JPS61104465A - Control circuit of optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform the recording/reproducing actions with no malfunction by detecting the discontinuousness of a synchronizing signal produced from an external input video signal to use this detection signal to decide that said video is switched frequently and waiting for synchronization of phase. CONSTITUTION:When the video signal sent from a video signal generating source 21 is switched frequently, the composite synchronizing signal produced from an external video signal contains noises owing to the switching noises. Then a frame signal has no cyclic properties and therefore the lock of a PLL circuit provided inside a reference signal producing circuit 23 is also released. This lock release is detected by a phase lock detecting circuit 47 of the circuit 23, and a signal of a low level is supplied to a system control 26 in the form of a phase lock signal (n). Under such conditions, no fault is detected at the control 26 and the circuit 27 is set at a high level. Then a recording or reproducing action is performed after a disk drive motor 19 reaches its stabilized rotational frequency.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides information such as a video signal on a disc-shaped recording medium.
It relates to an optical recording and reproducing device that records or reproduces information in the form of optical characteristic changes in this medium,
More specifically, the present invention relates to a control circuit when performing a recording operation on a medium using this apparatus.

[Background of the invention]

In optical recording and reproducing devices, a disk-shaped recording medium is generally used, and information signals are recorded on the disk-shaped recording medium as spiral or concentric recording loci, and are reproduced from there.

Concentric recording trajectories are suitable for recording information divided into fixed intervals, such as still image information; A recording trajectory (hereinafter referred to as a track) is suitable.

Furthermore, in order to be able to record information on a disk with high density, a guide track is generally provided on the disk, and when the guide track is formed, address information is also formed on the guide track. Address information is recorded by the phase change of the unevenness formed on the disk surface.
From the outer circumference (or inner circumference) of the disc to the inner circumference (or outer circumference)
Each track is recorded with a serial number.

In a disc with a guide track, address information is recorded on each track in an arc shape at a certain angle with respect to the center of the disc. Now, when recording an image line signal on one track of this disk, the address information section of this track must be located within the vertical retrace period of the image line signal. To do this, it is necessary to control the rotation of the disk motor so that the vertical synchronization signal of the Eirin signal and the address information part are recorded with almost the same phase.

For this purpose, it has been proposed to separately provide a rotation start end position mark at a position corresponding to the address information, as described in, for example, Ikai@57-105155. Well, using this rotation start position mark, JP-A-58-941
As described in No. 57, during recording, the disk motor rotates at a constant rotation speed in synchronization with the external input Eirin signal, and during playback, the disk motor rotates at a constant rotation speed in synchronization with the internal reference oscillator. let

Here, if the external input Eirin signal changes frequently during recording, the reference synchronization signal generated from the input Eirin signal becomes discontinuous, causing the disc motor to become out of synchronization, resulting in fluctuations in rotation speed. Phase disturbance occurs. On the other hand, system control, which controls the entire system,
We constantly check whether the disc motors are rotating in phase synchronization, and if the disc motors are not rotating in phase synchronization for a long period of time (for example, 30 seconds), it is determined that the system is operating abnormally. Generally, it operates in an attempt to stop the rotation. Therefore, as mentioned above,
Especially when trying to record information, for example, to select a desired one from among various types of bonds.

If the external input signal is switched frequently, the disk motor will be out of synchronization for a long time, and the system control will not be able to distinguish this from a general abnormal operation, so it will try to stop the rotation of the disk rotation motor and the information will not be recorded. The problem arises that it cannot be done.

[Purpose of the invention]

The present invention has been made in order to solve the problems with the prior art as described above, and an object of the present invention is to enable recording and playback without malfunction even if the external input video signal is frequently switched. The purpose of this invention is to provide various control circuits.

[Summary of the invention]

Therefore, in the present invention, in order to distinguish it from general abnormal operation, the discontinuity of the synchronization signal generated from the external input signal is detected, and the external input signal is frequently switched based on this detection signal. y in this state.
When the disk rotation motor is out of phase synchronization, the control method is configured to wait until the phase synchronization is achieved without determining whether there is an abnormality in the system.

[Example of actual invention]

The present invention will now be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram showing an example of a disk used in the present invention. As seen in the figure, in addition to the groove-shaped guide track 2, the disk 1 includes an address area 4 in which an address signal specific to each guide track is stored, and an address area 4 used for recording position alignment for each guide track. Mar
- Ri 3 is formed. In the figure, in order to simplify the explanation, only the spiral track 2 is shown, but it goes without saying that this may be a concentric track.

FIG. 2 is an explanatory diagram showing the structure of the optical head 16 for recording and reproducing used in the present invention.

In the figure, a light beam from a laser diode 5 is collimated by a collimating lens 6, passes through a polarizing beam splitter 7 and a 174-wave plate 8, and is focused onto a disk 1 as a light spot by an objective lens 10 attached to an actuator 9. The reflected light from the disk 1 is converted back into plain light by the objective lens 10,
After passing through the wavelength plate 8, the light beam is reflected by the polarization reflecting surface of the polarization beam splitter 7, and after passing through the convex lens 11, the light beam is divided into two by the mirror 12, one of which is sent through the concave lens 13 to receive the two-split light beam for detecting focus errors. One light beam enters the light receiving element 14, and the other light enters the two-split light receiving element 15 for detecting tracking errors.

FIG. 3 is a block diagram showing an example of an optical recording/reproducing device, which is the subject of the present invention. In the figure, 1 is a disk, 17 is a 7-point sensor for detecting recording positioning marks,
18 is a waveform shaping circuit, 19 is a disk motor, 20 is a disk motor drive circuit that controls the disk motor 19 so that one rotation of the disk 1 corresponds to one frame of the video signal, and 21 is a video signal generator such as a TV camera. source, 22
25 is a recording signal processing circuit, 25 is a reference signal generation circuit, 24 is a laser drive circuit, 25 is a keyboard for inputting various control commands, and 26 is a microcombi.

27 is a recording control circuit, 16 is an optical head shown in FIG. 2, 28 is a carriage on which the optical head 16 is mounted, 29 is a carriage 28
a carriage motor for moving the disk 10 in the radial direction; 30 is a carriage motor drive circuit; 31 is an I
-■ Conversion processing circuit, 32 is a reproduction signal processing circuit, 35 is T
34 is a focus control circuit, 35 is a tracking control circuit, 36 is an RF detection circuit for detecting the presence or absence of a reproduced RF signal, and 37 is an address demodulation circuit.

The Eirin signal from the Eirin signal generation source 21 is subjected to FM modulation in the recording signal processing circuit 22, and is input into the laser drive circuit 24 as an RF scratch signal. The laser drive circuit 24 receives the recording/reproduction switching signal (7) from the recording control circuit 27 at a high level H.
then high level H (or low level L if low level L)
), the output light of the laser mounted on the optical head 16 is modulated in intensity according to the input RF signal and irradiated onto the disk 1.
Information is recorded as changes in the reflectance of laser light from the disk 1. Also, during reproduction, if the recording/reproducing switching signal (7) from the recording control circuit 27 is at a low level L, it is set to a low level L (or if it is a high level H, it becomes a high level H), and the laser drive circuit 24 outputs a constant low output. The recorded information is irradiated onto the disc 1 with a light beam of I.
It is detected through the V conversion processing circuit 31, FM demodulated by the reproduction signal processing circuit 52, and the reproduction image is displayed on the TV receiver 33.

FIG. 4 is a schematic diagram showing the configuration of the reference signal generation circuit 23 which is used as a reference signal when controlling the disk motor 19. As shown in FIG. In the figure, 38 is a synchronization separation circuit, 59 is a synchronization signal detection circuit, 40 is a frame detection circuit for detecting the odd field (or even field) of the Eirin signal, and 41
42 is a phase comparison circuit, and 42 is a low-pass filter (hereinafter referred to as LP).
43 is a switch, 44 is a voltage controlled oscillator circuit (hereinafter referred to as vCO 5), 45 is a synchronizing signal generating circuit, 4
6 is a frame detection circuit, 47 is a phase lock detection circuit, 4
8 is a switch, 49 is a frame signal output terminal, and 50 is a phase lock detection signal output terminal.

The Eirin signal from the Eirin signal generation source 21 is input to a synchronization separation circuit 38, where a composite synchronization signal is extracted from the Eirin signal. The composite synchronization signal is further input to a frame detection circuit 40, where odd field (or even field) detection is performed.

The phase comparison circuit 41, LPF 42, VCO 44, synchronization signal generation circuit 45, and frame detection circuit 46 constitute a so-called PLL circuit, and the frame detection circuit 40
The frame signal of the frame detection circuit 46 and the frame signal (0) of the frame detection circuit 46 are controlled to be phase synchronized. Phase comparison circuit 4
1 is a digital phase comparator such as T050ml manufactured by Toshiba Corporation, and the synchronizing signal generating circuit 45 is an NTSC type composite synchronizing signal generator such as MN6064R manufactured by Matsushita Electric Co., Ltd., for example. The loop switch 43 is controlled by the output of the synchronization signal detection circuit 39.

The synchronization signal detection circuit 39 rectifies the input composite synchronization signal by, for example, known peak rectification, detects from this rectified voltage whether or not an external video signal is input, and detects the detected signal (p). The loop switch 43 is controlled to be turned on when there is an external video signal, and turned off when there is no external video signal. This detection signal (p) is also input to the system control 26 and is used to detect the presence or absence of an external video signal.

The phase lock detection circuit 47 is connected to the phase comparison circuit 41°VCO.
44, a synchronization signal generation circuit 45, etc.
This is to detect whether the circuit is phase-locked. When phase-locked, the high level H (or low level L) is detected, and when the external video signal is in the process of being pulled in due to various switching, the low level L (or low level) is detected. High level H)
becomes. This signal is input as a phase lock signal 4ir (n) to the system control 26 of FIG. 3 from the output terminal 50. Note that this signal also controls the switch 48, and when the pull-in process is in progress, the switch 48 is turned on and the synchronization signal generation circuit 45, for example MN6064
The frame signal of the frame detection circuit 4a is input to the R(DV-REST terminal).

FIG. 5 shows a block diagram of the disk motor control circuit 20. As shown in FIG. 54 is a phase comparison circuit, 55 is a phase compensation circuit, 56 is an amplifier circuit, 57 is an adder, 58 is a waveform shaping circuit, 59 is an F-V conversion circuit, 60 is an error amplifier circuit, 6
1 is a reference voltage for determining the target rotation speed, 62 is a phase compensation circuit, and 63 is a drive circuit.

The waveform shaping circuit 58, the F-V conversion circuit 59, the error amplification circuit 60, and the phase compensation circuit 62 are connected to the so-called disk motor 1.
A signal (m) from a frequency generator (not shown) attached to the disc motor 19 is input to the input terminal 65 in a speed control loop for controlling the speed of the disc motor 19.
After this signal is waveform-shaped by the waveform shaping circuit 58, the F
The voltage converted by the -V conversion circuit 59 is compared with a reference voltage 61 that determines the target rotation speed, and the rotation speed is controlled to be constant.

The phase comparator 54, phase compensation circuit 55, and amplifier circuit 56 are
This is a so-called phase control loop for controlling the rotational phase of the disk motor 19, and the frame signal (0) output from the output terminal 49 of the reference signal generation circuit 23 in FIG.
This frame signal (0) is input to the input terminal 52 in the figure.
The rotation of the disk motor 19 is controlled so that the phase error between the mark signal (1) of the waveform shaping circuit 1B inputted to the input terminal 55 and the mark signal (1) of the waveform shaping circuit 1B is reduced.

If the Eirin signal from the external Eirin signal generation source 21 is input without switching during recording or playback,
The frame signal generated from the external video signal and the frame signal (o) output from the frame detection circuit 46 in FIG.
) is in a phase-locked state, and the disk rotation motor 19
is the frame signal (o) output from the output terminal 49 of the reference signal generation circuit 23 shown in FIG. 4 and the waveform shaping circuit 18.
The rotation speed is controlled so that the phase of the mark signal (i) outputted from the rotor is in phase with the mark signal (i).

The Eirin signal '7'+5 from the Eirin signal generation source 21 is generated from the Eirin signal outside the busy area due to the switching noise when switching frequently to select a desired image from various image conditions. The composite synchronization signal generated by this signal contains noise, and the frame signal generated from this signal also becomes a signal without a period. Therefore, the PLL circuit provided inside the reference signal generation circuit 25 shown in FIG. The lock will also come off. This locking is detected by the phase lock detection circuit 47 of the 41st reference signal generation circuit 250, and a low level signal is inputted to the system control 26 as a phase lock signal (n).

In this state, although the rotational phase and rotational frequency of the disk rotation motor 19 are out of alignment, the system control does not judge it as an abnormal operation, and the phase lock detection circuit 47 of the reference signal generation circuit 23 in FIG. 4 goes to High level. After the disk rotating motor 19 reaches a stable rotational speed, each recording or reproducing operation is performed. FIG. 6 is a schematic flowchart showing the control method at this time.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to distinguish between a general abnormal operation and an abnormal operation of the disk rotation motor caused by switching the external input signal. There are no problems such as the rotation of the disk rotation motor stopping. It is also possible to inform the user of the cause of rotational deviation in the disk rotation motor.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of a disk, FIG. 2 is an explanatory diagram showing the configuration of an optical head, FIG. 3 is a block diagram showing an example of an optical recording/reproducing apparatus to which the present invention is implemented, and FIG. The figure is a block diagram showing one embodiment of the reference signal generation circuit 25.
FIG. 5 is a block diagram showing one embodiment of the motor control circuit 20, and FIG. 6 is a flowchart for explaining one embodiment of the control method of the present invention. 1... Disc, 2... Guide track, 3
...recording positioning mark, 4...address area of guide track, 5...laser diode, 6...collimating lens, 7...polarizing beam splitter-1 8...1/4 wavelength plate , 9...actuator,
10...Objective lens, 11...Convex lens, 12...
・Mirror, 13...Concave lens, 14, 15...2
Divided light receiving element, 16... Original head, 17... Photo sensor for detecting recording alignment mark, 18... Waveform shaping circuit, 19... Motor, 20...
...Motor control circuit, 21...Eirin signal generation source, 22...Recording signal processing circuit, 26...Reference signal generation circuit, 25...Keyboard, 26...System control, 32... Reproduction signal processing circuit, 34... Focus control circuit, 35... Tracking control circuit, 36... RF signal detection circuit. ¥11 Mouth height 2 concave

Claims (1)

[Claims] 1. Information is recorded by projecting a laser beam in the form of a light spot onto a track on the medium, and recorded information is reproduced from the track on the medium by receiving reflected light from the projected light spot. An optical recording and reproducing apparatus comprising: a detection means for a reproduction signal obtained by reproducing recorded information; a rotation means for rotating a recording medium; a control means for controlling the rotation means; and an external information signal input means. , a reference signal generating means for generating a reference signal that serves as a reference for the control means; a signal detecting means for detecting the presence or absence of an external information signal; A controllable signal generation circuit that generates a synchronized signal; and a phase lock detection circuit that detects that an external information signal and an output signal of the controllable signal generation circuit are phase-synchronized, the phase lock detection circuit comprising: 1. A control circuit for an optical recording and reproducing apparatus, characterized in that the abnormal operation of the rotating means is discriminated and controlled according to the output of the rotating means. 2. In the control circuit according to claim 1,
When a signal indicating a phase-locked state is output to the output of the phase lock detection circuit, the rotating means operates normally after a signal indicating a phase-locked state is output to the output of the phase lock detection circuit. 1. A control circuit for an optical recording and reproducing device, characterized in that the control circuit performs control after inspecting whether the