substantially equal to the IV period of the video signal in the steady state and is provided to the motor control circuit 34 and the system control circuit 40 by the connecting line 38.

An erase circuit 68 is also connected to the switch 14 as shown. The erasing circuit 68 is a circuit for generating an erasing carrier wave for substantially erasing the video signal recorded on one track of the magnetic disk 28. Recorded on the track
The FM-modulated video signal will be overwritten with this erased carrier and will be effectively erased.

The connecting line 42 from the magnetic head 24 is also connected to the input 46 of the reproducing circuit 44 via the switch 22. Playback circuit 44
Is a circuit that amplifies and demodulates the FM modulated video signal read by the magnetic head 24 from the track of the magnetic disk 28.
The playback output 48 is output via the switch 50 to the output terminal of the device.
Connected to 54. Switch 50 is also connected to switch 12 via connection 58, as shown. Output terminal
54 includes, for example, a video monitor and a hard copy creation device,
A utilization device 56 such as a printer is connected.

The reproduction circuit 44 also envelope-detects the FM modulation signal,
The envelope waveform is output from the output 66 to the dropout detection circuit 52. The dropout detection circuit 52 is a circuit that detects whether or not the video signal has a dropout based on a predetermined reference based on the envelope signal obtained from the reproduction circuit 44 at the input 48. The detection circuit 52, for example, when the period during which the envelope is at a predetermined level or less exceeds a predetermined length, determines that a video signal dropout has occurred, and outputs a detection output 60 indicating that to the system control unit 40. Output.

The system control circuit 40 is a control circuit that controls the operation of the entire apparatus, and is advantageously configured by a processing system such as a microcomputer. An operation unit 64 is connected to the system control circuit 40. The operation unit 64 has a manual operation key, by which an operator's instruction is input to the present apparatus. When the present device is applied to, for example, an electronic switch camera, the operation unit 64 corresponds to an operation button such as a shutter release button. Further, in the case of a magnetic disk video recording apparatus that receives a video signal from a video signal source and records it on a magnetic disk, it corresponds to an operation key such as a recording instruction key. A signal for instructing recording on the magnetic disk 28 is given to the system control circuit 40 from the output 70 of the operation unit 64.

In addition to these components, the system control circuit 40 is also connected to the recording circuit 18, the head transfer mechanism 29, the motor control circuit 34, and the like. It is also connected to the drive circuit of the switches 12, 14, 22 and 50, as symbolically shown by connection line 62.
These switches are selective connection circuits that selectively take two connection states as shown in the figure, and the system control circuit 40
Directs the operation of these switches at appropriate timing according to the control sequence.

The system control circuit 40 controls the motor control circuit 34 in response to an instruction signal from the operation unit 64, and thereby the motor 30
Is rotated at a predetermined speed. Obtained from phase detector 36
According to the PG signal, the system control unit 40 controls the rotation phase of the magnetic disk 28 so that the rotation phase of the magnetic disk 28 becomes a predetermined phase angle with respect to the video signal received at the input terminal 10. Therefore, the recording circuit 16 and the switches 12 and 22 are controlled to record a still image signal of one unit, for example, one field, on one track of the magnetic disk 28 with reference to the predetermined phase angle. The video signal recorded on the track is read from the reproduction circuit 44 to the dropout detection circuit 52, and the dropout is detected. The system control unit 40 also controls the switch 50 to output the read video signal from the output terminal 54 to the utilization device 56.

The operation of the present apparatus will be described with reference to the flowchart of FIG.
When the magnetic disk 28 is mounted on the rotary shaft 32 of the motor 30,
The system control circuit 40 controls the head transfer mechanism 29 to transfer the magnetic head 24 onto an unrecorded track.

When the recording button of the operation unit 64 is operated (100), the system control circuit 40 controls the motor 30 via the motor control circuit 34, and causes the magnetic disk 28 to steadily rotate at a predetermined speed. The system control circuit 40 switches the switch 12 to the input 18 of the recording circuit 18.
, A predetermined phase difference with respect to the vertical synchronizing signal of the video signal from the input terminal 10, for example, so that the phase detector 36 outputs the phase detection signal PG in advance of a period of 7H ± 2H, The motor control circuit 34 is controlled. In this way, the rotation phase of the motor 30 is locked to the phase of the video signal of the input 10.

Therefore, the system control circuit 40 controls the switch 22,
When signal PG occurs, input to magnetic head 24 for IV period 42
To the output 20 side of the recording circuit 16. Therefore, the video signal arriving at the input terminal 10 is recorded by the recording circuit 16 only during that period.
It is FM modulated by and given to the magnetic head 24.
It is recorded on one track of 28 (101).

Therefore, the system control unit 40 connects the switch 22 to the input 46 side of the reproducing circuit 44, and the video signal is read by the magnetic head 24 from the recorded track (102). This is envelope-detected by the reproduction circuit 44, and the dropout detection circuit 52 detects whether or not the dropout of the video signal is for a period of a predetermined length or longer. The detection result is reported to the system control circuit 40. If the switch 50 is connected to the output 48 side of the reproduction circuit 44, the reproduced video can be output to the utilization device 58 such as a video monitor.
This makes it possible to observe the presence or absence of dropout on the video monitor. When the dropout is observed, enter an instruction from the operating unit 64 to erase the track and
24 vibrations may be performed.

If the dropout is not substantially detected, the system control circuit 40 controls the head moving mechanism 29 to move the magnetic head 24 onto the next new track for the recording of a new video signal (106).

When the dropout is substantially detected, the system control circuit 40 connects the switch 14 to the erase circuit 68 side to supply the erase carrier wave to the magnetic head 24 for a predetermined period. As a result, the FM-modulated video signal recorded on that track is substantially erased (104). Therefore, the system control unit 40
Controls the head transfer mechanism 29 to "vibrate" the head 24 (105). That is, in this embodiment, the magnetic head 24 is once moved in a predetermined direction and then returned to the track concerned to be on-track. In this specification, the term “vibration” is used to have this meaning.

For example, as shown in FIG. 4, in the present embodiment, the head 24 is once returned from the track in which the dropout is detected to the other track on which recording has been performed, and then the track is again set to the on-track. That is, the above-mentioned predetermined direction is, in this example, the direction in which there is a track on which recording was performed before that.

For example, if the track where the video signal is currently recorded and the dropout is detected is the nth track,
The head is once returned to the (n-1) th track on which recording was performed before that. After that, the nth track is turned on again. In this way, the video signal is recorded again 101 in the state of being on-tracked again. The distance for returning the magnetic head 24 may be one track as in this example, or may be more, for example, two or three tracks. Even one track is sufficiently effective, and such a small transfer amount is advantageous in that the time required for vibration of the head is short.

For example, in the method of recording video signals in order from the outermost track, the magnetic head 24 is once returned to the adjacent track outside the track. In this way, once the head 24 is returned in the direction opposite to the direction in which the head is moved, the foreign matter may be caught between the tip of the head 24 and the recording surface of the magnetic disk 28 to cause dropout. In this case, the foreign matter may be removed by the vibration operation of the head 24, and therefore, dropout often does not occur even when the desired track is again ontracked. It has been found that the probability that the dropout once generated will not occur due to the vibration of the head 24 is quite high.

In this embodiment, the head 24 is vibrated after the track in which the dropout has occurred is erased.
Alternatively, the track may be erased after vibrating.

As described above, when the head 24 is once returned in the opposite direction to the head moving direction and then on-tracked to the intended track again, the error due to the backlash generated in the head transferring mechanism 29 and the supporting mechanism 26 thereof. This is advantageous because it is not included in the head position. In other words, foreign matter removal and backlash cancellation can be realized by one reciprocating vibration of the head 24. Therefore, it is possible to shift to the next re-recording 101 in a short time.

As illustrated in FIG. 5, vibration may be performed so as to move the head 24 in the same direction as the head moving direction. In this case, from the nth track in which the dropout has occurred to the n + th track
The influence of the backlash can be removed by moving the head 24 to one track, then returning the head 24 to the (n-1) th track and then moving it again to the nth track.

By the way, as shown in FIG. 3, before the desired video signal is properly recorded on the magnetic disk 28, it is tested whether or not dropout occurs, and it is finally confirmed that the dropout does not occur. The system control circuit 40 may be configured so that the normal video signal is recorded after the recording. This method is advantageous because in the state where the dropout does not occur, the dropout often does not continue thereafter. This is suitable for a system, such as an electronic still camera, in which the device side is not allowed to fail to miss a photo opportunity.

In the case of an electronic still camera, the operation unit 64 is provided with a shutter release button. In the first half of the operation stroke of the button, the system control circuit 40 starts and locks the spindle motor 30 and records the test of the first steps 100 to 104. This operation may be the same as the flow shown in FIG.

If no dropout of a predetermined length or more is detected in step 103, the system control circuit 40 connects the switch 14 to the side of the erase circuit 69 to supply the erase carrier wave to the magnetic head 24 for a predetermined period of time. The FM modulated video signal recorded experimentally on the track is virtually erased (11
3).

Next, when the shutter release button of the operation unit 64 enters the latter half of its operation stroke, the system control circuit 40
By the same operation as described above, the video signal is properly recorded on the magnetic disk 28 (114). When the recording is completed, the system control circuit 40 moves the magnetic head 24 onto the next new track to prepare for recording a new video signal (115).

When a dropout of a predetermined length or more is detected in step 103, the system control circuit 40 erases the test record (104) and vibrates the head 24 (111). If a dropout is not detected next in the operation loop from this test record 101 to the head vibration 111, a normal record will be given.
114 is performed. The system control circuit 40 uses this loop 1
The number of times is counted every time it goes around 01 to 111, and when it reaches a predetermined number N (110), the head transfer mechanism 29 is controlled to transfer the head 24 onto the next new track, and the former track. Abandon the record. In this embodiment, since it is possible to record on the track almost certainly without dropout, it is suitable for an electronic still camera or the like in which failure of the device side in video recording is not allowed.

Although the head 24 is vibrated after erasing the track in which the dropout has occurred in this embodiment, the head 24 may be vibrated and then the track may be erased.

The present invention is effectively applied not only to recording video signals, but also to other rotary magnetic recording devices such as a magnetic disk device used as a file storage device in a data processing system.

The present invention can be effectively applied not only to the magnetic disk as in the above-described embodiment but also to other forms of rotary magnetic recording medium such as a magnetic drum. In these rotary magnetic recording bodies, a recorded signal is recorded on a plurality of tracks formed along a locus where the recording start end and recording end coincide with each other. For example, in a magnetic disk, recording is performed on a rotating magnetic recording medium for each of a plurality of tracks formed concentrically around the rotation axis, and for a magnetic drum, each of a plurality of tracks formed in parallel with the longitudinal direction of the circumferential surface. One unit of recorded signal is recorded without changing the relative position of the head.

Effects As described above, according to the present invention, when a dropout is detected during recording of a signal on the rotating magnetic recording medium, the magnetic head is vibrated and then re-recording is performed. This is because the signal dropouts on the magnetic recording medium are often temporary with poor reproducibility, and when foreign matter is caught between the rotary recording medium and the tip of the head, the foreign matter is generated by the vibration operation of the head. It is based on the experience that if the head is not moved unless dropout occurs, it will not occur even after that.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of an embodiment of a rotary magnetic recording medium recording apparatus according to the present invention, FIGS. 2 and 3 are operation flow diagrams showing an operation example of the embodiment shown in FIG. 4 and 5 are explanatory views showing an example of the vibration operation of the head in the embodiment. Description of main part code 16 …… Recording circuit 24 …… Magnetic head 28 …… Magnetic disk 29 …… Head transfer mechanism 40 …… System control circuit 44 …… Playback circuit 52 …… Dropout detection circuit 64 …… Operating section 68 ... Erase circuit

Claims (4)

[Claims] 1. A rotary magnetic recording medium recording apparatus for recording a signal to be recorded on a track of the rotary magnetic recording medium by a magnetic head slidingly contacting the rotary magnetic recording medium, the device rotating the rotary magnetic recording medium, Recording means for supplying a recorded signal to the magnetic head to record the recorded signal on the rotating magnetic recording body; and head moving means for moving the magnetic head along a recording surface of the rotating magnetic recording body, An erasing means for erasing a signal recorded on the rotating magnetic recording medium via the magnetic head; a dropout detecting means for detecting a dropout of a signal read by the magnetic head from the rotating magnetic recording body; Control means for controlling the recording means, the head transfer means, and the erasing means, the control means controlling the recording means in response to a recording instruction signal, and the rotating magnetic recording medium. After the recorded signal is recorded on the track, the signal recorded on the track is read from the magnetic head to the dropout detection means, and when the dropout detection means detects a dropout in the read signal, the erasure is performed. Controlling the means to erase the signal recorded on the track and controlling the head moving means to vibrate the magnetic head, and then the magnetic head is turned on the track again, and the recording means. A magnetic recording device for a rotary magnetic recording medium, characterized in that the recorded signal is recorded on the track by controlling the. 2. The apparatus according to claim 1, wherein the control means vibrates the magnetic head in the direction of the recorded track before recording the track in which the dropout has occurred. A recording device characterized by the above. 3. The apparatus according to claim 1, wherein the control means does not detect a substantial dropout in the signal read by the dropout detection means.
A recording apparatus which controls the erasing means to erase a signal recorded on the track, and controls the recording means to record a recorded signal on the track. 4. The apparatus according to claim 1, wherein when the control means performs dropout detection by the dropout detection means and erasure by the erasing means a predetermined number of times for the same track, A recording apparatus which controls a head transfer means to turn the magnetic head on a new track on a track, and controls the recording means to record a recorded signal on the track.