JPH01118267A - Reproducing device for recording disk with high density - Google Patents

Abstract

PURPOSE:To reproduce only digital voice out of a digital voice signal and a video signal by providing a means which sets the rotating speed of a spindle motor at the optimum value to reproduce a digital signal including a synchronizing signal by the output of a synchronization extracting means. CONSTITUTION:A switch 34 is set at an H side at the time of reproducing a video area, and the output of an EFM filter 33 is inputted to a digital voice demodulation circuit 35 and a digital voice synchronization extraction circuit 36, and the digital voice synchronization extraction circuit 36 extracts a synchronizing signal component from an input signal and sends it to a phase comparator 37. The output of a digital voice reference synchronization generation circuit 38 is connected to the input on the other side of the phase comparator 37, and the output of the phase comparator 37 is inputted to a servo circuit 40, and the rotation of the spindle motor 42 is controlled so as to be synchronized with the digital voice by the output of the servo circuit 40, and an audio signal demodulated at the digital voice demodulation circuit 35 is outputted from a terminal 43.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for reproducing only digital audio from a high-density recording disc, such as a video disc, on which digital audio signals and video signals are recorded.

2. Description of the Related Art In recent years, high-density recording disc playback devices such as video disc players and compact disc players have become widespread. One of these is CDV (compact disc video), which was introduced to the market as an application field for compact discs, in which digital audio signals are recorded on the inner circumference.
Digital audio and FM modulated video signals are recorded on the outer periphery by frequency multiplexing, and it is expected that various types of CDV players will be introduced into the market in the future. In particular, it is expected that an inexpensive CDV player, which does not have a video output and can reproduce only the digital audio from the inner and outer circumferences of a CDV, will be introduced into the market to be incorporated into an audio system that does not have a video monitor.

An example of the above-mentioned conventional high-density recording disk reproducing apparatus will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of a conventional high-density recording disk reproducing apparatus C. In the figure, 1 is a high-density recording disk, 2
is a pickup, 3 is a first switch, 4 is a bypass filter, 5 is a video demodulation circuit, 6 is a horizontal synchronization extraction circuit,
7 is a video reference synchronization generation circuit; 8 is a first phase comparator;
9 is a first servo circuit, 1o is an EFM filter, 11 is a digital audio demodulation circuit, 12 is a digital audio synchronization extraction circuit, 13 is a VCXO (variable frequency crystal oscillator port g),
14 is a second switch, 15 is a digital audio reference synchronization generation circuit, 16 is a second phase comparator, 17 is a second servo circuit, 18 is a third switch, 19 is a spindle motor, 2o is a control circuit, 21 is a third servo circuit, 22 is a constant voltage source, and 23 and 24 are terminals.

FIG. 3 is a diagram showing the recording area of a high-density recording disk. In the figure, a is the digital audio area and b is the video area.

The operation of the conventional high-density recording disk reproducing apparatus constructed as described above will be explained below.

In FIG. 3, a digital audio signal including a synchronizing signal (hereinafter referred to as an EFM signal because it is EFM modulated on a compact disc) is recorded at a. In b, an EFM signal and an FM modulated video signal are frequency-multiplexed and recorded. The frequency component of the EFM signal is 2M
Hz or less, the frequency components of the FM modulated video signal are 3
The frequency is not less than MHz and not more than 13 MHz. Therefore, the frequency components of the signal recorded in a and the signal recorded in b are significantly different. Since the maximum frequency that can be recorded on a high-density recording disk is mainly proportional to the rotational speed of the high-density recording disk, the recording rotational speed is changed between a and b in this high-density recording disk.

In FIG. 2, a pickup 2 converts signals recorded on a high-density recording disk 1 into electrical signals. When reproducing the digital audio area a in FIG. 3, the first switch 4 is set to the A side. Therefore, the pickup output is directly input to the digital audio demodulation circuit 11 and the digital audio synchronization extraction circuit 12. At this time, the second switch 14 is set to the C side, and the fixed voltage generated by the constant voltage source 22 is input to the control voltage of the VCXO 13.

Therefore, the vCXo 13 oscillates a fixed frequency clock, and the clock is transmitted to the digital audio reference synchronization generation circuit 16.
Enter. The digital audio reference synchronization generation circuit 16 is
The frequency of the clock is divided to generate a digital synchronization signal of a regular frequency.

The digital audio synchronization extraction circuit 12 extracts a synchronization signal component from the input signal and sends it to the second phase comparator 16. Second
The output of the digital audio reference synchronization generating circuit 15 is connected to the other input of the phase comparator 16. Second
The output of the phase comparator 16 is input to the second servo circuit 17, and at this time, the third switch 18 is set to the E side, and the system spindle motor 3 receives the output of the second servo circuit 17. controlled by That is, the spindle motor 19 is controlled so that the frequency of the output signal of the digital audio synchronization extraction circuit 12 becomes equal to the frequency of the output signal of the digital audio reference synchronization generation circuit 15. At this time, the audio signal demodulated by the sidigital audio demodulation circuit 11 is output from the terminal 23.

When the video area shown in FIG. 3 is being reproduced, the output signal of the pickup 2 includes an EFM signal and an FM modulated video signal. Among the converted signals, the FM modulated video signal extracted by the bypass filter 4 is input to the video demodulation circuit 5. The reproduced signal converted into a video signal by the video demodulation circuit is output to the terminal 24 and simultaneously sent to the horizontal synchronization extraction circuit 6. The horizontal synchronization extraction circuit 6 extracts only the horizontal synchronization signal from the input video signal. The video reference synchronization generation circuit 7 generates reference synchronization of the horizontal synchronization frequency that a regular video signal has. The output of the horizontal synchronization extraction circuit 6 and the output of the video reference synchronization generation circuit 7 are input to the first phase comparator 8 . The output of the first phase comparator 8 is input to the first servo circuit 9. At this time, the third switch 18 is set to the F side and the first
A spindle motor 19 is controlled by the output of the servo circuit 9. That is, the spindle servo system 19 is controlled so that the frequency of the output signal of the horizontal synchronization extraction circuit 6 becomes equal to the frequency of the output signal of the video reference synchronization generation circuit 7.

At this time, since the first switch 3 is set to the B side, the output of the EFM filter 1o is input to the digital audio demodulation circuit 11 and the digital audio synchronization extraction circuit 12. The EFM filter 1o has pE as the output of the pickup 2.
Only FM signal components are passed. The digital audio synchronization extraction circuit 12 extracts a synchronization signal component from the input signal and sends it to the second phase comparator 16. The other input of the second phase comparator 16 is connected to the digital audio reference synchronization generation circuit 1.
5 outputs are connected. The output of the second phase comparator 16 is input to the third servo circuit 17, and at this time,
The second switch 14 is set to the D side, and the output of the third servo circuit 17 is input to the control voltage of the VCXOl3. At this time, the above-mentioned connection υ, spindle motor 1
Since 9 is controlled by the first servo circuit 9, the EFM signal and FM signal recorded on b of the high-density recording disk 1 are controlled by the first servo circuit 9.
Since the recording speeds of the modulated video signals are the same, the output of the digital audio synchronization extraction circuit 12 should be at the normal frequency, but in reality, the frequency is slightly shifted from the normal frequency due to residual errors in the spindle servo system. (2) The CXo 13 absorbs this by slightly shifting the digital audio reference synchronization frequency from the normal frequency. That is, the second
This is achieved by inputting the output of the phase comparator 16 to the third servo circuit 19 to control the oscillation frequency of the VCXOl 3 using the phase error detected by the second phase comparator 16. Note that this causes a slight frequency fluctuation in the audio signal output to the terminal 23, but this does not pose a practical problem.

The control circuit 20 switches the first switch 3 and the second switch 14 depending on which of the two areas a and b in FIG. 3 is to be reproduced.
, and the third switch 18 respectively.

Problems to be Solved by the Invention However, in a high-density recording disc playback device with such a configuration, in the digital audio area, the synchronization signal included in the digital audio signal is used to apply servo to the spindle servo system.
In the video area, the spindle motor is servoed by the horizontal synchronization signal included in the video signal. Therefore, even when providing a high-density recording disk playback device that can only reproduce digital audio in both the digital audio and video areas and does not have a video output, it is not necessary to use a video demodulation circuit or a synchronization separation circuit. The drawback was that the density recording disk reproducing device was expensive.

Means for Solving the Problems In order to solve the above problems, the high-density recording disk reproducing apparatus of the present invention includes a pickup that converts the signals recorded on the high-density recording disk into an all-electric signal, and a synchronous signal from the pickup output. a filter for extracting all digital signals including the synchronization signal; a synchronization extraction means for extracting a synchronization signal from the filter output; and a servo means for adjusting the rotational speed of the Nubindle motor to an optimal value for reproducing the digital signal including the synchronization signal by the output of the synchronization extraction means. Equipped with.

Effects of the Invention With the above-described configuration, the present invention provides a digital audio synchronization signal in a double-head area of a high-density recording disk having an area where only digital audio is recorded and an area where digital audio and video signals are frequency-multiplexed. By controlling the rotation of the spindle motor, it is possible to provide a high-density recording disc playback device that can play back only digital audio in the double-head range at a low cost.

Embodiment Hereinafter, a video signal reproducing device according to an embodiment of the present invention will be described.
This will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the structure of a high-density recording disk reproducing apparatus according to an embodiment of the present invention. In the figure, 31 is a high-density recording disk, 32 is a pickup, 33 is an EFM filter, 34 is a switch, 35 is a digital audio demodulation circuit,
36 is a digital audio synchronization extraction circuit, 37 is a phase comparator, 38 is a digital audio reference synchronization generation circuit, 39 is a crystal oscillation circuit, 4o is a servo circuit, 41 is a control circuit, 42 is a spindle motor, and 43 is a terminal.

The operation of the high-density recording disk reproducing apparatus according to one embodiment of the present invention constructed as described above will be described below.

A pickup 32 converts the video signal recorded on the high-density recording disk 31 into an electrical signal.

When reproducing the digital audio area a of FIG. 3, the switch 34 is set to the G side. Therefore, the pickup output is directly input to the digital audio demodulation circuit 11 and the digital audio synchronization extraction circuit 12. Crystal transmitter circuit 39
oscillates a clock with a constant frequency, and the digital audio reference synchronization generation circuit 38 divides the frequency of the clock to generate a reference synchronization signal that is equal to normal digital audio synchronization.

The digital audio synchronization extraction circuit 36 extracts a synchronization signal component from the input signal and sends it to the phase comparator 37. The other input of the phase comparator 37 is connected to the output of the digital audio reference synchronization generating circuit 38. The output of the phase comparator 37 is the servo time gf! r40, and the spindle motor 42 is rotationally controlled by the output of the servo circuit 40 so as to synchronize the digital audio. At this time, the audio signal demodulated by the sidigital audio demodulation circuit 35 is output from the terminal 43.

When the video area shown in FIG. 3 is being reproduced, the output signal of the pickup 2 includes an EFM signal and an FM modulated video signal. At this time, since the switch 34 is set to the H side, the output of the EFM filter 33 is input to the digital audio demodulation circuit 35 and the digital audio synchronization extraction circuit 36. The crystal oscillator circuit 39 oscillates a clock with a constant frequency, and the digital audio reference synchronization generating circuit 38 divides the frequency of the clock to generate a reference synchronization signal that is equivalent to regular digital audio synchronization. The digital audio synchronization extraction circuit 36 extracts a synchronization signal component from the input signal,
The signal is sent to the phase comparator 37.

The other input of the phase comparator 37 is connected to the output of the digital audio reference synchronization generating circuit 38. The output of the phase comparator 37 is input to the servo circuit 4°, and
The spindle motor 42 is rotationally controlled by the output of the servo circuit 40 so as to synchronize the digital audio. At this time, the audio signal demodulated by the digital audio demodulation circuit 35 is output from the audio signal 43.

The control circuit 41 operates to switch the switch 34 depending on which region a or b in FIG. 3 is to be reproduced.

As described above, one embodiment of the present invention includes a pickup, an EFM filter, a switch, a digital audio demodulation circuit, a digital audio synchronization extraction circuit, a phase comparator, a digital audio reference synchronization generation circuit, and a crystal. By including a transmitting circuit, a servo circuit, a control circuit, a spindle motor, and a terminal, a high-density device with an area where only digital audio is recorded and an area where digital audio and video signals are frequency-multiplexed is recorded. By controlling the spindle motor twice in the double-headed area of the recording disk using a digital audio synchronization signal, it is possible to provide a high-density recording disk playback device that can reproduce only the digital audio in the double-headed area at a low cost. .

Effects of the Invention As described above, the video signal reproducing device of the present invention includes a pickup that converts signals recorded on a high-density recording disk into electrical signals, a spindle motor that rotates the high-density recording disk, and a pickup. a filter for extracting a digital signal including a synchronization signal from an output; a synchronization extraction means for extracting a synchronization signal from the filter output; By providing a servo means for adjusting the optimum value to the digital signal, the digital It becomes possible to provide at low cost a high-density recording disk reproducing device that can reproduce only audio and does not have a video output.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a high-density recording disk reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a conventional high-density recording disk reproducing apparatus, and FIG. 3 is a high-density recording disk reproducing apparatus. FIG. 3 is a perspective view showing a recording area of a recording disk. 31...High-density recording disk, 32...Pickup, 33...EFM filter, 34...
...Nuitch, 35...Digital audio demodulation circuit, 36...Digital audio synchronization extraction circuit, 37...Phase comparator, 38... Digital audio reference synchronization generation circuit, 39...Crystal oscillation circuit, 4o...Servo circuit, 41...
...control m times g, 42...spindle motor,
43...Terminal. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure b-11 Bidet X Cold η Publication (

Claims (1)

[Claims] In a high-density recording disk reproducing device that reproduces a high-density recording disk having an area in which a digital signal including a synchronization signal and an FM modulated video signal are frequency-multiplexed, the signal recorded on the high-density recording disk is electrically transmitted. a pickup for converting into a signal; a spindle motor for rotating the high-density recording disk; a filter for extracting a digital signal including the synchronization signal from the pickup output; and a synchronization extraction means for extracting the synchronization signal from the filter output. , servo means for adjusting the rotational speed of the spindle motor to an optimum value for reproducing the digital signal including the synchronization signal by the output of the synchronization extraction means.