KR100354737B1 - Adaptive recording method and circuitry for high density optical recording device - Google Patents

Abstract

An adaptive recording method and a circuit thereof for a high density optical recording device are disclosed. A discriminator for determining the size of the current mark of the input data and the size of the space before and after the generator; a generator for generating an adaptive recording pulse by controlling the waveform of the recording pulse according to the size of the current mark and the size of the space before and after; The present invention includes a driver for driving a laser diode by converting an adaptive recording pulse into a current signal according to the drive level of the optical output of each channel, according to the size of the current mark and the size of the space before and after the input NRZI data. By varying the width of the first and last pulses of the write pulse, the jitter is minimized to improve the reliability and performance of the system.

Description

Adaptive recording method and circuitry for high density optical recording device

The present invention relates to an adaptive recording method and a circuit thereof for a high density optical recording device, and more particularly, to an adaptive recording method and a circuit thereof for optimizing the optical output of a laser diode to the characteristics of a recording medium.

The multimedia era requires high-capacity recording media, and optical recording apparatuses using such high-capacity recording media include MODD (Magnetic Optical Disc Drive) and DVD-RAM (Digital Versatile Disc Random Access Memory) drivers.

These optical recording devices require an optimal system state as recording density increases and require precision. In general, when the recording capacity is increased, the jitter in the time axis direction of the recording data domain increases (hereinafter referred to as jitter). Therefore, minimizing such jitter is important to realize high density recording.

Conventionally, as shown in FIG. 1 (b) for input Non Return to Zero Inversion (NRZI) data composed of 3T, 5T, 11T, etc., the recording mark length as shown in FIG. An overwrite pulse was constructed and recorded in the state specified in the book. Here, this NRZI data is divided into a mark and a space, and this space is in an erased light output state for overwriting. The recording marks of NRZI data of 3T, 4T, ..., 11T, and 14T, respectively, in T (T: channel clock) units are represented by first pulse, last pulse and multi pulse train. The number of the multi-row pulses is changed and recorded according to the length of the mark.

That is, read power (c) of FIG. 1, peak power (also referred to as write light output: d) of FIG. 1, and bias power (also known as bias power) Also known as erase light output: The waveform of the recording pulse shown in FIG. 1B is constituted by the combination of FIG. 1E. At this time, each optical output signal shown in (c), (d) and (e) of FIG. 1 is a low active signal.

This recording pulse waveform is also the same as the first generation, 2.6 GB (Giga Byte) DVD-RAM standard. That is, according to the 2.6GB DVD-RAM standard, the waveform of the recording pulse is composed of the first pulse, the multi-pulse sequence and the last pulse, and the rising edge of the first pulse or the falling edge of the last pulse in the lead-in area. Although it is possible to read and use it, the recording pulse of fixed type is recorded by the set value once.

Therefore, according to the NRZI data input when the recording pulse is constructed and recorded as shown in Fig. 1B, thermal interference may occur particularly at the front end or the rear end of the recording mark. That is, jitter is most severely generated when the recording mark is long and the space is short, or conversely, when the space is large and the recording mark is small. This is the biggest factor that degrades the performance of the system, there is a problem that will be difficult to use in the future high-density DVD-RAM, for example, the second generation, 4.7GB DVD-RAM.

In order to solve the above problem, an object of the present invention is to provide a method for recording an adaptive recording pulse generated according to the size of the current mark of the input data and the size of the space before and after.

It is another object of the present invention to provide a recording circuit for a high density optical recording device that generates an adaptive recording pulse in accordance with the size of the current mark of the input NRZI data and the size of the space before and after, to optimize the optical output of the laser diode. There is.

In order to achieve the above object, the adaptive recording method according to the present invention controls the waveform of the recording pulse in accordance with the size of the current mark and the size of the space of the input data to generate an adaptive recording pulse and the adaptive recording pulse Recording on the optical recording medium.

In order to achieve the above another object, the adaptive recording apparatus according to the present invention is a device for controlling the optical output of a laser diode, the discriminator for discriminating the size of the current mark of the input data and the size of the space before and after By controlling the waveform of the recording pulse according to the size of the current mark and the size of the space before and after, the generator generating the adaptive recording pulse and the adaptive recording pulse are converted into the current signal according to the drive level of the optical output of each channel. And a driver for driving the laser diode.

1A to 1E are waveform diagrams showing the configuration of a conventional recording pulse.

2 is a block diagram according to an embodiment of an adaptive recording circuit for a high density optical recording device according to the present invention.

3A to 3G are waveform diagrams of adaptive recording pulses recorded by the adaptive recording circuit shown in FIG.

4 is a diagram for describing grouping of input data.

FIG. 5 is a table of pulse combinations generated by the grouping shown in FIG. 4.

6 is a table of shift amounts of rising edges of initial pulses according to an embodiment of the present invention.

7 is a table of shift amounts of falling edges of the last pulses according to an embodiment of the present invention.

8 is a flowchart according to an embodiment of an adaptive recording method according to the present invention.

9 is a graph comparing the amount of jitter generated by the adaptive recording method and the conventional recording method according to the present invention.

Hereinafter, with reference to the accompanying drawings, a description will be given of a preferred embodiment of an adaptive recording method and a circuit for a high density optical recording apparatus according to the present invention.

The adaptive recording circuit according to the present invention comprises a data discriminator 102, a write waveform controller 104, a microcomputer 106, a write pulse generator 108 and a current driver 110 as shown in FIG. do. That is, the data discriminator 102 determines the input NRZI data, and the recording waveform controller 104 determines the waveform of the recording pulse according to the result determined by the data discriminator 102 and the land / groove signal. To correct. The microcomputer 106 initializes the recording waveform controller 104 or controls the data stored in the recording waveform controller 104 to be updated in accordance with recording processing conditions. The write pulse generator 108 generates an adaptive write pulse according to the output of the write waveform controller 104, and the current driver 110 outputs the adaptive write pulse generated by the write pulse generator 108 to the optical output of each channel. The laser diode is driven by converting the current signal according to the level.

Next, the operation of the apparatus shown in FIG. 2 will be described with reference to FIGS. 3 to 7.

In FIG. 2, the data discriminator 102 corresponds to the size of a mark corresponding to the current recording pulse (hereinafter referred to as the current mark), and the previous pulse of the current recording pulse. Record the size of the previous and subsequent pulses and the size of the current mark by determining the size of the space before it (hereinafter referred to as the space before) and the space (after space) that corresponds to the pulse after the current recording pulse. To the waveform controller 104.

Here, since the size of the previous space, the size of the current mark, and the size of the space after each may have the shortest 3T to the maximum 14T, considering all these combinations, about 1000 or more cases occur, so the first of all the cases The system can be complicated and hardware can be increased because a circuit or memory is needed to obtain the shift amounts of the rising edge of the pulse and the falling edge of the last pulse. Accordingly, in the present invention, the size of the current mark of the input NRZI data and the size of the previous and subsequent pulses are grouped into short pulses, medium pulses, and long pulses to use the size of the current mark grouped and the size of the previous and subsequent pulses. It may be.

The recording waveform controller 104 shifts the rising edge of the first pulse back and forth according to the size of the previous space and the size of the current mark supplied from the data discriminator 102, or changes the size of the current mark and the size of the subsequent space. Accordingly, the falling edge of the last pulse is shifted back and forth to produce a recording waveform having an optimum light output. At this time, the multi-pulse string of the mark has the same shape as 0.5T as shown in (b) of FIG.

The recording waveform controller 104 further includes the rising edge of the first pulse of the current mark according to a LAND / GROOVE signal introduced from the outside indicating whether the input NRZI data is the data of the land track or the groove track. The falling edge of the last pulse of the current mark can be modified to each other value. The reason for this is to create a recording waveform in consideration of the optimum light output of each land and groove. The optimal light output of land and groove may be about 1-2mW, and the standard can be set or managed separately.

Accordingly, the write waveform controller 104 may include a memory in which data corresponding to the shift value of the rising edge of the first pulse and the falling edge of the last pulse is stored according to the current mark size of the input NRZI data and the space before and after. It can be configured as a logic circuit. When the recording waveform controller 104 is composed of a memory, the width of the first pulse and the last pulse is determined by the data value (shift value) stored in the channel clock T + memory. In addition, the memory may store the shift value of the first pulse and the last pulse of the recording pulse reflecting the case of the land track and the groove track, respectively. The table in which the shift value of the rising edge of the first pulse is stored and the table in which the shift value of the falling edge of the last pulse are stored may be configured as one table, but may be configured as separate tables as shown in FIGS. 6 and 7. .

The microcomputer 106 initializes the recording waveform controller 104 or controls such that the shift value of the first pulse and / or the last pulse which is optimally adjusted according to the recording conditions is updated. In particular, the light output may be changed depending on the recording zone, or the respective shift values of the first pulse and the last pulse may be reset.

The pulse width data for controlling the waveform of the recording pulse in this way is applied to the recording pulse generator 108. The recording pulse generator 108 generates an adaptive recording pulse as shown in FIG. 3 (f) in accordance with the pulse width data controlling the recording pulse waveform supplied from the recording waveform controller 104, thereby generating this adaptive recording pulse. The control signals ((c), (d), and (e) of FIG. 3) for controlling the flow of current in each channel (regeneration, peak, and bias) are applied to the current driver 110.

The current driver 110 converts the driving level of the optical output of each input channel (regeneration, peak, bias) into a current by a control time corresponding to a control signal for controlling the flow of each channel current, and flows the current through a laser diode. The desired recording waveform is recorded by applying appropriate heat to the recording medium through the continuous on and off operation of the diode or by changing the amount of light. At this time, a recording domain as shown in Fig. 3G is formed on the recording medium.

That is, Fig. 3A is input NRZI data, which is divided into a mark and a space. 3 (b) shows a basic recording waveform, in which the rising edge of the first pulse of the recording pulse is 0.5T behind the rising edge of the current mark. (C) of FIG. 3 is a waveform of reproduction light output of the adaptive recording pulse, (d) of FIG. 3 is a waveform of peak light output of the adaptive recording pulse, and (e) of FIG. This is a waveform of bias light output.

3 (f) shows a waveform of an adaptive recording pulse proposed in the present invention. The rising edge of the first pulse of this adaptive recording pulse waveform can be shifted back and forth according to the combination of the previous space size and the current mark length, and the shifted period is filled with any light output (here reproducing light or recording light output). Similarly, the falling edge of the last pulse can be shifted back and forth in accordance with the combination of the current mark length and the subsequent space size, and the shifted period is filled with any light output (here, reproduction light output or recording light output).

However, as another example of the present invention, the falling edge of the last pulse may be processed back and forth according to the length of the current mark without considering the size of the space after the current mark, and both the rising edge of the first pulse and the falling edge of the last pulse may be processed. The edge of one pulse may be shifted without shifting, and the shift direction may be shifted only before, after, before, or after.

FIG. 4 is a diagram for explaining grouping of input NRZI data, and a configuration example of two groupings is shown. In the first example, when the low grouping pointer is 3 and the high grouping pointer is 12, the short pulse group is 3T, the medium pulse group is 4T to 11T, and the long pulse group is 14T. In the second example, if the low grouping pointer is 4 and the high grouping pointer is 11, the short pulse group is 3T, 4T, the medium pulse group is 5T, 6T, 7T, 8T, 9T, 10T, and the long pulse group is 11T and 14T. As such, row grouping pointers and high grouping pointers are used to increase usability and can be grouped differently according to zones.

FIG. 5 shows the number of cases according to a combination of before and after spaces and current recording marks when classifying into three groups as shown in FIG. 4 by using a grouping pointer, and FIG. An example of a table showing shift values of the rising edge of the first pulse depending on the size of the recording mark, and FIG. 7 is a table showing the shift values of the falling edge of the last pulse depending on the size of the current recording mark and the size of the subsequent space. Yes.

8 is a flowchart according to an embodiment of an adaptive recording method according to the present invention. First, a recording mode is set (step S101), and if a recording mode is set, it is determined whether the recording mode is an adaptive recording mode (step S102). If the mode determined in step S102 is the adaptive recording mode, a grouping pointer is set (step S103), and a grouping table according to the set grouping pointer is selected (step S104). This selected grouping table may be not only a grouping pointer but also a table reflecting a land / groove as mentioned, or a table reflecting a zone of a recording medium.

According to the combination of the previous space and the current mark, the shift value of the rising edge of the first pulse is read out from the table as illustrated in FIG. 6 (step S105), and the shift of the falling edge of the last pulse according to the combination of the current mark and the subsequent space. The value is read from the table as illustrated in FIG. 7 (step S106).

According to the read shift amount, an adaptive recording pulse in which the first pulse and the last pulse are controlled are generated (step S107), and the optical output of each channel (reproduction, peak, bias) for the generated adaptive recording pulse is controlled to provide a layer. The low diode is driven (step S108) and recorded on the disc (step S109). If the adaptive recording mode is not set in step S102, a general recording pulse is generated by performing step S107 of generating a recording pulse.

9 is a graph comparing the amount of jitter generated by the adaptive recording method according to the present invention and the conventional recording method, wherein the peak light output is 9.5 mW, the base light output of the multi-pulse string is 1.2 mW, and the cooling pulse. When the optical power is 1.2mW and the bias optical power is 5.2mW, it can be seen that the amount of jitter generated when the adaptive recording pulse of the present invention is recorded is much smaller than the amount of jitter generated when recording a fixed recording pulse. have. Initialization conditions were performed 100 times at 7.2 mW erased light output at a speed of 4.2 m / s.

That is, the present invention adaptively controls the waveform of the recording pulse by adaptively shifting the rising edge of the first pulse according to the size of the previous space of the input NRZI data and the size of the current mark in adaptively changing the width of the recording pulse. And / or the jitter is minimized by controlling the waveform of the recording pulse by adaptively shifting the falling edge of the last pulse in accordance with the size of the current mark and the size of the subsequent space. In addition, the waveform of the recording pulse can be optimized according to the land / groove signal. In addition, the present invention may be grouped differently by zone using a grouping pointer.

The novel adaptive recording pulse waveform proposed in the present invention enables use in most high density optical recording devices.

As described above, the present invention changes the width of the first pulse and the last pulse of the recording pulse according to the size of the current mark of the input NRZI data and the size of the space before and after, thereby minimizing jitter and improving the reliability and performance of the system. By controlling the width of the recording pulse by grouping the size of the current mark and the size of the space before and after the current mark, the size of the hardware can be reduced.

Claims (23)

(a) generating an adaptive recording pulse by controlling the waveform of the recording pulse according to the size of the current mark and the size of the space of the input data; And (b) recording the adaptive recording pulse onto an optical recording medium. 2. The adaptive recording method according to claim 1, wherein in step (a), an adaptive recording pulse is generated in which the rising edge of the first pulse is varied according to the size of the previous space and the size of the current mark. 2. The adaptive recording method according to claim 1, wherein in step (a), an adaptive recording pulse is generated in which the falling edge of the last pulse is varied according to the size of the current mark and the size of the subsequent space. The method of claim 1, wherein in step (a), the rising edge of the first pulse is varied according to the size of the previous space and the size of the current mark, and the falling edge of the last pulse is varied according to the size of the current mark and the size of the subsequent space. Adaptive recording method comprising generating an adaptive recording pulse. The method of claim 1, wherein in step (a), the rising edge of the first pulse is shifted back and forth according to the size of the previous space and the size of the current mark, and the falling edge of the last pulse is changed according to the size of the current mark and the size of the subsequent space. Adaptive recording method characterized by generating an adaptive recording pulse shifted back and forth. 6. The adaptive recording method according to claim 5, wherein the period in which the rising edge of the first pulse is shifted and the period in which the falling edge of the last pulse is shifted are filled with light output of a predetermined channel. The method of claim 1, and (c) remodifying the waveform of the adaptive recording pulse according to a land / groove signal indicating whether input data is data of a land track or a groove track. (a) selecting a grouping table using a grouping pointer for grouping input data; (b) calculating width data of a recording pulse using data stored in the grouping table; And (c) recording an adaptive recording pulse in response to the calculated width data on the optical recording medium. 9. The method of claim 8, wherein the grouping table stores the width of the first pulse and the last pulse of the recording pulse by grouping the size of the current mark of the input data and the size of before and after space into short pulses, medium pulses, and long pulses, respectively. Adaptive recording method characterized in that. 9. The adaptive recording method according to claim 8, wherein the grouping table stores width data of the first pulse and the last pulse of the recording pulse according to whether the input data is the data of the land track or the groove track. 9. The adaptive recording method according to claim 8, wherein the grouping table stores width data of the first pulse and the last pulse of the recording pulse for each zone on the recording medium. According to claim 8, wherein step (b) is, (b1) calculating the width data of the first pulse by reading the shift amount of the rising edge of the first pulse according to the combination of the size of the previous space and the size of the current mark; And and (b2) calculating the width data of the last pulse by reading the shift amount of the falling edge of the last pulse in accordance with the size of the current mark and the size of the subsequent space. A method of recording a write pulse that optimizes the light output of a laser diode: (a) determining the size of the current mark and the size of the space before and after the non-return to zero inversion (NRZI) data; (b) generating pulse width data for varying the widths of the first and last pulses of the recording pulses according to the determined size of the current mark and the size of the space before and after; And (c) generating an adaptive write pulse according to the pulse width data and converting the laser diode into a current signal according to the drive level of the optical output of each channel for the adaptive write pulse to drive the laser diode. Recording method. The method of claim 13, wherein step (b) comprises: (b1) generating first pulse width data for shifting the rising edge of the first pulse back and forth according to the size of the previous space and the size of the current mark; And (b2) generating second pulse width data for shifting the falling edge of the last pulse back and forth according to the size of the current mark and the size of the subsequent space. 15. The adaptive recording method according to claim 14, wherein the period of shifting the rising edge of the first pulse back and forth and the period of shifting the falling edge of the last pulse back and forth are filled with light output of a predetermined channel. The method of claim 13, and (d) remodifying the widths of the first and last pulses of the adaptive recording pulse according to the land / groove signal indicating whether the input NRZI data is the data of the land track or the groove track. Way. A discriminator for determining the size of the current mark of the input data and the size of the space before and after; A generator for generating an adaptive recording pulse by controlling the waveform of the recording pulse according to the size of the current mark and the size of the space before and after the current mark; And And a driver for converting the adaptive write pulse into a current signal in accordance with the drive level of the optical output of each channel to drive the laser diode. The method of claim 17, wherein the generator, A recording waveform controller for outputting pulse width data for varying an initial pulse width according to the size of the previous space and the size of a current mark and for varying the width of the last pulse according to the size of the current mark and the size of a subsequent space; And And a write pulse generator for generating an adaptive write pulse in accordance with the pulse width data. 19. The width waveform of claim 18, wherein the recording waveform controller groups the size of the current mark and the size of the before and after space into short pulses, medium pulses, and long pulses, respectively, so that the width data of the first pulse and the width of the last pulse of the recording pulse are grouped. An adaptive write circuit, comprising: a memory having a table in which is stored. 20. The adaptive recording circuit of claim 19, further comprising a microcomputer that initializes the write waveform controller and controls to update the pulse width data stored in the memory in accordance with a write condition. 20. The adaptive recording circuit according to claim 19, wherein the memory stores the width data of the first pulse and the last pulse of the recording pulse according to whether the input data is the data of the land track or the groove track. 20. The adaptive recording circuit according to claim 19, wherein the memory stores width data of the first pulse and the last pulse of the recording pulse for each zone on the recording medium. 20. The adaptive recording circuit according to claim 19, wherein a period of shifting the rising edge of the first pulse and a period of shifting the falling edge of the last pulse are filled with light output of a predetermined channel.