JPH1069730A - Optical disk reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single, optical disk reproducing device which reproduces an optical music disk, etc., or an optical disk recorded with data and promptly accesses data. SOLUTION: Multiplexers 21-25 are used to designate the reproducing mode at a constant linear velocity(CLV) for an optical disk 1 of music, etc., and the reproduction mode at a constant angular velocity(CAV) for an optical disk recorded with data, etc. The specific bit pattern signal reproduced from the disk 1 is used to control rotation in the CLV mode for CLV control and also to generate system clocks for reproduction in the CAV mode and change the frequency of system clocks in response to the change of linear velocity for the readout diameter. When reproducing the optical disk 1 recorded with data, due to the elimination of variable velocity control of heavy things such as a spindle, seek time is made faster due to prompt pursuit to the change of readout diameter at the time of seek, allowing fast access.

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 adapted to reproduce an optical disk at a constant linear velocity or a constant angular velocity by switching the reproducing mode, adapted to the type of the optical disk.

[0002]

2. Description of the Related Art Conventionally, CDs (Compact Discs)
Is read and demodulated as a ROM (Read Only Memory). The code data of the CD-ROM is also generally constant linear velocity (CLV) like the music CD.
And reproduced / demodulated by the control system used for music.

FIG. 4 is a block diagram showing a rotation control section and a signal section in a control system of a conventional CD reproducing apparatus. The code data on the optical disk 100 is read by the pickup 101 and then binarized. From the binarized read signal, a bit pattern is detected by a Tmax detection circuit 102 and its maximum time width Tmax is measured. The time width Tmax indicates a width of a predetermined number of clocks (11 channel clock length for a CD) and corresponds to a linear velocity during reproduction. Therefore, in order to adjust this time width to the reference time, the rotation speed of the spindle motor is controlled via the spindle control unit 104 by a Pull in signal obtained by subtracting the reference voltage (refV) in the subtractor 103. After the speed of the spindle motor is brought into the capture range of the PLL (phase locked loop) for reproducing the pit clock in this way, the phase control is performed between the PLL and the crystal to control the rotation. As a result, even if the diameter of the readout changes due to the movement of the pickup, the linear velocity is always controlled to be constant, and if it is a music CD, the sound recorded on the CD is faithfully reproduced.

[0004]

However, in the case of reproducing and demodulating the code data of a CD-ROM by the above-described conventional CD reproducing apparatus, a heavy load such as a spindle is required to keep the linear velocity constant. Since the rotation of the object is variably controlled, a considerable time delay occurs until the rotation changes following the change in the reading diameter, and the seek time, which is the main performance as an external memory, is extremely slow. Was.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is possible to reproduce an optical disk such as music with a single reproducing apparatus or reproduce an optical disk on which data is recorded with a CLV. It is another object of the present invention to provide an optical disk reproducing apparatus capable of accessing data at high speed.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a rotation control means for rotating a disk on which data is recorded at a constant linear velocity at a constant linear velocity or a constant angular velocity; Reading means for reading data from the read disk; linear velocity signal generating means for generating a linear velocity signal corresponding to a linear velocity at the time of reproduction from a predetermined bit pattern in the read data; A system clock generating means for generating a system clock whose frequency changes correspondingly; and, when the disk is controlled to rotate at a constant linear velocity, the linear velocity signal is input to the rotation control means to generate a linear velocity signal. When the disk is controlled to rotate at a constant angular velocity, the linear velocity signal is input to the system clock generating means for reproduction. It and a switching means for switching control so as to change based on the system clock to the line speed signal for characterized.

According to the present invention, a constant linear velocity (C
LV), and specifies the playback mode at a constant angular velocity (CAV) when accessing an optical disk on which data or the like is recorded. Then, a specific bit pattern signal reproduced from the disk is used for rotation control in the CLV mode, and a constant linear velocity control is performed. , The frequency of the reproduction system clock is changed in accordance with the change in the linear velocity. As a result, the optical disk for music etc.
In the mode, the optical disk on which data is recorded by CLV is CA
It is possible to reproduce in V. When reproducing an optical disk on which data is recorded, variable speed control of a heavy object such as a spindle is eliminated, so that the seek time quickly follows the change in the read diameter during seek, and the seek time becomes faster. Access can be realized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
This will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In this embodiment, a CD and a CD-ROM are used.
In consideration of the switching, a circuit for reproducing data at substantially the same CLV as in FIG. 4 and a circuit for reproducing data at a new CAV are provided as multiplexers 21, 22, 2 arranged as mode switching means.
3, 24 and 25 are switchable. Here, each of the multiplexers 21, 22, 23, 2
4 and 25 are A for CD mode (hereinafter, CLV mode)
Side input, CD-ROM mode (hereinafter, CAV mode)
If so, the input on the B side is selected and output.

First, components other than the multiplexer will be described.

The rotation of the optical disc 1 is controlled at a constant linear velocity (CLV) or a constant angular velocity (CAV) by a mode switching described later by a spindle controller 2 including a spindle motor, a phase comparator 3, and the like.

The pickup 5 is servo-controlled by a servo system (not shown) (focus servo and tracking servo).
Is read, a signal is read from the optical disc 1. Reading during the seek operation is performed with the focus servo being applied, so that it is completed,
Executed immediately after the tracking servo is applied. The read signal is input to the RF processing unit 6, subjected to equalization and the like, and input to the binarization unit 7 as an RF signal. The binarizing unit 7 binarizes the waveform into a high level and a low level after removing waveform distortion by asymmetry correction. The binarized signal is connected to the Tmax detector 8, a phase locked loop circuit described later, and the like.

The Tmax detector 8 detects and measures the maximum time width Tmax of the bit pattern in the binary signal. The bit pattern of the maximum time width Tmax is always included in one frame of the code data as a frame synchronization signal, and represents a time width of a predetermined number of clocks (for a CD, 11 channel clocks). In the CLV mode, the time width Tmax corresponding to the linear velocity during reproduction is adjusted to the reference time. In the CAV mode, the system clock used for reproduction is adjusted according to the measured maximum time width Tmax, that is, according to the linear velocity during reproduction. The maximum time width Tmax is set to a voltage value by generating a sawtooth wave at a change point of the signal and holding the peak voltage thereof, and is input to the subtracter 10 via the bottom hold circuit 9. Bottom hold circuit 9
Has a function of preventing the input value of the subtractor 10 from increasing within a sufficient period of time even if the maximum time width Tmax erroneously increases due to signal dropout.

One input of the subtractor 10 is supplied with a reference voltage refV in the CLV mode, and a detection signal of a T'max detection circuit 20 described later in the CAV mode, and the difference signal is supplied to the center of the phase locked loop. Keep frequency constant (CLV mode) or change frequency (CA
VCO (voltage controlled oscillator) 1
1 is input.

In the CAV mode, since the linear velocity at the time of recording a CD is actually arbitrarily set within a range of 1.2 to 1.4 m / s, the system clock of the VCO 11 is reduced to 1/11.
The voltage value representing the 11-channel clock time width T'max when the frequency is divided by the frequency dividing circuit 19 and operated by the channel clock (system clock) is used as the T'max detecting circuit 2.
0 is detected, and this voltage value is input to the subtracter 10 instead of the reference voltage refV. As described above, in the closed loop, the 11-channel clock time width T'max of the system clock and the maximum time width Tmax of the bit pattern from the optical disc 1 (11-channel clock time width)
By providing a means for controlling the center frequency of the VCO 11 with the difference signal, it is possible to deal with optical disks having different linear velocities of 1.2 to 1.4 m / s. Further, it is possible to sufficiently cope with an optical disk recorded by CAV.

The phase-locked loop circuit includes the VCO 1
1, a phase comparator 12 and a low-pass filter 13 to generate a reproduction system clock. VCO11
Is an oscillator whose oscillation output changes according to the input voltage, which will be described in detail later. The phase comparator 12 outputs to the low-pass filter 13 a signal proportional to the phase difference between the binarized signal and the oscillation output of the VCO 11. The low-pass filter 13 is
The high frequency component is removed, and the phase difference signal is input to the VCO 11. By forming the feedback circuit in this way, the phase locked loop circuit operates so that the phase difference signal becomes zero or a constant value, and when the binarized signal is near the center frequency determined by the output of the subtractor 10, Follow in and pull in. The oscillation output of the VCO 11 is sent out as a system clock.

The D-type flip-flop 14 is a circuit for fetching data.
Is connected, and the clock terminal is connected to VC
An oscillation output of O11, that is, a system clock is input, data is taken in synchronization with the system clock, and a logic LSI (for example, CXD1135 manufactured by Sony Corporation) is input.
Q).

The logic LSI 15 has a read address counter, a write address counter, an ECC (error check correction) function, a serial-parallel conversion function and the like, and writes the fetched data to a RAM (for example, CXK5816 manufactured by Sony Corporation) 16. The data is read and sent to an external circuit with a delay. The above-described system clock is input to the crystal connection terminal of the logic LSI 15. However, when the system clock is CAV, the system clock changes according to the reading diameter of the optical disk 1. Therefore, the logic circuit including the logic LSI 15 operates at the expected maximum frequency. Needless to say, it must be configured with a functioning one. With the above configuration, overflow and underflow of the RAM 16 are prevented.

Next, the operation of mode switching in the above configuration will be described.

A CD mode (CL
When either the V mode) or the CD-ROM mode (CAV mode) is designated, each of the multiplexers 21, 22, 23, 24, and 25 inputs the A-side input in the CD mode and the CD-ROM mode based on the designation. If so, the input on the B side is selected and output.

In the CD mode, the multiplexer 2
The reference voltage refV is input to the subtracter 10 by 1 and the difference signal is input to the spindle control unit 2 by the multiplexer 22 as a pull-in signal, and the optical disk 1 is controlled by CLV. On the other hand, a predetermined preset voltage is input to the control input of the VCO 11 from the multiplexer 23, and its center frequency is fixed. The multiplexer 24 connects the oscillation output of the crystal oscillator 4 to the crystal connection terminal of the logic LSI 15. The phase control for the spindle controller 2 is performed by selecting the write address output by the multiplexer 25 and comparing the phase with the read address input.

In the CD-ROM mode, a predetermined preset value is input from the multiplexer 22 to the spindle control unit 2, and the FG output of the spindle motor is input from the multiplexer 25 to the phase control.
This is performed based on the periodicity of the read address input timing, and the optical disc 1 is controlled by CAV. in this case,
The number of teeth of the FG is set to be close to the frequency of the write address counter of the logic LSI 15. On the other hand, as for the center frequency of the VCO 11, the 11-channel clock time width T'max detected from the system clock of the VCO 11 is given to the subtractor 10, and the output of the subtracter 10 is applied from the multiplexer 23 to the control input of the VCO 11, The center frequency can be changed. The system clock generated from the VCO 11 by the multiplexer 24 is input to the crystal connection terminal of the logic LSI 15.

FIG. 2 is a diagram showing a circuit example of a two-input VCO. This VCO is a modification of the clap oscillation circuit, and includes an inductance L, a capacitor C, a capacitor C ₁ and a varicap diode BC ₁ connected in series,
Similarly, a capacitor C ₂ and a varicap diode BC ₂ connected in series are connected in parallel, and are connected to the base of the emitter follower transistor Tr via a capacitor C ₀ . The oscillation output is sent from the emitter of the transistor Tr. Control Input (1) is applied so as to reverse bias the varicap diode BC _1, the control input (2) is applied so as to reverse bias the varicap diode BC _2. Since the capacitances of the varicap diodes BC ₁ and BC ₂ change according to the values of these control inputs (1) and (2), it is necessary to change the frequency of the oscillation output determined by the combined capacitance and the inductance L. Can be. There are various other types of VCOs.
Either of them may be used, and when the frequency is made variable, it may be realized by using a switch circuit and changing the capacitance in a broken line shape.

In the above embodiment, naturally C
In the case of AV, the motor is turned to the outermost circumference at the innermost rotation angular velocity (around 500 rpm). In this case, the inner circumference is C
Assuming the same regular rotation speed as that of D, the clock frequency is 4.3 MHz, and the linear velocity at the outer circumference of the above CAV is 2.5 times the inner circumference (in the case of 12 cm CD).
It is around 0.7 MHz. If the outer periphery is sought, the maximum time width T of the bit pattern detected at that time is
max is smaller than the reference voltage set for the CD, and the difference signal generated from the subtractor 10 is output in the direction of decreasing the rotation as shown in FIG. The difference signal is level-converted and used as the VCO control input,
Move the center frequency of CO11. If the linear velocity at the time of writing on the optical disk is fixed to one or can be measured accurately, the center frequency can be preset by calculation, and the control of the center frequency may be an open loop.

In the above-described embodiment, an example in which control is performed in an analog manner is shown. However, it is needless to say that digital control can be appropriately performed. For example, Tmax detection from an optical disc is performed by a VCO. It may be performed using a clock. As described above, the present invention can be variously applied according to the gist and can take various embodiments.

[0026]

As is apparent from the above description, according to the present invention, the reproduction mode switching means specifies the reproduction mode at a constant linear velocity (CLV) during reproduction of an optical disk such as music and the like. When accessing the optical disk on which is recorded, a specific angular pattern (CAV) reproduction mode is designated, a specific bit pattern signal reproduced from the disk is used for rotation control in the CLV mode, and a constant linear velocity control is performed. Since the frequency of the system clock for reproduction is changed in accordance with the change in the linear velocity which changes according to the reading diameter at the time of reproduction at a constant angular velocity by using the generation of the system clock for reproduction, Is a CLV mode, and an optical disc on which data is recorded in the CLV can be reproduced in the CAV mode, and the Since the time of reproducing the recorded optical disk data eliminates the variable speed control of such heavy spindle, seek time is faster to quickly follow the change of the reading diameter of the seek, high-speed access can be realized.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a circuit example of a VCO in the embodiment.

FIG. 3 is a diagram showing a control input example of a VCO in the embodiment.

FIG. 4 is a block diagram showing a conventional example.

[Description of Signs] 1 ... Optical disk 2 ... Spindle controller 3 ... Phase comparator 4 ... Crystal oscillator 8 ... Tmax detector 10 ... Subtractor 11 ... VCO 12 ... Phase comparator 13 ... Low-pass filter 15 ... Logic LSI 16 ... RAM 19: 1/11 frequency dividing circuit 20: T'max detector 21 to 25: multiplexer

Claims (1)

[Claims] 1. A rotation control means for rotating a disk on which data is recorded at a constant linear velocity at a constant linear velocity or a constant angular velocity; a reading means for reading data from the rotation-controlled disk; A linear velocity signal generating means for generating a linear velocity signal corresponding to the linear velocity at the time of reproduction from the predetermined bit pattern; and a system clock generating means for generating a system clock whose frequency changes according to the linear velocity signal. When the disk is controlled to rotate at a constant linear speed, the linear speed signal is input to the rotation control means to perform rotation control based on the linear speed signal, and the disk is controlled to rotate at a constant angular speed. The linear velocity signal is input to the system clock generating means, and a system clock for reproduction is based on the linear velocity signal. Optical disk reproducing apparatus, characterized by comprising and a switching means for switching control so as to reduction.