JP3080648B2 - Switching device for playback speed of optical disc - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for switching the reproduction speed of an optical disc reproduced at a constant linear velocity (hereinafter referred to as CLV).

2. Description of the Related Art In recent years, the penetration rate of optical disc playback devices has increased due to cost reductions, securing their position as high-quality music sources, and as DATs (digital audio tapes) have spread, they have also played an important role as digital dubbing sources. Plays. Hereinafter, an example of a conventional optical disc playback speed switching apparatus will be described with reference to the drawings.

FIG. 3 is a block diagram showing a conventional optical disk reproducing speed switching device. In FIG. 3, 1
Is an optical pickup for reading signals recorded on the optical disk D. The optical disk D is rotated by the spindle motor 2. The focus and tracking of the optical pickup 1 are controlled by the focus / tracking control device 3. Reference numeral 4 denotes a signal processing device, which constitutes a PLL by comparing a reproduction signal obtained from the optical pickup 1 with a reference clock, and
Is controlled to be in the CLV state, and the digital audio signal is reproduced. The digital audio signal obtained from the signal processing device 4 is configured to be subjected to digital signal processing by a digital mute device 5 to be muted. Reference numeral 6 denotes a clock generator for generating a basic clock for signal reproduction. The clock signal of the clock generator 6 is divided by a frequency divider 7 and
Sent to Reference numeral 8 denotes a timer device that counts a predetermined time. Reference numeral 9 denotes a reproduction speed input device, which inputs a reproduction speed and controls the frequency dividing device 7, the digital mute device 5 and the timer device 8 by the input signal.

The operation of the conventional optical disc playback speed switching device configured as described above will be described below.

First, when an optical disk (hereinafter, abbreviated as "disk") D is loaded, a signal recorded on the disk D is read by the optical pickup 1, and a reproduction signal obtained by the optical pickup 1 is read by a focus / tracking control device. 3 and the optical pickup 1 is fielded back and controlled. On the other hand, the reproduced signal is also input to the signal processing device 4. The clock signal generated by the clock generator 6 is frequency-divided by the frequency divider 7 and input to the signal processor 4 as a basic clock for signal reproduction. The signal processing device 4 forms a PLL by comparing the phase of the basic clock with the reproduction signal from the optical pickup 1, and controls the rotation of the spindle motor 2 so that the disk D rotates in the CLV state. The signal processing device 4 reproduces a digital audio signal from the reproduction signal obtained by the optical pickup 1. This digital audio signal is transferred to the D / A converter or digital audio interface at the subsequent stage via the digital mute device 5.

When the reproduction speed is switched by the reproduction speed input device 9 in the state where the reproduction is performed, the frequency dividing device 7 is first controlled to set the frequency dividing ratio as shown in FIG. Mute,
Activate the timer device 8. Since the basic clock input to the signal processing device 4 changes by changing the frequency division ratio, the CLV state up to that point is lost, and the spindle motor 2 is fed back so as to be drawn back into the CLV state. Then, the timer device 8 notifies that the predetermined time has elapsed.
The mute is released by giving a command to the digital mute device 5 at that time. The above operation flowchart is shown in FIG.

However, in the above-described configuration, when the reproduction speed is switched, mute is applied for a predetermined time and then the mute is simply released. Due to a difference in the lock range or the like, the reproduced sound may be output without the disk D rotating in the CLV state. As a result, there is a problem that digital noise is generated and a problem that the reproduction portion for the predetermined time is not reproduced.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an optical disk playback speed switching device that does not generate digital noise even when the playback speed is switched during playback, and that does not cause a missing playback portion.

Means for Solving the Problems In order to solve the above problems, the optical disk playback speed switching device according to the present invention is obtained from a signal processing device in comparison with a conventional optical disk playback speed switching device. A current position storage device for storing current position information of the optical pickup included in the subcode signal, and a logical operation device are provided, and the logical operation device controls and accesses a focus / tracking control device and the signal processing device. Perform an operation or a reproducing operation, control a frequency divider of a clock signal by a signal of a reproducing speed input device, control a digital mute device, and store current position information included in a subcode signal in the current position storage device. Giving an access operation command to access the stored position, and detecting the CLV state from the signal processing device. It was done.

Operation According to the present invention, when the playback speed is switched during playback, the current position information of the position at which the playback speed was switched is stored in the current position storage device, and the stored position is accessed while being muted. , The access operation is terminated after detecting the CLV state, and the mute is released. As a result, there is no digital noise due to the CLV state, and there is no part that is not played back to access the position where the playback speed was switched to resume playback, and there is no missing playback part. Become.

Hereinafter, an apparatus for switching the reproduction speed of an optical disc according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an apparatus for switching the reproduction speed of an optical disk according to an embodiment of the present invention.
In FIG. 1, reference numeral 10 denotes an optical pickup for reading a signal recorded on a disk D. The disk D is rotated by the spindle motor 11. Optical pickup 10
The focus and tracking are controlled by the focus / tracking control device 12. Reference numeral 13 denotes a signal processing device which composes a PLL by comparing a reproduction signal obtained from the optical pickup 10 with a reference clock, controls the spindle motor 11 to be in a CLV state, and reproduces a digital audio signal and a subcode signal. I do. The digital audio signal obtained from the signal processing device 13 is configured to be subjected to digital signal processing by a digital mute device 14 to be muted. Reference numeral 15 denotes a clock generator for generating a basic clock for signal reproduction. The clock signal of the clock generator 15 is frequency-divided by a frequency divider 16 and sent to a signal processor 13. Reference numeral 17 denotes a reproduction speed input device for inputting a reproduction speed. Optical pickup 10
Is included in the subcode signal obtained from the signal processing device 13 and stored by the current position storage device 18.

Reference numeral 19 denotes a logical operation device, which controls the focus / tracking control device 12 and the signal processing device 13 to perform an access operation and a reproduction operation, and controls a clock frequency dividing device 16 by a signal from a reproduction speed input device 17, Digital mute device
While controlling the current position information included in the subcode signal in the current position storage device 18, an access operation command is issued to access the stored position, and the CLV state is transmitted from the signal processing device 13. To detect.

The operation of the apparatus for switching the reproduction speed of the optical disk constructed as described above according to one embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

First, when the disk D is mounted, a signal recorded on the disk D is read by the optical pickup 10,
The reproduction signal obtained by the optical pickup 10 is input to the focus / tracking control device 12, and the optical pickup 10 is field-backed and controlled. On the other hand, the reproduced signal is also input to the signal processing device 13. The clock signal generated by the clock generator 15 is
Signal processing device as the basic clock for signal reproduction
Enter in 13. The signal processing device 13 compares the phase of the basic clock with the reproduction signal from the optical pickup 10 and performs PLL.
The rotation of the spindle motor 11 is controlled so that the disk D rotates in the CLV state. Signal processing device 13
Is, from the reproduction signal obtained by the optical pickup 10,
The digital audio signal and the subcode signal are reproduced. Digital audio signal is digital mute device
Via 14, it is transferred to the D / A converter or digital audio interface at the subsequent stage.

When the playback speed is input to the playback speed input device 17 in such a playback state, the playback speed input device 17 transfers the playback speed information to the logical operation device 19.

The logical operation device 19 controls the frequency dividing device 16 so as to achieve the set reproduction speed, and sets the frequency dividing ratio of the clock,
The digital mute device 14 is used to mute. Then, the current position information is stored in the current position storage device 18 as an access point, and an access operation is performed toward this access point. Then, the signal processing device 13 detects that the vehicle has reached the access point and is in the CLV state, ends the access operation, releases the mute using the digital mute device 14, and resumes the reproduction operation.

As described above, according to the present embodiment, the current position storage device 18 that stores the current position information of the optical pickup 10 obtained from the signal processing device 13 with respect to the conventional optical disc reproduction speed switching device, A logical operation device 19 is provided, and the logical operation device 19 controls the focus / tracking control device 12 and the signal processing device 13 to perform an access operation and a reproduction operation. Controlling the frequency divider 16 and controlling the digital mute device 14, while storing the current position information included in the subcode signal in the current position storage device 18, an access operation command is issued to access the stored position. Give
By detecting the CLV state from the signal processing device 13, when the playback speed is switched during playback, the CLV
Until the state is reached, no reproduced sound is produced, but no digital noise is generated, and there is no part that is not reproduced, that is, there is no part missing reproduction.

Effect of the Invention As described above, the present invention is greatly improved by providing a current position storage device and a logical operation device for detecting an access operation and a CLV state, in contrast to a conventional optical disc playback speed switching device. Even if the reproduction speed is changed, it is possible to reproduce the disk without generating digital noise and without a reproduction missing portion. In the future, it is expected that tabbing from an optical disc to a DAT with a digital signal as it is will become popular, but in that case, it will be more likely to be performed by changing the playback speed, and the present invention should be used effectively. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus for switching the reproduction speed of an optical disk in one embodiment of the present invention, FIG. 2 is a flowchart of the operation of the apparatus of FIG. 1, and FIG. FIG. 4 is a block diagram of the speed switching device, and FIG.
FIG. 4 is a flowchart of the operation of the illustrated device. 10 optical pickup, 12 focus / tracking control device, 13 signal processing device, 14 digital mute device, 16 frequency divider, 17 playback speed input device, 18 current position storage Apparatus, 19 ... Logic operation unit.

Claims (1)

(57) [Claims] 1. A focus and tracking control device for controlling focus and tracking of an optical pickup for reading a signal recorded on an optical reproduction disk, and a PLL by comparing a reproduction signal obtained from the optical pickup with a reference clock. A signal processing device for controlling the spindle motor so as to have a constant linear velocity and reproducing a digital audio signal and a subcode signal; and a digital signal processing of the digital audio signal obtained from the signal processing device to mute. A digital mute device to be applied, a frequency dividing device for dividing a clock signal of a clock generating device for generating a basic clock for signal reproduction and sending the divided signal to the signal processing device, a reproducing speed input device for inputting a reproducing speed,
A current position storage device for storing current position information of an optical pickup included in a subcode signal obtained from the signal processing device; and an access operation and a reproduction operation performed by controlling the focus / tracking control device and the signal processing device. Controlling the frequency divider of the clock signal by the signal of the reproduction speed input device, controlling the digital mute device, and storing the current position information included in the subcode signal in the current position storage device. Access operation command to access the specified position,
And a logical operation device for detecting a state of constant linear velocity from the signal processing device, when switching the reproduction speed,
Digital mute, access to the position where the playback speed was switched, and detection of the constant linear velocity state cancels the digital mute and resumes playback of the optical disc that resumes playback. apparatus.