JPS6361465A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a reproduced image having uniform picture quality, by fetching the output of a track position detecting means, controlling the recording current of a magnetic head corresponding to a track position, and stabilizing the level of the reproduced signal of each track obtained from the head, at a constant level. CONSTITUTION:A table in which recording current value information to uniform a signal level obtained from the magnetic head 64 at time of reproduction is contained, is stored in the ROM of a control circuit 82 corresponding to each track of a magnetic disk 66. The circuit 82 refers the table, and outputs the recording current value information to be supplied to the head, to D/A converter 102, corresponding to the current track position of the head 64, and furthermore, the gain of a preamplifier 86 is varied through a control amplifier 104. The head 64 moves a disk 66 plane in a diameter direction according to the rotational direction of a motor 62, and a moving distance is proportional to the angle of rotation 18 deg./pulse. The control circuit 82 fetches the detected output of an origin HP 100, and counts the number of the driving pulses of the 62 from the origin HP, and detects the current position position of the head. The reproduced image having the uniform quality can be obtained by such a constitution.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides a method for rotationally driving a rotating recording medium such as a magnetic disk,
The present invention relates to a magnetic recording and reproducing apparatus that records a video signal on each track or reproduces a video signal from each track while moving a magnetic head in the radial direction of the rotating recording medium.

[Background of the invention]

Recently, imaging devices such as solid-state image sensors and image pickup tubes have been combined with recording devices that use magnetic disks, which are inexpensive and have a relatively large storage space, as recording media. Electronic still camera systems have been developed in which images are recorded on a disk and reproduced using a separately provided television system, printer, or the like. In addition, there is a video magnetic recording system that captures still images recorded on visible recording media such as ordinary film and photographic paper and records them on a magnetic disk, and a video magnetic recording system that reads video signals from the magnetic disk and displays them on a television etc. In conventional magnetic recording and reproducing devices of this kind, which have also implemented video reproducing systems, a rotating recording medium such as a magnetic disk is driven to rotate at a constant speed, and recording or reproducing is performed on each track in this state. However, the relative speed between the magnetic head and the magnetic disk is different between the inner circumferential side and the outer circumferential side of the magnetic disk. In this case, since the gap width of the magnetic head is constant, there will be a difference in the reproduction level depending on the frequency of the recording signal even when recording is performed with the same recording current. Therefore, when a magnetic disk is played back from the first track on the outermost track to the last track on the innermost track, the problem arises that the image quality deteriorates as the playback moves to the inner tracks due to the difference in the playback level. there were.

[Purpose of the invention]

The present invention was made in view of these circumstances, and
It is an object of the present invention to provide a magnetic recording/reproducing device capable of recording video signals so as to obtain reproduced images of constant image quality over all tracks of a rotating magnetic recording medium such as a magnetic disk.

[Summary of the Invention] In order to achieve the above object, the present invention rotates a rotating recording medium such as a magnetic disk, and records a video signal on each track while moving a magnetic head in the radial direction of the rotating recording medium. Alternatively, in a magnetic recording and reproducing apparatus that reproduces video signals from each track, track position detection means detects the current track position of the magnetic head on the rotating recording medium when recording the video signal, and a recording device that supplies a recording current to the magnetic head. The detection output of the current supply means and the track position detection means is taken in, and the recording current supplied to the magnetic head is controlled according to the track position so that the level of the reproduction signal obtained from the magnetic head on each track is constant. The invention is characterized in that it has a control means for controlling.

〔Example〕

Preferred embodiments of the magnetic recording/reproducing apparatus according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the configuration of an electronic still camera as an embodiment of the magnetic recording/reproducing apparatus according to the present invention. In the figure, the imaging section of the electronic still camera is mainly an afocal lens.
O1 aperture 12, master lens 14, shutter 16, and solid-state image sensor (COD is used in this embodiment)
18, an aperture drive device 20 that drives the aperture 12, a shutter drive device 22 that drives the shutter 16, an aperture drive device 20, and a shutter drive device 2.
2, and an automatic exposure control circuit 24 that controls the exposure control circuit 2.

The solid-state image sensor 18 is operated by a vertical drive circuit 2 that operates in response to a pulse signal output from a timing pulse generation circuit 26.
8. Driven by a drive signal from the horizontal drive circuit 30. The timing pulse generation circuit 26 is a circuit that generates various pulse signals for controlling each circuit section of the electronic still camera.

Furthermore, the imaging section receives the primary color signal R obtained from the solid-state imaging device 18.
. Process circuit 3
4, and primary color signals R and G output from the process circuit 34.
, B, a gamma correction circuit 3 that performs color signal processing for gamma correction.
6 and the primary color signal R output from the gamma correction circuit 36,
A luminance signal Y having a predetermined signal bandwidth based on G and B
N T
It includes an encoder 40 that synthesizes an SC system video signal NTSC, a luminance signal Y+S including a composite synchronization signal S, and color difference signals RY and BY.

Further, the NTSC signal outputted from the encoder 40 is outputted to the electronic viewfinder 43 via the high voltage generation circuit 42, and the image of the subject is displayed on the screen of the electronic viewfinder 43.

On the other hand, the recording system circuit includes a pre-emphasis circuit 48 that performs a predetermined frequency correction on the X11 signal Y+S among the 13 signals synthesized by the encoder 40, and an F-frequency modulator that performs FM modulation on the luminance signal y+s output from the pre-emphasis circuit 48.
An M modulation circuit 50, a line sequential circuit 52 that converts the color difference signals R-Y and B-¥ out of the signals synthesized by the encoder 40 into line sequential color difference signals, and a line sequential color difference signal output from the line sequential circuit 52. a pre-emphasis circuit 54 that performs predetermined frequency correction on the image data; a differential phase shift keying (DPSK) circuit 58 for recording according to the frequency of the FM modulation circuit 50; a mixer 59 that mixes three signals: the FM line sequential color difference signal output from the modulation circuit 56 and various data signals output from the DPSK circuit 58 to create an FM video signal for recording; A preamplifier 86 that sets the recording FM video signal output from the FM video signal to a predetermined level.
and a magnetic head 64 for recording the FM video signal output from the preamplifier 86.

The preamplifier 86 is described as having two components, a recording amplifier and a reproducing amplifier, which will be described later, and performs a switching operation in response to a gate signal output from the gate circuit 84 for a predetermined period.

The preamplifier 86 is controlled by a control signal outputted from the D/A converter 102 via the control amplifier 10.4 so that the gain of the amplifier is varied. Recording current value data such that the signal level obtained by the magnetic field during reproduction is constant is stored in the R in the control circuit 82 as a table corresponding to each track of the magnetic disk 66.
The control circuit 82 refers to this table and outputs data indicating the recording current value to be supplied to the magnetic head 64 corresponding to the current track position of the magnetic head 64 to the D/A converter 102. is configured to do so.

The magnetic helmet 64 is movable in the radial direction along the recording surface of the magnetic disk 66 by the head drive motor 62, as conceptually indicated by a dashed line 65. The head drive motor 62 is operated by a motor drive circuit 60 that operates in response to an 8-bit motor drive signal output from a control circuit 82, and has four phases A, A,
B and B drive pulses are given. The moving direction of the magnetic head 64 is determined by the rotating direction of the head drive motor 62, and the moving distance of the magnetic head 64 is proportional to its rotation angle. For example, one of the shift pulses of the head drive motor 62
The head drive motor 62 rotates approximately 18 degrees per pulse,
As a result, the magnetic head 64 is moved by h5 μm. Therefore, LOOtlm (
1 truck) is transferred.

There is a home position H on the outermost side of the magnetic disk 66.
P is provided. This home position HP is not attached to the magnetic disk 66, but is an extreme position allocated on the movement path of the magnetic head 64. The home position I (P) is detected by the home position switch, and the control circuit 82 takes in the detection output of the home position 100 and controls the movement of the magnetic head 64 using the home position HP as a reference position. 82 returns the magnetic head 64 once to the home position HP, and sequentially moves the magnetic head 64 from the home position HP to a designated track, for example, or from the first track to the last track.
control to transport. The current position of the magnetic head 64 is determined by counting the number of drive pulses output from the motor drive circuit 60 to the head drive motor 62 from the time when the magnetic head 64 reaches the home position HP; by a counter provided in the MIW circuit 82. It is detected by

Moving the magnetic head 64 from the outer circumferential side to the inner circumferential side of the magnetic disk 66 is forward feeding, and moving in the opposite direction is called reverse feeding.

-4, the magnetic disk 66 is removably attached to the rotating shaft 68 of the spindle motor 70, and the spindle motor 70,
A frequency generator (FC) 72, a PG detection carimuff 4-waveform shaping circuit 76, a servo control circuit 78, and a motor drive circuit 80 cause steady rotation in a predetermined direction.

The PC detection coil 74 detects a magnetic PG yoke (not shown) embedded in the rotating shaft of the magnetic disk 66, and the PG signal obtained from the yoke is passed through the waveform shaping circuit 76 and subjected to servo control. The signal is input to the circuit 78, the gate circuit 84, and the timing pulse generation circuit 26, respectively.

The gate circuit 84 outputs a gate signal to the preamplifier 86 based on the PC signal detected by the PG detection car muff 4 and the recording/reproduction command signal output from the control "Fn circuit 82."

When the power switch SW3 is closed, the aperture drive circuit 2
0, the aperture 12 is driven and controlled, and the solid-state image sensor 18 is also driven.
Power is supplied to the process circuit 34, gamma correction circuit 36, matrix circuit 38, encoder 40, high voltage generation circuit 42, electronic viewfinder 43, etc., and as a result,
The electronic viewfinder 43 allows the subject image to be monitored.

The spindle motor 70 is started by operating the shirt release button 90 after closing the power switch SW3. That is, the number of shirt release buttons 90 is 2 in this embodiment.
The step stroke is activated, and in the first stroke of the pushing operation, the switch S W 1 is closed and power is supplied to each circuit section of the recording system including the motor drive circuit 60, 80. As a result, the servo control circuit 78 outputs a drive signal for driving the spindle motor 70 to the spindle motor 70 via the motor drive circuit 80. Furthermore, shirt tallerize button 9
The switch SW2 is closed in the second stroke of the 0 push operation, and as a result, the control circuit 82 performs functions such as shirt release, photographing, and
The operation of each circuit section is controlled to perform recording. This configuration avoids wasting power from a power source such as a battery.

Further, 88 is an envelope detection circuit, and the envelope detection circuit 88 performs envelope detection on the reproduced FM video signal outputted through the preamplifier 86 and outputs the detection output to the control circuit 82 . Based on the detection output of the envelope detection circuit 88, the control circuit 82 performs a track search on the magnetic disk 66 or determines whether or not drop-out has occurred on the magnetic disk 66.

The NTSC video signal output from the encoder 40 passes through a high voltage generation circuit 42 and is visualized on an electronic viewfinder 43, and after passing through a buffer amplifier 46,
The signal is output to the outside via the video signal output terminal T1.

The control circuit 82 stores various interfaces and control programs, as well as a table showing the relationship between each track of the magnetic disk 66 and the recording current value described above.
Supervises the operation of the entire device equipped with memory devices such as OM,
This is a control circuit.

When recording a video signal on the magnetic disk 66, this control circuit 82 controls the recording current supplied to the magnetic head 64 so that the level of the reproduced signal is constant according to the track position. The control J'J11 circuit 82 further includes, for example, a quick-shooting speed setting switch 92 for setting the number of frames to be shot per predetermined time (continuous shooting speed), a group of switches for instructing the number of frames to be shot during quick shooting, or the form of shooting and recording. 9
Various controls are performed based on the 3rd grade.

The control circuit 82 is also provided with a frame counter that counts the number of frames taken in the continuous shooting mode, and is also provided with a memory such as a RAM that stores the number of unrecorded tracks on the magnetic disk 66, that is, the number of frames that can be shot. It is being

Furthermore, an auto power-off timer is provided in the control circuit 82 to automatically turn off the power if no release operation is performed for a certain period of time after the power is turned on. .

The continuous shooting speed setting switch 92 is provided with eight manually selected contacts (contacts a, b, c, d, e, f, g, h), and the continuous shooting speed setting switch 92 is provided with eight contacts (contacts a, b, c, d, e, f, g, h) that are manually selected. The number of frames to be shot is determined. In this embodiment, for example, by selecting the contact point a, shooting is performed at 15 frames/second, and thereafter, by selecting the contact points,
10 frames/second (contact B), 5 frames/second (contact C), 2 frames/second (contact d), 1 frame/second (contact e), 1 frame/2
seconds (contact f), 1 frame 15 seconds (contact g), 1 frame/10
Seconds (contact point h) are each photographed.

The key group 93 includes, for example, a shooting mode selection switch 94 that selects a single shooting mode in which the shooting operation ends for each frame, or a continuous shooting mode in which the shooting operation is continued for a predetermined number of frames in a predetermined time, and a recording mode switch 95 that instructs field recording or frame recording of still images photographed frame by frame;
It is composed of an overload frame number setting switch 96 that sets the number of frames to be photographed during quick shooting, and an up/down switch 97 that instructs to increase or decrease the set value of the number of frames to be photographed. For example, the shooting mode selection switch 94 selects a single shooting mode when it is in the open state, and the continuous shooting mode when it is in the closed state, and the recording mode switch 96 selects, for example, field recording when it is in the open state. However, in the closed state, each frame is recorded.

The number of shooting frames setting switch 96 is a push switch, and if the number of shooting frames setting switch 96 is held down when the amplifier down switch 97 is switched to the contact UP side, the set value of the number of shooting frames will increase, and the contact DOWN will increase. With the up/down switch 97 switched to the side, switch 9
The configuration is such that if you keep pressing 6, the set value for the number of frames to be taken will decrease. This set value of the number of frames to be photographed is displayed on a liquid crystal display device 98.

Further, 99 is a buzzer for issuing a warning when there is no unrecorded track on the magnetic disk, that is, when the number of frames that can be photographed is zero.

Next, the contents of the program executed by the control circuit 82 are shown in FIG. In the same figure, power switch SW3 is set to O.
When the N state is reached, TLB is supplied to each circuit section of the photographing section and the electronic viewfinder. (Step 2'00,
Step 202). Next, release switch SW 1
is in the ON state, the auto power-off timer T is cleared, and power is supplied to each circuit section of the recording system (steer knobs 204, 206, and 208). Here, after the power switch SW3 is turned on, the timer T starts -
This is a timer for automatically cutting off the power supply when the release switch SWI is not operated for a certain period of time.

Furthermore, when the release switch SW2 is turned on in the second stroke of the pressing operation of the release button 90, the current track position of the magnetic head 64 on the magnetic disk 66 is determined from the detection output of the home position switch 100 and the motor drive circuit 60. It is detected based on the output drive pulse (steps 210 and 212).

Next, the control circuit 82 refers to a table stored in the ROM and retrieves data indicating the recording current value corresponding to the detected track of the magnetic disk 66, and sends it to the control amplifier 104 via the D/A converter 102. . Then, the gain of the preamplifier 86 is determined based on the output signal of the control amplifier 104, and a recording current is supplied to the magnetic head 64 so that the output signal is always at a constant level during reproduction (step 214).

FIG. 2 shows the relationship between the recording current supplied to the magnetic head 64 and the reproduction output. CA) to (C) in the figure are the first track, the 25th track, and the 25th track of the magnetic disk 66, respectively.
The curve P shows the characteristics obtained from the actual measurements on the 50th track.
Hz, and curve Q is 1.3 MHz. Figure 2 (A
) to (C) are collectively shown in FIG. 3 only for curve P. As is clear from the figure, when recording is performed with the same recording current, the reproduction level of the tracks on the inner circumferential side of the magnetic disk 66 decreases. Therefore, in order to make the reproduction level the same, for example, in the same figure, to make the reproduction level 0.4 mVP-P for the 1st, 25th, and 50th tracks, the recording current should be set to 17, 20, and 40 mAP-P, respectively.
Must be P. A table showing the relationship between each track and the recording current value created based on the actual measured values is stored in the ROM.

Now, in step 214, a predetermined recording current is applied to the magnetic heald 6.
At the same time, in step 214, a still image of the subject is recorded on a predetermined track of the magnetic disk 66 by the operation of the imaging section and each circuit section of the recording system. Only one truck is transferred.

Next, if the release switch SW2 continues to be in the ON state at the stage where image recording is completed, it is determined whether the shooting mode specified by the shooting mode selection switch 94 is the snapshot mode or not (step 218). .220
). If the shooting mode specified here is the continuous shooting mode, it is determined whether or not the shooting mode is ready, and if shooting is possible, steps 216 to 22 described above are performed.
2 is repeated (steps 218 and 220).
．． 222).

On the other hand, if the release switch SW2 is in the ON state and the shooting mode specified by the shooting mode selection switch 94 is the single shooting mode, the release switch SW2 waits until it becomes the FF state, and then the switch SW2 is turned on.
2 becomes OFF, the process returns to step 204 (steps 218, 220, and 224). If the release switch SW2 is turned off in step 218, the process similarly returns to step 204.

If the release switch SWi is not in the ON state when power is supplied to each circuit section of the overimage section and the electronic viewfinder and the subject image can be visually recognized in the electronic viewfinder, the auto power-off timer T is set to T. =X
(see), starts the timer T (step 202.2゜4.226), and turns the power switch SW
3 is in the ON state, the release switch SWI remains OFF until the timer T setting time) C (sec) has elapsed.
If the F state remains, the power switch SW3 is forced to the OFF state (steps 228 and 230).
.

On the other hand, after the power switch SW3 is turned on, the release switch SW1 is activated for the set time X (Sec) of the timer T.
If the timer T becomes ON within
Power is supplied to the recording unit (steps 228, 204.
206.208).

After power is supplied to the recording section and the recording preparation state is established, if the release switch SW2 is in the OFF state, it is determined whether the release switch SWI is in the ON state (steps 210 and 232). Here, if the release switch SWl is maintained in the ON state, the process returns to step 210 and the same determination is made.

On the other hand, when the release switch SWI is in the OFF state, the power supply to the recording section is stopped, the process returns to step 226, and the same process as described above is performed (step 232
．． 234).

Figure 3 shows power switch SW3 and release switch SW.
An example of the operation timing of SW2 is shown. In the figure, when the power switch SW3 is operated at time t1, the release switch SWI is turned OFF in the first stroke of the pressing operation of the release button 90, that is, at time L2.
The state is N, and then the second stroke of the release button 90,
That is, it becomes an ON state at time t3. and time t3
When time T2 has elapsed (time t4), release button 9 is pressed.
When you release your hand from 0, the release switch SW2 turns OFF at time t4, and then at time t5, that is, at an appropriate point in time T1 from time t2 when the release switch SWI turns ON, the release switch SWI turns OFF.
FF state [Effect of the invention] As explained above, in the present invention, a rotating recording medium such as a magnetic disk is driven to rotate, and a video signal is sent to each track while moving a magnetic head in the radial direction of the rotating recording medium. In a magnetic recording and reproducing device that records video signals or reproduces video signals from each track, when recording video signals on a rotating recording medium, the recording current supplied to the magnetic head is obtained from the 'LX Tll' head depending on the track position. According to the present invention, it is possible to reproduce images with constant image quality over all the tracks of the rotary recording medium.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the overall configuration of an electronic still camera to which the present invention is applied, and Figs. 2 (A) to (C) show recording currents and output voltages of the magnetic head in a plurality of specific tracks of a magnetic disk. FIG. 3 is a characteristic diagram comparing the characteristic diagrams shown in FIGS. 2(A) to (C) with respect to a specific frequency of the recording signal. FIG. 4 is a characteristic diagram showing the relationship between
FIG. 5 is a flowchart showing the contents of the program executed by the circuit. FIG. 5 is a timing chart showing an example of the operation timing of the power switch SW3 and the shirt release switches SW1 and SW2. 60...Motor drive circuit, 64...Magnetic head, 66...Magnetic disk, 82...Control circuit,
86...Preamplifier, 100...Home position switch, 102...D/A converter,
104...Control amplifier.

Claims (1)

[Scope of Claims] A magnetic device that rotationally drives a rotating recording medium such as a magnetic disk, and records a video signal on each track or reproduces a video signal from each track while moving a magnetic head in the radial direction of the rotating recording medium. In the recording and reproducing apparatus, the following steps are provided: track position detection means for detecting the current track position of the magnetic head on the rotating recording medium when recording a video signal; recording current supply means for supplying a recording current to the magnetic head; and the track position detection means. control means for taking in the detection output of the magnetic head and controlling the recording current supplied to the magnetic head according to the track position so that the level of the reproduced signal obtained from the magnetic head on each track is constant. magnetic recording and reproducing device.