KR19980069624A - Recording waveform generator of optical disk system - Google Patents

Abstract

The present invention relates to an apparatus for generating a recording waveform of an optical disk system, which can generate a recording waveform for data recording with high accuracy by controlling on-time of a laser for recording data in an optical disk system. Over-sampling means for over-sampling the converted data by N times; First counting means for counting the data converted into the channel code and detecting which length value among the plurality of predetermined pit length values corresponds to the pit length; Selector control means for inputting data converted into channel codes to detect a section corresponding to a recording section and to generate an enable signal; An adjustment value corresponding to each of a plurality of preset pit length values is stored, and in response to the enable signal from the selector control means, corresponding to the detected pit length value provided by the first counting means among the plurality of adjustment values. Selecting means for selecting and outputting an adjustment value; Second counting means for counting an over sampled pit length value provided from the over sampling means and calculating a pulse width thereof; Comparison means for comparing the selected adjustment value provided from the selection means with the calculated pulse width provided from the second counting means, determining when the selected adjustment value coincides with the pulse width, and generating a corresponding pulse signal; Delay means for delaying the over sampled pit length value provided from the over sampler for a predetermined time; And flip-flops for generating an updated recording waveform having a pulse width at least narrower than the original recording waveform based on the pulse signal applied from the comparison means to the reset terminal and the delayed over sampling pit length value provided from the delay means to the set terminal. Include.

Description

Recording waveform generator of optical disk system

The present invention relates to an apparatus for generating a recording waveform in an optical disc system. More particularly, the present invention relates to a compact disc recorder (CD-R), a digital video disc recorder (DVD-R), and the like. Generation of recording waveforms suitable for generating driving pulses for driving lasers when recording desired data (video, audio, text, etc.) on an optical disc that is recorded several times and read several times, such as an optical disc or DVD-RAM of a type to be performed. Relates to a device.

As is well known, an optical disc system is a reproduction type that can only reproduce recorded information, and additional recording types and information which can be read (played back) but not recorded again by the user once recording and then only when necessary. There is an erasure recording type capable of arbitrarily performing recording and erasing, wherein the present invention relates to an additional recording type or an erasure recording type.

On the other hand, an optical disc system such as a CD-R or a DVD-R is modulated according to a predetermined principle before recording data on the optical disc.

When converting to a Non Return to Inverted (NRZI) code waveform, one of the methods, the waveform width is limited to a limited number of lengths. That is, in the EFM (Eight to Fourteen Modulation) of the CD-R, there are 9 limited pulse widths ranging from 3T to 11T.

At this time, in recording data on the optical disc, it is necessary to precisely readjust the laser drive pulse width at the time of recording so that the recording mark (or pit) on the disc is recorded with the correct length corresponding to the limited pulse width.

That is, when data is recorded by driving the laser as a waveform corresponding to the data to be recorded on the optical disk, the recorded mark tends to be larger than the original intended length. This is mainly because the on type of light emitted from the laser is driven by the laser. This is because heat is accumulated in the disk media at the time of recording, which is larger than the period width of the pulse.

Therefore, in order to prevent the tendency to increase the mark to be recorded, it is necessary to compensate for this in advance when generating a recording waveform for recording data on an optical disc, that is, to compensate for the laser drive pulse width, and in particular, to increase the density of data recording. In light of recent trends, more precise laser drive pulse width compensation is required.

Accordingly, the present invention has been made in view of the foregoing, and provides an apparatus for generating a recording waveform of an optical disk system, which can generate a recording waveform for data recording with high precision by controlling on-time of a laser for data recording in an optical disk system. The purpose is to provide.

In order to achieve the above object, the present invention converts EFM data to be recorded on an optical disc into an arbitrary recording channel code according to a system clock, and based on the pulse converted into this channel code, An apparatus for generating a recording waveform for driving a laser provided in a pickup, said apparatus comprising: an over sampling means for over sampling the data converted into said channel code by N times; First counting means for counting the data converted into the channel code to detect which length value among the plurality of preset pit length values; Selector control means for inputting the data converted into the channel code to detect a section corresponding to a recording section and generating an enable signal; An adjustment value corresponding to each of the preset plurality of pit length values is stored, and in response to an enable signal from the selector control means, a detected pit provided in the first counting means among the plurality of adjustment values Selecting means for selecting and outputting an adjustment value corresponding to the length value; Second counting means for counting an over sampled pit length value provided from said over sampling means and calculating a pulse width thereof; A comparison comparing the selected adjustment value provided from the selection means with the calculated pulse width provided from the second counting means, determining when the selected adjustment value coincides with the pulse width, and generating a corresponding pulse signal. Way; Delay means for delaying an over sampled pit length value provided from said over sampling means for a predetermined time; And generating an updated recording waveform having a pulse width at least narrower than the recording waveform based on the pulse signal applied from the comparing means to the reset terminal and the delayed over sampling pit length value provided from the delay means to the set terminal. Provided is a recording waveform generating apparatus for an optical disc system composed of flip flops.

1 is a schematic block diagram of a typical optical disc recording system suitable for applying a recording waveform generating apparatus according to the present invention;

2 is a block diagram of a recording waveform generating apparatus of an optical disk system according to a preferred embodiment of the present invention;

3 is a pulse waveform diagram showing an output waveform of each block of the recording system of FIG. 1 and the recording waveform generating apparatus of FIG.

<Description of the code | symbol about the principal part of drawing>

100: NRZI encoding block 200: recording pulse width control block

202: oversampling block 204,214, 216: delay

206,218: Reset block 208,220: Counter

210: selector control block 212: selector

222: comparator 224: flip-flop

300: clock generation block 400: laser power drive block

500: Deck

The above and other objects and various advantages of the present invention will become more apparent from the preferred embodiments of the present invention described below with reference to the accompanying drawings by those skilled in the art.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 shows a schematic block diagram of an optical disc recording system suitable for applying the recording waveform generating apparatus according to the present invention.

As shown in the figure, a typical optical disc recording system includes an NRZI encoding block 100, a recording pulse width control block 200, a clock generation block 300, a laser power drive block 400 and a deck 500. do. The deck 500 also includes an optical pickup 502, a disk seat 504 and a driver 506.

Referring to FIG. 1, the NRZI encoding block 100 converts each EFM data for recording provided from an EFM modulator, not shown, into a waveform having nine pulse widths of 3T-11T. For example, when EFM data in the form shown in FIG. 3 (a) is received, the NRZI encoding block 100 is shown in FIG. 3 (b) according to the system clock provided from the clock generation block 300 described later. The waveform is converted into a waveform having a pulse width in the form as described above, and the signal waveform having the pulse width of the predetermined length is provided to the next recording pulse width control block 200.

Meanwhile, the write pulse width control block 200 is a part substantially related to the present invention, and is limited in the NRZI encoding block 100 described above according to the system clock provided in the clock generation block 300 described later. A recording waveform for driving the laser in the optical pickup 502 based on a pulse waveform having a number of lengths, for example, a recording having a pulse width compensated according to the present invention, as shown in FIG. Generate a waveform. A detailed operation process of the recording pulse width control block 200 will be described later in detail with reference to FIG. 2 showing a detailed block configuration.

In addition, the clock generation block 300 may be configured as, for example, a PLL clock generator, and the present invention is based on a clock and a conversion waveform required when converting the EFM data into a waveform having a limited number of lengths. According to the present invention, a clock required to generate a recording waveform having a compensated pulse width is generated and provided to the NRZI encoding block 100 and the recording pulse width control block 200, respectively.

On the other hand, the laser power drive block 400 generates a laser drive signal for driving the laser of the optical pickup 502 based on the recording waveform having the compensated pulse width provided from the recording pulse width control block 200 described above. As a result, the laser is driven in accordance with the drive signal from the laser power drive block 400 so that the desired data will be recorded on the optical disc.

The optical pickup 502 includes a laser, and the deck 500 includes a disk seating unit 504 and a driver 506 in addition to the optical pickup 502, and records data in the disk seating unit 504. The optical disc to be mounted is mounted, and the driver 506 drives, i.e., rotates, the disc seat 504 based on a control signal from a controller not shown when writing data to the optical disc.

Next, a recording waveform generating apparatus of the optical disk system according to the present invention applicable to a typical optical disk recording system having the above-described configuration will be described.

2 is a block diagram of a recording waveform generating apparatus of an optical disk system according to a preferred embodiment of the present invention.

As shown in the figure, the recording waveform generating apparatus of the present invention substantially corresponds to the recording pulse width control block 200 of FIG. 1, which includes an oversampling block 202 and three delayers 204, 214, and 216. , Two reset blocks 206 and 218, two counters 208 and 220, a selector control block 210, a selector 212, a comparator 222 and a flip-flop 224.

Referring to FIG. 2, a signal waveform having a predetermined pulse width as shown in FIG. 3 (b) output from the NRZI encoding block 100 of FIG. 1 is an oversampling block 202 and a delayer 204. Are simultaneously applied to the reset block 206 and the selector control block 210.

First, in the oversampling block 202, over-sampling the data converted into NRZI by N times, as shown in FIG. 3 (c), for example, over-samples the input data by N times to generate on the line L21. This oversampling is to readjust the data input for recording in fine time units.

Next, the counter 208 detects which of 3T-11T pulses of the EFM data converted into NRZI, that is, counts the pulses of the EFM data input through the delay unit 204, and selects nine pulse width types. Is detected, and the detected pulse width type value is provided to the selector 212 described later via the line L23. At this time, the counter 208 is reset based on the reset signal from the reset block 206 for counting successive input pulses. Here, the delay unit 204 delays the input data for a predetermined time in order to match the data processing time in each path.

In addition, the selector control block 210 generates an enable signal of the selector 212 by inputting pulses of the EFM data converted into NRZI, that is, when a value of "1" corresponding to the actual recording period is input. An enable signal is generated on the line L25, and when a value of "0" is input, a disable signal is generated on the line L25 and provided to the selector 212.

On the other hand, the selector 212 includes a register or a memory to store adjustment values corresponding to pulse width types (i.e., pit lengths) of 3T-11T, respectively, for example, 3T = 16, 4T = 21, and the like. Select an adjustment value corresponding to the type of pulse width (ie, pit length) provided by the counter 208 via line L23 when an enable signal is applied from the selector control block 210 via line L25. To the comparator 222 to be described later through the line L27.

On the other hand, the delay unit 214 receives the oversampled pulse provided by the above-mentioned oversampling block 202 through the line L21, that is, N times oversampled pulses as shown in FIG. As shown in Fig. 2), a delay is performed for a predetermined time (for example, 2T, 3T, etc.) and then provided to the set terminal S of the flip-flop 224 described later, which is a data processing time in each path. In order to fit the time.

In addition, the counter 220 calculates the width of the recording pulse in the over-sampled data, that is, over-sampled by N times provided from the above-described over sampling block 202 through the line L21 and the delayer 216. The pulse width is counted to calculate the pulse width, and the calculated pulse width value (feet length information) is provided to the comparator 222 described later via the line L29. At this time, the counter 220 is reset based on the reset signal from the reset block 218 for counting consecutive input pulses. Here, the delayer 216, like the delayer 204 described above, delays the input data for a predetermined time in order to match the data processing time in each path.

The comparator 222 then adjusts the corresponding values of the respective pulse width types provided from the selector 212 through line L27 and the oversampled pulse width values provided from the counter 220 via line 29 (feet length). Information) to determine when the calculated recording pulse width coincides with the time output from the selector 212, i.e., as shown in FIG. 3 (e) as an example, an adjustment in which the width of the recording pulse is output from the selector. In order to turn on only the set time width, a pulse signal having a predetermined period (for example, 2T, 3T, etc.) is generated at a time when the recording pulse value and the selector output time coincide with each other, thereby resetting the reset terminal R of the flip-flop 224. To provide.

Meanwhile, in the flip-flop 224, the recording waveform controlled based on the delayed waveform provided from the delay unit 214 through the S terminal and the reset signal provided from the comparator 222 through the R terminal, that is, FIG. 3 (f). As shown in FIG. 1, a controlled output waveform having a compensated pulse width is generated and provided to the laser power driving block 400 of FIG. That is, the flip-flop 224 generates an output waveform in which the on-time of the laser is substantially reduced by a predetermined period in front and rear in accordance with the present invention.

Accordingly, the laser power driving block 400 of FIG. 1 generates a laser driving signal for driving the laser of the optical pickup 502 based on the recording waveform having the compensated pulse width provided from the flip-flop 224. As a result, the laser in the optical pickup 502 is driven in accordance with this drive signal, thereby recording data for recording purposes on the optical disc.

As described above, according to the present invention, the actual recording waveform for driving the laser is suppressed at least narrower than the original recording waveform corresponding to the data to be recorded, thereby effectively recording data on the optical disc without the phenomenon that the recorded mark becomes large. Can be.

Claims (4)

EFM data to be recorded on the optical disc is converted into an arbitrary recording channel code according to the system clock, and recording for driving a laser included in the optical pickup when recording data to the optical disc based on the pulses converted into the channel code. An apparatus for generating a waveform, Over sampling means for over sampling the data converted into the channel code by N times; First counting means for counting the data converted into the channel code to detect which length value among the plurality of preset pit length values; Selector control means for inputting the data converted into the channel code to detect a section corresponding to a recording section and generating an enable signal; An adjustment value corresponding to each of the preset plurality of pit length values is stored, and in response to an enable signal from the selector control means, a detected pit provided in the first counting means among the plurality of adjustment values Selecting means for selecting and outputting an adjustment value corresponding to the length value; Second counting means for counting an over sampled pit length value provided from said over sampling means and calculating a pulse width thereof; A comparison comparing the selected adjustment value provided from the selection means with the calculated pulse width provided from the second counting means, determining when the selected adjustment value coincides with the pulse width, and generating a corresponding pulse signal. Way; Delay means for delaying an over sampled pit length value provided from said over sampling means for a predetermined time; And A flip for generating an updated recording waveform having a pulse width at least narrower than the recording waveform based on the pulse signal applied from the comparing means to the reset terminal and the delayed over sampling pit length value provided from the delay means to the set terminal. A recording waveform generating apparatus for an optical disk system consisting of flops. The recording waveform generating apparatus of claim 1, wherein the recording channel code is an NRZI code. 3. The apparatus of claim 1 or 2, wherein the first counting means comprises: a first delayer for delaying the data converted into the channel code for a predetermined time; A first counter for counting delayed data provided from said first delayer and detecting a pit length value thereof; And a first reset block configured to provide a reset signal to the first counter for a next counting operation. 3. The apparatus of claim 1 or 2, wherein the second counting means comprises: a second delayer for delaying the N times over sampled data for a predetermined time; A second counter for counting over-sampled data provided from the second delayer and calculating a pulse width thereof; And a second reset block providing a reset signal to the second counter for a next counting operation.