JPS62239384A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To detect a deletion pulse with high accuracy by setting the head '0' section of the 1st pulse train superposed with the 2nd short pulse train at the value larger than the detection time of a marking signal. CONSTITUTION:A sector detecting part 17 extracts the address information out of an optical disk drive 22 and transmits a sector detection signal 101. Then a microprocessor 15 transmits a data recording/deletion pulse recording enable signal 104 and then sends a prescribed pattern 103 through a serial port after a prescribed time. Furthermore a short pulse train generating part 19 produces a short pulse train to secure an OR with the information 103 and transmits a deletion pulse train 105 to the drive 22 via a data recording part 20. Here the head '0' section t1+t2 of a pulse train consisting of repetition of an interval TA wider than the inverse interval of data is set larger than the time td needed for detection of the deletion pulse.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention records and reproduces information sector by sector on an optical recording disk having an optically detectable guide track and in which the guide track is divided into a plurality of sectors. The present invention relates to an optical information recording/reproducing device.

Conventional technology Optical recording disks have optically detectable guide tracks arranged in concentric circles or spirals in order to increase track density. For reasons such as data processing, each track is divided into a plurality of sectors, and information is recorded, reproduced, and erased in sector units. Information is recorded by irradiating the recording layer formed on the disk with a laser beam focused to a diameter of 1 μm or less to create holes in the recording layer or to cause changes in reflectance and transmittance, depending on the manufacturing process and usage environment. Various defects that occur on the disk surface due to such factors cause dropouts in the reproduced signal. Due to the occurrence of such dropouts, the raw error rate of optical recording disks is only about 10-4 to 1o-6,
Various error control techniques have been proposed to overcome errors.

For example, in Japanese Patent Application Laid-Open No. 187971/1989, a marking signal with a special pattern is written in a defective sector where the recorded data cannot be reproduced due to an error and cannot be corrected. An error control method that performs alternative recording on a sector, writes a marking signal to an unrecorded sector with a large defect as a bad sector, or writes a marking signal to a sector that is no longer used due to file updates, etc., making it an unnecessary sector. It is shown. This operation of recording a marking signal with a special pattern in a defective or unused sector and preventing the data in that sector from being reproduced is called a delete, and the marking signal with a special pattern to be recorded is called a delete pulse.

This delete pulse consists of a repeating pulse train of "1" and "○" with a width wider than the maximum inversion interval of data recorded on the disk, and by detecting this delete pulse during playback, defective and unnecessary sectors can be determined. do. FIG. 8 shows a state diagram of the reproduced signal at the time of deletion. FIG. 8a shows a reproduction signal when data is recorded in a sector, and is composed of a sector identifier section 1 containing track and sector address information and a data section 2. FIG. 8 shows a delete pulse 3 written at the time of deletion, which is composed of a pulse train consisting of repetitions of "1" and "0" with a width wider than the maximum inversion interval of the data section 2. FIG. 8C shows a reproduction signal when an unrecorded sector is deleted, and FIG. 8D shows a reproduction signal when a recorded sector is deleted. Deleting a recorded sector is performed by overwriting a delete pulse. During playback, this pulse train is detected and recognized as a delete sector.

However, when writing a pulse train with a wider width than the data section, the power when writing the first pulse becomes unstable due to the transient response characteristics of the recording power servo system of the semiconductor laser when switching from the reproduction state to the recording state. Because of this, the delete pulse cannot be written normally, or the laser output is zero during the period of "0" of the delete pulse.
If the period of "0" is not long, there will be a problem that the focus/tracking control will become unstable. The second
A method has been proposed in which a signal is recorded with a short pulse train superimposed on it.

FIG. 9 shows a state diagram of the reproduced signal at the time of deletion with this configuration. FIG. 9a shows a delete pulse in which the second short pulse train is superimposed on the "O" section of the first pulse train. 9th
The figure shows a reproduction signal when the delete pulse is recorded in an unrecorded sector, and FIG. 9C shows a reproduction signal when it is overwritten in a recorded sector. In this way, if the delete pulse is a signal in which the second short pulse train is superimposed on the "0" section of the first pulse train, the loss in the rise of the recording power during recording will be absorbed in the section shown in Figure 9a. This also eliminates the instability of focus and tracking control.

Detection of such a delete pulse train takes advantage of the fact that the first pulse train is wider than the maximum data reversal interval, and detects an interval of "1" that is longer than the maximum data reversal interval from the reproduced signal. The first pattern written by “1”
This is done by determining whether the pulse train pattern matches the pulse train pattern. Therefore, the second short H/L/S train superimposed on the "0" interval is unrelated to the detection of the first pulse train of the delete pulse, and henceforth, the detection of the delete pulse is the first pulse train of the first pulse train. shall refer to detection.

FIG. 10 shows a circuit for detecting a "1" section wider than the maximum data inversion interval in a delete pulse, and FIG. 11 shows signal waveforms at various parts. The reproduction signal 4 when deleting an unrecorded sector is longer than the maximum data reversal interval,
It is input to a double-edge retrigger monomultim 5 having a time constant tm shorter than the reversal interval of the wide first pulse train of delete pulses. This re-trigger mono multi A5
By taking the AND of the inverted signal 7 of the output 6 and the original reproduced signal 4, a pulse longer than tm, which is longer than the maximum data inversion interval, can be detected. This AND output 8 is used as the first delete pulse.
has a time constant of the same length as the "1" section of the pulse train,
If the signal is input to the re-trigger monomulti B9 which is triggered by the rising edge of the input signal, a signal identical to the first pulse train pattern of the delete pulse can be obtained as its output.

By providing a comparison circuit between the output signal of the monomulti B and the first pulse train pattern during writing, a sibling pulse can be detected. As a comparison circuit, JP-A-60-1
There is a method using the serial port of a microprocessor, as described in 8797°1. The output signal 10 of the monomulti B is input to the serial port, and the pulse pattern of the input signal between the time when the first pulse is input and the comparison time tdO is read to check whether it matches the delete pulse pattern. This method is a very effective means because it does not require any hardware pattern-number circuits and results in a simple circuit configuration.

Problems to be Solved by the Invention However, when detecting a delete pulse pattern using the serial port of a microprocessor in this way, since the input pattern of the time td from the first input pulse is captured and compared, the reproduced signal When the time constant tm or more of the re-trigger monomultiply of the delete pulse detection circuit is
A signal with a level of "1" is generated for some reason, and it is a "1" level signal at the beginning of the first pulse train of the original delete pulse.
”, the pattern is imported into the comparator circuit from that point and overlaps with the original pattern position, and the delete pulse pattern is not imported into the comparator circuit at the regular timing and the delete pulse is generated. There was a problem that detection became impossible.

In particular, this is often caused by dropout immediately before a delete pulse recorded on an unrecorded sector. Furthermore, as described above, if the write power is maintained for a certain period of time tm or more in an unstable part of the rise of the semiconductor laser recording power servo system, a shift in the acquisition of the delete pulse pattern will occur.

To explain this shift in pattern capture timing with reference to FIG. 12, in the reproduced signal 4 in FIG.
” occurs, the detection signal is output to the AND output 8 shown in FIG. 12, and as shown in FIG. From the generated pulse 12 td, (t
The pulse pattern is taken into the comparator circuit only during the period (equal to d). After this acquisition is completed, from the next pulse 13, td
2 (equal to td) is captured, and in the end it is not captured at the original pulse pattern position, making it impossible to detect this delete pulse. Means for recording a marking signal in which a second short pulse train is superimposed on a "0" section of a first pulse train consisting of repetitions of roJ and "1" having a width wider than the interval, and detecting the marking signal during data reproduction. The optical information recording/reproducing apparatus is provided with means for detecting a marking signal, and has a period of "0" at the beginning of the first pulse train on which the second short pulse train is superimposed, which is longer than the detection time of the marking signal.

The present invention has the above-described configuration, and when detecting a delete pulse pattern using a serial port of a microprocessor, it is possible to prevent dropout of unrecorded sectors or instability of the semiconductor laser recording power servo system when writing delete pulses. Delete pulse pattern that can occur due to

This prevents deviations in the import timing and enables accurate detection of delete pulses.

Example The present invention will be explained below with reference to Examples.

FIG. 2 shows a delete pulse pattern in this embodiment. With an interval wider than the data reversal interval.

The pattern consists of a first pulse train consisting of repetitions of , and a second short pulse train superimposed on the "0" section of the first pulse train. and “0” at the beginning of the first pulse train.
'' is made longer than the time td required to detect the delete pulse. Strictly speaking, tl is set to be larger than the unstable time of the semiconductor laser recording power servo system, and tl is set to a value larger than td. With such a pattern configuration, dropout of unrecorded sectors and inability to detect delete pulses caused by instability of the semiconductor laser recording power servo system when writing delete pulses can be eliminated.

With reference to FIG. 3, it will be explained that the pattern of this embodiment is effective against dropout of unrecorded sectors.

FIG. 3 IL1 shows an example of a reproduced signal in a portion where dropout exists, and the signal level is τ. . The binarization comparator level 13 is also raised by the time of . Therefore, as shown in FIG. 3 &2, the binarized reproduced signal after the comparator becomes a pulse with a width of 'l'no. If the length of this 'rno is longer than the time constant tm of the retrigger monomulti A5 of the delete pulse detection circuit shown in FIG. If this dropout existed immediately before the pattern, the acquisition position of the delete pulse pattern would be shifted, but as in this embodiment, the "0" section at the beginning of the first pulse train is set to the de-IJ-to pulse detection time. By making the ta width longer and writing the second short pulse train superimposed on that portion, the possibility of false detection at the dropout portion is reduced, as shown in FIG. 3 b1 and b2. In other words, it is possible to divide the part that is "1" during TDO into a short pulse train, and it is possible to reduce misrecognition of the "1" part of the first pulse train.

With reference to FIG. 4, it will be explained that the pattern of this embodiment is effective when the start-up of the semiconductor laser recording power servo system is unstable. Binarized playback signal 4 as shown in Figure 4 &
Due to the unstable start-up of the recording power servo system, the beginning of T is in the write power state for TL8, and if T,8 is longer than the time constant tm of the retrigger monomultime in FIG. As shown in Figure 4(d), it appears at the output 10 of the monomulti B. However, by setting the interval it, +t2 of "0" at the beginning of the first pulse train, making tl longer than the unstable time of the recording power servo system, and making tl longer than the delete pulse detection time t(i), Although the pulse pattern is captured from the erroneously recognized part, it does not overlap with the original delete pulse pattern, and the delete pulse can be detected at the correct position.

FIG. 1 is a block diagram of an optical information recording/reproducing apparatus in an embodiment of the present invention. 16 is a microprocessor that controls the recording and reproduction of data and delete pulses; 16 is a sector buffer that temporarily stores recording and reproduction information; 17 is a sector detection unit that detects a target sector; and 18 is a unit that detects delete pulses from playback signals. a delete pulse detection section; 19, a short pulse train generation section that generates a second short pulse train in the delete pulse; 20, a data recording section that records data; 21;
22 is an optical disk drive; 10o is a target address; 101 is a sector detection signal; 1o2 is a delete pulse detection signal; 103 is a wide first pulse train of delete pulses generated by the microprocessor 15; 104 is a data recording/delete pulse recording enable signal, 105 is a delete pulse train, 1
o6 is recording data, 107 is reproduction data, 108 is a reproduction signal, and 109 is a recording signal.

The operation of the optical information recording/reproducing apparatus of this embodiment configured as described above will be explained using FIG. 6.

When recording a delete pulse in a defective sector or an unnecessary sector, the microprocessor 16 sets the target address 100 of the sector in the sector detection unit 17. The sector detection section 17 extracts address information from the reproduction signal 108 sent out from the optical disk drive 22 and sends out a sector detection signal 101. The microprocessor 15 detects a predetermined timing from the sector detection signal 101 9, FIG.
Data recording/delete pulse recording enable 1
04 as a delete pulse record, and according to the format of the delete pulse, a predetermined pattern 103 is transmitted from the serial port for tbO after time t & as shown in FIG. Furthermore, the delete pulse recording is disabled after a time tc after the pattern is sent out. Short pulse train generator 1
9 is data recording/delete pulse recording enable signal 1
04, generate a short pulse train as shown in FIG.
The data recording unit 20 performs the logical sum of the special information 1o3 of the microprocessor 15 and the short pulse train and sends the IJ-to-pulse train 106 shown in FIG. 5d to the data recording unit 2o.
If the data recording enable signal 104 is a delete pulse recording enable, the special signal 106 is sent to the optical disk drive 22 as it is as a recording signal 109 without being encoded or modulated.

As described above, the delete pulse is recorded, but if it is recorded in a sector where data has already been recorded, it will result in double recording. The recorded data pulse train disappears, and the "1" portion appears as is in the reproduced signal. However, in the second short pulse train portion, the short pulse train may be written between the data pulse trains depending on the positional relationship with the data pulse train recorded in advance, and unnecessary wide pulses may be generated. Therefore, the pulse width of the short pulse train superimposed by the short pulse train generator 19 is equal to the minimum inversion length of data, and the duty is at least 174.
Must be below.

To explain this phenomenon in FIG. 6, when a short pulse train of the duty hammer shown by the solid line and dotted line in FIG. 6 is written to the data pulse train of FIG. In this case, a wide pulse as shown by the dotted line is generated, which is inconvenient. In this embodiment, the duty is set to 1/4 as shown by the solid line in FIG. At this time the 6th
As shown by the solid line in Figure C, no wide pulses appear in the reproduced signal.

Delete pulse detection during data reproduction is performed by a delete pulse detection section 18, which has the same configuration as the circuit shown in FIG. When reproducing data, the reproduction signal 108 sent from the optical disk drive 22 is input to the sector detection section 17, the data reproduction section 21, and the delete pulse detection section 18. Processor 15 and data reproducing unit 21
is output and data playback begins. At the same time, the microprocessor 15 monitors the delete pulse detection signal 102 through the serial port, and while data in a certain sector is being reproduced, the delete pulse detection signal 102 is sent to the serial port.
is input and the pattern matches a predetermined delete pulse pattern, data reproduction of that sector is stopped and the sector is treated as a defective or unnecessary sector.

A method of detecting a deleted sector using a serial port of a microprocessor will be explained with reference to FIG. FIG. 7a shows a wide first pulse train of delete pulses generated by the microprocessor 15, and FIG. 7a shows a delete pulse detection signal input to the microprocessor.

The serial port of the microprocessor detects the start bit St at a falling edge from a high level to a low level, and from that point on takes in multiple bits of data according to a determined baud rate.

Better yet, if you set the delete pulse to be recorded in a certain pattern according to the baud rate and send the delete pulse detection signal detected during playback directly to the microprocessor's serial port, the microprocessor can immediately detect the deleted sector. . In this embodiment, 8 bits of data are taken in from the next bit after the start bit St.
The pattern is "10101o10". The 9th bit is a stop bit Sp.

Since the microprocessor samples and reads data at a frequency higher than the baud rate, the data pulse train T
, should be as wide as possible, but if a MU amplifier is used in the reproduction system, the low frequency range will be cut, so the delete pulse IIIT, is determined by taking both of these into account.

For example, when the CPU 8051 is operated with a 12 MHz clock and the baud rate is 187.6 kbps, the frequency of the delete pulse is 187.5 K)lz, and this value can be set outside the low frequency range to be cut.

As described in detail, according to the present invention, when detecting a delete pulse pattern using a serial port of a microprocessor, dropout in an unrecorded sector,
Alternatively, it is possible to prevent deviations in the input of the delete pulse pattern into the comparator circuit caused by unstable start-up of the semiconductor laser recording power servo system, etc.
This has the effect that deleted sectors can be detected with high precision.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an optical information recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a delete pulse pattern diagram of the same embodiment, and FIG. 3 shows that this embodiment is effective for a dropout section. FIG. 4 is an explanatory diagram showing that this embodiment is effective when the semiconductor laser recording power servo system is unstable. FIG. 6 is a timing diagram when generating a delete pulse pattern. is an explanatory diagram for determining the width of the short pulse train, Fig. 7 is a timing diagram of the delete pulse train and the delete pulse detection signal, Figs. 8 and 9 are explanatory diagrams of the conventional delete operation, and Fig. 10 is the conventional delete operation. FIG. 11 is a block diagram of the pulse detection circuit, FIG. 11 is a timing diagram at each point in FIG. 10, and FIG. 12 is an explanatory diagram showing that pattern capture deviation occurs due to a conventional delete pulse pattern. 1... Sector identifier section, 2... Data section, 3... Delete pulse pattern, 4...
...Reproduction signal, 13...Comparator level, 1oo...[17 dress, 1o1...
- Sector detection signal, 102... Delete pulse detection signal, 1o3... Broad first pulse train of delete pulses, 104... Data recording - Delete pulse recording enable signal, 106 ...Delete pulse train, 1o6...Record data, 10
7...Reproduction data, 108...Reproduction signal, 109...Record signal. Fig. 1 Nog Fig. 3 °i (3 limbs Fig. 6 Fig. 8 Fig. 9 Fig. 10 Fig. 12

Claims (2)

[Claims] (1) A means for recording and reproducing data in sector units on an optical recording disk having an optically detectable guide track, the guide track being divided into a plurality of sectors, and having a width wider than the maximum data reversal interval. means for recording a marking signal in which a second short pulse train is superimposed on the "0" section of the first pulse train consisting of repeated "0" and "1", and means for detecting the marking signal during data reproduction. An optical information recording/reproducing apparatus comprising: a first pulse train on which a second short pulse train is superimposed; (2) The period of "0" at the beginning of the first pulse train on which the second short pulse train is superimposed is defined as the time required for the recording power of the semiconductor laser to stabilize at the start of recording and the detection time of the marking signal. 2. The optical information recording and reproducing apparatus according to claim 1, wherein the optical information recording and reproducing apparatus is made longer than the added time.