JPS62270074A - Erasable still picture recorder - Google Patents

Abstract

PURPOSE:To erase satisfactorily the video signal of a prescribed track by positioning a magnetic head to the peak position of the envelope of a video signal, and after an erasure signal is supplied for a fixed time, shifting the head by one shifting pulse in the normal and reverse directions respectively and impressing the erasure signal. CONSTITUTION:When a magnetic head 51 is positioned to the peak position of the envelope of a video signal, an erasure signal to occur from an erasure signal generating circuit 62 is fed to the magnetic head 51 over a fixed length of time and the erasure of the part A of the track is executed. The width of the head 51 is equal to the track width and there is the danger that the erasure is not carried out on both sides. The head 51 is sent for one shifting pulse in the normal direction and a part B is erased. Further, the head 51 is fed for two shift pulses in the reverse direction and a part C is erased. Thus, the erasure based upon the video signal actually recorded in the designated track is executed.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Summary of the Invention When recording a still image on a predetermined track on a magnetic disk, the absolute track position is determined by the distance from the reference position rIl (home position). The position of the magnetic head is set using the bank location method. Erasing is also a form of recording.

When erasing a predetermined track, the magnetic head is positioned based on the envelope detection output. This makes it possible to perform erasing in accordance with the position of the actually recorded video signal.

Table of contents (1) Background of the invention (2) Overview of the invention (2, 1) Purpose of the invention (2, 2) Structure and effects of the invention (3) Description of embodiments (3, 1) Still image recording and playback device Appearance (3, 2) Operation modes and their transitions (3, 3) Electrical configuration and operation of the still image recording/playback device (3, 4) Recording processing and erasing processing (1) Background of the invention It relates to a still image recording device that can record a video signal on any track by moving a magnetic head in the radial direction of a magnetic disk having tracks, and more specifically, video output from a television camera, television receiver, etc. A still image recording and reproducing device capable of recording one image of a signal on the magnetic disk, and a still image recording device including an electronic still camera that records a still image of a subject photographed with a fixed electronic image pickup device on a magnetic disk. Regarding.

Although a plurality of concentric recording tracks are provided on a magnetic disk, no data indicating the position of each track is magnetically recorded on the magnetic disk. Therefore, a device for moving the magnetic head provided in the still image recording device must determine the track position. Therefore, an absolute track number system is generally adopted in which the track position is determined based on the distance from a certain reference position.

Since the magnetic disk expands and contracts slightly depending on temperature, lj degrees, etc., the position of the magnetic head may differ slightly each time a track is accessed, according to the above-mentioned absolute track address system. When erasing the video signal of a previously recorded track, if the magnetic head is positioned away from the location where the video signal of that track is recorded, sufficient erasing will not be performed and the unerased portion will remain. There is a risk that this may occur. To prevent this, it is possible to scan the magnetic head to erase the vicinity of the track, but if the scanning range is too wide, there is a risk that part of the video signal of the adjacent track will be erased. occurs.

(2) Summary of the Invention (2,1) Purpose of the Invention The present invention is capable of erasing the video signal of a predetermined track without excess or deficiency in a still image recording device that determines the position of a recording track using an absolute track number system. The purpose is also to do so.

(2, 2> Structure and Effects of the Invention This invention holds a magnetic head while moving in the radial direction of a rotating magnetic disk on which a plurality of concentric tracks are set, and holds the magnetic head in a predetermined direction. In a still image recording device, the still image recording device includes a magnetic head transfer device that transfers a fixed amount, and a control device that controls the magnetic head transfer device during recording to position the magnetic head on a designated track based on a distance from a predetermined reference position. , an input switch for instructing erasure, an envelope detection circuit for detecting the envelope of the signal reproduced from the magnetic head, and in response to an input from the erasure command input switch,
means for controlling the magnetic head transfer device to position the magnetic head based on the detection envelope output of the envelope detection circuit; and an erase four-way for supplying an erase signal to the magnetic head after the positioning of the magnetic head. It is characterized by

Preferably, erasing is performed at a position where the center of the magnetic head coincides with the peak position of the detection envelope, and then the magnetic head is moved a predetermined distance on both sides from the bead position of the detection envelope to sequentially perform erasing. If erasing is performed at both positions, erasing at the position coinciding with the peak position may not necessarily be performed.

According to this invention, when erasing a video signal on a predetermined track of a magnetic disk, the position of the video signal actually recorded on that track is searched by the envelope detection to position the magnetic head. Therefore, it becomes possible to reliably erase the video signal, and it is possible to prevent a situation in which unerased areas are left unerased or adjacent tracks are erased as well.

Hereinafter, an embodiment in which the present invention is applied to a still image recording/playback device will be described in detail.

(3) Description of Embodiments (a, i) Appearance of Still Image Recording and Reproducing Apparatus FIG. 1 shows the external appearance of the still image recording and reproducing apparatus, particularly its front operation panel.

On the left side of the front operation panel 11 of the still image recording and reproducing apparatus 10, a packet 13 for storing a disc back 20 and its cover 12 are rotatably supported at their lower ends. Eject button (so-called eject button)
The cover 12 that was closed by pressing the button) 16
and the packet 13 is mechanically opened as shown in dashed lines. If you press cover 12, cover 12 and packet 1
3 is closed and locked. Further to the left side of the cover 12, a power button 14 and its indicator light 15 are provided.

The disk back 20 is a thin, small-diameter magnetic disk 21.
It consists of a case that rotatably accommodates the . A circular opening 22 is formed approximately in the center of the case, and the hub or core at the center of the magnetic disk 21 can be exposed through this opening. The disc back 20 is further provided with a shutter 23 movable in a direction parallel to one side thereof. This shutter 23 is opened when the disk back 20 is inserted into the packet 13, and a regulating plate 53 and a magnetic head 51 (see FIG. 4), which will be described later, can come into contact with the magnetic disk 21 inside. A claw 24 for preventing erroneous recording is provided on one side of the case of the disc back 20.

A certain number (for example, 50) of tracks are provided concentrically on the magnetic disk 21, and each track carries one image (
One frame of FM-modulated color video signals (including brightness signals, chroma signals, etc.) can be magnetically recorded. As shown in part in FIG. 6, the width of each track T is 60 μm.

The track pitch is 100 μm. A guard band G having a width of 40 μm is provided between the tigers 121.

FIG. 2 shows the relationship between the tracks provided on the magnetic disk 21 and the home position HP of the magnetic head. The 50 tracks arranged concentrically on the magnetic recording surface of the magnetic disk are numbered 1 to N in order from the outermost track.
Track numbers up to 50 are assigned. The home position HP is outside the track No. 011. This home position HP is not attached to the magnetic disk 21, but is an extreme position assigned on the movement path of the magnetic head. Home position HP is home position fist switch 84 (see Figure 4)
Detected by.

Referring again to FIG. 1, a half of the front operation panel 11 is provided with an indicator 17 and various key switches and indicator lights. The display 17 is, for example, a liquid crystal display, and 6! ! The track number of the magnetic disk 21 where the magnetic head 51 is currently located, various warnings (17a
), back q (indicated by 17b), etc., indicating that the disk back 20 is contained in the packet 13 and the packet 13 is closed.

The key switches include keys 31, 32, 33, 34, 35 and 36 for instructing various operations, keys 41, 42, 43 and 44 for setting various modes.
There are keys 18 and the like for setting automatic forwarding time in playback mode. Indicator light 45.46.47 is key 41.4
2 and 43, and when these keys are pressed, the corresponding indicator lights are lit. The functions of these key switches will become clear in the next section, ``Operating modes and their transitions.''

(3, 2) Operation modes and their transitions The still image recording and reproducing device is capable of recording and reproducing still images. When a video signal is recorded on the above-mentioned magnetic disk 21, it is possible to reproduce the video signal from the recorded track. Reproduction means reading an FM modulated signal from a predetermined track of a magnetic disk using a magnetic head, demodulating it, and outputting a standard color television video signal in NTSC format or the like.

If the output terminal of this video signal is connected to a television receiver, the reproduced still image will be displayed on the cathode ray tube. Recording assumes input of standard color television video signals. This video signal may be provided by, for example, a television camera or television receiver. Recording involves FM modulating one frame of a given video signal and writing it onto a predetermined track on a magnetic disk using a magnetic head.

When displaying a screen on a television, interlaced scanning is generally performed, so a video signal is created so that one frame consists of two fields.

However, in still image recording devices such as the above-mentioned electronic still cameras, magnetic disks are stored so that one field corresponds to one frame (one image) in order to save the recording surface of the magnetic disk for recording video signals and for four other purposes. Video signals are often recorded on. This is called a field record. Furthermore, the manner in which one frame of image is obtained using the two fields described above is called frame recording. In this embodiment, field recording is performed, but it goes without saying that the present invention can also be applied to frame recording.

There are three recording modes: single-frame recording, recording review, and snapshot. In the recording mode (more specifically, the recording standby mode to be described later), the magnetic head must be kept on standby in an unrecorded track of the magnetic disk. When 1 frame recording is selected, 1 frame (1 field)
A video signal for 20 minutes is recorded on that track, and immediately thereafter the magnetic head moves to the next (inner) track and waits. In recording review mode, after recording one frame worth of video signal on the track,
Immediately, the video signal recorded on that track is reproduced and output for a certain period of time (for example, 2 seconds), and then the magnetic head moves to the next track and waits. In the snapshot mode, the above-described one-frame recording operation is performed continuously (for example, about 6 to 8 times per second).

The above-mentioned recording operations and other operations will be explained with reference to FIG. 3 in relation to the various keys shown in FIG. 1.

In stop mode, single frame key 43. When the review key 42 or the continuous shooting key 41 is pressed, the corresponding indicator light 47, 46 or 45 lights up, the pressed key is memorized, and the apparatus enters the recording standby φ mode. Next, when the record key 33 is pressed, the 1-frame key 43 is pressed.
If there is a memory of pressing the review key 42, a one-frame recording operation 5 is performed, and if there is a memory of pressing the review key 42, a recording review operation is performed. After these operations, the device returns to recording standby mode again. If the record key 33 is pressed while there is a memory of pressing the quick copy key 41, the quick copy operation is performed while the record key 33 is pressed, and when the record key 33 stops being pressed, the mode returns to recording standby mode. .

In order to prevent double recording on one track, if any signal has already been recorded on the track where the magnetic head is located, the various recording operations described above are prohibited, and the first indicator lights 45 to 47 The corresponding one flickers. Whether a signal is recorded on a track is determined by the envelope detection output, which will be described later.

In such a case, the forward key 32 or reverse key 31 can be pressed to move the magnetic head to the adjacent inner or outer track.

This is track feed mode. These keys 31.
32 is pressed once, the magnetic head is advanced one track at a time, and then returns to the recording standby φ mode.

However, it is also possible to search for the next unrecorded track after recording the video signal in each recording operation.

When erasing the signal of a recorded track.

From the stop mode, press the 1-frame key 43 and press the erase key 44.
Just press . When the erasing process for that track is completed, it returns to recording standby mode.

When the stop key 34 is pressed from recording standby mode, the magnetic head will move to the outside (unless erasing has been performed).
(in the opposite direction) by one track and returns to stop mode.

This is because in the three recording modes described above, the magnetic head is moved inward (forward direction) by one track after recording.

When the forward rekey 32 or the reverse key 31 is pressed from the stop mode, the mode shifts to the playback mode, and the video signal recorded on the track where the magnetic head is located is played back. If the forward key 32 or the reverse key 31 is pressed again, the magnetic head is sent to one track inside or outside, and the signal of that track is reproduced. Automatic feed key 3
5 is pressed and the automatic feed time is set using the key group 18, the magnetic head is sequentially fed in the forward direction at the set time intervals, and u# raw is performed on each track. Furthermore, when the track position display key 36 is pressed, a signal for displaying the track position where the magnetic head is located is superimposed on the reproduced video signal and output. to that truck yang,
is displayed. When the stop key 34 is pressed, the system returns to the stop mode.

In any of the above modes, the track Nα where the magnetic head is currently located is displayed on the display 17.

In the 11th state when the power is turned on by the power switch 14, some of the magnetic heads are at the home position HP.
It is returned to the position shown in FIG.

In the recording mode, the magnetic head is moved in a so-called absolute track number system. That is, the magnetic head is moved in the radial direction of the magnetic disk, but the position of each track where the magnetic head is to be positioned is always based on the home position HP, and the distance from the home position HP (specifically, is determined by the number of shift conflict pulses applied to the head transfer device 57, which will be described later.

In playback mode, after the position of the magnetic head is determined by the above-mentioned absolute track number formula, the center of the magnetic head is located at the center of the recorded signal based on envelope detection, which will be described later. As such, minute position control is performed.

Although the erasing operation can be considered a modification of the recording operation, in the erasing mode, the magnetic head is positioned in the same manner as in the reproducing mode, as will be explained in detail later.

(3, 3) Still Image 11] Electrical FM Configuration and Operation of Image Recording and Reproducing Apparatus FIG. 4 shows the electrical configuration of the still image recording and reproducing apparatus.

The overall operation of this still image recording and playback device is controlled by the control device 5.
Controlled by 0. This control device 50 is composed of a central processing unit, preferably a microprocessor (hereinafter referred to as CPU), a memory that stores its programs and necessary data, and interfaces with each of the peripheral elements 9 circuits, devices, etc. There is.

Once the disk back 20 is placed within the packet 13 and the packet 13 is closed, the magnetic disk 21 within the disk back 20 is mounted on the spindle of the disk motor 54. Since recording or reproduction is performed by the magnetic head 51 while the magnetic disk 21 is being rotated, a conditioning plate is provided inside the cover 12 in order to maintain good contact between the magnetic head 51 and the magnetic disk 21 at all times. 53 are provided. This current adjustment board 53 is.

It has a groove along the moving path of the magnetic head 51, and is in contact with or close to the magnetic disk 21 at a portion other than the groove, so that the magnetic disk 21 is sandwiched between the magnetic head 51 and the magnetic disk 21. The magnetic helad 51 is connected to the magnetic disk 2 as described above.
A magnetic disk 2 is arranged so as to be movable in the radial direction of 1.
It is in contact with the magnetic recording surface of No. 1. In addition, the magnetic disk 21
A magnetic material is provided in one place of the core to leak a part of the magnetic flux of the permanent magnet for chucking provided in the core, and this leakage magnetic flux is detected and a magnetic material is inserted every rotation of the magnetic disk 21. A phase detector 52 that generates a phase detection pulse PC is adjacent to the core.

Phase detection pulse PG from phase detector 52 is input to servo control circuit 56 and control device 50 .

A frequency generator 55 provided in the disk motor 54 outputs a signal with a frequency proportional to the number of rotations of the motor 54, and is applied to a servo control circuit 56. Furthermore, a vertical synchronization reference signal rarV is input to this servo control circuit 56. Based on such an input signal, the servo control circuit 56 rotates the disk motor 54 at a constant speed, for example, 3.60 Or, p, i, and also outputs a phase pulse PC as shown in FIG. is the reference signal rel
'Control the rotational phase of the motor 54 so that it is 7H ahead of the rising edge of V (H is the period between two consecutive horizontal synchronization signals). Further, the servo control circuit 56 starts and stops the motor 54 in response to commands from the control device 50.

The phase control of the motor 54 by the servo control circuit 56 has the following meaning. Consider a case where an F'M modulated video signal is recorded on a predetermined track of the magnetic disk 21 by the magnetic head 51. A standard format color video signal applied to the input terminal 60 from a television camera, television receiver, etc. is subjected to FM modulation of its luminance signal component and chroma signal component in a recording processing circuit 61, and these modulated signals are combined and sent to an amplifier circuit. 63.

This amplified FM variable 2N signal is sent to the recording control switch 64.
and the magnetic head 5 via the recording/playback switch 65.
1 is given. On the other hand, horizontal and vertical synchronization signals of the input video signal are extracted by a synchronization separation circuit 61a and provided to a waveform shaping circuit 66. The waveform shaping circuit 66 creates and outputs a reference signal rcfV having a leading edge synchronized with the leading edge of the input vertical synchronizing signal V5yne and having a duty ratio of approximately 1/2, as shown in FIG. It is something. This reference signal ratV is given to the servo control circuit 56 via the synchronization changeover switch 68 (this is called external synchronization). Therefore, on the magnetic disk 21, the 7! Recording of the video signal is performed so that recording of the vertical synchronization signal starts from the quasi-position.

In the case of reproduction, a similar vertically identical reference signal re('V) is applied from the oscillator circuit 67 to the servo control circuit 56 via the switch 68 (this is called internal synchronization). By controlling the phase of the motor 54 using ref'V and the phase pulse PC, the magnetic head 51 reads out a video signal whose vertical synchronization signal always starts 7H behind PG.

The phase pulse PG is given to the control device 50, and since the video signal is synchronized with this pulse PG with a certain delay in both recording and reproduction, the control device 50 uses this pulse to control timing in various processes. This can now be done using PG as a reference. Is this the motor 5'4 1r? This is the meaning of control.

The modulated video signal read from the magnetic helad 51 is input to the amplifier circuit 73 via the changeover switch 65, and further sent to the reproduction processing circuit 71 and the envelope detection circuit 72. The reproduction processing circuit 71 is.

The input modulated luminance signal and chroma signal are respectively demodulated and combined and outputted to the output terminal 70 as a standard color video signal. When this video signal is applied to a television receiver, a still image for one frame is displayed on a cathode ray tube.

The erase signal generation circuit 62 generates an erase signal, for example, for a certain period of time (
An erasure signal whose frequency is continuously swept from about 4.5 to 20 MHz for about 1 second) is generated. This erase signal is sent to the recording processing circuit 61. Amplification circuit 63. Since the erase signal is applied to the magnetic head 51 via the switch 64 and the changeover switch 65, the video signal is erased by writing the erase signal to a predetermined track of the rotating magnetic disk 21 by the magnetic head 51.

The magnetic bed 51 is supported movably in the radial direction of the magnetic disk 21 by its transfer drive control device 57, and is controlled to be transferred in the same direction. The control device 50 controls the magnetic head 5
1 is given to the device 57 as to the direction and amount of transfer. The device 57 includes a stepper motor, which transports the magnetic heald 51 in proportion to the rotation angle of the stepper motor. For example, per one driving pulse of the steller motor, this motor rotates about 15'', thereby moving the magnetic head 51 about 8.3.3 μm (1 pitch). Therefore, the movement of the magnetic head 51 is extremely accurate. It is done.

The envelope detection circuit 72 is a detection circuit that detects the envelope of the read signal of the magnetic head 51, that is, the FM modulated video signal recorded on the track of the magnetic disk 21, and outputs a voltage signal corresponding to the envelope. be.

The voltage signal representing the envelope is converted by an analog/digital converter (A/D converter) built into the circuit 72 into an 8-bit digital signal representing, for example, 256 quantization levels, and is input to the control device 50. do.

The envelope detection signal is used to search for unrecorded tracks on the magnetic disk 21 and to detect the center position of recorded tracks (in playback and erase modes). If the level of the detected signal does not reach a predetermined threshold level when the magnetic head 51 is moved across the track, that track is unrecorded. When reproducing a video signal, after the magnetic head 51 is positioned by the above-mentioned absolute positioning method, the detected signal reaches its peak by moving the Fa air head 51 inward or outward one pitch at a time, as described later. The position showing this peak is determined to be the center of the track where the video signal is recorded, and the video signal is reproduced with the magnetic head 51 positioned at this center. This peak search is similarly performed for erasing a video signal, and the areas within a certain range on both sides of the peak position are the opposite areas for erasure, which will be described in detail later.

Recording control switch 64. Record/playback switch 65.
Synchronization changeover switch 68 and video output control switch 69
is shown as a contact switch, but of course it is generally realized by a non-contact switch made of a semiconductor element or the like. These switches are controlled to be turned on and off by the control device 50 as follows.

In the recording mode, the switch 64 is turned on at a certain timing, and the switch 65 is turned on at a certain timing, with exceptions described later.
is connected to the recording processing circuit 61 side, the switch 68 is connected to the waveform shaping circuit 66 side, and the switch 69 is turned on. That is, when the recording standby or mode is entered, the changeover switches 65 and 68 are respectively switched as described above by the recording/playback switching signal REC/PB and the synchronization switching signal 5YCH from the control device. Further, the switch 69 is turned on by the video output control signal VIDCH. When the recording key 33 is pressed, the switch 64 is turned on by the recording control signal REC only between two consecutive pulses PG, as shown in FIG. Therefore, the FM-modulated video signal is sent to the magnetic disk 51 during this period, and is transmitted once per rotation of the magnetic disk 21.
One field is recorded. At this time, switch 6
9 is on, the video signal input to the input terminal 60 is output to the output terminal 70 as is.

When the recording review 42 is stored (recording review mode), playback is performed after recording as described above. Therefore, when the recording by the magnetic head 51 is completed, the switch 65 is activated by the reproduction processing circuit 7 in synchronization with the PG double signal.
1 side, the video signal read by the magnetic head 51 is outputted and the switch 69 is turned off. This will be outputted from the resistor 70 as a playback output. Then, after a certain period of time, these switches 65, 69 return to the above-mentioned state again.

Even during the above-described playback in the recording review mode, the changeover switch 68 remains connected to the waveform shaping circuit 66, and external synchronization is performed. That is, since a video signal is input to the input terminal 60, servo control is performed based on the synchronization signal.

As shown later, in playback mode, selector switch 6
8 is connected to the oscillation circuit 67 side to provide internal synchronization, but during playback in the recording review fist mode, switching from external synchronization to internal synchronization is not performed, and external synchronization continues throughout. This is because when switching from external synchronization to internal synchronization, the rotational phase of the disk motor 54 is temporarily shifted, causing distortion in the video signal output from the output terminal 70 and causing the video signal to be displayed on the cathode ray tube. This is because distortion occurs in the image.

Even in the erase mode, the states of switches 65, 68 and 69 are the same, except during envelope detection.

This is the same as in recording mode. The switch 64 is kept on continuously during the erase operation.

In the reproduction mode, switches 64 and 69 are kept off, switch 65 is switched to the reproduction processing circuit 71 side, and switch 68 is switched to the oscillation circuit 67 side.

All operation mode switching and various operations are performed based on inputs from various switches and various keys. The various switches have packets 13 and magnetic disks 21 in them.
is closed to a position where it will be securely attached to the spindle of the disk motor 54.
End switch 81. A pack switch 82 for detecting that a disk pack 20 is contained within a closed packet 13. An erroneous recording prevention switch 83 detects that the erroneous recording prevention claw 24 of the disk pack 20 housed in the packet 13 has been removed and does not exist (that is, recording is prohibited). Home position mentioned above - switch 8
There are 4 etc. Each key has 1. There are a group of keys 31 to 36, 41 to 44, and 18 provided on the front operation panel 11 described above. The control device 50 operates at a constant period (for example, 1/
A key scan routine is performed every 60 seconds), and in this key scan routine, the control device 50 sends a key scan pulse to the above-mentioned switch group and key group, and depending on whether this pulse is returned or not, the control device 50 performs a key scan routine. Detects and stores key on/off status.

Furthermore, the control device 50 controls the display of the indicator lights 45 to 47 based on the above-mentioned key scan routine.

It also controls the display of the display 17 based on routines for various operations.

(3, 4) Recording processing and erasing processing Finally, the operations of the recording mode and erasing mode described above are controlled by the control bag v! This will be explained from the perspective of the processing procedure of the CPU in the ISO.

Before explaining, let's summarize the main conditions for recording.

This is because the track on which the magnetic head 51 is located is unrecorded (the envelope detection output is below the threshold number level), and the erroneous recording prevention claw 24 of the disk pack 20 is not removed ( (This can be determined by the output of the erroneous recording prevention switch 83), and that the recording standby mode is in effect (one of the single-frame, revinie, or snapshot key switches 43, 42, or 41 is pressed). be. The former two conditions will not be particularly mentioned in the following explanation to avoid complexity.

Further, the conditions for erasing are that the erroneous recording prevention claw 24 is not folded and that the one-frame key 43 is pressed to enter the recording standby mode.

FIG. 8 shows part of the key scan routine.

To make it easier to understand, this flowchart is expressed as the processing that is performed when a key is input.

Control device 50. Especially in that memory, 1 frame key 4
Flag F to remember that 3 was pressed, Flag F to remember that Levigny key 42 was pressed, Flag F to remember that continuous copying key 41 was pressed, Erase key 4
Flag F to remember that 4 was pressed, recording key 33
Flag F for determining the beginning of pressing (rise)
A flag F5 is provided to remember that 4° and the recording key 33 are pressed. It is assumed that the flag F4 is set (-1) in the initial processing.

When the 1-frame key 43 is pressed, the flag Fo is set and the other flags Fl and F2 are reset to 1.
The indicator light 47 is turned on (steps 101, 102, 1
03,104). Review key 42. When the continuous shooting key 41 is pressed, corresponding processing is also performed (steps 111 to 114 and 121 to 124).

When the recording key 33 is pressed, the flag F5 is set on the condition that the flag F4 is set (that is, it is the first rise), and then the flag F4 is set.
is reset (-〇) (steps 131 to 134)
. Therefore, once flag F4 is reset, 2
In the next key scan routine, even if it is determined that the record key 33 is pressed (YES in step 131)
), the determination of "F41-1" in step 132 is NO, so the flags F 1 and F 2 are kept as they are.

When it is determined in the key scan routine that the record key 33 is not pressed, the flag F5 is reset;
Flag F4 is set (steps 135, 136
).

When the erase key 44 is pressed, flag F3 is set (steps 141 and 142).

FIG. 9 shows the processing performed when any of the flags Fo-F2 is set. The processing in FIG. 9 and the processing in FIGS. 10 and 11 described later are performed by checking the states of the above-mentioned flags every fixed period of time (for example, 10 mS), and if any flags are set, proceeding to the corresponding processing. It is processing.

If any of the flags F, F, F2 is set, the recording standby mode setting process, that is, the above-mentioned switch 69 is turned on, and the changeover switch 65,
6g is switched to the recording side. At this time,
The first two main conditions for recording mentioned above will also be checked. If these conditions are not met, a warning is displayed on the display 17.

FIG. 10 shows interrupt processing due to flag F5 being set.

First, it is checked whether any of the flags F, Fl, and F2 are set to zero (step 161). This corresponds to checking the third recording condition mentioned above. If none of these flags are set, a warning is displayed on the 1 display 17, and the interrupt process ends (step 162).

When the flag Fo is set, one frame recording is performed. In this case, the input of the one-phase pulse PC is waited, and when the pulse PG is input (step 151), the recording control signal REC is set to H level and the switch 64 is turned on (step 152). When the primary phase pulse PC is input, the signal REC is set to L level and the switch 64 is turned off (steps 153 and 154).

In this way, one frame of the input video signal is recorded on the magnetic disk 21.

Thereafter, 12 forward shift pulses are applied to the step motor of the head transfer drive control device 57, and the rotation of this motor moves the magnetic head 51 inward by one track, 100 μm (step 155). lastly,
Flag F5 is reset (step 156). Since the flag F5 is reset, this one-frame recording process will not be performed unless the record key 33 is pressed again and the flag F5 is set in step 133 in FIG.

This is because the movement of the magnetic head 51 in the recording mode is based on the absolute track number system as described above.

In order to move the magnetic head 51 a predetermined distance, a number of shift pulses corresponding to the distance are applied to the step motor of the head transfer device 57.

Between steps 151 to 153 and step 15
During the processing in step 5, interrupts for transition to other operation modes are prohibited.

In the case of Fl-1, recording review processing is performed. Since this process is the same in many respects as the one-frame recording process described above, the same steps are given the same reference numerals. In this recording review process, steps 151 to 154
After one-frame recording is completed, playback processing is performed. This regeneration process is performed by switching only the changeover switch 65 to the playback side for 2 seconds as described above.
This is the number 9. Thereafter, the magnetic head 51 is moved one track in the forward direction and the flag F5 is reset.

When F2 is set, it is quick-shot recording, and this process also has many steps in common with single-frame recording. Since continuous recording is a process in which single-frame recording is performed continuously as long as the recording key 33 is pressed, there is no process for resetting the flag F5 in step 156 in the single-frame recording process.

Instead, after moving the magnetic head 51 one track in the forward direction, until the magnetic head 51 completely stops,
A routine is included to wait for only a short period of time (step 158). After this WAIT process, the program returns, but if the record key 33 is still pressed and F5 is set, the interrupt routine is entered again, and one frame is recorded in the same way.

FIG. 11 shows an overview of the erasing process performed when flag F3 is set.

First, it is checked whether the flag Fo is set, that is, whether the 1-frame key 43 has been pressed (step 171), and if so, envelope peak detection processing is performed, and if not, a warning display 17a is performed. .

Recording of video signals onto the tracks of the magnetic disk 21 is performed using an absolute track number system.
Due to expansion and contraction due to temperature, humidity, etc., as shown in Figure 6, the center of the track determined by the absolute track number system and the center (peak position of the envelope) P of the video signal recorded on that track are are not necessarily consistent. Therefore, when deleting that track,
Processing is performed to detect the peak position of the envelope of the actually recorded video signal (step 17).
2).

In this process, referring to FIG. 7, the switch 65 is connected to the envelope detection circuit 72 side, and the envelope A/D conversion value input from the circuit 72 is first taken in at a position determined by the absolute track number system. be remembered. Next, the magnetic head 51 operates at a one-shift pulse-pitch (8,33 μm
) is sent in the forward direction, and the A/D conversion value at that point is captured. Last time's A/D'& exchange value and this time's A/
If it increases when compared with the D conversion value, it means that the magnetic head 5 is approaching the peak as in case I.
1 is sent in the forward direction, and when the A/D conversion value decreases, it returns in the opposite direction and is positioned at the peak position. Case ■
, ■, if it is decreasing, it is moved in the opposite direction by one shift pulse, the A/D conversion value at each point is obtained, and the A/D conversion value increases and then If it decreases, it is positioned at the peak position by being sent again in the forward direction.

In this way, when the magnetic head 51 is positioned at the peak position of the envelope of the video signal, the erase signal generated from the erase signal generation circuit 62 is applied to the magnetic head 51 for a certain period of time (for example, 1 second) as described above. The track is erased (step 173).
). This is the erasure of part A shown in FIG.

As shown in FIG. 6, the width of the magnetic head 61 is 60 mm.
It is μm and equal to the track width. Since there is a possibility that unerased portions may exist on both sides with only the erasing process in step 173, the magnetic head 51 is moved in the forward direction by one shift-pulse (8.33 μm) in the ninth step (step 174).
, 26, the portion indicated by B in FIG. 26 is erased in the same manner (step 175). Furthermore, the magnetic head 51
is sent in the opposite direction for two shift pulses (step 176).
), the portion indicated by C in FIG. 6 is erased (
Step 177). In this way.

Erasing is performed in accordance with the video signal actually recorded on the designated track, and finally flag F3 is reset (step 178).

Note that when the envelope level of the designated track is below a predetermined threshold level, erasing processing may be performed or may be prohibited. Further, the synchronization changeover switch 63 may be either internal synchronization or external synchronization.

Basically, if there is an input video signal, external synchronization based on the synchronization signal is preferable.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the appearance of a still image recording and reproducing device. FIG. 2 shows the track numbers and home positions on the magnetic disk. FIG. 3 shows various operating modes and how the operating modes change in response to inputs from various keys. FIG. 4 is a block diagram showing the electrical configuration of the still image recording and reproducing device. FIG. 5 is a time chart showing the synchronous control of the disk motor by the servo control circuit and the recording timing. FIG. 6 shows the relationship between absolute track addresses and envelopes and the erasure range. FIG. 7 is for explaining envelope peak detection processing. Figures 8 to 11 show an example of the procedure of recording processing and erasing processing by the CPU. Figure 8 shows the key scan routine, and Figures 9 to 11 show the interrupt processing. There is. 10... Shizuka II--image recording and playback device. 21... Magnetic disk, 33... Recording key. 41... Continuous shooting key, 42... Review key. 43...1 frame key, 44...Erase key. 50...Control device, 51...Magnetic head. 57...Head transfer drive control device. 60...Video signal input terminal. 61... Recording processing circuit. 62... Erasing signal generation circuit. 65...Record/playback switch. 72...Envelope detection circuit. Patent applicant: Fuji Photo Film Co., Ltd. Representative
Patent attorney Hosomichi Kato (one other person) Figure 7 Figure 8 Scanning process for other keys Figure 9 Figure 10

Claims (3)

[Claims] (1) A magnetic head transfer device that holds a magnetic head movably in the radial direction of a rotating magnetic disk on which a plurality of concentric tracks are set, and that transfers the magnetic head by a predetermined amount in a predetermined direction; In a still image recording device equipped with a control device that controls a magnetic head transfer device to position the magnetic head on a designated track based on a distance from a predetermined reference position, an input switch for commanding erasing; an envelope detection circuit that detects an envelope of a signal reproduced from the magnetic head; and an envelope detection circuit that detects an envelope of a signal reproduced from the magnetic head; An erasable still image recording device comprising: means for controlling a transport device; and an erasure circuit for applying an erasure signal to the magnetic head after said positioning of the magnetic head. (2) Erasing is performed at a position where the center of the magnetic head coincides with the peak position of the detection envelope, and then the magnetic head is moved a predetermined distance on both sides from the peak position of the detection envelope to sequentially perform erasing. The erasable still image recording device according to item (1). (3) The erasable still image recording device according to claim (1), wherein erasing is performed by detecting a peak position of a detection envelope and moving a magnetic head a predetermined distance on both sides from this peak position.