JPH04170767A - Optical disk device - Google Patents

Abstract

PURPOSE:To enable performance of a device to be improved by generating timing signal accurately without being affected by rotary fluctuation and capturing information needed for compensation accurately. CONSTITUTION:A sector mark signal is detected from a read data 100 which is output from a recording medium by a sector mark detection means 101 and then an operation of a position signal generation means 102 is started by an output of the means 101. Counting is performed by a read clock 104 which is from the read data 100 by a separation means 103 within the means 102, agreement of a sector ID information which is detected from a read signal 105 and an ID which is set by an identification setting means 107 is waited and then counting is started from the location of agreement. When counting is made by a value which is set by a starting position setting means 108, starting signal is output from a position starting means 109, an end signal is output from a position signal end means 110 when a specified value is counted by an end position setting means 111, signals of means 109 and 110 are synthesized by a position signal output means 112, and then a timing signal is output at any position after the ID matches.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method of controlling an optical disc device.

[Prior Art] FIG. 2 shows the format of a 5.25' magneto-optical disk conforming to ISO. The area is thick (divided into two) due to the difference in recording method. One is called the pre-pit area,
This is an area in which sector identification information (hereinafter referred to as ID) has been written in advance, and data cannot be written on the device side. The other area is called the MO area and is an area where data can be written.

Immediately after the prepit section, that is, at the beginning of the MO section, the FL
There is an AG area, which contains information that can be used as a reference when controlling the drive. For example, in ALPC, the laser is turned on and the reflectance is evaluated by observing the reflected light, and the subsequent driving current for the laser is determined. Further, the parameters of the drive are corrected by referring not only to the information existing in the FLAG area but also to the information existing in the ID section.

In this way, high performance is achieved by referring to this information and correcting the laser power, but in order to refer to the signals at these positions,
A timing signal must be generated to indicate its position.

Conventionally, as shown in FIG. 3, the output of a sector mark detection circuit 302 obtained from read data 301, a sector mark detection signal, generates a write clock (output of 303) inside the device using ALPC. ,VFO
Only the fixed value needle corresponding to the value was counted and generated.

[Problems to be Solved by the Invention] However, there is a slight difference between the period of the read clock created from data on the disk and the period of the write clock created inside the device. This is due to the inherent difference between the clock generated inside the device and the read clock, and to fluctuations in the rotation of the disk. Although the former can in principle be reduced to zero by using an extremely accurate crystal oscillator, it is difficult to absorb the latter difference.

The present invention is intended to solve these problems, and makes it possible to accurately generate timing signals without being affected by rotational fluctuations, to accurately capture the information necessary for various corrections, and to improve the performance of equipment. The purpose is to improve the performance of

[Means for Solving the Problems] The optical disc device of the present invention includes: sector mark detection means for detecting a signal indicating the start of a sector from a read signal output from a storage medium; An optical disc device comprising: a separation circuit that separates a clock; and a position signal generation means that generates a position signal at an arbitrary position within a sector based on a sector mark detection signal generated from the sector mark detection means, the position signal generation means includes: a start position setting means for setting a start time of the position signal; an end position setting means for setting an end time of the position signal; and an identification number setting means for setting an identification number of a specific sector. means, a coincidence detection means for detecting a coincidence between a setting value of the identification number setting means and an identification signal on the disk obtained from the data signal, and a coincidence detection means for detecting a coincidence between a setting value of the identification number setting means and an identification signal on the disk obtained from the data signal, and a coincidence between the sector mark detection signal output from the sector mark detection means and the coincidence a position signal start means for starting the position signal after a time set by the start position setting means based on the output of the detection means; and a position signal start means for terminating the position signal after the time set by the end position setting means has elapsed. The apparatus is characterized in that it comprises a position signal terminating means, and a position signal output means for outputting a position signal from the output of the position signal starting means and the output of the position signal terminating means.

[Function] According to the present invention, as shown in FIG. The operation begins.

Inside 102, the read clock 104 extracted from 100 by separation means 103 is used as a counting clock, and waits until the sector ID information detected from read signal 105 matches the ID set by identification setting means 107. Counting starts from the point where there is a match.

When the start position setting means 108 counts the value set, the position signal starting means 109 outputs a start signal. Furthermore, when the end position setting means 111 counts the value set, the position signal ending means 110 outputs an end signal. By combining the signals 109 and 110 in the position signal output means 112, a timing signal is output at an arbitrary position after ID matching.

[Example] FIG. 4 shows an example of the present invention. Hereinafter, the present invention will be explained in detail based on this figure. Data on the disk is read by a head and sent as read data 401 to a sector mark detection circuit 402 and a PLL circuit 403. At 402, a sector mark is detected and output as a sector mark detection signal 404. 404 serves as a load signal for 4-bit up counters 417, 418, 419, and 420, and also as a ripple carry holding circuit 421.
422 is used as a reset signal for the comparator holding output circuit 414. At 403, the synchronization clock included in 401 is extracted, and undecoded data is output in synchronization with this.

Both the synchronization clock and the data before decoding are sent to the number decoding circuit 405. At 405, the decoding power f is performed, and as a result, a read clock 406 synchronized with the NRZ serial read data 407, and a 1 (item boundary signal 408) to indicate the byte boundary of the read data are output.
06 becomes the shift clock of the serial to parallel conversion circuit 412 and is used to synchronize the entire system, and 417, 418, 419, 420, 4
21,422 clock inputs. 407 is 4
It is connected to 12 data inputs and converted into parallel data (in 3 Neuite units). The parallel output of 412 is connected to one of the comparison inputs of comparator 413. 4
The output of the sector ID setting register 411 is connected to the other of the 13 comparison inputs. Sector ID is track number HIGH byte, LOW byte, sector number 3
Consists of bytes. 413 is a 3-byte long comparator, which can be easily realized using existing circuits. When the set value in 411 and the parallel data in 412 are equal, a match signal is output and sent to 414. 409 starts operation by 408, and the fifth
At the timing shown in the figure ((1), the first sector ID is
A comparator synchronization signal 410 is output immediately after the completion of the comparator synchronization signal 410. 410 becomes the clock of 414, and by 414,
The coincidence signal is maintained (FIG. 5(e)). The match signal, the output of 414, is used as a count enable signal for 417.419. The ripple carry output of 417 is 41
It is cascade-connected to the count enable of 8 to form an 8-bit down counter. Similarly, 419
, 420 constitute an 8-bit down counter. 417 and 418 are used to generate position signal start timing. 419 and 420 are used to generate the end timing of the position signal. When the counter output reaches zero, a ripple carry of 418 is output and held at 421. The output of 421 is 4
17. Connect to the count enable terminal of 418, -
When the i-force → count output becomes zero, the subsequent counting operation is stopped. This timing is shown in FIG. 5(f). Similarly, the operations of 419, 420, and 422 are also shown in Figure 5 (
g).

The respective generation timings are determined by the CPU 424 to 415.
It can be controlled by writing an appropriate setting value to 416. The AND gate 423 provides a position signal as shown in FIG. 5(h).

Now, when a sector mark is detected from 401, 404 is generated, and the values set in 415 and 416 are loaded as initial values of 417, 418, 419, and 420. At the same time, 414, 421, and 422 are reset, and the coincidence signal, position start signal, and position end signal are initialized.

After that, the ID is regenerated by the ID regeneration circuit composed of 403, 405, and 412, and the target I set in 411 is
It is compared with D, and when the two match, 414 is output, and thereafter, counting operations of 417, 418 degrees, 419, 420 start. When the contents of the counters 417 and 418 become zero, a position start signal is output, and 419,
When the contents of 420 become zero, a position end signal is output, and both are held until the next sector mark detection signal arrives. As a result, a position signal can be generated in the output of 423 at any bit position and any pit width after the first ID.

In this embodiment, the counter is a down counter, but it goes without saying that it can be similarly implemented as an up counter. In that case, two's complement numbers will be used for the setting. In addition, the count for generating position start timing and the count for generating position end timing are started simultaneously, but after the counting operation for generating position start timing stops, the count for generating position end timing starts. The same can be achieved by starting the method. In this case, the generation of the position end timing would rather mean the time width setting of the position signal.

[Effects of the Invention] As described above, according to the present invention, when generating timing using a write clock, it is necessary to set the reference clock with high precision. There is no need to increase the accuracy of the reference clock for use. Counting starts when the read clocks are finally fully synchronized, so position signals can be generated extremely accurately without being affected by rotational fluctuations. Even if a sector mark is erroneously generated, the condition is that the IDs match, so there is less chance of malfunction.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the present invention. FIG. 2 is an explanatory diagram of the format. FIG. 3 is a block diagram of a conventional example. FIG. 4 is a block diagram of an embodiment of the present invention. FIG. 5 is an operation timing waveform diagram of the embodiment. 304 ・ ・ ・ CPU 305...Register 306...Register 307...up counter 308...up counter 309...up counter 310...up counter 311...Holding circuit 312...Holding circuit 313...AND gate that's all Applicant Seifu Ebson Co., Ltd. Agent: Patent attorney Ehon Kisanbe and 1 other person Figure 1 Figure 4 Figure 5

Claims (1)

[Scope of Claims] Sector mark detection means for detecting a signal indicating the start of a sector from a read signal output from a storage medium, a separation circuit for separating data and a synchronization read clock from the read signal, and a separation circuit for separating data and a synchronization read clock from the read signal, In an optical disc apparatus having a position signal generating means for generating a position signal at an arbitrary position within a sector based on a sector mark detection signal generated from a mark detecting means, the position signal generating means detects a start time of the position signal. a start position setting means for setting an end time of the position signal; an identification number setting means for setting an identification number of a specific sector; and an identification number setting means for setting an identification number of a specific sector. a coincidence detection means for detecting a coincidence between a set value and an identification signal on the disk obtained from the data signal; position signal starting means for starting the position signal after the time set by the start position setting means; position signal terminating means for ending the position signal after the time set by the end position setting means; and the position signal. An optical disc apparatus comprising a position signal output means for outputting a position signal from an output of the start means and an output of the position signal end means.