KR100207615B1 - Device and method for the compensating of an optical disc recording - Google Patents

Abstract

The present invention discloses a recording compensation device and method thereof in an optical disc recording / reproducing system.

The present invention is a system controller for recognizing an area to be currently written on a disc divided into predetermined areas when the write mode is set, which is smaller than the normal data pulse width in the data string, and the smaller the inner pulse area of the optical disk, the smaller the data pulse width A write pulse correction unit for compensating the write pulse and an optical power control unit for adjusting the optical power in response to the corrected write pulses output from the write pulse correction unit can reduce the error between the recording signal and the reproduction signal.

Description

Optical disc record compensator and method

1A to 1D are waveform diagrams for explaining the conventional recording method.

2A and 2B are diagrams for explaining a teardrop phenomenon and a thermal interaction phenomenon formed on a magnetic region when recording by the recording method shown in FIGS. 1A to 1D. .

3 is a block diagram of an optical disc recording / reproducing apparatus to which the present invention is applied.

4 is a block diagram according to an embodiment of the optical disc recording / compensation apparatus according to the present invention.

5 is a diagram for explaining area classification of an optical disc according to the present invention.

6A to 6E are waveform diagrams of pulses corrected in the write pulse correction unit.

7A to 7C are waveform diagrams of output pulses of the recording compensator shown in FIG.

FIG. 8 is a flowchart for explaining an optical disc recording compensation method performed by the system controller shown in FIG.

* Explanation of symbols for main parts of the drawings

31: system controller 32: recording control switch

33: pulse width adjusting unit 34: pulse train generating unit

35: tracking servo unit 36: focusing servo unit

37: warning unit 38: optical power control unit

39: write pulse compensation unit

The present invention relates to an optical disc recording compensator and a method thereof, and more particularly to a digital video disc recorder for compensating a waveform of a recording signal to be suitable for recording and reproducing characteristics in order to minimize errors that may appear between recording areas. It's about how.

Current technology trend of video / audio recording / playback device is changing from analog method to digital method that provides high definition and high quality. Video cassette recorder (VCR) using video tape is a typical analog video / audio recording / playback device. Examples of the digital video / audio recording and reproducing apparatus include a laser disk player (LDP) using an optical disk, a magneto-optical disk driver (MODD) system, and the like.

This optical disc includes a rewritable type disc capable of rewriting any number of times in the same area as a write type disc which cannot be erased once data has been written.

A digital video disc recorder (D-VDR) has been proposed and developed that combines a home VCR function with a rewritable disc.

The D-VDR is a device that converts video and audio signals into digital data to record and play back on a magneto-optical disc. Is needed. In particular, the following four technologies should be applied for high-density recording technology.

① Reduction of Track Pitch: Conventional magneto-optical discs have a pitch of 1.6 μm, but digital video discs have 1.0 μm.

(2) Short wavelength recording / reproducing medium (disc): The amount of reflected light varies depending on the refractive index of the medium of the disc. This refractive index is related to the spot size.

③ use of short wavelength lasers; Conventional MODD uses a semiconductor laser having a wavelength of 780nm, but in order to reduce the spot of the laser beam, D-VDR uses a semiconductor laser having a wavelength of 532nm.

④ Using Mark Length Recording method: Mark length modulation is a method of generating and recording a waveform sequence from NRZI (Non Return Zeoro Inverse) from a series of codes. During playback, both ends of a mark on a disc are detected. Signal detection increases the recording density.

What is the solution of Thermal Interaction and Inter Symbol Inteferance (ISI), which are the most basic problems that can occur when recording on a magneto-optical disk for high density recording in the above-described manner? More important than ever.

Here, thermal interaction refers to thermal expansion caused by interaction between data when a laser beam is fired at a temperature above the Curie temperature in the magnetic region of the disc.

Code Interference (ISI) means that when a certain mark is read, the mark interval is narrow, so that the front and back marks may be affected, and the signal to be read causes waveform interference.

On the other hand, when recording the recording signal without compensation, the conversion is made on the magnetic region in FIG. 1b according to the write pulse shown in FIG. 1a. Therefore, the reproduction pulse shown in FIG. 1d detected from the reproduction signal shown in FIG. 1c has a large error with the write pulse (FIG. 1a), which may cause an error.

The teardrop phenomena causing the results of FIG. 1d are shown in FIG. 2a, and an example of a region formed by thermal interaction is shown in FIG. 2b.

Therefore, in order to solve this problem, there is a need for a recording compensator for changing a signal to be recorded into a signal most suitable for recording / reproducing characteristics of a medium.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical disc recording compensating apparatus and a method for correcting and recording a recording signal in order to minimize errors that may appear between the recording areas.

In order to achieve the above object, an optical disc recording / compensation apparatus according to the present invention comprises: an optical disc recording / reproducing system for converting a video / audio signal into a data sequence to record and reproduce the optical signal as an optical signal; A system controller for recognizing a region to be currently written on a disk divided into a predetermined region in advance if the writing mode is set; Write pulse correction means for compensating the write pulse to be smaller than the normal data pulse side in the data string and having a smaller data pulse side in the inner circumferential region of the optical disc; And optical power adjusting means for adjusting the optical power corresponding to the corrected writing pulse output from the writing pulse correcting means.

An optical disc recording / compensation method according to the present invention comprises: an optical disc recording / reproducing method of converting a video / audio signal into a data sequence, recording the optical disc as an optical signal, and reproducing: a write mode setting step of setting an enterprise mode; An area information input step of inputting current area information on the optical disc previously divided into a predetermined number of areas when the write mode is set; A write pulse correction step of inputting the current area information to correct a write pulse so as to have a smaller data pulse width than a normal data pulse width in the data string and an inner peripheral area of the optical disc; And an optical power adjusting step of adjusting the optical power corresponding to the corrected writing pulse output in the writing pulse correcting step.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the optical disk recording compensation device and method according to the present invention.

3 is a block diagram of an optical disc recording / reproducing apparatus to which the present invention is applied.

Referring to FIG. 3, the A / D converter 10 inputs a video signal and an audio signal to be recorded and converts them into a digital signal form.

The DSP encoder 20 converts an input data bit string consisting of 1,0 pieces of binary information into a recording code string according to a modulation method, and then improves the recording density characteristics of the recording compensator 30 and reduces waveform interference during reproduction. Write pulse compensation is performed. The write pulse is corrected to minimize errors that may occur due to interference of adjacent tracks or adjacent recording areas when data is recorded on the optical disc.

In the laser diode 40, the corrected writing pulse is converted into an optical (laser) signal and recorded on the optical disc DISC.

The optical signal reflected from the optical disc DISC by the photodiode 50 is converted into a current signal and amplified by the reproduction amplifier 60. The laser diode 40 and the photodiode 50 correspond to the pickup portion.

In the reproduction equalizer 70, the output waveform of the reproduction amplifier 60 is corrected to reduce the waveform interference, thereby achieving higher density.

The synchronization signal generation unit 80 generates a synchronization signal synchronized with the basic period of the output signal of the reproduction equalizer 70.

The DSP decoder 90 detects whether there is a reproduction pulse signal of light in a time period determined by using the synchronization signal generated by the synchronization signal generator 80, and finally, in the detection window. The detection code string is a data bit. Demodulate by heat.

The D / A changing unit 100 converts the demodulated bit string into analog video and analog audio signals for final output.

4 is a block diagram according to an embodiment of the optical disc recording / compensation apparatus according to the present invention.

An optical disc recording compensation apparatus according to the present invention includes a system controller 31 for recognizing an area currently being written on a disc divided into predetermined areas, a recording control switch 32 for setting a recording mode, The pulse width adjusting unit 33 corrects the write pulse by adjusting the pulse width when the recording area corresponds to the outer circumferential area (track or sector). The write pulse is corrected by the pulse string when the recording area of the disc corresponds to the inner track. Under the control of the write pulse compensator 39, which is the pulse train generator 34, and the system controller 31, the laser beam accurately reads the track in order to accurately read and write on the track in response to the eccentricity of the center hole of the optical disc. Under the control of the tracking servo unit 35 and the system controller 31 for tracking, there is always a surface vibration of about 0.2-0.3 mm between the optical pickup unit and the optical disk. However, since the depth of focus in the objective lens of the optical disc pickup unit is only about ± 1 μm, that is, the disk surface vibration is much larger than the depth of focus, the distance between the lens and the optical disc is adjusted within the lens depth of focus by moving the objective lens up and down. The focusing servo unit 36 and the warning generating unit 37 for displaying an error, and the pulse width adjusting unit 33 and the pulse train control unit 34 are outputted when the current writing area is not a pre-classified area. And an optical power adjusting unit 38 for adjusting the optical power corresponding to the corrected writing pulse.

Next, the operation of FIG. 4 will be described with reference to FIGS. 5 to 7d.

First, in the present invention, recording compensation is performed by dividing the optical disc into four areas as shown in FIG.

When the recording mode is set by the recording switch 32, the system controller 31 recognizes this and the area where the modulated data string output from the DSP encoder 20 is to be recorded is divided into four areas shown in FIG. The drive control signal is output to the pulse width adjusting unit 33 or the pulse train generating unit 34 by determining which area is used.

Here, in the case where the normal recording data is as shown in FIG. 6A, if the area to be recorded is the B area, the pulse train generation unit 34 outputs a pulse train (hereinafter referred to as a second pulse train) as shown in FIG. 6B. If the area to be recorded is the A area, the pulse train generation unit 34 outputs a pulse train (hereinafter referred to as a first pulse train) as shown in FIG. 6C.

Here, the optical power controller 38 adjusts the optical power of the signal shown in FIG. 6B to be larger than the signal shown in FIG. 6A.

When the area to be recorded is a signal corresponding to the area D, a pulse signal in which the pulse width is adjusted to be smaller than the normal pulse width as shown in FIG. 6d by the pulse width adjusting unit 33 (hereinafter referred to as second pulse width). Outputs

When the area to be recorded is a signal corresponding to the C area, a pulse signal whose pulse width is adjusted to be smaller than the normal pulse width as shown in FIG. 6f by the pulse width adjusting unit 33 (hereinafter referred to as first pulse width). do.

Here, the optical power adjusting unit 38 adjusts the optical power of the signal shown in FIG. 6d to be larger than the optical power of the signal shown in FIG. 6e. Therefore, the optical power is adjusted more in the outer circumference than in the inner circumference of the disc.

When writing with pulses output from the pulse width adjusting unit 33 and the pulse train generating unit 34, the area read signal and the read pulse formed as shown in FIGS. 7A to 7D are written pulse waveforms without error. The same waveform as can be obtained.

That is, Fig. 7a is a write pulse waveform, the signal shown in Fig. 7b is formed in a magnetic region, Fig. 7c is a waveform of a read signal, and Fig. 7d shows a read pulse with respect to the read signal.

FIG. 8 is a flowchart for explaining an optical disc recording compensation method performed by the system controller shown in FIG.

Step S1 is a recording mode setting step, step S2 is a current disc area information input step, steps S3 to 18 are write pulse correction steps, and step S19 corresponds to an error warning step.

Next, each step shown in FIG. 8 will be described in detail in conjunction with the device shown in FIG.

The system controller 31 recognizes this when the write mode is set through the write mode setting control switch 32 while the main flow is performed (step S1).

The current recording area information is input from the disc DISC classified into a predetermined number of areas in advance (step S2).

Then, it is determined whether the classified area is A area (step S3).

In the area A, the recording signal is output as the second pulse train (Fig. 6C) (step S4), and the optical power is adjusted (step S5). It is determined whether the recording of the area A is completed, and if it is completed, the feedback is fed back to the step S2, otherwise, the feedback is fed back to the step S4 (step S6).

It is determined whether the classified area is the B area (step S7).

If the area B, the recording signal is output in the first pulse train (FIG. 6B) (step S8), and the optical power is adjusted to record (step S9). It is determined whether the recording of the area B is completed, and if it is completed, the feedback is returned to the step S2, otherwise, the feedback is returned to the step S8 (step S10).

It is determined whether the classified area is the C area (step S11).

In the case of the C region, the recording signal is adjusted to the second pulse width (Fig. 6f) and output (step S12), and then the optical power is adjusted (step S13). It is determined whether the recording of the area C is completed, and if it is completed, the feedback is returned to the step S2, otherwise, the feedback is returned to the step S12 (step S14).

It is determined whether the classified area is the D area (step S15).

In the D area, the recording signal is adjusted to the first pulse width (Fig. 6d) and output, and then the optical power is adjusted (S17). It is determined whether the recording of the D area is completed, and if it is completed, the feedback is fed back to the step S2, otherwise the feedback is fed back to the step S16 (step S18).

If the classified area is not A, B, C, or D area, it indicates that the system operation is an error so that the user can know and continue the main flow (step S19).

That is, various methods of ringing a bell or displaying an error message on the display may be used.

In the present invention, recording compensation by the method of pulse train generation or pulse width adjustment is performed to match the optical power of the laser to the medium in order to prevent the occurrence of ISI or thermal interaction. This is to make the recorded area phenomenon have an ideal shape.

The present invention can be applied to all devices such as a video disc recorder, a MODD, and the like that apply a magneto-optical system.

As described above, the optical disc recording compensation apparatus and method thereof according to the present invention can reduce the error of the recording signal and the reproduction signal by adjusting the pulse string or pulse width for each disc area in order to minimize errors that may appear between the recording areas. It has an effect.

Claims (6)

1. An optical disc recording / reproducing system for converting a video / audio signal into a data stream, recording an optical signal as an optical signal, and reproducing: a system for recognizing an area currently written on a disc previously divided into predetermined areas when the writing mode is set. Controller; Write pulse correction means for compensating write pulses to be smaller than a normal data pulse width in the data sequence and to have a smaller data pulse width in the inner circumferential region of the optical disc; And optical power adjusting means for adjusting the optical power corresponding to the corrected writing pulse output from the writing pulse correcting means. The recording pulse compensation means of claim 1, further comprising: a pulse width adjusting section for correcting the writing pulse by adjusting the pulse width when the current recording area is an outer peripheral area of the disk; And a pulse string generating portion for generating write pulses as pulse strings if the current recording region is an inner circumferential region of the disc. 2. An optical disc recording compensation apparatus according to claim 1, further comprising warning means for displaying an error if the current recording area does not belong to a pre-classified area. 1. An optical disc recording / reproducing method for converting a video / audio signal into a data sequence and recording and reproducing the optical signal as an optical signal. An area information input step of inputting current area information on the divided optical disc; A write pulse correction step of inputting the current area information to correct a write pulse so as to have a smaller data pulse width than a normal data pulse width in the data string and an inner peripheral area of the optical disc; And an optical power adjusting step of adjusting the optical power in response to the corrected writing pulses output in the writing pulse correcting step. 5. The method of claim 4, wherein the write pulse correction step comprises: a pulse width adjustment step of correcting the write pulse by adjusting the pulse width if the current recording area is an outer peripheral area of the optical disc; And a pulse string generating step of correcting a write pulse with a pulse string if the current recording region is an inner circumferential region of the optical disc. 6. The optical disc recording compensation method according to claim 5, further comprising an error display step of displaying an error if the current recording area is not a previously classified area in the area information input step.