KR100492181B1 - Method of recording/reproduce for optical disc and apparatus of the same - Google Patents

Abstract

The present invention relates to an optical disc recording / reproducing apparatus and method for recording / reproducing information by accurately determining mountain / goal tracks.

An optical disc recording / reproducing method according to the present invention comprises a first step of detecting a wobble signal from an optical disc, a second step of creating a square wave using the detected wobble signal, a third step of detecting an edge signal from the square wave, and an edge. In the fourth step of outputting a predetermined reference signal based on the signal, and in the second step, the phase wave is compared with the phases of the square wave and the reference signal in the fourth step, and when the phase is changed, And a fifth step of performing recording / reproducing according to the recording / reproducing condition according to the present invention.

Description

Method and apparatus for recording / reproducing optical discs {Method of Recording / Reproduce for Optical Disc and Apparatus of The Same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc recording / reproducing apparatus and method, and more particularly to an optical disc recording / reproducing apparatus and method for recording / reproducing information by accurately determining mountain / valley tracks.

Recently, the demand for large capacity has increased in the field of optical recording / reproducing or magneto-optical recording / reproducing. Accordingly, in recording media such as DVD-RAM (Digital Versatile Disc-Random Access Memory) (hereinafter referred to as "DVD-RAM"), a so-called acid / gol recording method for recording information in both land and groove is proposed. It is becoming.

In fact, as shown in Fig. 1, a recording medium having a mountain / goal track structure includes an identification information area (hereinafter referred to as an " ID area ") for recording address information and a recording area for recording user information (Recording Field). ). In the ID area, a prepit for recording address information for identifying a sector defining a recording unit of information is formed, and the prepit 6b of the valley and the prepit 6a of the hill are formed. It is divided and formed on the extension line of the boundary between the mountain and the valley. In addition, the sector is divided into a preformatted ID area and a recordable recording area. In the ID area, address information is recorded in a PrePit column, and a prepit row of hills and valleys is alternately located. This is detected to detect whether the next track is a land track or a groove track.

On the other hand, a recording area having a peak and valley structure so as to record user information such as an audio or video signal has a shape bent at the same width and depth, which is called a "wobble part". In addition, a signal detected by the wobble unit during recording or reproduction is referred to as a "wobble signal". In detail, the wobble unit (for example, a recording area of a groove track) records a wobbling signal in a pre-format in the same phase, so that a wobble signal is detected during recording or playback, and the wobble signal is a disc rotation control. And recording channel signal control. To this end, the wobble signal is changed to a square wave by zero-crossing and logic. However, since this control is applied to an optical disc of a mountain / goal recording method, the wobble signal is 180 degrees out of phase depending on which of the tracks 2 and 4 of the valley tracks are accessed. The polarity of the wobble signal of the other side should be changed based on one side.

FIG. 2 is a diagram illustrating a change in a radial position of a tracking control signal detected by the recording medium of FIG. 1, wherein the tracking control signal when tracking a land track and the tracking control signal when tracking a groove track. The polarities are different from each other. For this purpose, in the case of a DVD-RAM, the signal pull following the ID area is detected as a land track or groove track according to the polarity of the signal detected in the sector ID area from the push pull signal. . On the other hand, if the ID area signal of the sector can be detected accurately, the polarity of the tracking control signal can be controlled by accurately determining whether the following signal track is a land or groove track from this signal information. However, mountain / goal discrimination is usually performed using the prepit sequence of the ID area. Therefore, mountain / goal discrimination cannot be performed before reading the ID area. Therefore, it is difficult to determine the mountain and the goal when the ID area such as track search cannot be read. . As a result, even if the wobble signal is detected, if there is no mountain / goal discrimination information, it is impossible to properly determine whether the track is a land track or a groove track, and the polarity of the tracking signal cannot be properly controlled so that accurate recording / reproduction of information cannot be performed. This is being derived.

Accordingly, it is an object of the present invention to provide an optical disc recording / reproducing apparatus and method for stably tracking control while recording / reproducing information by accurately determining mountain / goal tracks in a disc having a mountain and valley track structure. will be.

In order to achieve the above object, the optical disc recording / reproducing apparatus of the present invention includes a channel signal generator for converting a wobble signal detected from an information recording medium into a square wave, an edge detector for detecting an edge signal from the square wave, and a predetermined value based on the edge signal. A reference signal generator for outputting a reference signal of a; and a hill / goal track determination unit for determining a hill / gol transition by comparing the phase of the square wave with the reference signal.

An optical disc recording / reproducing method according to the present invention comprises a first step of detecting a wobble signal from an optical disc, a second step of creating a square wave using the detected wobble signal, a third step of detecting an edge signal from the square wave, and an edge. Comparing the phase of the square wave in the second step and the reference signal in the fourth step with the fourth step of outputting a predetermined reference signal based on the signal, it is determined that there is a hill / valley variation when the phase is changed. And a fifth step of performing recording / reproducing with the recording / reproducing condition according thereto.

Other objects and features of the present invention other than the above object will become apparent from the description of the embodiments with reference to the accompanying drawings.

3 to 5, an optical disc recording / reproducing apparatus according to the present invention will be described.

Referring to FIG. 3, a band pass filter (hereinafter referred to as a "BPF") for detecting a wobble signal distributed in a constant frequency region among the signals detected by the wobble portion of the optical disc, and a slicer for converting the signal into a square wave An optical disc information recording / reproducing apparatus according to the present invention having a channel signal generation section 34 composed of (Slice) is shown. In the optical pickup, the optical disk of the mountain / gol recording method is irradiated with a light beam, and the amount of reflected light reflected by the optical disk is converted into an electrical signal. In addition, the wobble detector 8 reads the preformatted information on the wobble portion of the optical disc to detect the wobble signal, and the BPF 10 detects the information of the high frequency component inherent in the wobble signal detected by the wobble portion. By removing the signal, a wobble signal existing in a predetermined frequency band is detected and converted into a square wave by the level slicer 12. The waveform of the output signal at this time is shown in Fig. 4C.

The optical disc information recording / reproducing apparatus further includes an edge detector 20 for detecting rising edges and falling edges from the square wave output from the channel signal generator 34. The edge detector 20 detects rising edges and falling edges of the square wave and generates edge detection signals of a specific logic at each of the rising and falling edges of the signal, thereby performing a phase-locked loop (PLL). Generates a clock. On the other hand, the output of the edge detector is the same regardless of the track of the mountain or the track of the valley, it can be seen that the frequency of the PLL clock is twice the frequency of the square wave. At this time, the waveform of the PLL clock is shown in FIG.

And a phase comparator 22 for comparing the phase of the edge detection signal and the clock signal from the first divider, a loop filter 24 for removing noise of the signal output from the phase comparator 22, and an input thereto. A voltage control oscillator (VCO) 26 which varies an oscillation frequency according to the voltage to be generated, and a first divider 28 that divides the signal generated by the VCO 26 by n And a reference signal generator 36 configured to form a circulating loop by the second divider 30, which divides the signal output from the first divider 28 by m, in the optical disc information recording / reproducing according to the present invention. The device is shown. The VCO 26 generates a channel signal having the same phase and frequency as the edge detection signal by adjusting the frequency of the square wave signal generated by itself according to the voltage signal of the phase comparator 22. In the first divider 28, the frequency of the oscillated signal from the VCO 26 is divided into n equal parts and input to the phase comparator 22. In addition, the phase comparator 22 compares the phase difference between the PLL clock signal applied from the edge detector and the square wave applied from the first divider and generates a voltage signal corresponding to the phase difference. In addition, the loop filter 24 removes noise of the signal applied from the phase comparator 22. On the other hand, the second divider 30 divides the PLL clock signal by m and converts it to the same frequency as the output signal of the channel signal generator 34. For example, in detail, if the frequency of the square wave applied from the channel signal generator 34 is 157 KHz, the square wave is used as a PLL clock having a frequency of 314 KHz via the edge detector 20. On the other hand, a square wave having a frequency of 29.18 MHz is generated by the voltage signal in the VCO 26, and the output signal of the VCO 28 is equally divided by 93 in the first divider 28 to be equal to the PLL clock frequency. In the phase comparator 22, the PLL clock signal and the output signal of the first divider 28 detect a phase difference between two signals having the same frequency. On the other hand, the second divider 30 divides the PLL clock signal having a frequency of 314 KHz into two and converts it into a frequency of 157 KHz to be equal to the frequency of the square wave applied from the channel signal generator 34.

In addition, the inverter I1 connected between the output terminal of the reference signal generator 36 and the a contact of the switching unit 32, the b contact connected to the output terminal, and the c contact for outputting a signal applied to it. A multiplier 14 configured to multiply the switching unit 32, the output signal C or C 'of the channel signal generator 34, and the output signal B or B' of the switching unit 32; And an optical disc information recording / reproducing apparatus according to the present invention further comprising an integrator 16 which accumulates the multiplied signal for a predetermined time. The switching unit 32 is switched by the logic state of the polarity control (Polarity Control) signal to form a path for inverting the polarity of the reference signal applied to it. The multiplier 14 multiplies the reference signal via the switching unit 32 and the channel signal applied from the channel signal generator 34 to the integrator 16. In detail, the switching unit 32 inverts the polarity of the reference signal by the logic state of the polarity control signal. At this time, the waveforms of the signal output from the switching unit 32 and the inverted signal are shown in FIGS. 4B and 4B. On the other hand, the waveform of the channel signal applied from the channel signal generator 34 is shown in Fig. 4C. The multiplier 14 calculates a C (C ') signal and a B (B') signal using an exclusive logical sum (EX-OR), and outputs a state of low ("0") when the two signals have the same phase. If inverted, it outputs high ("1") and inputs it to the integrator. At this time, the signal input to the integrator 16 is shown in (D) of FIG.

The first and second comparators A1 and A2 are connected to the integrator 16 and have a logic state opposite to the voltage state of the integrator, and the first flip-flop connected to the output terminal of the first comparator A1. Reset terminal of FF1, Set terminal of first flip-flop FF1 connected to the output terminal of second comparator A2, and third terminal connected to the output terminal of first flip-flop FF1 Reset of flip-flop FF3, third flip-flop FF3 connected with second comparator A2, second flip-flop FF2 connected with first flip-flop FF1, and third flip-flop According to the present invention, there is provided a hill / goal track judgment portion composed of a fourth flip-flop FF4 connected to FF3 and an exclusive logical sum 18 circuit connected to the second and fourth flip-flops FF2 and FF4. An optical disc information recording / reproducing apparatus is shown.

The operation of the mountain / goal track discrimination unit will be described by dividing the wobble unit and the mountain / goal transition point. First, when the pickup passes the wobble part, since a signal having the same polarity is applied to the multiplier 14, the integrator 16 maintains a voltage level of "0" (Zero), and the second comparator A2 has a low logic. The value is applied. In addition, the first flip-flop FF1 is reset and the third flip-flop FF3 is reset by the output of the second comparator A2. Accordingly, the hill / gol control signal becomes high logic and the polarity control signal has a low logic state, so that the hill / gol control signal and the polarity control signal having opposite logic states are shown in FIG. 4.

Next, when the pick-up passes the hill / valley transition point, a signal of opposite polarity is applied to the multiplier 14, and a high ('1') signal is accumulated in the integrator 16. The output voltage is applied to the first comparator A1, and the output signal of the first comparator A1 sets the first flip-flop FF1 so that the high logic signal E is output to the second flip-flop FF2. The mountain / gol control signal has low logic by toggling the signal, and the third flip-flop FF3 receives a signal E 'having a high logic signal E applied by the first comparator A1 delayed by a time constant. Input signal by inverting the phase of the input signal by toggling the third flip-flop (FF3) and the output of the third flip-flop (FF3) by the fourth flip-flop (FF4). The phase of is inverted to have a high logic state, while in the exclusive OR circuit 18, the land / groove (mount / gol) control scene is used. And the logic state of the polarity control signal is determined by the logic state of the output signal of the fourth flip-flop FF4, and the polarity control signal at this time is shown in Fig. 4. The signal of the opposite polarity is applied, which causes high logic to accumulate in the integrator 16 and sets the first comparator A1. As a result, a polarity control signal is output to switch the reference signal or the path of the switching unit to the reference signal. The polarity of the signal is reversed by detecting the phase of the wobble signal reversed at the hill / valley transition point.

Meanwhile, the information recording / reproducing method according to the present invention will be described.

An information recording / reproducing method according to the present invention includes a first step of detecting a wobble signal in a wobble portion of an optical disc, and a second step of making a square wave using the detected wobble signal. As shown in FIG. 4, when an optical beam is scanned along a signal track of A in an optical disc having a transition point of a hill / a valley, a wobbling signal due to the wobbling of the signal track is detected, and the slicer 12 is used. A square wave is shown in (C). That is, the phase is changed by 180 degrees as it moves from the track of the land to the groove, thereby inverting the signal.

The information recording / reproducing method according to the present invention also includes a third step of detecting an edge signal from the square wave. The edge signal 20 detects the rising edge and the falling edge of the square wave, generates a frequency corresponding to twice the square wave, and uses the edge signal as the PLL clock.

The information recording / reproducing method according to the present invention includes a fourth step of outputting a predetermined reference signal based on the edge signal. The PLL clock generated in synchronization with the rising edge and falling edge of (C) becomes a continuous constant signal regardless of the groove or land. The reference signal generator including the phase comparator 22, the loop filter 24, the voltage controlled oscillator 26, and the first and second dividers 28 and 30 outputs a predetermined reference signal.

In addition, the information recording / reproducing method according to the present invention compares the phases of the square wave signal of the second step and the reference signal of the fourth step, and determines that there is a mountain / bone shift when the phase is changed, and the information is determined according to the conditions. And a fifth step of recording / reproducing.

Since the multiplier 14 performs an exclusive-OR operation on the two signals, a signal of the same polarity is applied at the wobble part to output low logic, and signals of opposite polarities are applied at the mountain / valley transition point to be high. The logic is output and input to the integrator 16. On the other hand, having the integrator 18, the first and second comparators A1, A2 and the first flip-flop FF1 can stably detect a slight phase change between the (B) and (C) signals. Is necessary. In addition, this is to stably operate when the wobbling signal is not properly detected due to a defect such as a fingerprint. Meanwhile, when the A track of FIG. 4 is rotated once, it moves to the track of A 'and can be detected to move from the groove track to the land track. In addition, since the polarity of the signal multiplied by B or B 'and C changes as the track changes, the signal processing by the integrator and the comparator must be different, so that the reference signal is controlled by the land / groove control signal for convenience. Is selected to compare (B) or (B ').

FIG. 5 is a diagram showing a first embodiment of the present invention, which will be described in the case of track jumping or optical disk replacement.

Looking at the information reproduction / recording of the optical disc in the case of transferring information to the groove track while reproducing / recording information on the land track, when the inverted operation as described above is performed, that is, the control is placed on the groove track of 4. If the reference signal b is in the reversed phase, it is determined as a land track. As a result, the land / groove control signal is changed to perform a track jump. This makes it difficult to reliably track during the information reproduction / recording process. In order to prevent this, when the track is skipped within a predetermined time, only the polarity of the polarity control signal is changed so that the polarity of the reference signal b is the same. In addition, in order to correct an error of hill / valley discrimination, the third and fourth flip-flops FF3 and FF4 and the exclusive logical sum circuit discriminate the hill / valley transition when the inversion is performed as described above. In the case of misjudgment due to hill / valley variation as described above (for example, the track of the current goal in the fall section of FIG. 5, where the B signal is out of phase), the land / groove (mount / goal) control signal is grooved in the land. Is converted to. It is the actual mountain track, and as a result of the determination of the track of the goal, the pickup moves from the mountain to the track of the adjacent goal. As described above, the phase of the C signal is changed when the track jump occurs, the voltage accumulated in the integrator is applied to the first comparator A1, and the output signal X of the first comparator is applied to the first flip-flop FF1. A third flip-flop FF3 is toggled by outputting an output signal e having a high logic and an E 'signal that delays the signal (E) by a time constant to the third flip-flop FF3. The output of the third flip-flop FF3 toggles the fourth flip-flop FF4 and converts the output from low to high. In the above configuration, when the initial start-up is misjudged by the hill / valley variation, the (X) signal is used to change the polarity control signal by using another occurrence before the first flip-flop FF1 is reset. Further, the (E ') signal serves to window the second pulse of the (X) signal. As a result, the polarity control signal is changed to switch the switching part so that stable tracking is possible.

As described above, the information recording / reproducing apparatus of the present invention detects the phase of the wobble signal recorded in most areas of the disc having the track structure of the hill and valley by detecting the inversion at the hill / valley transition point. In addition to recording / reproducing information by accurately discriminating, there is an advantage that stable tracking control can be performed.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined in particular by the claims.

1 shows a recording medium having a track structure of hills and valleys.

2 is a waveform diagram of a tracking control signal detected by the recording medium of FIG.

3 is a view showing an optical disc recording / playback apparatus according to the present invention;

4 is a waveform diagram detected in FIG.

5 is a waveform diagram according to a first embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

2: track of the mountain 4: track of the goal

 6a, 6b: prepit 8: wobble detector

10 bandpass filter 12 slicer

14 multiplier 16 integrator

18: exclusive OR circuit 20: edge detector

22: phase comparator 24: loop filter

26: voltage controlled oscillator 28: first divider

30: second divider 32: switching unit

34: channel signal generator 36: reference signal generator

38: mountain / goal track determination unit A1, A2: first and second comparators

FF1 to FF4: first to fourth flip-flops

Claims (9)

In the recording / reproducing method of an optical disc made of tracks of hills and valleys and of which the tracks are wobbled, a) a first step of detecting a wobble signal from the optical disc; b) a second step of producing a square wave using the detected wobble signal; c) detecting an edge signal from the square wave; d) outputting a predetermined reference signal based on the edge signal; e) comparing the phase of the square wave in the second step with the reference signal in the fourth step and determining that there is a mountain / bone shift when the phase is changed, and performing recording / reproducing according to the recording / reproducing conditions accordingly. And a fifth step. The method of claim 1, Comparing the phase of the square wave in the second step and the reference signal in the fourth step, it is determined that there is a mountain / goal jump when the phase changes within a predetermined time, and recording / reproducing is performed according to the recording / reproducing conditions accordingly. And a sixth step. The method of claim 2, And if it is determined that there is a mountain / goal jump in the sixth step, the polarity of the reference signal is inverted and outputted. The method of claim 1, The third step, And an edge signal is detected from the rising edge and the falling edge of the square wave. An apparatus for recording / reproducing an information recording medium consisting of tracks of hills and valleys and of which wobbled tracks, a channel signal generator for converting the wobble signal detected from the information recording medium into a square wave; b) an edge detector for detecting an edge signal from the square wave; a reference signal generator for outputting a predetermined reference signal based on the edge signal; and d) a hill / valley track determination unit comparing the phase of the square wave with the phase of the reference signal to determine hill / valley transitions. The method of claim 5, wherein A switching unit for switching according to the polarity control signal output from the mountain / goal track determination unit; A multiplier for multiplying a phase of the square wave and a reference signal; And an integrator which accumulates the voltage output from the multiplier. The method of claim 5, wherein The channel signal generator, A wobble detector for sensing a wobble portion of the optical recording medium; A band pass filter for removing noise of the wobble signal detected by the wobble unit; And a slicer for converting the wobble signal into a square wave. The method of claim 6, The multiplier, An optical disc recording / reproducing apparatus, characterized in that implemented by an exclusive OR circuit. The method of claim 6, The switch unit, And the track is skipped within a predetermined time so as to be switched according to the polarity control signal so that only the polarity of the reference signal is changed.

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