KR100223820B1 - Method for generating multi-pulse codes and optical recording device thereof - Google Patents

Abstract

The present invention relates to data recording and reproduction on a phase change type optical disc, and more particularly, by generating a multi pulse by mapping a code to a complicated hardware part by a data modulation method, it is simple and highly reliable for hardware, And '0', it is possible to easily adjust the pulse width for any part of the mark and to compensate for the space. Therefore, data is recorded on the disk with the desired shape and size of the pit Therefore, when data is recovered from the disk, the jitter of the RF signal is reduced to restore the correct data.

Description

Multi-pulse code generation method and optical recording apparatus using the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to recording and reproducing data in a phase change type optical disc (Phase Change Disc). More particularly, the present invention relates to a method and apparatus for recording and reproducing data in a phase change disc Pulse code generation method and an optical recording apparatus using the same.

Generally, in a phase change type disk, the laser light is incident on the opposite side of the reflection surface on which the pit Pit exists.

Therefore, the pits appear to be projections when viewed from the laser incident side.

The pit is about 0.6 占 퐉 wide, and the length of one pit and the distance between the pit and the pit are divided into 9 steps (or 12 steps) from 3T to 11T (or 14T), respectively.

Here, T means one clock pulse, 3T means three clock pulses, and 11T corresponds to 11 clock pulses.

In the track group of the spiral-wound track, there is a specific pit array at a certain interval, a regularly existing pit array has a sync signal, and a block from a sync signal to a next sync signal is a frame do.

One frame is composed of data of a plurality of symbols (for example, 34 in the case of a CD).

FIG. 1 is a block diagram of a recording apparatus using a single pulse code. The data processing unit 11 forms an ECC (Error Correction Code) by assigning an address to an input signal according to a format shown in a standard Data interleave (data interleave) and scramble (scramble) are performed to recover data when an error occurs.

On the other hand, a code table by EFM + (Eight to Fourteen Modulation Plus) (or EFM) modulation is mapped to the memory 13.

Therefore, the data modulator 12 fetches the 16-bit code value corresponding to the 8-bit data of the symbol output from the data processing unit 11 from the code table of the memory 13, EFM modulation is performed to convert to bits.

2A is a waveform chart showing a single pulse modulation process. In FIG. 2A, (1) is data to be recorded modulated by EFM + (or EFM) in the data modulator 12.

The EFM + (or EFM) modulated data in the data modulator 12 is NRZI-modulated to non-return-to-zero (NRZI) as shown by (2) in FIG.

The NRZI modulation is a modulation rule for inverting data in the signal of '1'. That is, if only '1' is encountered, the current state is inverted.

When the NRZI modulation is performed, the laser diode power modulation and the laser diode driving unit 15 modulate the power of the laser diode to the recording power to drive the laser diode, so that the NRZI modulated signal is outputted to the optical disk .

As shown in FIG. 2A, the power of the laser diode is the strongest at the time of recording, and then is lowered in the order of the laser power and the read power.

FIG. 2B shows a pit shape when data is recorded on a disk by the pulse modulation method. As shown in FIG. 2A, the shape of the pit is formed like a tear drop due to the thermal property of the disk itself or the edge of the pit is smooth .

Where t _f is the time delay due to thermal diffusion.

Therefore, when reading the recorded data, it becomes a factor of jitter in the RF signal and the accurate data can not be restored.

Therefore, a multi-pulse modulation method was used to prevent diffusion of heat and to form a smooth elliptical shape of the pit.

FIG. 3 is a block diagram of an optical recording apparatus using a conventional multi-pulse code (Multi Pulse Code). The data processing unit 31 rearranges the input signal according to the standard.

Since the code table for EFM + (or EFM) modulation is mapped in the memory 33, the data modulator 32 generates a 16-bit code value corresponding to 8-bit symbol data output from the data processing unit 31 Is fetched from the code table of the memory 33, EFM modulation is performed to convert the 8-bit symbol data into 16-bit data.

The EFM + (or EFM) modulated data in the data modulator 32 is modulated in the NRZI converter 34.

The NRZI modulation is a modulation rule for inverting data in the signal of '1'. That is, if only '1' is encountered, the current state is inverted.

The multi-pulse modulator 35 performs multi-pulse modulation in which one single pulse is divided into a plurality of pulses by scanning the disc by turning on / off multiple times within a single NRZI-modulated pulse.

That is, the multi-pulse modulated signal for the NRZI signal is obtained as shown in FIG. 5A or 5B by masking the system clock from the gate logic to the NRZI modulation code as in FIG.

At this time, since the multi-pulse modulation uses the system clock, it is divided to adjust the clock (for example, 3 minutes).

FIG. 5A shows an example in which the NRZI signal is multi-pulse modulated up to this laser power, and FIG. 5B shows an example in which the NRZI signal is multi-pulse modulated up to the read power.

That is, since a single pulse is divided into several pulses and scanned to the disc, the accumulation of heat in the high section where the signal pit is present is prevented to prevent the pit shape from spreading as shown in FIG. 5C.

In addition, since the width of the beginning of the pit is adjusted by widening the high section (the recording pulse high section) of the first pulse (th recording pulse high section), diffusion of heat is prevented to smoothly compensate the edge portion of the pit.

When the multi-pulse modulation is performed, the laser diode power modulation and laser diode driving unit 36 drives the laser diode by modulating the power of the laser diode with a recording wave to generate a multi-pulse modulated signal Is recorded on the optical disk.

However, in the recording apparatus using the conventional multi-pulse modulation described above, only the width of the high section of the first pulse is adjustable, and the remainder is fixedly modulated with a constant interval and period, so that it is difficult to control the pulse width. The heat accumulation can not be solved.

Therefore, in this case, the pit shape is larger than the pit of the desired shape and size. As a result, when data is read from the disk, it acts as a jitter factor of the RF signal, which makes it difficult to restore accurate data.

In addition, since complicated circuits such as a timing control circuit, a gate circuit, and a delay circuit are required in the gate logic for generating the multi-pulse, there is a problem that it is difficult to implement in hardware and the cost is increased.

An object of the present invention is to provide a multi-pulse code generation method that simplifies hardware reliability by generating a multi-pulse by mapping a code of a complicated hardware part using a data modulation method .

An object of the present invention is to modulate a multi-pulse code using a code map so as to easily adjust the pulse and compensate for a space, so that data is recorded on the disk in a pit shape having a desired shape and size, The present invention provides an optical recording apparatus for reducing jitter of an RF signal to recover accurate data.

According to another aspect of the present invention, there is provided a multi-pulse code generation method for converting EFM + (or EFM) -modulated data into a multi-pulse code and recording the same on a disk, Detecting a length of a high section forming a mark from the data and a length of a low section not forming a mark, mapping the multi-pulse conversion code table to a memory, and determining a length of a high section detected from the modulated data Pulse code is accessed from the memory and the detected high interval is converted into an accessed multi-pulse code, and NRZI modulation of the multi-pulse code converted in the step is performed.

According to another aspect of the present invention, there is provided a multi-pulse code generation method for converting EFM + (or EFM) modulated data into a multi-pulse code and recording the data on a disk, The method comprising the steps of: detecting a length of a low section not forming a high section and a mark; mapping a multi-pulse conversion code table to a memory; determining a length of a high section detected from the modulated data; Pulse code in the memory based on the length of a section and converting the detected high section into an accessed multi-pulse code; NRZI modulating the converted multi-pulse code in the step; Storing the length of the high section and the length of the low section detected from the data, It is in the point of lure.

According to another aspect of the present invention, there is provided a recording apparatus for recording input data onto an optical disk by EFM + (or EFM) modulation, the recording apparatus comprising: Pulse code corresponding to the length of the high section detected by the data section detecting section, and a multi-pulse code corresponding to the length of the low section detected by the data section detecting section, Pulse code converter for accessing the multi-pulse code from the memory and converting the high section detected by the data section detector into an accessed multi-pulse code, an NRZI converter for NRZI-modulating the multi- And laser diode driving means for writing the NRZI-modulated data to a disk It has a point.

Another aspect of the optical recording apparatus according to the present invention is a recording apparatus for recording input data on EFM + or EFM-modulated optical discs, wherein a length of a high section forming a mark in the modulation data, A memory section to which a multi-pulse conversion code table is mapped; a memory section for storing the length of the high section detected by the data section detecting section, the length of the previous high section and the previous section of the memory, Pulse code converter for accessing the corresponding multi-pulse code and converting the high section detected by the data section detector into an accessed multi-pulse code, and a controller for controlling the length of the high section and the length of the low section detected by the data section detecting section A multi-pulse code conversion unit for converting the multi- An NRZI conversion section for NRZI modulating a scan code, and a laser diode driving means for recording the NRZI-modulated data on a disk.

1 is a block diagram of an optical recording apparatus using a conventional single pulse code

FIG. 2A is a waveform diagram obtained by NRZI-modulating an EFM or EFM + modulated code value and a code value in FIG.

FIG. 2B is an exemplary view showing a pit shape recorded on the disc in FIG.

3 is a block diagram of an optical recording apparatus using a conventional multi-pulse code

FIG. 4 is a detailed block diagram of the multi-pulse modulation unit of FIG.

FIGS. 5A and 5B are waveform diagrams of NRZI-modulated multi-pulse codes modulated in FIG.

FIG. 5C is an illustration showing a pit shape recorded on the disc in FIG.

6 is a block diagram of an optical recording apparatus using multi-pulse modulation according to the present invention

7 is a flowchart showing a multi-pulse modulation process according to the present invention.

FIGS. 8A to 8L are diagrams showing modulation code values and NRZI modulation waveforms

DESCRIPTION OF THE REFERENCE NUMERALS

61: Data processing section 62: Data modulation section

63: memory 64: data section detecting section

65: Multi-pulse code conversion unit 66: Memory

67: previous space section, high section storage section 68: NRZI conversion section

69: laser diode power modulation and laser diode driver

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

6 is a block diagram of an optical recording apparatus using multi-pulse modulation according to the present invention.

6 shows a memory 63 to which a data processing unit 61, a data modulating unit 62 and an EFM + (or EFM) modulation code are mapped. A memory section 66 to which a multi-pulse conversion code is mapped, and a memory section 66 for comparing a previous high, a previous space, and a current high section with each other, Pulse code converting section 65 for accessing the pulse code and converting the high section detected by the data section detecting section 64 into the accessed multi-pulse code, a multi-pulse code converting section 65 for converting the multi- A storage section 67 for storing a high section and a space section of the signal, an NRZI converting section 68 for NRZI modulating the multi-pulse modulated signal, and a laser diode power modulation and laser diode driving section 69.

Here, the high section is the size of the recording pit, which is the portion to be modulated by the multi-pulse, and the space is the low section of this laser section, that is, EFM + modulated clock pulse skipping without recording.

FIG. 7 is a flowchart illustrating a case where compensation for thermal diffusion is performed in consideration of the previous high section, the space section and the current high section in the multi-pulse modulation according to the present invention.

8A is an EFM + (or EFM) modulation code, FIG. 8B is a waveform obtained by NRZI-converting the EFM modulation code of FIG. 8A, FIG. 8C is a multi-pulse conversion code in the case of not compensating for thermal diffusion, 8C is the NRZI-converted waveform of the multi-pulse conversion code of FIG. 8C, FIG. 8E is the multi-pulse conversion code of the case of compensating for thermal diffusion, and FIG. 8F is the NRZI-converted waveform of the multi-

8G to 8L show a state in which FIG. 8A to FIG. 8F continue.

In the present invention configured as described above, the data processing unit 61 rearranges the input signals so as to conform to the standard and provides an error correction code (step 701).

Since the code table for EFM + (or EFM) modulation is mapped in the memory 63, the data modulator 62 generates a 16-bit code value corresponding to 8-bit symbol data output from the data processor 61 EFM + (or EFM) modulation is performed (step 702), as shown in FIGS. 8A and 8G, by converting 8-bit symbol data into 16-bit data.

When the EFM + (or EFM) modulated codes of FIGS. 8A and 8G are subjected to NRZI conversion, they are converted into waveforms as shown in FIGS. 8B and 8H.

At this time, the data detector 64 checks the length of the high section and the length of the low section with the EFM-modulated data in the data modulator 62 (step 703).

Here, the length of the section is determined by T as a basic unit.

T is the reference pulse width to be marked.

The high section to be checked by the data detecting section 64 is a portion to be modulated into multi pulses upon recording, and the low section (or this laser section) is a space, that is, a section to skip without being recorded.

The multi-pulse code conversion unit 65 accesses the multi-pulse conversion code corresponding to the EFM + (or EFM) modulated signal from the memory 66 and outputs the high section of the EFM + (or EFM) Code.

At this time, the multi-pulse code converter 65 modulates a high section of the EFM-modulated signal without multiplying the heat spread by multipulses or compensates for the thermal spread, while the high section of the EFM- Modulate with pulses.

This can be determined by the code table mapping value in the memory 66.

In the memory 66, a multi-pulse conversion code value is mapped in a case where the system clock is three times, that is, the speed of the EFM modulation signal pulse x 3 and the minimum pulse width is 1 / 3T.

Here, T is the reference pulse width to be marked.

i) If you do not compensate for heat spread

The code map in the case of not compensating for thermal diffusion is divided into the laser section and the recording section. The laser section is further divided into the case where the high section immediately before the odd number T and the case where the even number T is present.

This laser section code map when the immediately preceding high section is an odd number T

[Table 1]

Table 1 shows a multi-pulse conversion code value of the laser section mapped to the memory 66 when the immediately preceding high section is an odd number T. The beginning part of each section is 1.

8B and 8C, when the number of multi-pulse conversion codes '1' is an odd number (for example, if 3T, the number of '1' is 9 and that of 5T is '1' 15, ...), this laser section should start with 1, and this laser section next to the odd number T (high section) appears to be low in the NRZI conversion as shown in FIG. 8d.

This laser section code map when the immediately preceding high section is an even number T

[Table 2]

Table 2 above shows the multi-pulse transform code value of this laser section that is mapped to the memory 66 when the immediately preceding high section is even T, and is all zero for all T's.

That is, when the immediately preceding high section is an even number T, since the number of the multi-pulse conversion codes '1' is an even number, NRZI conversion of the number of the multi pulse conversion codes '1' falls to 1 / 3T first low when falling from high to low as shown in FIG.

Therefore, during NRZI conversion, this laser section after the even T (high section) appears as low.

Write interval code map

[Table 3]

Table 3 is all 1 as the multi-pulse conversion code value of the recording section that is mapped to the memory 66. That is, if 3T, 9 '1' is mapped to a multi-pulse conversion code value, and if 4T, 12 '1's are mapped to a multi-pulse conversion code value.

Accordingly, when NRZI is converted, the recording interval is repeated periodically with high and low with a 1 / 3T pulse width as shown in FIG. 8D.

ii) compensation for heat spread

In this case, the recording interval is modulated by an arbitrary multi-pulse code without considering the previous high interval and the previous space interval, and the recording interval is divided into multi-pulse codes in consideration of the previous high interval, the previous space interval, There is a case where modulation is performed.

This laser section code map, when compensating thermal spreading irrespective of the previous high and previous space sections,

[Table 4]

Table 4 shows a code map of this laser section in the case of compensating thermal diffusion irrespective of the previous high period and the previous space period, and '0' is mapped to all Ts.

Record interval code map of odd number T when compensating thermal spread regardless of previous high and previous space interval

[Table 5]

The write interval code map of the even T when the heat spread is compensated regardless of the previous high and previous space intervals

[Table 6]

Table 5 and Table 6 show the code maps of the odd-numbered T and the even-numbered T recording intervals when the thermal spreading is compensated regardless of the previous high interval and the previous space interval. When the multi- 'And' 0 ', respectively.

Therefore, as shown in FIG. 8F, the pulse width of the preceding pulse and the pulse width of the backward pulse are increased by NRZI conversion to compensate for the thermal diffusion at the front and the end of the mark.

Since the multi-pulse conversion code value of the code table is easy to modify, it is easy to adjust the pulse width in either the first or the rear part of the multi-pulse as well as in the multi-pulse section. Therefore, have.

On the other hand, when a pit is recorded by the mark edge method, the thermal diffusivity differs depending on the size of the pit to be currently recorded, the previous space length, and the size of the previous recording pit.

Therefore, the code to be converted is determined according to the length of the immediately preceding high section, the space length, and the length of the current high section.

That is, the multi-pulse code conversion unit 65 compares the length of the high section detected by the data detector 64 with the length of the previous high section stored and the length of the previous space section, and outputs a multi-pulse conversion code corresponding to the comparison result And accesses from the memory 66 to convert the current high period into the accessed multi-pulse code as shown in FIG. 8E (step 704).

The recording interval code map (when the row interval is 3T or 4T) in the case of compensating the thermal diffusion considering the previous high and the previous space interval,

[Table 7]

Table 7 shows a recording interval code table according to the lengths of the previous high interval and the current high interval when the previous space interval is 3T or 4T.

If the stored previous space period is 3T or 4T, the previous high period is 6T, and the current high period is 3T, the multi pulse conversion code to be accessed from the memory 66 becomes '010111101'.

In other words, heat diffusion at the beginning and the end of the mark portion is compensated.

In this case, when the space interval is 5T or more, the influence on the previous interval is small, so the case of compensating the heat spread irrespective of the previous high interval and space interval may be applied.

Meanwhile, when the high section detected by the data section detector 64 is converted into the multi-pulse code accessed in step 704, the converted multi-pulse code is NRZI-modulated by the NRZI converter 68 as shown in FIG. 8F Step 706).

At the same time, the length of the high section and the length of the space section detected in step 703 are stored in the storage section 67 (step 705).

That is, the previous high interval flag (Flag) and the previous space interval flag are set for the detected T. [

At this time, the initial values of the two flags are 0.

The value stored in the storage unit 67 becomes the previous high interval and the previous space interval length at the next data interval check and is updated every time the code table is accessed.

This process is repeated to implement multi-pulse modulation.

When the multi-pulse modulation is performed, the laser diode power modulation and laser diode driver 69 drives the laser diode by modulating the power of the laser diode with the power at the time of recording so that the multi-pulse modulated signal as shown in FIG. 8d or FIG. And recorded on the optical disk (step 707).

The code maps of Tables 1 to 7 shown in the present invention are not experimental data but can be applied to the most optimal state as one example that can be applied.

Since the space part of the modulated code is actually used as this laser pulse, it is converted into '0' regardless of the size, and only the high section forming the mark is converted into the multi pulse code.

This is realized by a combination of '1' and '0', and also various combinations of various types are generated. Therefore, it is possible to prevent heat diffusion and heat accumulation by selecting an optimal code, .

Meanwhile, the present invention is applicable to all codes regardless of a modulation code in an apparatus for recording data on a disc.

As described above, according to the multi-pulse code generation method and the optical recording apparatus using the same according to the present invention, multi-pulse is generated by mapping a complicated hardware part to a data modulation method to generate a multi pulse, By generating various combinations of multi-pulse codes with a combination of '1' and '0' for the recording interval, it is possible to easily adjust the pulse width for any portion of the mark and to compensate for the space, The data can be recorded on the disk, and therefore, when data is recovered from the disk, there is an effect of reducing the jitter of the RF signal and restoring the accurate data.

Claims (12)

A multi-pulse code generation method for converting an EFM + (Eight to Fourteen Modulation) (or EFM) modulated data into a multi-pulse code and recording the multi-pulse code on a disc, comprising the steps of: Pulse code code table corresponding to the length of a high section detected from the modulated data is accessed from the memory and the detected high Pulse code into an accessed multi-pulse code; and NRZI modulating the multi-pulse code converted in the step. 2. The method of claim 1, wherein a multi-pulse conversion code table is mapped to the memory according to a length of a current high interval. The method of claim 1, wherein the memory maps a multi-pulse conversion code table according to a previous high interval, a previous low interval, and a current high interval. A multi-pulse code generation method for converting EFM + (Eight to Fourteen Modulation) or EFM-modulated data to a multi-pulse code and recording the multi-pulse code on a disc, the method comprising the steps of: A step of mapping the multi-pulse conversion code table to a memory, a step of detecting a length of a high section detected from the modulated data, and a length of a previous high section and a previous section section, Pulse code and converting the detected high section into an accessed multi-pulse code; NRZI-modulating the multi-pulse code converted in the step; and detecting a length of a high section detected from the modulated data, And storing the length of the low section. DE generated. 5. The method of claim 4, wherein the memory maps a multi-pulse conversion code table according to a length of a previous high interval, a previous low interval, and a current high interval. A recording apparatus for recording input data on an optical disk by performing Eight to Fourteen Modulation (EFM +) or EFM modulation, the apparatus comprising: means for detecting a length of a high section forming a mark from the modulation data and a length of a low section not forming a mark A memory section to which a multi-pulse conversion code is mapped, a multi-pulse code corresponding to a length of a high section detected by the data section detecting section, from the memory, and converting the section into an accessed multi-pulse code An NRZI converter for performing NRZI modulation on the multi-pulse code converted by the multi-pulse code converter; and a control unit for writing the NRZI-modulated data on a disk And a laser diode drive means for driving the laser diode. 7. The optical recording apparatus according to claim 6, wherein a multi-transform code table is mapped to the memory according to a length of a current high section. The optical recording apparatus according to claim 6, wherein the memory is mapped with a multi pulse conversion code table according to a previous high interval, a previous low interval and a current high interval. 7. The optical recording apparatus of claim 6, wherein the data interval detector stores a length of the detected high interval and a length of the low interval. A recording apparatus for recording input data on an optical disc by performing Eight to Fourteen Modulation (EFM +) or EFM + modulation, the apparatus comprising: means for detecting a length of a high section forming a mark in the modulation data and a length of a low section A memory section to which the multi-pulse conversion code table is mapped, and a memory section for storing the multi-pulse code in the memory based on the length of the high section detected by the data section detecting section, the length of the previous high section, A multi-pulse code conversion unit for accessing the high-speed section and for converting the high section detected by the data section detecting section into the accessed multi-pulse code, a storage section for storing the length of the high section and the length of the low section detected by the data section detecting section, Pulse code conversion unit converts the multi-pulse code converted by the multi- Inverted (NRZI) modulation and NRZI conversion unit, the optical recording apparatus, characterized by configured to include a laser diode driving means for recording the NRZI modulated data on the disc. 11. The optical recording apparatus according to claim 10, wherein a multi-pulse conversion code table is mapped in the memory according to a previous high section, a previous low section length, and a current high section length. 11. The optical recording apparatus of claim 10, wherein the multi-pulse code value of the recording interval mapped to the memory is a combination of '1' and '0'.