KR100360680B1 - An apparatus and method for controlling a characteristic of equalization in optical disc driver - Google Patents

Abstract

The present invention relates to an apparatus and method for controlling equalization characteristics of a reproduced RF signal of an optical disc drive apparatus, wherein the method for controlling equalization characteristics of an optical disc drive apparatus according to the present invention is an optical disc that is rotationally driven by a constant angular velocity (CAV) method. A first step of generating and outputting a clock whose period varies from a high frequency reproduction signal read out from the same according to the reproduction speed; And a second step of variably setting waveform equalization characteristics of the reproduction signal based on a period of the generated clock, wherein setting of equalization characteristics of the R / F waveform equalizer according to the current reproduction speed is controlled. It is possible to reduce the load of the control part by realizing all speed ranges in real time based on the frame clock generated from the reproduction signal, and the equalization characteristics of the R / F waveform equalizer are precisely set. It is a very useful invention with the effect of improving the characteristics of the signal.

Description

An apparatus and method for controlling a characteristic of equalization in an optical disc drive device

The present invention relates to an apparatus and method for controlling equalization characteristics of reproduction RF signals of an optical disk drive apparatus.

High speed data access is essential in drivers that drive optical discs such as compact discs (CDs) and digital multifunction discs (DVDs). As the disk rotation method, the device adopts the constant angular velocity (CAV) method instead of the constant linear velocity (CLV) method.

However, in the CLV method, unlike the control of the rotational speed of the disc so that the linear velocity in the track is constant, the CAV method maintains the rotational speed of the disc so that the speed varies according to the position of the playback disc. However, as the RF signal detected by the optical pickup becomes faster as the disc playing speed increases, the frequency characteristic of the high band becomes worse. Therefore, the RF IC performs a waveform equalization process to compensate for the waveform attenuation in the high band. That is, as shown in FIG. 1, signal attenuation of a high band (3T signal) is compensated for in the equalization process. A conventional method for such waveform equalization processing will be described below with reference to the configuration of the general optical disk drive apparatus of FIG.

Fig. 2 shows a configuration of a general optical disc drive device, which includes an optical pickup 20 for reading out a signal recorded on the optical disc 10; A spindle motor 11 for rotating the optical disc 10; An R / F waveform equalizer 30 generating a reproduction RF signal from the signal detected by the optical pickup 20, and outputting the reproduction RF signal as a binary signal by filtering the filtered RF signal; A phase-locked loop and digital signal processor 40 for restoring the binary signal to original data with its clock phase-locked to the binary signal; A drive unit 50 for driving the spindle motor 11 and the optical pickup 20; And a control unit 60 for setting the waveform equalization characteristic corresponding to the current reproduction speed of the optical disc 10 in the R / F waveform equalizer 30.

In the optical disk drive device configured as described above, first, when the optical disk 10 is inserted into the optical disk drive device and is requested to be reproduced, the control unit 60 drives the drive voltage to the spindle motor 11 through the drive unit 50. The optical disk 10 is rotated and driven according to the current CAV method, and the optical pickup 20 reads recording data on the optical disk 10 that is rotated and is an electrical signal for the read data. Generate and output a signal.

The R / F waveform equalizer 30 waveform-equalizes the RF signal generated by the optical pickup 20 to output a waveform equalized RF signal, and the phase-locked loop and the digital signal processor 40 Signal processing the waveform-equalized RF signal detects sub-Q data (positioned when the optical disc 10 is a CD and becomes ID data when the DVD is a DVD) which is position information of the optical disc 10. . The controller 60 determines the current playback position of the optical disc 10 from the detected sub-queue data, and calculates the playback speed at the identified playback position. When the reproduction speed at the current position is calculated as described above, the controller 60 sets the waveform equalization characteristics corresponding to the current reproduction speed of the optical disc 10 in the R / F waveform equalizer 30.

By the way, in the case of a CD, the sub-queue data, which is position information, can be read by the controller 60 every 13.3 ms at 1x speed. Therefore, the controller 60 has a maximum time interval for setting the waveform equalization characteristics accurately according to the R / F waveform equalizer 30 at a maximum speed of 13.3 ms, and decreases to 0.333 ms (13.3 ms / 40) at 40 times the speed. do. To this end, the control unit 60 periodically reads subqueue data by an interrupt using an internal general-purpose timer.

FIG. 3 shows a section in which the playback speed and the waveform equalization characteristics of the optical disk 10 vary depending on the playback position of the optical disk 10 during the CAV playback of the optical disk 10. The graph indicated by solid lines in FIG. The playback speed is changed according to the playback position of the optical disc.

In the normal playback of the optical disc 10, the equalization characteristic is set in the same manner as described above, and the subqueue data cannot be read during the search of a specific position, so the equalization characteristic corresponding to the target position to be searched is determined. The R / F waveform equalizer 30 is set in advance, and the RF waveform equalization operation is performed according to the search for the desired target position and the set equalization characteristic at the target position.

However, in the conventional equalization characteristic adjusting method, the subqueue data is used to set the equalizing characteristics. Therefore, in the case of continuous reproduction, the equalizing characteristics are variably adjusted at 13.3 ms discontinuous periods. There is a problem that the characteristics of the RF waveform is worsened by lowering the precision for the variable setting of the equalization characteristics.

In addition, as the speed increases, the control unit reads the sub-queue data as soon as possible, and thus adopting a control unit IC requiring a high processing speed has a problem of causing an increase in the cost of the driving apparatus.

Accordingly, the present invention has been created to solve the above problems, and the optical disk drive device for more precisely and quickly setting the equalization characteristics corresponding to the current playback speed without affecting the processing speed of the controller. It is an object of the present invention to provide a control device and a control method of the equalization characteristics.

1 shows frequency characteristics of an RF signal and frequency characteristics of an equalized RF signal.

2 shows a configuration of a general optical disc drive device,

FIG. 3 shows a section in which the playback speed and waveform equalization characteristics vary depending on the playback position of the optical disc in the CAV method.

Fig. 4 shows the structure of an optical disc drive device configured with an equalization characteristic control device of a reproduction signal according to the present invention.

5 shows a detailed configuration of the control signal generator of FIG.

FIG. 6 is a waveform diagram illustrating, for example, a relation between a frame clock and a crystal clock required for setting equalization characteristics of an optical disk drive apparatus according to the present invention.

FIG. 7 shows a flow of a preferred embodiment of a method for controlling equalization characteristics of an optical disk drive apparatus according to the present invention;

FIG. 8 illustrates the output signal form of the control signal generator of FIG. 4.

※ Explanation of code for main part of drawing

10: optical disc 11: spindle motor

20: optical pickup 21: sled motor

30: R / F unit 40: phase locked loop and digital signal processing unit

50: drive unit 60: control unit

61: selection switch 70: control signal generator

71: counter 72: subtractor

73: control signal generator

An equalization characteristic control apparatus for an optical disc drive apparatus according to the present invention for achieving the above object comprises: equalizing means for equalizing a waveform of a high frequency reproduction signal read out from an optical disc based on a set waveform equalization characteristic; Generating means for generating and outputting a clock whose period changes from the read high frequency reproduction signal according to a reproduction speed; And adjusting means for variably setting waveform equalization characteristics of the equalizing means based on a period of the generated clock.

In addition, the method for controlling the equalization characteristic of the optical disk drive apparatus according to the present invention comprises: generating and outputting a clock whose period varies according to the reproduction speed from a high frequency reproduction signal read out from the optical disk rotated by a constant angular velocity (CAV) method; Stage 1; And a second step of variably setting a waveform equalization characteristic for the reproduction signal based on the period of the clock that is generated and output.

Best Mode for Carrying Out the Invention Preferred embodiments of the equalization characteristic control apparatus and control method of the optical disk drive apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

Fig. 4 shows a configuration of an optical disc drive device in which an equalization characteristic control device of a reproduction signal according to the present invention is configured, and in addition to the same configuration as in Fig. 1 described above, the signals are reproduced at the time of normal reproduction and search reproduction. The current playback speed of the optical disc 10 is calculated using the selection switch 61 for switching the connection state, the input frame clock and the crystal clock, and the waveform equalization control signal accordingly. It further comprises a control signal generator 70 for outputting the control signal generator 70 is a frame input from the phase synchronization loop and the digital signal processor 40 as shown in FIG. A counter 71 for counting a clock using an input crystal clock and outputting the count value; A subtractor 72 for subtracting the reference speed setting value R output from the control unit 60 and the output count value and outputting a result value; And a control signal generator 73 for outputting an equalizer control signal by pulse width modulation (PWM) of the output subtraction result value.

Fig. 6 is a waveform diagram illustrating the relationship between the clocks as an example.

7 is a flow chart illustrating a preferred embodiment of the method for controlling equalization characteristics of the optical disk drive apparatus according to the present invention. Hereinafter, the control method of FIG. 7 according to the present invention in parallel with the operation of the drive apparatus of FIGS. It will be described in detail.

First, as described above, in response to a reproduction request of the optical disc 10 (S10) in the state in which the optical disc 10 is rotated in a CAV manner (in this state, the input terminal of the selection switch 61 is connected to the b terminal). Signal connection) (S11), the optical pickup 20 detects the recording data on the optical disk 10. At this time, the R / F waveform equalizer 30 waveform-equalizes and outputs an RF signal output from the optical pickup 20 by a predetermined equalization coefficient (S12), and the phase-locked loop and digital signal processor 40 ) Generates a channel clock phase-locked to the binary signal inputted by the equalization process and outputs a frame clock which is its divided signal (S13).

FIG. 6A shows a frame configuration which is a basic data unit of the optical disc 10. The frame includes a synchronization signal for classifying a frame, and the synchronization signal is 11T-11T-2T for a CD. (24-bit) and in the case of DVD in the form of 14T-14T-2T (30-bit) to distinguish it from other signals. Such a synchronization signal is periodically represented by the frame clock shown in (c) of FIG. 6, and the channel clock of the form (b) of FIG. 6 is a clock obtained by phase-locking the phase-locked loop and the digital signal processor 40. When counted in (T period), 588 CDs are used and 1488 DVDs are used.

Meanwhile, as the control clock generator 70 is applied to the control signal generator 70, the frame clock of FIG. 6C and the crystal clock of FIG. 70 is used to calculate the current reproduction speed of the optical disc 10 using the applied clocks (S14) to variably set the equalization characteristics of the R / F waveform equalizer 30 to the corresponding equalization characteristics. This process is described with reference to the waveform diagram of FIG. 8 (S15).

The counter 71 of the control signal generator 70 receives a frame clock inputted from the phase synchronization loop and the digital signal processor 40 (the clock of which is changed in cycle according to the rotational speed of the disk). Counting using a fixed crystal clock and outputting the count value as shown in Figure 8 (a), the subtractor 72 is the count value and the reference speed setting value input from the controller 60 ( Subtract R) and output the result as shown in Fig. 8B. The control signal generator 73 outputs an equalizer control signal of the type (c) of FIG. 8 by performing pulse width modulation (PWM) on the value of FIG. 8 (b) output from the subtractor 72. If the current playback speed is faster than the reference speed (speed at the center of the area) in the current playback position area of the optical disc 10, the interval of the frame is relatively narrowed so that the counted value for the section of 1 or 0 Since the value becomes smaller than the value corresponding to the reference speed, the value obtained by subtracting the coefficient value from the reference value becomes positive (+). At this time, the equalizer control signal becomes 1, and conversely, if the current speed is slower than the reference speed, it becomes 0. If both speeds are the same, the output is in a high impedance state.

By the above process, the control signal of the type (c) of FIG. 8 output by the control signal generator 73 is applied to the R / F waveform equalizer 30 through the selection switch 61, thereby. The equalization characteristic of the R / F waveform equalizer 30 is to compensate more high frequency characteristics in the case of +1 pulse, and lower the compensation degree of the high frequency characteristics in the case of 0 pulse, so that the normal reproducing operation of the optical disc 10 is performed. In this continuous state, the equalization characteristic variable setting operation of the R / F waveform equalizer 30 as described above is continuously performed in real time according to the current speed.

When the search of a specific position of the optical disc 10 is not a normal playback operation, the controller 60 controls the selection switch 61 to switch the signal connection state from the b terminal to the a terminal. By outputting a control signal for setting the equalization characteristic of the R / F waveform equalizer 30 corresponding to the target position in advance through the selection switch 61, the search for the desired target position and the appropriate target at the searched target position are performed. Enable waveform equalization.

The equalization characteristic control apparatus and control method of the optical disk drive apparatus according to the present invention configured as described above are generated from the reproduction signal without setting the equalization characteristic of the R / F waveform equalizer according to the current reproduction speed without the involvement of the controller. It is possible to reduce the load of the controller by realizing all the speed ranges in real time based on the frame clock, and the equalization characteristics of the R / F waveform equalizer can be precisely set, thereby improving the characteristics of the reproduction signal. It is a very useful invention.

Claims (9)

In the optical disk drive method, A first step of generating and outputting a clock whose period varies according to the reproduction speed from a high frequency reproduction signal read out from the optical disk rotated by a constant angular velocity (CAV) method; And And a second step of variably setting waveform equalization characteristics for the reproduction signal based on the period of the clock generated and output. delete The method of claim 1, And the second step is performed during normal playback of following the track of the optical disc. The method of claim 1, And the second step detects the period by counting the state of one or zero of the clock with an oscillation clock having a fixed frequency. The method of claim 1, And the variable setting of the waveform equalization characteristic in the second step corresponds to a difference value between the center speed of the reproduction area of the optical disc and the current speed. In the optical disk drive device, Equalization means for performing waveform equalization on the basis of the set waveform equalization characteristics of the high frequency reproduction signal read out from the optical disc; Generating means for generating and outputting a clock whose period changes from the read high frequency reproduction signal according to a reproduction speed; And And control means for variably setting waveform equalization characteristics of the equalization means based on a period of the clock generated and output. The method of claim 6, The adjusting means detects the period of the generated clock based on a fixed frequency clock and variably sets the waveform equalization characteristics of the equalizing means corresponding to the current reproduction speed of the optical disc based on the detected period. Equalization characteristic control apparatus of an optical disk drive, characterized in that. The method of claim 6, The adjusting means, Counting means for counting the generated output clock as a frequency fixed reference clock and outputting the count value; Subtraction means for subtracting the output count value and a predetermined reference speed setting value and outputting a result value; And And control signal generating means for applying a waveform equalizing control signal obtained by pulse-modulating the output subtraction result value to the equalizing means. The method of claim 6, And a signal selecting means for selectively applying the output of the adjusting means and the output of the control means for setting the equalizing characteristics at the time of crossing the track to the equalizing means. .