JPS58158007A - Recording and reproducing device using disc-like recording medium - Google Patents

Abstract

PURPOSE:To correct the drop-out only the address signal part, by using the AND of a pulse which synchronize with a detecting signal of revolution detecting marks and include the period for reproducing address information, and a detecting pulse for drop-out. CONSTITUTION:An address signal and a color signal included in a reproduced signal are removed with an HPF25 from the reproduced signal. A signal processed with an address signal processing circuit 13 is inputted to a control circuit 14 and a pulse circuit 28 for detecting drop-out. A changeover switch circuit 29 is controlled by a detecting pulse for drop out of a detecting pulse circuit 28 for drop-out. If there is no detecting pulse for drop-out in the circuit 29, the circuit 29 transmits the output signal of the HPF25 to a video signal processing circuit 12. If there is said pulse, the signal delayed with a 1HDL circuit 26 is transmitted to the circuit 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording and reproducing device that records and/or reproduces video information signals in real time on concentric or spiral guide tracks provided on a disc-shaped recording medium (disk). This system is characterized by a means for correcting the address information part recorded in advance on the guide trunk using a dropout correction circuit.

An example of the configuration of a general optical disc/device is shown in FIG.

1 is a light source such as a laser, 2 is a light receiver that receives reflected light from the disk 7, 3 is a half mirror, and 4 is a tracking device.
5 is an objective lens for focusing the light beam to about 1 μmφ or less; 6 is a voice coil for moving the objective lens 6 up and down to focus it on the disk surface; 7 is a reflective optical disk.

8 is a disk motor for rotating the disk 7 at a constant speed, and 9 is a preamplifier.

Light emitted from a light source 1 passes through a half mirror 3, is reflected by a tracking mirror 4, is focused by an objective lens 5 to a spot of 1 μm or less, and is irradiated onto a disk 7. The light beam is subjected to intensity or polarization depending on the unevenness or density of the disk 7, passes through each of the elements 5, 4, 3, and is input to the light receiver 2, where a signal is reproduced from the preamplifier 9.

Generally speaking, in optical disc devices capable of recording and reproducing, there are two methods: one method is to record address information including the address information in a recording signal such as a video signal, and the other is a method where the address information part is recorded in advance on a guide track that has been cut. There is.

In the former case, an address signal generating section must also be provided on the disk device, making the device expensive. The latter not only does not require an address signal generator, but also allows recording on the guide track at a predetermined address while reading the address signal already present in the guide track, making it easy to realize random access recording.

In the following description, a disc will be described in which a guide track has an address signal unique to that track recorded in advance.

FIG. 2 shows an example of a disc on which a digital address signal is recorded in advance on the guide trunk.

In the figure, only one guide trunk N is shown for the sake of simplicity. n, , n2 of this guide track N indicate a portion in which a unique address signal assigned in advance to this guide track is recorded. When recording a signal on the guide track N, when reproducing a recorded signal, or when searching this guide track, this address signal is reproduced from the preamplifier 9 in FIG. is used to confirm that the light beam is scanning. Furthermore, when recording a video signal on this information trunk, for example, a wideband video signal is recorded over the entire guide track H in real time.

The video signals recorded in real time are as follows.

Performs signal processing. It is common practice to FM-modulate a video signal with a carrier signal of an appropriate frequency, convert this into a binary signal using a limiter, etc., and record and reproduce the video signal as a long or short recording bit length.

Next, in order to detect one rotation of the disk, a prerecorded groove 10 is provided on an extension of the address signal section in the radial direction of the disk, in addition to the recording area on the disk, as shown in FIG. Hereinafter, this will be referred to as the V mark.

This V mark can be formed by adhesion of aluminum foil or vapor deposition of mirror material, but in consideration of positional accuracy and productivity, the information track address signal part is formed using unevenness, similar to the method used to form the address signal part. It can also be formed together when forming .

The present invention will be explained below.

The positional relationship between the address signal preliminarily recorded on the disk and the video signal to be recorded will be explained using the waveforms shown in FIG. FIG. 3a shows a V mark signal recorded on the disc. For this V mark, a detection pulse is output from the detector every time the disk rotates once. This V mark is used as a reference signal to control the disk motor drive circuit by comparing it with a vertical synchronizing signal separated from the video signal during recording. This keeps the motor's rotation speed constant. Here, it is assumed that the motor rotates at 1800 rpm. FIG. 3 shows an address signal recorded on the disk, and the ■ mark is recorded in synchronization with the mark as described above, and the synchronization is one-half of the V mark. FIG. 3C shows an FM modulated signal for recording a video signal. A signal recorded and reproduced on the disk by directly or indirectly driving a laser using the signal shown in FIG. 3C is shown in d.

A signal obtained by demodulating the reproduced signal shown in d by a demodulator is shown in e. e is an enlarged view of a part of the demodulated signal. As shown in e, the reproduced FM signal is interfered with by the address signal, and the demodulated signal is disturbed.

Therefore, the present invention corrects the disturbance of the reproduced FM signal and the disturbance of the demodulated signal caused by the address signal mentioned above.

FIG. 4 shows a schematic configuration of a specific recording/reproducing apparatus and will be described below. In FIG. 4, 7 is a disk, 18 is a guide track provided on the disk 7, and 1o is a V mark provided on the disk 7.

The light driven by the laser drive circuit 11 passes through the aperture optical system 3.4.
The aperture lens 6 illuminates the disk 7 through the diaphragm lens 6 to record a video signal on the guide track 18 or reproduce a prerecorded signal.

When reproducing the recorded signal on the disc 7, the light reflected from the disc 7 is received by the light receiver 2 and the video signal processing circuit 12 receives the reflected light from the disc 7.
is played. Reference numeral 13 denotes a circuit that extracts and processes only address information from the reproduced signal.

Reference numeral 14 denotes a control circuit for determining address information and sending out control commands for the apparatus, and is mainly composed of a microcomputer or the like. 16 is a control and drive circuit for a disk motor that rotates the disk 8. 146 is a detector composed of a light emitting diode, a phototransistor, etc. to detect the V mark 1o. 17 is a waveform shaping circuit that processes the reproduced V mark signal from the detector 16.

The V mark signal from this waveform shaping circuit 17 is input to the motor drive and control circuit 16 and is used as a reference signal for the rotation of the disk motor 8! FIG. 6 shows an example of the configuration of the detector 16 and waveform shaping circuit 17 of the V+-ri 1o shown in FIG. Identical numbers are the same as described above.

The detector 16 is a light emitting diode light source 19. It is composed of a phototransistor light receiver 2o, and converts the amount of light reflected by the V mark 100 on the disk 7 into an electrical signal and outputs it. The output of the light receiver 2o is transmitted through an amplifier 21 and a bandpass filter 22.
．． The signal is inputted to a waveform shaping circuit 17 composed of a comparator 23 and outputted from a terminal 13 as a V mark signal. FIG. 6 shows an example of waveforms at each part in FIG. 5. The waveform f in FIG. 5 is the output waveform of the light receiver 20. A in the waveform f is a DC fluctuation waveform caused by uneven reflectance of the disk 9, and the opening and opening' are waveforms of the V mark signal. The waveform g is the output waveform of the bandpass filter 22 from which the high frequency components and low frequency components of f are removed. The dotted line shown together with waveform g indicates the comparison voltage level input to the terminal of comparator 23. The waveform 2 is the output waveform of the comparator 23, and indicates the mark signal (■), and the period from opening to opening' corresponds to one rotation period of the disk.

Next, the address signal processing circuit 13 will be explained.

i in FIG. 7 is a reproduced signal obtained by amplifying the output from the photoreceiver 2. In order to extract the address signal component from this signal, the signal j is passed through a low-pass filter. One of the signal components of the signal j is a low-frequency converted version of the color signal component of the video signal (for example, 626 kHz). The other component is pre-recorded on the disc, for example 2
This is a PIC (7z-sampling) address signal of 20KHz to 6soKHz. They are in the same frequency band and are very difficult to separate. Next, the signal of j is compared with a comparison voltage shown by a dotted line using a comparator or the like, and the extracted signal is shown as k. The originally desired signal is a pulse only during the address signal period. However, the level ratio between the level of the video signal recorded and reproduced on the disk and the level of the address signal recorded in advance changes due to variations in the reflectance of the disk. This makes it difficult to separate the two using the aforementioned comparator or the like.

Therefore, the method shown in FIG. 8 is used to extract only the address signal period on the disk.

The waveform shown in FIG. 81 is the same signal waveform as that shown in FIG. 6 described above. m is the same address signal as shown in FIG. Next 1
At the rising edge of the V mark signal, a monostable multivibrator (hereinafter referred to as M) or the like generates a pulse with a delay time T1 located between the two V mark signals. Next, from this pulse T1, a pulse O having a delay time T2 slightly longer than the reproduction period of the address information is generated by MlM or the like. Similarly, at the rising edge of the V mark signal l, a signal p having a delay time T3 including the next V mark signal period is generated. Here, it is assumed that the pulse width of the o and p waveforms OT2 is wider than that of the address signal of m. Next is the aforementioned 0. Q indicates the logical sum of the signals of p. Q is used for the dropout correction pulse described below.

The configuration of a dropout correction circuit for correcting the address signal period is shown in FIG. 9 and will be described.

The signal recorded on the disk 7 is extracted by the optical receiver 2. This signal is amplified by a preamplifier 24. The amplified signal is the one shown in FIG. 7 described above, and this signal is input to the HPF 2B and the LPF 27. The address signal and color signal contained in the reproduced signal are removed from the reproduced signal by the HPF 25. This reproduced signal is transmitted through a delay circuit (I HDL) for one horizontal scanning period, which is a dropout correction circuit.
circuit) 26 and the changeover switch circuit 29. Next, looking at the address signal of waveform l in FIG. 7, the reproduced signal of the preamplifier 24 is a signal j in FIG. 7 in which the high-frequency luminance component is removed by the LPF 27.

This signal is input to the address signal processing circuit 13. The signal processed by the address signal processing circuit 13 is input to the control circuit 14 and the dropout detection pulse circuit 28. The dropout detection pulse of the dropout detection pulse circuit 28 (
The changeover switch circuit 29 is controlled by k) in FIG.

The changeover switch circuit 29 sends the output signal of the HPF 25 to the video signal processing circuit 12 when there is no dropout detection pulse, and sends the output signal of the HPF 25 to the video signal processing circuit 12 when there is the above-mentioned pulse.
The delayed signal via the DL circuit 26 is sent to the video signal processing circuit 12. This corrects dropouts. In the pulses shown in FIG. 7, pulses appear in areas other than the address signal portion.

This occurs because the frequency bands of the address signal and color signal component are in the same band. If the difference between the level of the address signal of the reproduced signal shown in FIG. 7j and the color signal level is small, it will be difficult to discriminate with a comparator as shown in FIG. 7k. If the dropout correction pulse of FIG. 7j described above is used to correct the dropout of the reproduced signal, the drawout correction will be performed even when no dropout has occurred. In other words, dropout correction is performed even on the normal portion of the image signal.

Therefore, in order to solve the above-mentioned problem, an explanation will be given using FIG. 10.

In FIG. 10, '' indicates the dropout detection pulse mentioned above. Figure 10 Q' is the pulse Q explained using Figure 8.
It is. The pulse R is the logical sum of the pulses ' and Q'. The present invention uses this H pulse to perform dropout correction on the address signal portion. As explained using FIG. 9, if dropout correction is performed using the R signal, only the address signal portion is corrected for dropout, and dropout correction can be performed without affecting other portions.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of an optical information recording device, FIG. 2 is a plan view showing an example of a disk used in the present invention, and FIG. 3 is a diagram showing a waveform of a reproduced signal from the disk. , FIG. 4 is a block diagram showing a schematic configuration of the optical information recording device, FIG. 6 is a block diagram showing an example of the V mark detection means, FIG. 6 is a waveform diagram explaining the same operation, and FIGS. 7 and 8. 9 is a block diagram showing the configuration of a dropout correction circuit, and FIG. 10 is a diagram showing the waveform of a dropout correction pulse according to the present invention. 2... Light receiver, 13... Address signal processing circuit, 24... Preamplifier, 25... H
PF, 26...1H delay circuit, 27...
・LPF, 28...dropout detection pulse circuit, 29...changeover switch circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 5
Figure 6 Figure 7 @ Figure 8

Claims (1)

[Claims] (1) Address information is recorded at a predetermined position on the recording trunk, and a one-rotation detection mark is provided at a certain rotation angle position from the address information recording position. From the reproduction signal from the trunk, a first pulse indicating a period in which the reproduction signal is at a predetermined level or higher is created, and a first pulse is generated which is synchronized with the detection signal of the one rotation detection mark and includes the reproduction period of the address information. 1. A recording/reproducing apparatus using a disk-shaped recording medium, characterized in that a dropout correction means for the reproduced signal is operated during an AND output period of the first and second pulses. (a) A recording/reproducing apparatus using a disc-shaped recording medium according to claim 1, wherein the pulse width of the second pulse is wider than the pulse width of the first pulse.