JPH0430788B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to an apparatus for recording signals on a disk-shaped rotating recording medium (hereinafter simply referred to as a disk) such as a magnetic disk, an optical disk, or a magneto-optical disk.

(Background of the Invention) Conventionally, in disk rotation control of a device for recording signals on a disk, phase control is used to control the rotational phase of a motor in accordance with the phase of a reference clock signal. With this phase control, it is possible to control the rotational speed with higher precision than with speed control that detects and controls the rotational speed, but compared to speed control, phase control is more accurate from the time the motor starts until the rotational speed becomes stable. That is, phase control has the disadvantage that it takes time to lock-in.

By the way, for example, in a disk rotation control device used in a small electronic still camera that integrates a recording device using a magnetic disk, one of the magnetic disks is
Comparing the phase of the output of a rotational phase signal generator (hereinafter abbreviated as PG) that generates one or more pulses per rotation with the phase of the vertical synchronization signal of the video signal to be recorded on the magnetic disk, Rotation control, ie phase control, of the motor for rotating the magnetic disk is performed so that the phase difference between the two signals becomes a predetermined value. For example, portable devices such as electronic still cameras have a built-in battery as a portable power source, and since the capacity of this battery is limited, the rotation of the disk is developed just before recording the signal, and the rotation is stopped as soon as the recording is finished. It is preferable to take measures to minimize power consumption due to disk rotation. For this reason, countermeasures are taken, such as starting the rotation of the disk by pressing the shutter button halfway or by some other method in conjunction with the photographing operation. In such electronic still cameras, images cannot be recorded from the time the desk starts rotating until the camera locks in, so it is necessary to shorten the time from startup to lock-in as much as possible.

Furthermore, portable disk signal recording devices, such as small electronic still cameras that incorporate the magnetic disk recording device, are different from stationary devices such as floppy disk drive devices and video disk devices. Unlike,
Since the disk drive device itself is held by hand and follows the subject, the disturbance torque applied to the motor varies considerably, and there is a possibility that the rotation of the disk may deviate from the locked state. In this case, as well as when starting up, video cannot be recorded, so
After locking out, it was necessary to minimize the time it took to lock back in.

However, with conventional rotational control using phase control, it has been difficult to shorten the time required for lock-in.

(Object of the Invention) The object of the present invention is to solve these drawbacks and provide a disk recording device that can immediately bring the rotation of the motor into the same state as the phase lock state only when necessary.

(Summary of the Invention) The present invention controls the rotation of a disk by speed control to achieve the same speed as the rotation speed in a phase lock state by phase control in an extremely short period of time, and synchronizes the signal when recording a signal. The technical point is to create a state similar to a phase lock state by generating a signal to match the rotational phase of the disk. For example, in a small electronic still camera with an integrated magnetic disk recording device, one field or one image is recorded in one shooting operation.
Since only a frame's worth of video signals are recorded on the magnetic disk, the still image signal is transferred to the magnetic disk by keeping the disk in the same state as the phase-locked state only during recording. By generating the vertical synchronization signal of the still image signal in accordance with the rotational phase of the disk when recording on the disc, a state similar to a phase lock state is created, and the rotational speed of the motor can be effectively controlled without the need for time-consuming phase control. By controlling only the control, the time required to lock-in at the time of startup and the like described above is shortened.

(Embodiment) Fig. 1 is a block diagram of an embodiment of the present invention, in which 1 is a motor, 2 is a magnetic disk, 3 is a magnetic recording head, and 4 is an analog switch, which is turned on and off when the control input C is at the H level. It turns off at the level,
5 is a frequency generator (hereinafter abbreviated as FG) that generates N pulses per rotation of the magnetic disk 2; 6 is a rotational phase signal generator that generates one or more pulses per rotation of the magnetic disk 2; (below
PG) 7 is a speed control circuit that controls the voltage applied to the motor so that the pulse interval of the output of FG 5 becomes a predetermined value. 8 is a synchronization signal generator which divides the frequency of the reference lock of the crystal oscillator to generate a synchronization signal, and when the input of the reset terminal is changed from the H level to the L level, it starts from the falling position of the vertical synchronization signal. 9, 10, 11, 1
2 is a D flip-flop (hereinafter abbreviated as DFF) and 13 is a monostable multivibrator (hereinafter abbreviated as MM). 14 is an imaging device including an imaging lens and an imaging device such as a CCD; 15
1 is a drive circuit that drives the imaging device 14, and 16 is a video signal processing circuit that processes video signals from the imaging device. 101 is FM recorded on magnetic disk
Modulated video signal, 102 is a vertical synchronization signal, 1
03 is a recording command signal, and for example, in an electronic still camera with a built-in mechanical shutter, a shutter close signal is used, or an exposure completion signal is used when an electronic shutter function of an image sensor is used.

FIG. 2 is a timing chart according to an embodiment of the present invention, in which A is a recording command signal 103 and B is a timing chart according to an embodiment of the present invention.
Output of DFF9, C is PG signal, D is DFF10
E is the output of the MM 13, F is the vertical synchronization signal (hereinafter abbreviated as VD signal) 102. G is DF
The output of F.11 is the output of DFF12.

The operation of the embodiment of the present invention will be explained below using FIGS. 1 and 2.

This embodiment is an example of an electronic still camera that records video signals for one field obtained in one photographing operation on independent endless tracks. The motor 1 is controlled only in speed by a speed control circuit 7 based on the signal from the FG 5, but not in phase. Therefore, the time it takes for the rotational speed to stabilize after starting the motor can be much faster than when phase control is applied. When the photographer presses the shutter button and the exposure to the image sensor is completed, the recording command signal 103a is output, and the recording command signal a becomes H.
When the level is reached, DFF9 is reset and DF
Output B of F.9 becomes L level. The output of DFF9 is input to the clock input of DFF10, and DF
As the output of F.9 falls, the output D of DFF10 becomes H level. The PG signal C is input to the reset input of the DFF10, and after the output N of the DFF10 rises to the H level, the DFF10 is reset by the first PG pulse A, and the DFF10 is reset.
The output D falls to the L level, and the falling edge of the DFF10 causes the MM13 to output a pulse H of a constant width. The pulse width of this MM 13 determines the phase difference between the rising edge of the PG signal pulse and the falling edge of the VD signal. While the output H of MM13 is at H level, the synchronizing signal generator 8 is reset, and the M.
The synchronizing signal generator 8 outputs the VD signal 102 in accordance with the falling edge of the output E of M.13. moreover
The output H of the MM 13 is also input to the clock input of the DFF 11, and the output H of the DFF 11 becomes H level in synchronization with the fall of the output H of the MM13. The output of DFF11 is input to the reset terminal of DFF12, and when the output of DFF11 goes to H level, the reset is released, and the PG signal is input to the clock input of DFF12, and DFF1 is reset.
The output CH of No. 2 becomes H level at the next PG pulse B after PG pulse A, and becomes L level at the next PG pulse C. The analog switch 4 is turned on only while the output of the DFF 12 is at H level. DFF1
The output chip of 2 is input to the clock input of DFF9, and it is output in accordance with the falling edge of the output chip of DFF12.
The output of DFF9 becomes H level, and DFF11
Reset.

As described above, when the recording command signal 103 based on the completion of exposure of the image sensor 14 is input to the DFF 9,
The next rising edge A of the PG signal generates a VD signal with a predetermined phase difference, and the analog switch 4 is turned on during the period from the rising edge B of the next PG signal to the next rising edge C, and the video signal 1
01 is recorded on the magnetic disk 2 by the magnetic recording head 3. Here, the time between B and C is the time it takes for the disk to rotate once, which is a very short time, and the phase difference between the PG signal and the VD signal at times B and C is determined by the speed control of the magnetic disk with sufficient accuracy. If it is, there will be no large fluctuations, and it is considered to be the same as when phase control is used, and the rise time at startup and the recovery time when disturbance is applied are only speed controlled in the case of the present invention. , it is possible to significantly shorten the time compared to the case of phase control.

If a mechanical shutter is used as the exposure control means, vibrations will always occur upon completion of exposure, and these vibrations may have an adverse effect on disk rotation control and the contact state between the magnetic head and disk sheet. However, if the present invention is used, actual recording will be performed when the vibration has almost subsided, making it possible to avoid the adverse effects caused by the mechanical shutter as described above.

In the embodiment of the present invention, a case has been described in which a video signal for one field is endlessly recorded on one track of a magnetic disk in one shooting operation, but one frame on one track or one frame on two tracks is recorded. It is clear that it is possible to similarly shorten the start-up time and the time for the disk to return to its rotational state due to disturbance torque in the case of recording. Further, the recording medium is not limited, and disks made of various storage materials can be used, and the signals to be recorded are not limited to still image signals, but various analog and digital signals can be recorded.

(Effects of the Invention) As described above, according to the present invention, when the recording time is as short as one rotation or several rotations of the disk, the synchronization signal of the video signal is kept constant with the rotational phase signal of the disk only during recording. By shifting the phase so that the relationship of Recovery time can be extremely shortened.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a timing chart of an embodiment of the present invention. Explanation of symbols of main parts, 1...Motor, 2...
Magnetic disk, 3... Magnetic head, 4... Analog switch, 5... FG,, 6... PG, 7... Speed control circuit, 8... Synchronous signal generator, 9, 10,
11, 12...DFF, 13...MM, 14...
...imaging device, 15...drive circuit, 16...video signal processing circuit, 101...FM modulated video signal, 102...VD signal, 103...recording command signal.

Claims (1)

[Claims] 1. In a disk recording device that records a video signal from an imaging means on a rotating disk-shaped recording medium in response to a recording command signal, a vertical synchronization signal generating means for generating a vertical synchronization signal of the video signal to be recorded; A driving means for driving the imaging means based on a synchronization signal, a rotational phase signal outputting means for outputting a rotational phase signal according to a rotational phase of the disk-shaped recording medium, and a rotating means for rotating the disk-shaped recording medium at a predetermined speed. and phase shifting means for shifting the phase of the vertical synchronization signal in response to the recording command signal so that the vertical synchronization signal has a predetermined phase difference with respect to the rotational phase signal. Recording device.