KR20060133297A - Recording/reproducing apparatus and recording/reproducing apparatus method - Google Patents

Abstract

A recording/reproducing apparatus and a method thereof are provided to suggest certain length if recording density gets higher, and to reduce the number of cases of a recording condition by limiting a run-length condition set within the suggested length, thereby making a recording process possible with effective resources. When information is recorded on an information storage medium, certain length which is an integer multiple of unit recording length is suggested, and recording parameters are set by considering cases of a run-length condition set within certain length which comes before and after on the basis of a start point and an end point of a recording signal. The certain length is obtained by relations of wavelength of a laser, laser size determined by NA(Numerical Aperture), and unit length of marks/spaces set within the laser size.

Description

Recording / reproducing apparatus and recording / reproducing apparatus method

1 is an example of a recording pulse according to the prior art,

2A, 2B, and 2C are reference diagrams for explaining the relationship between laser size and mark / space (or feet),

3 is a view for showing a case where the size of the laser light source is configured to eight times the unit recording length;

4 is a view showing a distribution of a light source viewed from a mark start point;

5 is a schematic block diagram of a recording / reproducing apparatus according to the present invention;

FIG. 6 is a detailed configuration diagram of the recording / reproducing apparatus shown in FIG. 5.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of recording information on an information storage medium. In particular, in the case where a mark is formed on an optical disk to record digital data, a recording waveform for forming a mark is defined by the length of the input binary signal. Related to a method and apparatus for recording a reduced number of cases.

Conventional recording, erasing and playback of optical discs include 650MB CD-R, CD-RW, 4.7GB DVD-RAM, DVD-R, DVD-RW, DVD + R, DVD + RW, and more. HD-DVDs and Blu-ray disks (BDs) that are over 23GB are being developed. In the case of recording on such a recordable disc, recording is generally performed by creating a recording pulse as shown in FIG.

Referring to FIG. 1, when the configuration of the recording pulse is N times the period T representing the length of time of the basic unit, N-1 recording pulses are composed, and operations for optimizing each parameter constituting the recording pulse are necessary. . In other words, in the case of the example shown in FIG. 1, the quality of the recorded waveform is determined by changing seven parameters such as Pw, Pe, dTtop, Ttop, Tmp, Pb, and dTe. It is necessary to set two parameters to an optimal value.

In order to optimize these parameters, it is common to set different parameters according to the length of the recorded mark. For example, the seven parameters in the case of recording a mark of nT (T is the unit length of the mark to be recorded) include Pw (n), Pe (n), dTtop (n), Ttop (n), Tmp (n), If Pb (n) or dTe (n), each value should be optimized according to run-length conditions. For example, in the case of DVD, since the run length conditions are 3T to 11T and 14T, Pw (3), Pe (3), dTtop (3), Ttop (3), Tmp (3), Pb (3), Determine the optimal values from dTe (3) to Pw (14), Pe (14), dTtop (14), Ttop (14), Tmp (14), Pb (14), dTe (14) for 14T Should give.

In this case, if the condition of the seven parameters for nT is defined as WSC (n), it can be defined as Equation 1 of the following set.

Equation 1

WSC (n) = {Pw (n), Pe (n), dTtop (n), Ttop (n), Tmp (n), Pb (n), dTe (n)}

Of course, this is for an example of the write pulse, so the number of elements for the WSC (n) may be increased or decreased when the condition for making the write pulse is changed so that the number of elements is not seven. Much research has been done on how to optimize these parameters using these methods.

Using this method, you only need to define WSC (n) for the case defined by runlength. For example, in the case of CD, the run length condition is 3T ~ 11T, so only WSC (3) ~ WSC (11) needs to be defined. In the case of DVD, the runlength condition is 3T ~ 11T, 14T, so WSC (3) ~ WSC ( 11) WSC 14 may be defined, and in the case of BD, run length conditions are 2T to 9T, so only WSC 2 to WSC 9 need to be defined.

However, experiments using this method have shown that to obtain a better signal, it depends not only on the run length corresponding to the mark signal, but also on the run length of the space before and after the mark. Better quality can be achieved by setting conditions and recording with these other conditions.

To explain further, the 5T recording condition is already defined as WSC (5). This WSC (5) is defined with different values when the preceding space is 3T, 4T, 5T ... Even if 3T, 4T, 5T ... are defined, they are defined with different values. So, for example, in the case of BD, the WSC of 5T is WSC (5), but the space in front can come from 2T ~ 9T, so there are 8 different cases, and the space in the back can come from 2T ~ 9T, so 8x8 = 64 different In some cases, the WSC waveform needs to be optimized.

To redefine Equation 1 for this purpose, Equation 2 is summarized as follows.

Equation 2

WSC (nprev, n, nnext) = {Pw (nprev, n, nnext), Pe (nprev, n, nnext), dTtop (nprev, n, nnext), Ttop (nprev, n, nnext), Tmp (nprev, n, nnext), Pb (nprev, n, nnext), dTe (nprev, n, nnext)}

Where nprev is the run length of the space immediately preceding the current mark and nnext is the run length of the space immediately following the current mark.

For example, if there is a 3T space in front of the 5T mark and a 6T space behind, it can be expressed as WSC (3,5,6).

In the case of BD, for example, the run length length of the space immediately preceding the mark and the run length length of the space immediately following the current mark can be defined as 2T to 9T. The number of cases is represented by 8x8x8.

As the recording density increases, the length of the recorded marks and spaces becomes shorter relative to the laser size, and the influence of adjacent signals such as the front and back spaces as well as the space before and after the recorded marks becomes more and more. You must consider a lot. In this case, the number of cases that need to be optimized increases exponentially, which requires a lot of resources to configure the system.

The present invention solves the problems described above, suggests a certain length corresponding to the increase in the recording density, limits the run length conditions within the suggested length, and reduces the number of cases in the recording to enable efficient recording. An object of the present invention is to provide a playback device and method.

One feature of the present invention for solving the above problems is, in the recording / reproducing apparatus, a starting point of a signal for presenting and recording a constant length, which is an integer multiple of the unit recording length, when information is recorded on an information storage medium. The recording parameters are set in consideration of the run length condition that comes within a certain length before and after the end point.

It is preferable to use the predetermined length obtained by the relationship between the wavelength of the laser, the laser size determined by NA (Numerical Aperture), and the unit length of the mark / space entering the laser size.

Since the run length combination that comes within the predetermined length, it is preferable to extract and use only those which satisfy the run length condition among the combination of signals that can come within the predetermined length.

The total number of parameters is preferably defined as the number of combinations before the mark x the number of combinations after the total kind x mark of the recording mark.

According to another aspect of the present invention, in the recording / reproducing method, when the information is recorded on the information storage medium, a predetermined length, which is an integer multiple of the unit recording length, is presented before and after the starting point and the ending point of the signal for recording. Considering the case of the run-length condition coming within a certain length, and setting the recording parameters and recording the data based on the set recording parameters.

The present invention will now be described in detail with reference to the accompanying drawings.

As described above, in order to obtain an optimal reproduction signal, the recording conditions for the current mark must be optimized differently in consideration of the front space and the rear space in the recording step. If the recording density is very low, only the parameters according to the mark length need to be optimized regardless of the space before and after. However, as the recording density increases, the recording conditions for the current mark are considered in consideration of the space before and after. Should be optimized differently.

However, if the recording density is higher than this, the optimum signal quality can be obtained by using different optimized parameters in each case depending on the length of the front mark that comes before the front space and the back mark that comes after the space after. Of course, if the recording density is higher, it may be able to determine the front and back signals.

The problem is that increasing the number of cases in this way results in too many cases. For example, when considering the front and rear signals, Equation 2 may be expressed as Equation 3 as follows.

Expression 3

WSC (nprevprev, nprev, n, nnext, nnextnext) = {Pw (nprevprev, nprev, n, nnext, nnextnext), Pe (nprevprev, nprev, n, nnext, nnextnext), dTtop (nprevprev, nprev, n, nnext, nnextnext), Ttop (nprevprev, nprev, n, nnext, nnextnext), Tmp (nprevprev, nprev, n, nnext, nnextnext), Pb (nprevprev, nprev, n, nnext, nnextnext), dTe (nprevprev, nprev, n, nnext, nnextnext)}

In the case of BD, there are 8 run lengths that can be reached in each step. Therefore, parameters should be set for 32768 cases of 8x8x8x8x8 when all the cases are counted. If the front to back signal and the back to back signal are considered, the optimal parameters can be set by considering the number of 2097152 cases of 8x8x8x8x8x8x8.

In general, in order to optimize these parameters, the structure obtained by extracting the characteristic from the input signals is updated to have an optimal value. As the number of cases increases, a large amount of memory is required and the updating time becomes too long. In order to solve this problem, we propose a method to reduce the number of cases by extracting only the code conditions corresponding to this length by giving a certain length constraint before and after the mark as follows.

The reason for limiting the length of a certain condition is that the waveform read from the actual disk is limited by the length of the marks and spaces that enter the size of the laser as follows.

Referring to Figs. 2A, B, and C, determining the one output signal in constructing a mark / space (called a pit in a ROM type disc) depends on the configuration of the mark / space signal coming into the laser light source. It can be seen that.

For example, if the size of the laser light source is composed of 8 times the unit recording length as shown in Fig. 3, the total number of all marks / spaces that can come in the laser light source is equal to the number of 8-bit binary numbers. There are 256 output signals. Of course, if there are run length constraints, the number of cases is much smaller. For example, the code (1.7) used for BD should exclude the case where 1T occurs since the minimum T is defined as 2T.

When viewed from the standpoint of the mark for recording, it can be represented as shown in FIG. 4 based on the time point at which the mark starts.

Referring to FIG. 4, it can be seen that determining the output signal of the start point of the mark is determined by four signals after the mark starts and four signals before the mark starts. That is, when the start point of the mark is at the center of the light source, it is the start point of the reproduction signal due to the mark. For example, in the case of BD using the (1,7) code, since the minimum T is 2T, the number of mark / space combination signals that can come in 4T before the recording mark starts is shown in Table 1 below.

Table 1. Record mark for (1,7) codes and mark / space combinations that may occur within 4T preceding this record mark

1) 4T space + record mark

2) More than 2T mark + 3T space + record mark

3) 2T Mark + 2T Space + Record Mark

4) More than 2T mark + 2T space + record mark

The four cases above are all. In the first case, the reason why the space of 4T or more is set to the same number is that the light source having the size of 4T or more is recognized as the same signal when viewed from the mark start point. All combinations of marks or spaces that can be in the 4T length are shown in Table 1 above.

In the same way, when the mark ends, the number of signals that can come within 4T is shown in Table 2 below.

Table 2. Record marks for (1,7) codes and mark / space combinations that can occur within 4T following this record mark

1) record mark + 4T or more space

2) Record mark + 3T space + 2T or more marks

3) Record Mark + 2T Space + 2T Mark

4) Record mark + 2T space + mark of 2T or more

The above four are all. Therefore, the optimization of the parameters considering the laser size is 4 (4 numbers according to Table 1) x 8 (number of records marks) x 4 (4 cases according to Table 2) when the laser light source is 8T in length. Only 128 cases are considered.

On the other hand, when using the conventional method, it is necessary to consider the signals before and after the recording mark, so all 32768 cases should be considered. Therefore, in the case of the method proposed in the present invention, 32768 consideration methods can reduce the effect to 128.

5 is a schematic diagram of a recording / reproducing apparatus according to the present invention.

Referring to FIG. 5, the recording / reproducing apparatus 200 according to the present invention is a device capable of recording or reproducing, and includes a recording / reading unit 220 and a control unit 210. The recording / reading unit 220 records data on the disk 400 which is an information storage medium under the control of the control unit 210 and reads the data to reproduce the recorded data. The controller 210 controls the recording / reading unit 220 to record data in a predetermined recording unit block or processes the data read by the recording / reading unit 220 to obtain valid data.

In particular, according to the present invention, the control unit 210 presents a recording parameter for recording data on the disk 400 before and after the starting point and the ending point for presenting and recording a constant length which is an integer multiple of the unit recording length. The recording parameters are determined and stored in consideration of the case of the run length condition that enters within a certain length, and data recording is performed based on these recording parameters.

FIG. 6 is a detailed block diagram of the recording / reproducing apparatus shown in FIG.

Referring to FIG. 6, the disc drive includes a pickup as the recording / reading unit 220. FIG. The disk 400 is mounted in the pickup. The disk drive also includes a host I / F 211, a DSP 212, an RF AMP 213, a servo 214, and a system controller 215 as the controller 210.

The host I / F 211 receives a data write command from the host 240 and sends it to the system controller 215.

The system controller 215 receives a data write command from the host I / F 211 and performs initialization for data writing.

The system controller 215 presents a run before and after a predetermined length based on the start and end points of the signal for presenting and recording a constant length, which is an integer multiple of the unit recording length, especially when recording information. The recording parameter is set in consideration of the case of the length condition. In this case, the predetermined length uses a predetermined length obtained by the relationship between the wavelength of the laser, the size of the laser determined by the NA, and the unit length of the mark / space entering the laser size. In addition, the run length combination that comes within a certain length is used to extract only those that satisfy the run length condition from among the combinations of signals that can come within a certain length. That is, the system controller 215 sets recording conditions for the number of cases (128 in the case of the example of FIG. 4) determined by the number of combinations before the mark x the number of combinations after the mark x the total type of the recording marks, and enters each recording condition. Slightly change each of the parameters present to observe the jitter values and determine the parameter set that provides the most optimal jitter values. As many parameters as the number of cases corresponding to the determined recording conditions are stored in the memory. Here, the process of determining and storing the parameter set as the preprocessing of the recording step may be performed at various steps according to the policy of the recording / reproducing apparatus. For example, such a parameter set may be determined only the first time after the disk is formatted, or such parameter set may be determined at each start of the data recording operation, or to improve recording quality even in the middle of the recording operation. Such a parameter set may be determined. Then, when recording the data, the report system controller 215 reports the recording pattern of the data, and controls the recording / reading unit to select the appropriate parameter set and record the data according to the recording parameter contained in the parameter set.

The DSP 212 adds additional data such as parity for error correction to the data to be recorded received from the host I / F 211 and performs ECC encoding to generate an ECC block, which is an error correction block, and then, in a predetermined manner. Modulate. The RF AMP 213 converts the data output from the DSP 212 into an RF signal. The pickup 250 records the RF signal output from the RF AMP 213 on the disc 230. The servo 214 receives a command necessary for servo control from the system controller 215 and servo controls the pickup 250.

During playback, the host I / F 211 receives a playback command from the host 240. The system controller 215 performs initialization required for regeneration.

The pickup 250 outputs an optical signal obtained by irradiating a laser beam to the disk 400 and receiving a laser beam reflected from the disk 400. The RF AMP 213 converts the optical signal output from the pickup into an RF signal and provides modulated data obtained from the RF signal to the DSP 212 while providing a servo signal for the control obtained from the RF signal to the servo 214. do. The DSP 212 demodulates the modulated data and outputs the data obtained through ECC error correction.

Meanwhile, the servo 214 receives the servo signal received from the RF AMP 213 and the command necessary for the servo control received from the system controller 215 to perform servo control on the pickup. The host I / F 211 sends data received from the DSP 212 to the host 240.

The process of the recording method according to the present invention is as follows.

First, the controller of the recording / reproducing apparatus selects a recording parameter in consideration of the case of a run length condition that comes within a predetermined length before and after the starting point and the ending point of a time signal for presenting and recording a certain length which is an integer multiple of the unit recording length. Set it.

The controller then looks at the pattern of data to be recorded, selects a recording parameter that matches the pattern, and then records the data according to the recording parameter.

The recording / reproducing method as described above can also be embodied as computer readable codes on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs, codes, and code segments for implementing the recording / reproducing method can be easily inferred by programmers in the art to which the present invention belongs.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

According to the present invention as described above, by optimizing the recording parameters by reducing the conditions for optimizing the recording parameters by presenting a certain length and referring to the run length conditions within the suggested length, the parameters can be optimized in a short time. .

Claims (5)

In the recording / reproducing apparatus, In the case of recording information on the information storage medium, the recording parameter is set in consideration of the case of the run length condition that comes within a predetermined length before and after the start point and the end point of the signal for recording and presenting a constant length which is an integer multiple of the unit recording length. Recording / reproducing apparatus. The method of claim 1, And a predetermined length uses a predetermined length obtained by a relationship between a laser wavelength determined by a laser wavelength and NA (Numerical Aperture) and a unit length of a mark / space coming into the laser size. The method of claim 1, And a run length combination that comes within a predetermined length, and extracts and uses only those that satisfy the run length condition from a combination of signals that can come within a predetermined length. The method of claim 3, And the total number of parameters is defined as the number of combinations before the mark x the number of combinations after the total kind x mark of the recording mark. In the recording / playback method, In the case of recording information on the information storage medium, the recording parameter is set in consideration of the case of the run length condition that comes within a predetermined length before and after the start point and the end point of the signal for recording and presenting a constant length which is an integer multiple of the unit recording length. Setting up, And recording data on the basis of the set recording parameter.

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