JPS62170072A - Reproducing device for discoid rotary recording medium - Google Patents

Abstract

PURPOSE:To reproduce a signal stably even when the recording mode is changed over into the reproducing device by applying the control so that the drive of the rotary recording disk medium at reproduction is in the same speed as the phase lock state by the phase comparison control at recording. CONSTITUTION:A control signal from a floppy disk drive motor 5 is waveform- shaped by a P.G. (pulse generator) amplifier 7 and the result is inputted to a speed control circuit 12. The circuit 12 detects the speed of the motor 5 depending on the period of the P.G. signal to control the drive speed of the motor 5 in response to the output of a phase comparator 11. When the comparator 11 is not reset, the motor 5 is controlled so that the phase difference between the phase of a vertical synchronizing signal 104 inputted to the comparator 11 and the phase of the P.G. signal is 7H+ or -2H and when the comparator 11 is reset, the motor 5 is subjected to speed control in the same sped at the phase lock. Through the control above, the drive control of the motor 5 is not disturbed even when the mode is changed over from the recording mode into the reproducing mode and the stable reproduction without the disturbance of pattern is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical outline of the invention! iF) The present invention relates to a disc-shaped rotating recording medium during playback by a playback device for a disk-shaped rotating recording medium or a recording/playback device having recording and playback functions. Regarding the rotating side i'in (background of the invention) In recent years, a system called a still video floppy system for recording and reproducing still images using a flexible disc-shaped magnetic medium (floppy disk) has been standardized. . This still video floppy system records one field of still image video signals endlessly on one track of a floppy disk, and the rotation of the floppy disk is controlled as follows. Pulse generating means (for generating one or more pulses per rotation to obtain a rotational phase signal of the floppy disk)
(hereinafter referred to as P and G), and in order to minimize screen disturbance when the playback head is moved between tracks during playback, during recording, the vertical dome signal of the video signal to be recorded and the floppy P, which is the rotational phase signal of the disk;
The rotation of the floppy disk drive motor is controlled by a phase comparison control method so that the output signal (P, G, signal) of Vertical synchronization of the synchronization signal generator built into the playback device (align the phase of No. 3, and It was used in place of the vertical synchronization signal of the recorded video signal to control the rotation of the floppy disk drive motor using a phase comparison control method.

If the rotation of the floppy disk is controlled as described above during recording and reproduction, the following problems will occur.

When switching from recording mode to playback mode on a recording/playback device, for example, if you want to record TV broadcast waves on a floppy disk and then immediately switch to playback mode and watch the playback image on the TV screen, the vertical distance during recording! Since the phase of the IJ1 signal is unrelated to the phase of the vertical synchronization signal of the synchronization signal generator built into the recording/playback device, the phase comparison control method is used to drive the floppy disk when switching from recording mode to playback mode. The rotation control of the motor usually enters a phase lockout state, and it takes a long time to lock from that state, and during this time the screen played on the TV becomes distorted, making it unsightly.

In order to avoid this, the rotation of the motor may be controlled by a phase comparison control method using a vertical synchronization signal included in a television broadcast wave from outside during recording even during reproduction.

However, in this case, if the receiving channel is changed during playback, the phases of the television broadcast wave channels are unrelated, so the motor rotation control using the phase comparison control method normally enters a phase lockout state. It takes a long time to lock from the state, and during that time the reproduced image on the TV screen is distorted and unsightly.Also, when the external video signal disappears during playback (for example, when an empty channel is received or when the broadcast is interrupted). There is also a drawback that the TV screen is distorted even when the program is finished (for example, when the program is finished). The above-mentioned drawbacks occur not only when recording television broadcast waves, but also when recording video signals from an external source (for example, video signals from a VTR, etc.).
There is a drawback that the television screen becomes distorted when the external video signal disappears. Therefore, in the recording mode, the vertical synchronization signal of the video signal to be recorded and +1.0. The signal is used to control the phase of the floppy disk drive motor, and the synchronization signal generator built in the recording/playback device is reset to synchronize with the video signal for recording. During playback, the reset built-in recording/playback device is synchronized with the video signal for recording. The above problem can be solved by controlling the phase of the floppy disk drive motor using the vertical synchronization signal of the synchronization signal generator, but it requires switching of the vertical synchronization signal input to the circuit for resetting the synchronization signal generator and the servo circuit. This has the drawback that it requires additional means and the configuration is complicated.

Furthermore, when the above-described reproduction method is adopted, there is a drawback that the configuration of a reproduction-only device becomes complicated.

(Purpose of the Invention) The present invention is a recording/playback device that solves these drawbacks (for the purpose of recording/playing). The purpose of the present invention is to obtain a recording/reproducing device for a disk-shaped rotating recording medium that can stably reproduce images without disturbance of the screen depending on the configuration.
The purpose is to obtain a device exclusively for car reproduction.

(4th Requirement of the Invention) The present inventor states that ``During playback, if the period of the vertical synchronization signal of the reproduced video signal is a predetermined period, it is not necessarily necessary to match the phase, and if the predetermined period is obtained, the rotation speed Based on this discovery, the present invention was completed based on this discovery.The present invention was developed based on this discovery. The technical point is to control the rotational speed of the disk-shaped rotating recording medium so that the speed is the same as the phase-locked state due to the four rotations.

(Embodiment) The figure is a block diagram of a still video floppy system which is an embodiment of the present invention, where ■ indicates a floppy disk,
2 is a magnetic recording/reproducing head, 3 is a reproduction amplifier, 4 is a recording amplifier, 5 is a floppy disk drive motor, and 6 is a plurality of (
A frequency generator (hereinafter referred to as F, G,
), 7 is an F that shapes the waveform of the output signals of F and G.
, G, amplifier, and the output signal of the amplifier 7 is referred to as F, G, signal 6 8 is a pin-shaped permanent magnet (hereinafter P, 9 is a coil that detects the magnetic force of the P, G, pin (hereinafter referred to as p, c, coil); 10 is an amplifier that amplifies the output signal of the P, G, coil 9 (hereinafter referred to as p, c); , amplifier), and the P, G
, the output signals of the amplifier 10 are referred to as P, G, signals.

The P, C, pin 8, P, C, coil 9, P, G, and amplifier 10 are configured to generate one P, G, and signal lot per rotation of the floppy disk 1.

11 is a phase comparator, 12 is a speed control circuit, 102 is a reproduced video signal, 103 is a recorded video signal, 104 is a vertical synchronizing signal synchronously separated from the recorded video signal 103, and 105 is a signal that resets the phase comparator 11 and In the reset state, the phase comparator 11 is configured to output the same signal as when the floppy disk drive motor 5 is in the phase locked state.

Next, the operation will be explained. The control of the Flo, P disc drive motor 5 is performed by F, G, waveform shaped by the amplifier 7.
The signal is input to speed control circuit 12. Speed control circuit 1
2, the speed of the floppy disk drive motor 5 is detected based on the cycles of the F, G and signals, and the rotational speed of the floppy disk drive motor 5 is controlled in accordance with the output of the phase comparator 11. Therefore, when the phase comparator 11 is not reset, the phase of the vertical synchronization signal 104 input to the phase comparison wall is 7H±2H with respect to the phase of the p, c, and signals.
The floppy disk drive motor 5 is adjusted so that the phase difference is
When the phase comparator 11 is reset, the speed of the floppy disk drive motor 5 is controlled at the same speed as when the phase is locked.

Although the embodiment described above uses a magnetic floppy disk, other disc-shaped rotating recording media may be used.

As mentioned above, the floppy disk drive motor 5 whose phase is controlled during recording does not require phase control during playback, so the phase comparator 11 is reset and the motor 5 is controlled at the same speed as in the phase locked state. For example, even when switching from the recording mode to the playback mode, the rotational control of the floppy disk drive motor 5 is not disturbed, and stable playback without screen disturbance is possible. Furthermore, although the above embodiment describes a recording/playback device, the present invention can of course also be applied to a playback-only device (playback device) that plays back what has been recorded by another recording device.
In that case, the circuit becomes simpler because phase comparison is not required.

(Effects of the Invention) As described above, according to the present invention, the floppy disk drive motor 5, whose phase is controlled during recording, resets the phase comparator 11, since phase control is not required during playback. Since the control is performed at the same speed as in the locked state, the rotation control of the floppy disk drive motor 5 will not be disrupted even when the recording/playback device is switched from recording mode to playback mode, allowing stable playback without screen disturbances. It is. Furthermore, in the playback mode, the speed of the floppy disk drive motor is controlled to 11 on the rotation side, so the time from startup to stabilization can be shortened.

In addition, as mentioned above, during playback, it is sufficient to control at the same speed as in the phase lock state, so in a playback-only device,
Since all that is needed is a circuit for controlling the speed, there is no need for a phase comparator circuit, and the advantage is that the circuit can be simplified, the cost can be reduced, and the device can be made smaller.

[Brief explanation of drawings]

The figure is a block diagram showing an embodiment of the present invention. (Explanation of symbols of main parts) 1-----・---1---Floppy disk 2--
−m−−・−1−−−−・−Magnetic recording/reproducing head 3−
−1−−−−−−−−・−・Reproduction amplifier 4 −1−−−
------- Recording amplifier 5 --------1 ------- Floppy disk drive motor 6 ----1-p, G. 7−−−−−−−−−−−−−−−−F, G, amplifier 8−=−−−−P, G, pin

Claims (1)

[Claims] (1) P.C. generates one or more pulses per rotation of a disc-shaped rotating recording medium on which video signals are recorded in endless tracks. G. and said P. G. The P. output from G. In a playback device for a disk-shaped rotating recording medium, in which the rotation of the disk-shaped rotating recording medium is phase-comparison-controlled and recorded so that the signal and the vertical synchronization signal of the video signal are in a phase-locked state, the recording is performed during playback. A reproducing apparatus for a disk-shaped rotating recording medium, characterized in that the rotational speed of the disk-shaped rotating recording medium is controlled so that the rotational speed of the disk-shaped rotating recording medium is the same as the rotational speed in a phase-locked state by phase comparison control.