JP2003030849A - Optical disk unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that the long time is required till input and output signals of a data slice circuit are stabilized and the PLL is locked when a reflection signal having the long passing time is omitted (at the defect passing time), since the variation of a DC voltage inputted to the data slice circuit is very large when the reflection signal is omitted (at the defect passing time), in the process of high speed playback of the low reflectance disk, and then the sound interruption of an output of audio signal occurs. SOLUTION: The unit is constituted in such a manner that a bypass filter means 47a for making only the high frequency component of a electrical signal pass through is arranged on a pre-stage of a data slice means 41 generating a modulation signal by binarizing a voltage signal, and a frequency changeover means 48 is provided for changing over a frequency of the bypass filter means 47a in accordance with a playback speed so as to changeover a signal frequency band inputted to the data slice means 41 in accordance with the playback speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc device for reproducing a digitally recorded optical disc, and more particularly to an optical disc device capable of reproducing at a reproduction speed faster than a normal speed.

[0002]

2. Description of the Related Art In recent years, audio equipment has tended to be digital audio, and with the development of technology, an optical disk device of high fidelity by digital recording and reproduction has been developed. Among them, compact discs (hereinafter referred to as CD) and mini discs (hereinafter referred to as MD) are the most popular recording media. In such a device, there are increasing opportunities to increase the playback speed of the playback data for the purpose of shortening the reading time and the dubbing time. As a conventional example of increasing the reproduction speed of the optical disk device, the one described in Japanese Patent Laid-Open No. 7-134873 is known.

FIG. 3 is a block diagram of a conventional optical disk device. In FIG. 3, the disk 1 is driven by the disk motor 5, the data recorded on the disk 1 is read by the photoelectric conversion means 2, and the read data is supplied to the amplification means 3 to generate a voltage signal (RF signal). The data slicing means 41 of the amplifying means 3 and the reproducing means 4 binarizes and reproduces the reproduced signal, for example, EF.
The M signal is supplied to the PLL means 42 of the reproducing means 4.
The data processing of the reproducing means 4 is output as a data output from the data processing means 46 which performs EFM demodulation, sub-code demodulation, error correction processing and the like. Further, the data processing means 46
The data output signal of the signal is supplied to a digital-analog converter (DAC) (not shown). And this D
The output of AC is supplied to a low pass filter (LPF) (not shown), and the output of LPF becomes an audio signal output. The PLL means 42 comprises a phase comparison means 43, a low-pass filter means 44, and a voltage controlled oscillation means 45. Input / output characteristics (V-
As for (F characteristic), the oscillation frequency F is substantially proportional to the input control voltage V. When the PLL means 42 is locked to the input data, that is, when the PLL clock is synchronized with the RF signal, the PLL clock frequency is proportional to the reproduction speed, and at the same time, the control voltage V of the voltage controlled oscillation means 45. Is also proportional to the playback speed.
By feeding back the control voltage V of the voltage controlled oscillator 45 to the amplifier 3, the frequency characteristic of the amplifier 3 is controlled to a frequency characteristic according to the reproduction speed.
It is configured.

[0004]

In such an optical disk device, the frequency characteristics of the amplifier clock and the amplifier means change depending on the reproduction speed, but the signal frequency input to the data slicing means is changed. Since the band is fixed, when a reflected signal is lost during high-speed playback of a disc with low reflectance (when a defect passes)
When the disc with high reflectance is played back at high speed, the fluctuation of the DC voltage input to the data slicing means is much larger than when the reflected signal is lost (when the defect passes), and therefore when the reflected signal with long transit time is lost. (When passing through the defect), the time until the input and output signals of the data slicing means become stable and the PLL means locks becomes long,
Since the audio signal output may be cut off, it is necessary to increase the signal frequency band input to the data slicing means in order to shorten the fluctuation time of the DC voltage input to the data slicing means during high-speed reproduction. There is.

The present invention provides an optical disk device capable of switching the signal frequency band input to the data slice means in order to shorten the fluctuation time of the DC voltage input to the data slice means according to the reproduction speed. It was made for the purpose.

[0006]

In order to solve this problem, the optical disk device of the present invention passes only the high frequency component of the electric signal before the data slicing means for binarizing the voltage signal and generating the modulated signal. The high-pass filter means and the frequency switching means for switching the frequency of the high-pass filter means according to the reproduction speed are provided, and the signal frequency band input to the data slice means can be switched according to the reproduction speed.

As a result, when a reflected signal is lost (when a defect passes) during high-speed reproduction of a disk having a low reflectance, the time until the input and output signals of the data slicing means are stabilized and the PLL means is locked is shortened. So
A stable audio signal output without sound interruption can be obtained.

The invention according to claim 1 of the present invention comprises means for generating an electric signal based on information data of an optical disk,
Means for amplifying the electric signal, means for passing only the high frequency component of the amplified electric signal, means for controlling the cutoff frequency of the means for passing only the high frequency component, and only the high frequency component For binarizing the voltage signal that has passed through the means for passing the signal to generate a modulated signal, a means for demodulating the modulated signal to generate reproduced data, and a means for responding to a change in the reproducing speed of the reproduced data. PLL clock generation means for generating a reproduction clock,
And a cut-off frequency of the means for passing only the high frequency component according to the reproduction speed of the reproduction data determined by the operation means. Optical disk device.

With this configuration, the cut-off frequency of the means for passing only the high frequency component of the electric signal is switched according to the reproduction speed determined by the operation of the operation means for determining the reproduction speed, whereby the disc having a low reflectance is changed. When a reflected signal is lost (at the time of passing a defect) during high-speed reproduction, the input and output signals of the means for binarizing the voltage signal that has passed through the means for passing only the high frequency component to generate the modulated signal are stable and the PLL. Since the time until the clock generating means is locked becomes short, there is an effect that a stable audio signal output without sound interruption can be obtained.

According to a second aspect of the present invention, there is provided means for generating an electric signal based on information data of an optical disk,
Means for amplifying the electric signal, means for passing only the high frequency component of the amplified electric signal, means for controlling the cutoff frequency of the means for passing only the high frequency component, and only the high frequency component For binarizing the voltage signal that has passed through the means for passing the signal to generate a modulated signal, a means for demodulating the modulated signal to generate reproduced data, and a means for responding to a change in the reproducing speed of the reproduced data. An optical disk device comprising: a PLL clock generating means for generating a reproduction clock; and controlling a cutoff frequency of means for passing only the high frequency component according to a reproduction speed of the reproduction data.

With this configuration, the PLL clock generated by the PLL clock generating means is an electric signal (voltage signal) proportional to the reproduction speed of the information data, and the means for cutting off the high frequency wave corresponding to this electric signal is cut. The off frequency can be controlled according to the reproduction speed of the reproduction data, and has the same operation as that of the structure of claim 1.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1) FIG. 1 is a block diagram of an optical disk device according to Embodiment 1 of the present invention.
, The disk 1, the photoelectric conversion means 2, the amplification means 3,
Disk motor 5, data slicing means 41, PLL means 42, data processing means 46, phase comparing means 43 in PLL means 42, low-pass filter means 4
4, the voltage control transmission means 45 and the like are the same as those in FIG. 3 of the conventional example, and the same reference numerals are given and the description thereof is omitted.

The difference from the conventional example shown in FIG. 3 is that the reproducing means 4a is used.
In addition, the frequency switching means 48 controlled by the control means 6a is added, and the frequency switching means 48 changes the cutoff frequency of the high-pass filter means 47a by the signal output from the control means 6a by operating the operation means 49. Is configured.

The operation of the optical disk device configured as described above will be described below. First, the control means 6a outputs a signal for driving the disk 1 at a constant linear velocity (CLV) to the disk motor 5 in accordance with the signal output from the operation means 49, and is recorded on the disk 1 by the photoelectric conversion means 2. The data is read, and the read data is supplied to the amplifying means 3, amplified by the amplifying means 3 and then output to the reproducing means 4a, and the data slice is transmitted through the high-pass filter means 47a which is an internal constituent element of the reproducing means 4a. It is binarized by the means 41. The binarized data (EFM signal) is output to the PLL means 42,
The phase comparison means 43, which is a component of the PLL means, compares the phase with the clock of the voltage controlled oscillation means 45, converts the error signal into a direct current signal through the low pass filter means 44, and then the voltage controlled oscillation means as a control voltage. A so-called PLL loop is formed by outputting the signal to the circuit 45, and the clock of the voltage controlled oscillator 45 is a PLL clock (PCK) synchronized with the data. 2 based on this PLL clock
The data processing means 46 converts the digitized data (EFM signal).
The output data is obtained after processing the data. At this time, the frequency switching means 48 is connected to the high-pass filter means 47a, and the frequency switching means 48 uses the signal output from the control means 6a.
Change the cutoff frequency of. For example, when the linear velocity of the disk is double, the cutoff frequency of the high pass filter means 47a is doubled. The clock of the voltage controlled oscillating means 45 is output to the data processing means 46, and the data processing means 46 performs EFM demodulation, subcode demodulation, error correction processing, etc., and the output thereof is a digital / analog converter (DAC) (not shown). ), The output of the DAC is
It is output as a reproduced audio output through a low pass filter (not shown). The control means 6a outputs the reproduction speed signal and the clock control signal to the data processing means 46.
And a control signal for controlling the entire system such as control of reproduction operation, stop operation, etc. to the data processing means 46 and the disk motor 5.

As described above, according to this embodiment, when the disc 1 is reproduced, the control means 6a which receives the output signal of the operating means 49 controls the reproduction speed and the frequency switching of the high pass filter means 47a. The high-pass filter means 47 corresponding to the reproduction speed of the disc 1
By setting the cutoff frequency of a to an arbitrary frequency,
The cutoff frequency of the high-pass filter means 47a of the input to the data slicing means 41 is switched so that the input and output signals of the data slicing means are output when the reflected signal is lost (when a defect passes) during high-speed reproduction of a disk having a low reflectance. The time until the PLL means is stable and locked can be shortened.

(Second Embodiment) FIG. 2 is a block diagram of an optical disk device according to a second embodiment of the present invention.
In the first embodiment, the difference from the first embodiment shown in FIG. 1 is that a reproducing speed discriminating means 50 is provided in place of the operating means 49, and the reproducing speed discriminating means 50 is controlled by the output of the low-pass filter means 44. Output means control means 6a
The other components are the same as those in FIG. 1 in that they are configured so as to control the same.

The operation of the optical disk device configured as described above will be described below. First, the disc motor 5 drives the disc 1 at a constant linear velocity (CLV),
The data recorded by the photoelectric conversion unit 2 is read, and the read data is supplied to the amplification unit 3, amplified by the amplification unit 3, and then output to the reproduction unit 4, which is a high-pass internal component of the reproduction unit 4. Filter means 4
It is binarized by the data slicing means 41 via 7a.
The binarized data (EFM signal) is transferred to the PLL means 42.
The phase comparison means 43, which is a constituent element of the PLL means, compares the phase with the clock of the voltage controlled oscillation means 45, converts the error signal into a DC signal via the low-pass filter means 44, and outputs it as a control voltage. A so-called PLL loop is formed by outputting to the voltage controlled oscillation means 45, and the clock of the voltage controlled oscillation means 45 becomes a PLL clock (PCK) synchronized with data. Binarized data (EFM signal) based on this PLL clock is output to the data processing means 46, and after data processing, output data is obtained. A reproduction speed discrimination means 50 is connected to the low-pass filter means 44, and if the reproduction speed is doubled by comparing the output voltage of the low-pass filter means 44 with an arbitrary voltage, a signal is sent to the frequency switching means 48. Then, the cutoff frequency of the high-pass filter means 47a is doubled, for example.

The output of the voltage controlled oscillation means 45 is output to the data processing means 46. The data processing means 46 is an EF
M demodulation, subcode demodulation, error correction processing, etc. are performed, and the output is supplied to a digital-analog converter (DAC) (not shown), and the DAC output is reproduced audio through a low-pass filter (not shown). It is output as output.

The control means 6a supplies a reproduction speed signal and a clock control signal to the data processing means 46, and outputs control signals for controlling the entire system such as control of reproduction operation and stop operation to the data processing means 46 and the disk motor 5. Supply to. The PLL clock output from the voltage controlled oscillator 45 changes in a substantially proportional relationship with the reference clock for controlling the disk motor that drives the disk motor 5 according to the reproduction speed. Therefore, the voltage controlled oscillator 45
Since the reproduction speed is almost known from the control voltage of, the control voltage of the voltage controlled oscillator 45 is compared with an arbitrary voltage,
For example, when the reproduction speed is doubled, the frequency switching means 48
It is possible to output the signal to and to double the cutoff frequency of the high pass filter means 47.

As described above, according to each of the above-described embodiments, in the first embodiment, when the reproduction speed of the disc is increased and the reproduction is performed, the output signal of the operating means for determining the reproduction speed is used. In No. 2, when the reproduction speed of the disk is increased and reproduced, a signal is output to the frequency switching means by the signal output in which the control voltage of the voltage controlled oscillation means is compared with an arbitrary voltage, and the cutoff frequency of the high pass filter means is output. Is set to an arbitrary frequency, the cutoff frequency of the high-pass filter means of the input of the data slicing means can be switched to a high frequency.

[0022]

As described above, according to each constitution of the present invention,
It is possible to switch the cutoff frequency of the high-pass filter means that passes only the high-frequency component of the amplified electric signal to one that corresponds to the reproduction speed of the reproduction data, and especially for the reflection signal during high-speed reproduction of a disc with a low reflectance. When missing (when passing a defect), by switching the cutoff frequency of the high-pass filter means of the input of the data slicing means to a high frequency, the time until the input and output signals of the data slicing means stabilize early and lock the PLL. Is shortened, so that there is an advantageous effect that a stable audio signal output without sound interruption can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of an optical disc device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of an optical disk device according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a conventional optical disc device.

[Explanation of symbols]

1 disc 2 photoelectric conversion means 3 amplification means 4 Reproduction means 5 disk motor 6a Control means 41 data slicing means 42 PLL means 43 Phase comparison means 44 Low-pass filter means 45 Voltage controlled oscillator 46 data processing means 47a High-pass filter means 48 frequency switching means 49 Operation means 50 Playback speed discrimination means

Claims (2)

[Claims] 1. A means for generating an electric signal based on information data of an optical disk, a means for amplifying the electric signal, a means for passing only high frequency components of the amplified electric signal, and only the high frequency components. Means for controlling the cutoff frequency of the means for passing the signal, means for binarizing the voltage signal passed through the means for passing only the high frequency component to generate a modulated signal, and demodulating the modulated signal. The operation unit determines the reproduction data, a PLL clock generation unit that generates a reproduction clock according to the change in the reproduction speed of the reproduction data, and an operation unit that determines the reproduction speed of the reproduction data. An optical disk device characterized by controlling a cut-off frequency of a means for passing only the high frequency component according to a reproduction speed of the reproduction data. . 2. A means for generating an electric signal based on information data of an optical disc, a means for amplifying the electric signal, a means for passing only a high frequency component of the amplified electric signal, and a high frequency component only. Means for controlling the cutoff frequency of the means for passing the signal, means for binarizing the voltage signal passed through the means for passing only the high frequency component to generate a modulated signal, and demodulating the modulated signal. Means for generating reproduction data, and PLL clock generation means for generating a reproduction clock according to a change in reproduction speed of the reproduction data, and means for passing only the high frequency component according to the reproduction speed of the reproduction data An optical disk device characterized by controlling the cutoff frequency of the optical disk.