JP2578543Y2 - Optical disc playback device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk reproducing apparatus and, more particularly, to an optical disk reproducing apparatus which removes a time axis fluctuation of audio digital data for optical output.

[0002]

2. Description of the Related Art In an optical disk reproducing apparatus such as a laser disk player apparatus, EFM data is obtained from digital data read from a disk via a pickup and supplied to a data reproducing apparatus 1. EFM data is PL
The input signal to the L circuit 3 and the output signal of the PLL circuit 3 are supplied to one input of the phase comparator 4. The oscillation output from the voltage variable crystal oscillator (VCXO) 2 is supplied to the other input of the phase comparator 4.

A low-pass filter (LPF) 5 extracts a low-frequency component of a phase difference signal between the output signal from the PLL circuit 3 obtained by the phase comparator 4 and the oscillation output signal from the VCXO 2. It is output as an oscillation control signal.
The data reproducing apparatus 1 generates audio digital data for optical output from the EFM data based on the oscillation output signal from the VCXO 2 which is the audio data reproduction reference clock generated in this manner, and performs optical output in the optical output module 14.

[0004]

As described above, in the conventional optical disk reproducing apparatus, the rotation control of the optical disk is performed by controlling the phase of the video signal obtained from the optical disk and the reference clock for video reproduction. The EFM data directly obtained from the optical disc includes a residual time axis fluctuation component of the phase control. The audio data reproduction reference clock from the VCXO2 also includes a residual time axis component.

Accordingly, audio digital data obtained from the data reproducing apparatus 1 is also reproduced by the reproduced light output module 14.
Since the audio digital data for optical output from the optical disc also includes this residual time axis fluctuation component, when the audio digital data for optical output is received by the optical input side (light receiving side device) such as an amplifier, the digital signal is not received. There is a problem that a PLL circuit (not shown) in the device is difficult to lock.

It is an object of the present invention to provide an optical disk reproducing apparatus which can reduce the residual time axis fluctuation of the digital audio data for optical output.

[0007]

In order to solve the above-mentioned problems, an optical disk reproducing apparatus according to the present invention is provided with a data reproducing apparatus for inputting an EFM signal reproduced from an optical disk and generating audio digital data, and a clock signal generating apparatus. A voltage-controlled oscillating means, a latch means for latching and outputting the audio digital data based on the clock signal, and a phase (frequency) comparison between the clock signal and the audio digital data to output a phase (frequency) difference signal. Phase (frequency) comparison means, time-axis fluctuation component output means for outputting a time-axis fluctuation component as a correction signal from a control signal for rotation control of the optical disc, and calculating the correction signal and the phase (frequency) difference signal Arithmetic means for controlling the voltage-controlled oscillating means in accordance with an output signal of the arithmetic means. Suppresses time base fluctuation of the data.

[0008]

According to the present invention, there is provided a VCO circuit using a control signal for controlling the rotation of an optical disk as an auxiliary signal, and a latch circuit controlled by an output clock of the VCO circuit. The audio reproduced from the optical disk by the latch circuit is provided. By latching the digital data, audio digital data for optical output without fluctuation in the residual time axis due to the rotation control of the optical disk is generated. Since audio digital data for optical output without residual time axis fluctuation is output from the optical output module, it is difficult to lock the PLL circuit inside the other light receiving side device such as an amplifier connected thereto. The problem has been solved.

[0009]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a main part configuration diagram showing an embodiment of an optical disk reproducing apparatus according to the present invention. In FIG. 1, components denoted by the same reference numerals as those in FIG. 2 indicate components having similar functions.

A video RF signal reproduced from the optical disk is input to a video reproduction device 6, and a video signal (horizontal synchronization signal) output from the video reproduction device 6 is converted by a phase comparator 7 into a video reference oscillator (crystal). 8 is compared with the reference clock for video reproduction.

The phase difference signal obtained by the phase comparator 7 is output as a motor control voltage,
Is supplied to one input terminal.

The rotation control of the optical disk uses a phase difference signal obtained by the phase comparator 7 as a control signal, and a motor for controlling the rotation is controlled based on the phase difference signal. EFM signal (E
FM data) includes a residual time axis component of the phase control.

The EFM data including the residual time axis component is input to the PLL circuit 3, and the output signal of the PLL circuit 3 is supplied to one input terminal of the phase comparator 4. The other input terminal of the phase comparator 4 has a voltage variable crystal oscillator (VCX).
O) The oscillation output signal from 2 is supplied.

From the phase difference signal between the output signal from the PLL circuit 3 obtained by the phase comparator 4 and the oscillation output signal from the VCXO 2, low-pass components are extracted by a low-pass filter (LPF) 5 and the VCXO 2 As an oscillation control signal. In the data reproducing apparatus 1, the VCX thus generated
The audio digital data is generated based on the clock including the residual time axis component from O2.

The audio digital data generated by the data reproducing device 1 is input to the latch circuit 13 and the phase comparator 9. The other input of the phase comparator 9 receives the output of a voltage-controlled oscillator (VCO) 12 that oscillates and outputs a clock by self-running at a frequency close to the clock frequency of the optical output data. Playback data and VC
The output data from O12 is compared in phase.

From the phase difference output signal from the phase comparator 9, a low-pass component is extracted by a low-pass filter (LPF) 10 and supplied to another input terminal of a subtractor 11. Subtractor 11
Subtracts the output signal of the phase comparator 7 and the output signal of the LPF 10 and supplies the subtracted output as an oscillation control signal of the VCO 12. The latch circuit 13 latches the audio digital data from the data reproducing apparatus 1 using the clock from the VCO 12 as an audio data reproduction reference clock, and outputs the audio digital data to the optical output module 14 as audio digital data for output.

In the above circuit, when the rotation control of the optical disk does not fluctuate on the time axis and the output of the phase comparator 7 does not fluctuate, the output of the subtractor 11 becomes substantially equal to the output of the phase comparator 9. . For this reason, the clock output from the VCO 12 is substantially synchronized with the clock component in the audio digital data generated from the data reproducing device 1.

If the rotation control of the optical disk has a time axis fluctuation and the output of the phase comparator 7 fluctuates, the output of the subtractor 11 acts in the direction opposite to the time axis fluctuation, and
The frequency of the clock output from O12 changes with the opposite residual time axis fluctuation component.

The latch circuit 13 latches digital audio data generated from the data reproducing apparatus 1 with a clock output from the VCO 12.
, Digital audio data synchronized with the clock output from the VCO 12 is obtained. VC
Since the clock output from O12 has the time axis fluctuation subtracted, the audio digital data output from the latch circuit 13 is constant without any residual time axis fluctuation.

[0020]

As described above, the optical disk reproducing apparatus according to the present invention includes a VCO circuit using a control signal for controlling the rotation of the optical disk as an auxiliary signal, and a latch circuit controlled by an output clock of the VCO circuit. The audio digital data reproduced from the optical disk is latched by the latch circuit, so that the optical digital data for optical output can be generated without any residual time axis fluctuation due to the rotation control of the optical disk.

Also, since audio digital data for optical output without residual time axis fluctuation can be output from the optical output module, it is difficult to lock the PLL circuit inside the other light receiving side device such as an amplifier connected thereto. This problem is also solved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of an embodiment of an optical disk reproducing apparatus according to the present invention.

FIG. 2 is a block diagram of a main part of a conventional optical disc reproducing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Data reproducing device 2, 12 Voltage controlled oscillator 3 PLL circuit 4, 7, 9 Phase comparator 5, 10 Low-pass filter 6 Video reproducing device 8 Crystal oscillator 11 Subtractor 13 Latch circuit 14 Optical output module circuit

Claims (1)

(57) [Scope of request for utility model registration] 1. A data reproducing apparatus that receives an EFM signal reproduced from an optical disc and generates audio digital data, a voltage control oscillator that generates a clock signal, and latches and outputs the audio digital data based on the clock signal. A phase unit for comparing a phase (frequency) between the clock signal and the audio digital data and outputting a phase (frequency) difference signal; and a time axis variation based on a control signal for controlling rotation of the optical disc. A time axis fluctuation component output unit for outputting a component as a correction signal; and a calculation unit for calculating the correction signal and the phase (frequency) difference signal, wherein the voltage control oscillation unit is controlled by an output signal of the calculation unit. An optical disc reproducing apparatus characterized in that the time axis fluctuation of audio digital data is suppressed by doing so.