JPH0896505A - Laser disk player - Google Patents

Abstract

PURPOSE: To reproduce video and audio of a laser disk without interuption. CONSTITUTION: At the time of search operation, a mode signal (search) is supplied from a system controller 24 to a servo circuit 25, and the servo circuit 25 moves a pickup 1 to a required position. During the searching, the pickup 1 can not read correctly information on the laser disk 2. Thus, the system controller 24 controls so as to read out the EFM demodulation signal read out in advance from CD-under and stored in a memory 15. The EFM demodulation signal read out in a video CD decoder 16 is demodulated and outputted as a digital information signal. Then, a video signal is outputted through a D/A converter 17 and an NTSC encoder 18, and an audio signal is outputted from the D/A converter 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser disc player capable of reproducing a reproduced image of a laser disc player without interruption.

[0002]

2. Description of the Related Art Conventionally, in the laser disc format, a video signal is FM-modulated at 4 to 14 MHz and an analog stereo audio signal is 2.3 MHz and 2.8 MHz.
It is FM-modulated by and recorded on the laser disk.
Furthermore, EFM (Eight to Fourteen Modu
The modulated digital audio signal, that is, the CD under is recorded.

Here, a block diagram of a conventional signal system of a laser disc player is shown in FIG. The signal recorded on the disc 2 is taken out from the pickup indicated by 1,
An RF signal is output. A system computer (hereinafter referred to as syscon) 39 controls the pickup 1 via a servo circuit 40. In reproducing the video signal, the RF signal supplied from the laser disk 2 is separated by a BPF (Band Pass Filter) 3, and the FM modulated video signal from the BPF 3 is supplied to the FM demodulator 4.

The FM demodulator 4 demodulates the FM-modulated video signal, and the reproduced video signal from the FM demodulator 4 is supplied to a TBC (Time Base Corrector) 5.
The reproduced video signal is subjected to jitter correction in the TBC 5 and supplied to one input terminal 6 of the switch 32.
Under the control of the system controller 39, the switch 32 switches between the input terminal 6 to which the video signal is supplied and the other input terminal 31 which is grounded, and supplies a desired signal to the output terminal 33.

Further, the reproduction of the analog audio signal is
The RF signal supplied from the laser disk 2 is BPF7.
Then, the FM-modulated audio signal from the BPF 7 is supplied to the FM demodulator 8. The FM demodulator 8 demodulates the FM-modulated audio signal and supplies the analog audio signal.
It is supplied to the CX decoder 9. The analog audio signal is subjected to noise reduction in the CX decoder 9 and is output as a reproduced audio signal by the switch 37.
Is supplied to one of the input terminals 10.

Further, when reproducing the digital audio signal, the RF signal supplied from the laser disk 2 is LP.
It is separated by an F (Low Pass Filter) 13 and the output signal of the LPF 13 is supplied to the EFM demodulator 14. The EFM demodulator 14 performs processing such as EFM demodulation and error correction. E
The digital audio signal from the FM demodulator 14 is D
In the / A converter 34, an audio signal converted into an analog signal and reproduced is supplied to the other input terminal 35 of the switch 37.

One of the audio signals supplied to the input terminal 10 and the input terminal 35 is selectively taken out to the output terminal 38 by the switch 37 controlled by the syscon 39. Further, during the search operation, the pickup 1 is moved independently of the video signal and the audio signal, so that the image and the sound are disturbed, so that the muting is performed by the control of the syscon 39 so that the switch 37 is grounded. Switched to connect with 36.

[0008]

As described above, during the search operation, the reproduced video signal and reproduced audio signal are muted by the switch 37. Therefore, there is a problem that video and audio are interrupted during the search operation. In addition, when reproducing a double-sided disc in which signals are recorded on both sides, when the pickup moves from one side to the other side, there is a problem that video and audio are similarly interrupted.

Therefore, an object of the present invention is to provide a laser disk player capable of interpolating a period in which a reproduction signal is interrupted in view of the above.

[0010]

The present invention provides a first FM.
A laser disk in which a signal obtained by frequency-multiplexing a first digital signal and a second digital signal, which are compression-encoded on the low frequency side of the frequency band of the modulated signal and the second FM modulated signal, is recorded. In the laser disc player to reproduce, the first read from the laser disc,
And memory means for storing the second digital signal,
While the reproduction of the first and second FM modulated signals is interrupted,
The laser disk player is characterized by comprising means for outputting the first and second digital signals from the memory means.

[0011]

The digital signal recorded based on the video CD format from the CD under of the laser disc while the pickup moves from the A side to the B side of the laser disc being reproduced or the pickup cannot read the signal due to the search operation. Etc. are supplied to the EFM demodulator, the EFM demodulated signal is stored by connecting a memory after the EFM demodulator, and the EFM demodulated signal is read from this memory to reproduce the digital signal and the like. That is, even if the pickup cannot read the signal,
And the sound can be played back without interruption.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a laser disc player according to the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of an embodiment of a signal system of a laser disc player of the present invention. In FIG.
In the laser disc shown by 2, an FM-modulated analog audio signal, an FM-modulated analog video signal (hereinafter referred to as an analog information signal), and a CD under are frequency-multiplexed and recorded. In the CD under, a digital audio signal and a digital video signal (hereinafter referred to as digital information signal) having the same contents as the above analog information signal are recorded. The digital information signal is, for example, an MPEG (Moving Picture image).
It is compressed by a code such as coding Experts Group 1) and recorded in the same data format as a CD (Compact Disc). Such a signal is called a video CD format.

During reproduction, the syscon 24 to the servo circuit 25
The servo circuit 25 to which the mode signal of reproduction is supplied, and the mode signal (reproduction) is supplied controls the servo of the pickup 1 such as focus and tracking to operate normally according to the mode signal (reproduction). Is done. The pickup 1 uses this servo circuit 25
The information on the laser disk 2 can be correctly read by the control from. R supplied from laser disk 2
The F signal is transmitted from the BPF 3, FM demodulator 4, TB as described above.
A video signal is supplied to one input terminal 6 of the switch 11 via C5, and similarly, an RF signal is supplied to the input terminal 10 of the switch 22 via the BPF 7, FM demodulator 8 and CX decoder 9. It

The system controller 24 includes a switch 11,
By controlling 1 and 22, one input terminal 6 of the switch 11 is connected, a video signal is taken out from the output terminal 12, one input terminal 10 of the switch 22 is connected, and an audio signal is output from the output terminal 23. Taken out. RF read from the laser disk 2
The signal is also supplied to the LPF 13, and the CD under is separated in the LPF 13. The output signal of the LPF 13 is supplied to the EFM demodulator 14. EFM demodulator 14
Performs processing such as EFM demodulation and error correction.

The EFM demodulated signal (video CD format signal) from the EFM demodulator 14 is supplied to the memory 15. The syscon 24 performs control so as to store the output signal of the EFM demodulator 14 in the memory 15. Memory 1
5 can store an EFM demodulated signal for 10 seconds, for example.
This time is determined in consideration of the time required for access during the search operation and the time required for switching the playback surface.

The EFM demodulated signal read from the memory 15 under the control of the syscon 24 is a video CD decoder 1.
Demodulated at 6. This video CD decoder 16 is a CD
It is composed of a ROM decoder and an MPEG decoder, and generates a digital video signal and a digital audio signal from the supplied video CD format signal. In the D / A converter 17, the digital video signal supplied from the video CD decoder 16 is converted into an analog video signal and supplied to the NTSC encoder 18. In the D / A converter 20, a video CD
The digital audio signal supplied from the decoder 16 is converted into an analog audio signal, and the switch 22
Is supplied to the other input terminal 21 of. The NTSC encoder 18 converts the supplied analog video signal to NTSC.
It is converted into a signal and supplied to the other input terminal 19 of the switch 11.

Here, when the search operation is performed during reproduction of the laser disc player of this embodiment, the mode signal of the search operation is supplied from the syscon 24 to the servo circuit 25, and the mode signal (search) is supplied. The servo circuit 25 moves the pickup 1 to a desired position according to this mode signal (search). During this search operation, the pickup 1 cannot correctly read the information on the laser disk 2. That is, the analog information signal cannot be reproduced normally. Then, the syscon 24 controls to read the EFM demodulated signal stored in the memory 15. Similarly, the syscon 24 controls the switch 11 to be connected to the input terminal 19, and the video signal is taken out from the output terminal 12. The switch 22 is controlled by the syscon 24 to be connected to the input terminal 21, and the audio signal is taken out from the output terminal 23. In this way, from the memory 15 to the EFM after the search operation is completed, the video and audio are reproduced.
The output signal of the demodulator 14 is read.

When a compressed signal having the same content as the currently reproduced analog information signal is recorded on the CD under, as described above, this memory 15 is located before the currently reproduced analog information signal. EFM for 10 seconds
The output signal of the demodulator 14 is recorded. Further, the compressed signal recorded on the CD under may be advanced by 10 seconds from the analog information signal actually reproduced. In this case, if the search operation is within 10 seconds, the video and audio after the start of the search operation are reproduced. Further, there is no problem if the currently reproduced analog information signal and the EFM demodulated signal recorded on the CD under are not the same in content.

Here, as another embodiment, when reproducing both sides of a laser disc using a laser disc player, first, an analog information signal of the A side of the laser disc moves the pickup 1 from the inner circumference to the outer circumference. Then, after the reproduction of the A side is completed, the pickup 1 moves to the inner circumference of the B side, and the B side is reproduced. Playback is interrupted for a few seconds when switching surfaces. During this time, the compressed signal recorded under the CD is reproduced. That is,
A compressed signal is read from the CD under 10 seconds before the end of reproduction on the A side, and the read compressed signal is processed and stored in the memory 15. Then, under the control of the system controller 24, the video signal stored in the memory 15 is taken out from the output terminal 12, and similarly, the audio signal is taken out from the output terminal 23. After the reproduction from the memory 15 is completed, the pickup 1 has already moved to the inner circumference of the B side, so that the B side reproduction is started.

Here, a timing chart of an example of this double-sided reproduction is shown in FIG. FIG. 2 shows a case where reproduction is performed in order of the A side of the laser disk, the CD under of the A side, and the B side. FIG. 2A shows the reproduction of the side A of the laser disk, where the analog information signal of the side A laser disk is reproduced and then the digital information signal of the CD under is reproduced. FIG. 2B shows reproduction of the B side of the laser disk, and the analog information signal of the B side laser disk is reproduced. While the signal shown in FIG. 2C is high level,
When the A side of the laser disk is reproduced and the signal shown in FIG. 2D is at a high level, the CD on the A side of the laser disk
Under reading is performed. While the signal shown in FIG. 2E is at a high level, reproduction of the CD under read read in FIG. 2D is performed. The laser disc is reproduced while the signal shown in FIG. 2F is at a high level.

FIG. 3 is a timing chart showing an example of a case where a CD under is used for long-time reproduction. This FIG. 3 shows the laser disk A side, A side CD under, B side, B side CD under, A side CD
The case where the reproduction is performed in the order of the under and the CD under of the B side is shown. FIG. 3A shows the reproduction of the side A of the laser disk. After the analog information signal of the side A laser disk is reproduced, the CD-under-digital information signal of the side A is reproduced. FIG. 3B shows the reproduction of the B side of the laser disk. After the analog information signal of the B side laser disk is reproduced, the CD under digital information signal of the B side is reproduced.

[0022]

According to the present invention, since the information recorded on the laser disk cannot be read, such as when the pickup is moving from the side A to the side B during the search operation or the reproduction of the double-sided disk, the image and the sound are reproduced. While not recorded, by reproducing the digital video signal / digital audio signal of the video CD format recorded on the CD under, it is possible to output the image on the monitor without interruption.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a laser disc player of the present invention.

FIG. 2 is a timing chart showing an example of double-sided reproduction of a laser disk according to the present invention.

FIG. 3 is a timing chart showing an example of long-time reproduction of the laser disk according to the present invention.

FIG. 4 is a block diagram showing an example of a conventional laser disc player.

[Explanation of symbols]

 1 Pickup 2 Laser Disc 3, 7 BPF 4, 8 FM Demodulator 5 TBC 9 CX Decoder 13 LPF 14 EFM Demodulator 15 Memory 16 Video CD Decoder 17, 20 D / A Converter 18 NTSC Encoder 24 Syscon 25 Servo Circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // G11B 20/18 560 J 8940-5D

Claims (2)

[Claims] 1. A first digital signal and a second digital signal compression-encoded on the low frequency side of the frequency band of the first FM modulated signal and the second FM modulated signal are frequency-multiplexed. In a laser disc player for reproducing a laser disc having the recorded signal, the memory means for storing the first and second digital signals read from the laser disc, and the first and second FMs. A laser disk player comprising: means for outputting the first and second digital signals from the memory means while the reproduction of the modulated signal is interrupted. 2. The laser disc player according to claim 1, wherein the first and second digital signals are compression-encoded and recorded on the laser disc. player.