JPH01208746A - Signal generator for optical disk - Google Patents

Abstract

PURPOSE:To make the cutting time of a master disk shorter so as to prevent deterioration of the quality of the disk by shifting fixed data stored in a ROM to a RAM and implementing master disk cutting signals by reading out the fixed data from the RAM. CONSTITUTION:A counter circuit 7 counts data clocks a' and outputs memory address signals b' of a ROM 8 and RAM 9. At the RAM 9, fixed data (d) read out from the ROM 8 are written at the address designated by the memory address signals b'. Then, the data read out from the RAM 9 are mixed with track address signals and sector address signals from the counter circuit 7 and signals to be stored on an optical disk are formed. As a result, the reading out speed of the fixed data can be improved and high-speed cutting of a master disk becomes possible. Thus, the chances of contaminating the master disk are reduced and a high-quality master disk is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical disc signal generating device for generating a preformat signal when creating an optical disc master.

[Conventional technology]

In an optical disc, preformat data consisting of a synchronization signal, a track address, a sector address, an ID signal, etc. is recorded in advance as a prepit string at the leading end of each sector. Optical discs are obtained by duplicating the master disc, but such preformatted data is
A cutting device cuts and records the master disc with a laser beam modulated with this preformat data.

An example of a conventional preformat data generating device will be described below with reference to FIG.

In the figure, a counter circuit 30 counts data clocks a, and at every predetermined count, an address signal b of the ROM 31 (hereinafter referred to as ROM address signal), a track address signal of the master (not shown), and a sector address signal (hereinafter referred to as ROM address signal). , these are referred to as preformat address signals C) are output in synchronization with the data clock a. In addition, R
OM address signal b1 reformat address signal C
It goes without saying that the interval between occurrences of is equal to the interval between sectors on the master disc being cut. The counter circuit 10 sequentially counts the data clock a, and includes, for example, a frequency division counter, a sector counter, a track counter, etc. The frequency division counter divides the data clock a into a period corresponding to the sector interval of the master disc. , the sector counter counts the output pulses of the frequency division counter to form a sector address signal, and the track counter forms a track address signal by counting the carries of the sector counter output every time the master disk rotates. The ROM address signal is formed by mixing these sector addresses and track addresses.

On the other hand, fixed data such as synchronization signals and ID signals are stored in ROMLI for each address, and when the ROM address signal is sent from the counter 10, the data clock a
Fixed data d at the address specified by this ROM address signal is read out in synchronization with .

The preformat address signal C from the counter circuit 10 and the fixed data d from the ROMII are connected to the mixing circuit 12.
At , the signals are mixed, parallel-to-serial converted, and modulated by a modulation circuit to form preformat data e. This preformat signal e is output as a master cutting signal.

[Problem to be solved by the invention]

Incidentally, although the ROM II is operated in synchronization with the data clock a, its read speed is low.

For this reason, the rotational speed during cutting of the master disk is determined by the ROM.
It is limited by the data read speed of the IL, and has to be much slower than the rotation speed when using an optical disk. As a result, the time required to cut the master disc becomes extremely long, and the time the master disc is exposed to the outside air increases accordingly, increasing the chance of contamination, leading to deterioration of the quality of the master disc.

SUMMARY OF THE INVENTION An object of the present invention is to provide a signal generator for optical discs that can solve these problems, significantly shorten the cutting time for master discs, and prevent quality deterioration.

[Means to solve the problem]

In order to achieve the above object, the present invention moves fixed data stored in a ROM to a RAM (Random Access Memory), and when cutting a master disc, reads the fixed data from the RAM to generate a master cutting signal. .

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an optical disk signal generator according to the present invention, in which 1 to 4 are input terminals, 5
1 is a spindle synchronization circuit, 6 is a control memory circuit, 7 is a counter circuit, 8 is a ROM, 9 is a RAM, 10 is a mixing circuit, 11 is a modulation circuit, 12 is a parallel/serial conversion circuit, 13 is a mixing circuit, 14 is a Output terminal, 15 is switch, 16 is F
F (flip-flop circuit).

In the figure, before starting cutting of a master disc (not shown), a data blocker a' is inputted from an input terminal 3, and a reset pulse h is inputted from an input terminal 4. This reset pulse h clears the counter circuit 7 and RAM 9, and sets the FF 16. This allows FF
The Q output g of 16 becomes H'' (high level), the switch 15 is closed to the A side, and the RAM 9 is set to the write mode.

The data clock a' inputted from the input terminal 3 is sent to the counter circuit 7.120M8 and the RAM via the switch 15.
9. Here, the frequency of the data clock a' is set to such an extent that fixed data can be read from the ROMB.
It is set low. The counter circuit 7 counts the data clock a' and outputs an address signal (hereinafter referred to as a memory address signal) b' for the ROM 8 and RAM 9. In this case, the counter circuit 7 is the control memory circuit 6
An output signal j of "L" (level) is supplied, and
Since the "H" Q output g of the FF 16 is supplied, a memory address signal b' whose value changes by 1 each time the data clocker a' is supplied is output.

In the ROM8, the fixed data d at the address specified by the memory address signal b' is read out and stored in the RAM.
At step 9, the fixed data d read from the ROMB is written to the address specified by the memory address signal b'. In this way, fixed data corresponding to one address is transferred from the ROM 8 to the RAM 9 every time the data clock a' is input from the input terminal 3.

When the counter circuit 7 counts the data clock a' for all addresses in the fixed data storage area of the ROMB (that is, when all the fixed data in the ROM 8 is transferred to the RAM 9), the counter circuit 7 generates a pulse f and resets the FF 16. do. As a result, the Q output g of FF16 is “L”
As a result, the switch 15 is switched to the B side, the RAM 9 is set to the read mode, and the input of the data clock a' from the input terminal 3 is stopped.

During the above operation period, the master may or may not be attached to the cutting device. In other words, fixed data can be written to the RAM 9 regardless of whether or not the master is attached to the cutting device.
Since fixed data is transferred from ROM 8 to RAM 9, writing of fixed data from ROM 8 to RAM 9 can be done in a relatively short time.

Next, a data clock a is inputted from the input terminal 2, the master is rotated, and cutting is started.

This data clock a is supplied to the control memory circuit 6, counter circuit 7 and RAM 9. In addition, input terminal 1
A spindle encode signal i having a frequency proportional to the rotational speed of the master disc is inputted from the spindle encoder 5, which is input to a spindle synchronization circuit 5 to form a spindle synchronization signal of one pulse for each revolution of the master disc.

The control memory circuit 6 is controlled by this spindle synchronization signal, and in response to the data clock a from the input terminal 2, outputs a control signal j that becomes "L" at each sector period of the master to be cut.

The counter circuit 7 is configured so that the supplied Q output g of the FF 16 is “
When the signal is "L", the counter circuit 30 operates in the same way as the conventional counter circuit 30 shown in FIG. C is output at the same time. RAM
9, the fixed data dI is synchronized with the data clock a from the address specified by this memory address No. 13 b'.
+d2 is read. Here, the fixed data d is the ID
This is data that is modulated such as signals and recorded on the master disc.
The fixed data d2 is data recorded on the master disc without modulation.

Preformat address signal C from counter circuit 7
and fixed data d1 are mixed in a mixing circuit 1O and converted into serial data, and furthermore, an EDC signal, an ECC signal, a CRC signal, etc. for error detection and correction are added in a modulation circuit 11. -7 modulation, EFM modulation,
The signal is modulated using a predetermined modulation method such as MFM modulation. on the other hand,
The fixed data dt read from the RAM 9 is converted into serial data in the parallel/serial conversion circuit 12, and then mixed in a time division manner with the output data of the modulation circuit 11 in the mixing circuit 13 to form preformat data e. be done. This preformat signal e is output from the output terminal 14 as a master cutting signal.

While the data read speed of ROM is several hundred nanoseconds,
The data read speed of RAM is extremely short, several tens of nanoseconds. Therefore, when the recording sensitivity of the master disc is high, by increasing the frequency of the data clock a accordingly, high-speed cutting of the master disc becomes possible. Therefore, depending on the characteristics of the master disc, it is possible to rotate the master disc at a speed as high as the rotational speed of the optical disc in a system that uses an optical disc obtained by copying from the master disc, and to cut the master disc. .

By the way, preformat data are recorded adjacently between adjacent tracks. For this purpose, the clock of the spindle that drives the data clock rough and the master must be sufficiently stable (>10-'). However, these clocks are obtained from independent sources, and even if they are stabilized in this way, there will be slight changes in frequency and phase differences between these clocks.
However, the servo may be disturbed by disturbances, etc., and these errors! ? ,, as the data is accumulated, the recording position of the preformat data will shift from the normal position. This positional deviation becomes larger as the master disk rotates faster.

In order to prevent this, the control memory circuit 6 and the counter circuit 7 are controlled by a spindle synchronization signal output from the spindle synchronization circuit 5 every rotation of the master. The control memory circuit 6 receives data from each at 1/1 from the counter circuit 7.
The timing of outputting the signal b', c and the mixing circuit 10.
13 is stored, and by reading this information pattern in synchronization with the data clock a, the control signal j of the counter circuit 7 and the mixing circuit 10. control signal k
is obtained. The spindle signal from the spindle synchronization circuit 5 regulates the timing at which this information pattern is read from the control memory circuit 6 for each rotation of the master disc. Therefore, the address signal output timing of the counter circuit 7 and the operation timing of the mixing circuit 10.13 are regulated for each rotation of the master disc, and the preformat data at the same sector address of each track on the master disc is accurate in the radial direction of the master disc. will be arranged in

Further, by controlling the counter circuit 7 by the spindle synchronization signal, the track address signal is updated by exactly 4*1 every time the master disk rotates, and the sector address signal is accurately returned to its initial value. This ensures that adjacent sectors between adjacent tracks on the master have the same sector address, and the track addresses differ by a value of 1. Furthermore, fixed data corresponding to the sector in which recording is to be performed is reliably read from the RAM 9 and recorded in this sector.

Encoder uniformity is best between 10-4 and 10-S
That's about it. The cutting device is servoed using the spindle encode signal from this encoder, and at this time, by increasing the tracking time constant of the servo system, the master is rotated with a stability that is higher than the uniformity of the encoder. . The uniformity of the encoder is at the above level, but if we look at the circumference of one revolution of the master disc, the master disc rotates with high stability, so this one revolution cycle is stable with a stability higher than the uniformity of the encoder. are doing. Therefore, the spindle synchronization signal obtained from the spindle synchronization circuit 5 is very stable, and the stability of the data clock a is at best 1.
Even if it is about 0-5, by controlling the control memory circuit 6 and the counter circuit 7 with the spindle synchronization signal, it is possible to set the recording position of the preformat data on the master disc to a high degree.

FIG. 2 is a block diagram showing a specific example of the counter circuit 7 in FIG. 1, in which 20 to 22 are input terminals, 23 is a frequency division counter, 24 is a sector counter, 25 is a track counter, and 26 is a memory address. 27 is a mixing circuit, 28 is a selector, and 29 is an output terminal.

In the figure, first, each counter 23 to 26 is reset by a reset pulse h (FIG. 1). Also, at this time, the "H" Q output g of the FF 16 (FIG. 1) is supplied from the input terminal 22, thereby causing the sector 28 to select the side of the memory address counter 26.

In this state, the data clock a' shown in FIG. 1 is input from the input terminal 20, and the memory address counter 26 counts this. The count value bI' of the memory address counter 26 is selected by the selector 28, and is set as the memory address signal b' in the ROM8. RAM9
(Figure 1). As a result, the fixed data of ROMB is written to RAM9. The memory address counter 26 is ROM8. , has the ability to count more than the number of addresses in the fixed data storage area of RAM9.
When the count value for the last address of MB and RAM 9 is reached, a pulse f is generated.

This pulse f is transmitted from the output terminal 29 to the FF 16 (Fig. 1).
is supplied as a reset pulse. As a result, the Q output g of the FF 16 input from the input terminal 22 becomes "L", and the selector 28 is switched to select the mixing circuit 27 side.

Next, when cutting the master disc, as the master disc rotates, a spindle synchronization signal β is inputted to the input terminal 21 from the spindle synchronization circuit 5 (FIG. 1).

Further, the data clock a that is input to the input terminal 2 in FIG. 1 is input from the input terminal 20.

The data clock a is frequency-divided by a frequency division counter 23 to have a period corresponding to every sector on the master disc,
It is counted by the sector counter 24. Frequency division counter 2
3 and the sector counter 24 are reset by the spindle synchronization signal E.

As a result, the value of the sector address signal output from the sector counter 24 is always the first value, such as "0", on the same radius on the master disc.

Further, the track counter 25 counts the spindle synchronization signal β. Therefore, the value of the track address signal obtained from the track counter 25 changes by a value of 1 for each sector where the sector address takes an initial value such as "0".

The sector address signal obtained from the sector counter 24 and the track address signal obtained from the track counter 25 are mixed by a mixing circuit 27 so that the sector address signal becomes the lower bit string and the track address signal becomes the upper bit string. Ru. The output signal b2' of this mixing circuit 27 is selected by the selector 28 and supplied to the RAM 9 (FIG. 1) as a memory address signal b'.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to sufficiently increase the reading speed of fixed data from the memory, and high-speed cutting of master discs is possible, reducing the chance of contamination of the master discs and producing high-quality master discs. Obtainable.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the signal generator for optical disks according to the present invention, FIG. 2 is a block diagram showing a specific example of the counter circuit in FIG. 1, and FIG. FIG. 1 is a block diagram showing an example of a signal generator. 2.3... Data clock input terminal,
5... Spindle synchronization circuit, 6...
...Control memory circuit, 7...Counter circuit, 8...ROM, 9...
...RAM, 10...Mixed circuit,
11...Modulation circuit, 13...
...Mixing circuit, 14... Output terminal. Figure 1!

Claims (2)

[Claims] (1) Equipped with a counter circuit that sequentially generates a memory address signal, a track address signal, and a sector address signal, and a nonvolatile memory in which data is stored in advance and the data is sequentially read out in accordance with the memory address signal. A signal generator for an optical disc includes a random access memory and a means for writing and reading data stored in the nonvolatile memory into the random access memory, and the data read from the random access memory and the counter circuit. 1. A signal generating device for an optical disc, which mixes a track address signal and a sector address signal to generate a signal to be stored on an optical disc. (2) The signal generating device for an optical disk according to claim (1), characterized in that the operation of the counter circuit is made to cycle in accordance with the rotation of the optical disk by a pulse corresponding to the rotation period of the optical disk.