JPH0391135A - Magneto-optical disk reproducing device and magneto-optical disk recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the reliability of information lowering by performing the retrying of a recorded signal as changing the characteristic of a reproduction circuit when an error occurs in the recorded signal and sending reproduced information after finding the optimum reproducing condition in which the error is minimized, CONSTITUTION:When the error occurs in the reproduction of the recorded signal, the retrying is performed as changing the characteristic of the reproduction circuit, and the optimum reproducing condition is found in which the error is minimized, and the information reproduced with the optimum reproducing condition is sent to a host device. Error information for targeted information can be obtained by changing the reproducing condition based on the optimum reproducing condition, and it is decided so that the error can be reduced from the error information. Also, as the information to obtain the error information, the information requested by the host device is used in a magneto-optical disk reproducing device, and the information requested by the host device or the information recorded on the test area of a medium with a magneto-optical disk recording and reproducing device is used in the magneto-optical disk recording and reproducing device. In such a way, the error in reproducing information can be reduce, which enables information reproduction with high reliability to be performed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magneto-optical disk reproducing device and a magneto-optical disk recording and reproducing device that use a magneto-optical disk as a recording medium, and particularly relates to a magneto-optical disk recording and reproducing device that uses a magneto-optical disk as a recording medium. Regarding possible devices.

[Conventional technology]

Some magneto-optical disk recording and reproducing devices employ a differential system in the reproduction system that reproduces signals recorded on the recording medium (magneto-optical disk) in order to remove noise components contained in the reproduced signal. be.

According to this differential method, in-phase noise components that depend only on the intensity of light can be removed from the input signal by performing differential amplification using a differential amplifier. Therefore, the differential amplifier needs to be adjusted at the time of shipment so that the levels of the two input signals are balanced in advance.

However, this adjustment takes time and effort, and after the adjustment.

There is a problem in that the adjustment becomes erroneous if there are temperature changes, aging of the optical system, etc.

In order to solve this problem, the conventional technology is
As described in Publication No. 162843, the amplitude and time difference of the signal input to the differential amplifier for detecting the magneto-optical signal is based on the pilot signal recorded in advance on the magneto-optical disk as an optical intensity modulation signal. The system was designed to control the amount of data generated, eliminating the need for adjustments during manufacturing, and automatically responding to changes in the usage environment and dirt on the optical system to prevent a decline in information reliability. .

[Problem to be solved by the invention]

However, the above-mentioned conventional technology does not take into consideration the following points, and therefore has the following problems.

In other words, the pilot signal is recorded as an optical intensity modulation signal, so it does not appear in the magneto-optical signal, but crosstalk of the pilot signal to the magneto-optical signal occurs due to the influence of birefringence caused by the pits. , this crosstalk becomes noise to the magneto-optical signal, and the magneto-optical signal is affected by birefringence due to the transparent resin substrate with a thickness of about 1 mm on the recording film of the magneto-optical disk. This is the point where the balance between the signals used to obtain the magneto-optical signal is lost.

From these points of view, in the conventional technology, even if the in-phase noise appearing in the magneto-optical signal is minimized, it does not necessarily mean that the errors in the reproduced information are minimized, and the most important performance of the magneto-optical disk reproduction device is There is a possibility that a problem may arise in that one information error cannot be sufficiently reduced.

An object of the present invention is to solve the above-mentioned problems and provide a magneto-optical disk reproducing device and a magneto-optical disk recording and reproducing device that are capable of highly reliable information reproduction with fewer errors in reproduced information.

[Means to solve the problem]

In order to achieve the above objective, if an error occurs during playback of a recorded signal, we will try again while changing the characteristics of the playback circuit, find the optimal playback conditions that minimize the error, and optimize the playback. The information reproduced under the conditions is sent to the higher-level device.

Optimal reproduction conditions are determined by obtaining error information for the target information while changing the reproduction conditions, and using the error information to reduce errors. The information to be reproduced to obtain error information is the information requested by the host device in the magneto-optical disk reproducing device, and the information requested by the host device in the magneto-optical disk recording and reproducing device.
Alternatively, the information recorded in the test area of the chrysanthemum medium by the magneto-optical disk recording/reproducing device is used.

The present invention relates to information reproduction on a magneto-optical disk.

Or, although it is preferably applied to information recording and reproduction, information reproduction on other recording media that causes similar problems, or
It may also be applied to information recording and reproduction.

[Effect]

If the number of errors in the reproduced information exceeds a predetermined value, the magneto-optical disk playback device or magneto-optical disk recording and playback device itself automatically controls playback conditions to reduce the degree of error occurrence. and try playback again.

Therefore, highly reliable information with few errors can always be provided to the host device.

In addition, it is also possible to prevent errors caused by variations in the characteristics of recording media, variations in the magneto-optical disk recording device that recorded information, and changes in the characteristics of the magneto-optical disk reproducing device and magneto-optical disk recording and reproducing device according to the present invention. Since it operates to minimize errors in the information ultimately provided to the host device, it has excellent compatibility with recording media and magneto-optical disk recording devices, and prevents the reliability of information from deteriorating due to changes over time. be able to.

Furthermore, when adjusting the magneto-optical disk reproducing device or the magneto-optical disk recording and reproducing device of the present invention, a standard recording medium that serves as a reference for adjustment is played back, and the optimum playback conditions at that time are determined as playback conditions for normal information playback. By storing it as the initial setting value.

It becomes possible to reduce adjustment items during manufacturing.

〔Example〕

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

1 is a block diagram showing the configuration of a magneto-optical disk recording and reproducing apparatus according to a first embodiment of the present invention.

In FIG. 1, 1 is a magneto-optical disk, 2 is an optical head,
3 (3a and 3b) is a photodetector, 4 is a semiconductor laser element, 5 (5a and 5b) is a current-voltage conversion circuit (hereinafter abbreviated as an IV conversion circuit), 6 (6a and 6b)
) is an amplifier, 7 is a variable amplifier, 8 is a delay circuit (DLY)
, 9 (9a.

9b and 9c) are variable delay circuits, 10 is an adder circuit, 1
1 is a differential amplifier circuit, and 12 is a signal processing circuit.

Further, 13 is a magneto-optical signal, and 14 is a light intensity signal.

15 is a gain control signal, and 16 (16a, 16b and 16c) is a delay time control signal.

The photodetector 3 for signal detection is divided into two sets,
In the output signal of the photodetector 3a and the output signal of the photodetector 3b, changes in the amount of light due to changes in the reflectance of the magneto-optical disk 1 appear in the same phase, and changes in the amount of light due to changes in the polarization plane of the magneto-optical disk 1 appear in opposite phases. The optical system inside the optical head 2 is configured as follows.

The signal processing port M12 is configured, for example, as shown in FIG. A host computer 19 is connected thereto.

Before explaining the operation of the first embodiment of the magneto-optical disk recording and reproducing apparatus of the present invention, a method for reproducing signals on the magneto-optical disk 1 will be explained with reference to FIG.

FIG. 2 is a schematic diagram showing the state in which signals are recorded on any one track of the magneto-optical disk 1 and the reproduced signals.

The prepit part PP contains address information such as tracks and sectors, servo data necessary for servo control,
Pre-pit information can be reproduced from changes in the intensity of reflected light from the magneto-optical disc 1 in areas where sync marks and the like are recorded as pits during the manufacture of the magneto-optical disc 1. This is an area where data can be recorded, reproduced, and erased. Recording is performed by reversing the magnetization direction on the magneto-optical disk 1, which is aligned in a certain direction in advance, according to a recording signal. Information on the magnetization direction is detected as a change in the polarization plane of the reflected light using magneto-optical effects such as the Kerr effect.Furthermore, optical components such as polarizing plates convert the information into changes in the amount of light, and a photodetector converts this change in the amount of light into an electrical signal. Convert it.

Therefore, the information due to the prepits appears only in the optical intensity signal 14 corresponding to the change in the optical intensity, and the magneto-optical signal 13 corresponding to the change in the polarization plane shows only a slight influence due to the disturbance of the polarization plane due to the prepits. Conversely, the recorded data appears only in the magneto-optical signal 13 corresponding to the change in the plane of polarization, and has only a slight effect on the optical intensity signal 14.

Next, the operation of the first embodiment of the magneto-optical disk recording/reproducing apparatus of the present invention will be explained with reference to FIG.

The laser light emitted from the semiconductor laser element 4 inside the optical head 2 is transmitted to the optical system (not shown), the focus servo system, and the tracking servo system (both not shown) that make up the optical head 2. As a result of the operation, the light is focused on the recording film of the magneto-optical disk 1, and after being modulated by the recording signal on the recording film, it enters the optical head 2 again and reaches the photodetector 3.

Signal currents proportional to the amount of light detected by the photodetectors 3a and 3b are sent to current-voltage conversion circuits 5a, respectively.

5b into a voltage, and is further converted into a voltage by amplifiers 6a, 6
Amplification is performed until a suitable signal level is reached at step b.

To detect the optical intensity signal, it is necessary to add the output signal of the photodetector 3a and the output signal of the photodetector 3b in order to remove the magneto-optical signal. Furthermore, in order to detect the magneto-optical signal, it is necessary to subtract the output signal of the photodetector 3a and the output signal of the photodetector 3b in order to remove the optical intensity signal. Therefore, in order to separate and detect the optical intensity signal and the magneto-optical signal, signal calculation is performed. However, before performing the above signal calculation, the amplitude and delay time between the signals are adjusted for the reasons described below. There is a need to.

That is, generally, since there is a protective layer made of transparent resin on the recording film of the magneto-optical disk 1, birefringence occurs, and therefore the detected signal is not recorded as bits or magnetization directions on the recording film. In addition to the information contained in the image, it is also affected by birefringence. The effect of birefringence appears as a fluctuation in the amplitude of the magneto-optical signal component, so when birefringence occurs,
A difference occurs in the magnitude of the magneto-optical signal component in the output signals of the photodetectors 3a and 3b. In addition, differences in signal amplitude, signal delay time, etc. occur due to differences in sensitivity between photodetectors 3a and 3b, differences in conversion resistance between current-voltage converters 5a and 5b, and differences in amplification degrees between amplifiers 6a and 6b. . Therefore, before performing arithmetic processing such as addition or subtraction, the signal amplitude,
It is necessary to adjust the delay time etc. so that unnecessary signals are almost completely removed as a result of the calculation.

Therefore, in this embodiment, the signal processing circuit 12,
The variable amplifier 7, which is paired with 11@6c, and the variable delay circuit 9a, which is paired with delay circuit 8, are used to control the signal amplitude and delay time, respectively, and thereby control the reproduction conditions. In this embodiment, the signal amplitude and delay time can be adjusted by controlling the relative amplitude difference and delay time difference between the output signals of the amplifiers 6a and 6b.
Only the output signal of the amplifier 116b is adjusted.

In addition, in this embodiment, the delay circuit 8 and the variable delay circuit 9
Although the output signal of the amplifiers 6a and 6b is input to the adder circuit 10, the influence of the signal amplitude difference and the delay time difference is small when adding them, so the configuration is such that the output signals of the amplifiers 6a and 6b are input to the adder circuit 10. You can also use it as

Note that the above control method will be explained in detail later.

The signal amplitude and delay time are adjusted.

The input signal is input to the adder circuit 10 and the differential amplifier circuit 11 and arithmetic is performed. As a result of the arithmetic operation, the output signal of the adder circuit 10 is the optical intensity signal 14, and the output signal of the differential amplifier circuit 11 is the magneto-optical signal 13. can get. The obtained optical intensity signal 14 and magneto-optical signal 13 are sent to the signal processing circuit 1 after adjusting the time difference between the two signals by variable delay circuits 9b and 9c, respectively.
2, and the information is reproduced and demodulated.

Next, data processing in the signal processing circuit 12 will be explained using FIG. 3.

FIG. 3 is a block diagram showing the configuration of the signal processing circuit 12 in the first embodiment.

The signal processing circuit 12 includes a recording system, a reproduction system, an error detection system,
Since it is composed of four clock recovery systems, the operation of each system will be explained.

First, the recording system will be explained.

The recording system includes a data interface 30, a data buffer 31, a data selector 32, an FCC (error correction code) encoder 33, and a modulation circuit 34. Data input from the host computer interface 19 is processed by the data interface 30 and then temporarily stored in the data buffer 31.

The data selector 32 selects and outputs either the output data of the data buffer 31 or the internal data of the test data memory 40.

The FCC encoder 33 performs processing necessary for error correction on the data output from the data selector 32.
The modulation circuit 34 performs processing on the output data of the FCC encoder 33 according to a modulation rule to generate recording data. The laser drive circuit 20 drives the semiconductor laser element 4 according to this recording data to record a signal.

Next, the reproduction system will be explained.

The reproduction system includes a binarization circuit 42. Demodulation circuit 35, ECC decoder 36. Data buffer 37. It is separated from the data interface 30 which is shared with the recording system.

The magneto-optical signal input 3 is input from the delay circuit 9b.

After being converted into a digital signal corresponding to the input signal by the binarization circuit 42, it is applied to the demodulation circuit 35. The demodulation circuit 35 decodes the signal by performing processing according to the decoding rules, and outputs data.

The ECC decoder 36 performs error correction on the data output from the demodulation circuit 35. The data buffer 37 temporarily stores the error-corrected data by the ECC decoder 36 until it is taken into the data interface 30. After the data interface 30 processes the data stored in the data buffer 37, , to the host computer interface 19.

Next, the error detection system will be explained.

The error detection system is separated from the test data memory 40, the mismatch detection circuit 38, and the error information memory 39.

Error detection is performed by detecting the number of discrepancies between the test data stored in the test data memory 40 and the reproduced signal corresponding to the test data.
against the test data.

Since recording is performed after FCC encoding and modulation processing, the reproduced signal to detect discrepancies is also demodulated and
A signal after FCC decoding is used. The discrepancy detection circuit 38 detects the number of discrepancies between two input signals, and specifically, processing by hardware combining an exclusive OR circuit, a counter, etc., or
This can be done by software processing, etc., and can be realized using known techniques, so the explanation will be omitted here.

The error information memory 39 stores the number of errors detected by the mismatch detection circuit 38 and the reproduction conditions at that time.

Next, the clock recovery system will be explained.

Clock regeneration is a reference clock signal that serves as a reference for the operation of the entire system, such as a conversion timing signal for converting a magneto-optical signal into a digital signal in a binarization circuit, and a synchronization clock that serves as a reference for synchronization during data modulation and demodulation. It is for playing. In this embodiment, since this reference clock signal is recorded in advance on the magneto-optical disk 1 as a clock pit, a signal corresponding to the reference clock is detected from the optical intensity signal, and based on this, the reference clock signal is occurs. Note that the technology of detecting a pre-recorded clock signal and generating a reference clock that serves as a reference for system operation has existed for a long time and is not directly related to the present invention, so it will not be explained here. Omitted.

The control logic 41 controls each circuit inside the signal processing circuit and interfaces with the control microcomputer 18.

Next, the overall operation of the signal processing circuit 12 will be explained based on the above explanation.

The clock regeneration system is based on the clock pit signal.

A reference clock signal that serves as a reference for system operation is constantly generated, and the signal processing circuit 12 synchronizes with this signal.
Perform various processing. The selector 32 is controlled by a control logic 41 based on instructions from the control microcomputer 18.
During normal data recording, the selector 32 is switched to the data buffer 31 side and the processing described in the above recording system operation is performed, and when test data is recorded, the selector 32 is switched to the test data memory 40 side. For data from test data memory 40.

Process. The contents of the error information memory 39 indicate the number of errors that could not be corrected by error correction and were output from the data buffer 37 as they were after the test data was recorded and reproduced. Therefore, the control microcomputer 18
The error rate of the test data can be known through the signal processing circuit 12.

Next, the reason why the time difference between signals is adjusted by the variable delay circuits 9b and 9c will be explained.

Signal recording formats on general optical discs include:
There are various things. For example, the so-called sampled servo method embeds a reference clock, which serves as a reference for the time required to reproduce a recorded data signal, in a prepit signal, and reproduces this reference clock from the reproduced prepit signal. Based on this regenerated reference clock,
Determine the timing to strobe the recording data signal.

Therefore, the relative time difference between the pre-pit signal and the recording data signal results in a strobe timing difference and is also related to the error rate of the signal. Therefore, it is necessary to accurately match the timing of both signals.

In a sampled servo type magneto-optical disk device, the pre-pit signal is generally created together with address information and the like when manufacturing the magneto-optical disk, and is obtained from the optical intensity signal 14. Further, the recording data signal is obtained from the magneto-optical signal 13 because the user records information on the magnetization direction.

As mentioned above, the optical intensity signal and the magneto-optical signal use different circuit systems to detect the signals, so a relative time difference tends to occur between the two signals. In order to reduce the signal processing circuit 12. Controlling the signal delay time using variable delay circuits 9b and 9c;
Note that the above control method will be explained in detail later.

Next, a variable amplifier 7 and variable delay circuits 9a and 9b.

9c will be explained.

The variable amplifier 7 is an amplifier whose amplification degree or attenuation degree can be changed by a gain control signal 15.
For example, voltage controlled amplifiers, multipliers.

Since it can be constructed using a known technique such as an attenuator whose taps can be switched electrically, a description thereof will be omitted here. The variable delay circuit 9 is.

This is a delay circuit whose signal delay time can be changed by a delay time control signal, and can be configured by a known technique such as a delay line that can be electrically switched up or down, so its explanation will be omitted here. . It should be noted that there is no essential difference in whether the variable amplifier 7° variable delay circuit 9 processes the signal as an analog signal or after converting the signal into a digital signal using an analog/digital converter. That is clear. In short, it is possible to perform necessary processing such as amplitude control, time axis control, etc. on data corresponding to input signals.

The configuration of the 5 circuits, etc. does not matter.

Next, the signal processing circuit 12 generates a gain control signal 15,
delay time control signal lea, 16b;

Variable amplifier 7 and variable delay circuit 9a using 16c.

A method of controlling 9b and 9c will be explained with reference to FIG.

FIG. 4 is a diagram showing a processing flowchart of the signal processing circuit 12 in the first embodiment. The purpose of this processing is to increase the gain of the variable amplifier circuit 7 so that the error rate during test data reproduction is approximately the lowest. , to set reproduction conditions such as delay times of the variable delay circuits 9a to 9C.

Hereinafter, the operation of the signal processing circuit 12 will be explained according to this processing flowchart. In addition, each step is shown using the code|symbol 81-S7 in FIG.

The flowchart consists of an optimal operating condition derivation routine (a) and a condition determination for activating the routine (b).

After overtime of the magneto-optical disk recording and reproducing device, the signal processing circuit 12 starts the optimum operating condition deriving routine (a) according to a command from the control microcomputer 18, and places the signal on the magneto-optical disk l at the position indicated by the control microcomputer 18 in advance. First, test data is recorded in a ROM (read-only memory) or the like (step 1).Next, the recorded test data is played back (step 2).The played test data is used as the stored test data. It is compared with the data, and if the result of the comparison is different, this is determined to be an error, and the number of errors and the reproduction conditions at that time are stored (step 3).

Next, it is determined whether the number of errors has been measured under all combinations of playback conditions (Step 4), and if the measurement has not been completed, the settings are changed to the next playback condition (Step 4').
After that, the number of errors is measured again, and when the number of errors has been measured for all combinations of playback conditions, the process proceeds to derivation of the optimum playback conditions (step 5). After deriving the optimal playback conditions, it is determined whether the above processing has been performed in all areas (step 6). If yes, proceed to the next step; if no, the position is changed (step 6'), and then step 1 Return to

Next, determine whether it is necessary to set the optimal playback conditions again (Step 7, b). If necessary, return to Step 1 and repeat the above process to ensure that the error rate is always low. Information can be reproduced. Conditions that require resetting the optimal playback conditions include, for example, when the error rate of the reproduced signal exceeds a predetermined value, or when the device warms up within a certain amount of time after the device is powered on. For example, when the device is in a standby state for a certain period of time or more, when the magneto-optical disk 1 is replaced, etc.

Next, the process for deriving optimal reproduction conditions (step 5) will be explained using FIG. 5.

FIG. 5 shows a processing flowchart for deriving optimal reproduction conditions in the first embodiment.

The purpose of this process is to perform playback so that the error rate during test data playback is approximately the lowest based on the combination of the measured number of errors and the playback conditions such as the gain of the variable amplifier circuit and the delay time of the variable delay circuit. The purpose is to derive combinations of conditions.

Hereinafter, a method for deriving optimal reproduction conditions will be explained according to this flowchart. In addition, each step is shown using the code|symbol 81-S3 in FIG.

First, the optimum differential signal amplification gain (gain) is determined to optimize the amplitude ratio between signals before performing differential amplification to obtain a magneto-optical signal (hereinafter also referred to as MO multiplied signal).
Next, determine the optimal MO/Prepit signal interval to optimize the delay time between the optical intensity signal (hereinafter also referred to as the Prepit signal) and the MO multiplied signal (Step 1). Delay time (d e 1 a
(referred to as y1) (step 2).Finally, the optimum differential signal amount delay time is determined to optimize the delay time between signals before performing differential amplification to obtain the MO multiplied signal. (referred to as delay2) is determined (step 3).

By performing the above processing, optimal reproduction conditions are derived.

Next, we will discuss the process for deriving the optimal reproduction conditions in steps 1 to 3 in FIG.

This will be explained in more detail using FIG. 6.

FIG. 6 is a part of a processing flowchart for deriving optimal reproduction conditions in the first embodiment.

In addition, in FIG. 6, each step is shown using the code|symbol 81-S2.

The processing of steps 1 to 3 in FIG. 5 is performed based on the respective playback conditions (gain, delay, etc.).

2 shows a process for determining delay2). In Fig. 6, each process first calculates the evaluation function value (corresponding to the number of errors) for each condition to evaluate the number of errors.Step 1)9 Next, the reproduction conditions that minimize the evaluation function value Step 1 in Figure 5
- Determine parameters for each process in step 3 (step 2); calculation of the evaluation function value and derivation of the condition for minimizing the evaluation function value can be performed by a known method; Since it is not directly related to this, the explanation will be omitted.

Next, in the first embodiment of the present invention, the signal processing circuit 12
The signal recording position on the magneto-optical disk 1 for recording test data will now be explained with reference to FIG.

FIG. 7 is a schematic diagram of the data format of one track of a sampled servo type optical disc according to the ISO standard.

Virtual tracks arranged in a spiral on an optical disc are
Each sector is divided into 32 sectors, and each sector is further divided into 43 segments. Each segment consists of 18 bytes. The first 2 bytes are servo bytes in which information necessary for servo control is recorded, and the remaining 16 bytes are
This is a logical sector information area.

The servo byte area is #1. Consists of #2. In this area, since the data modulation method of this embodiment employs the 4-15 modulation method, one byte corresponds to 15 channel pits on the virtual track. 7th
Numbers 1 to 15 attached to the virtual pits shown in the figure indicate channel pits.

In addition, this servo bite area includes two pits that wobble between the virtual track at the 3rd channel pit (or 4th channel pit) and the 8th channel pit in #1, and on the virtual track at the 12th channel pit in #2. There are 3 pits, 1 pit and 1 pit.

The logical sector information area is a user data area except for the #0 segment, and the #0 upper segment logical sector information area is called a sector header and contains a sync mark, sector address, track address, spare area, and laser power control field. recorded. A specific signal modulated using the 4-15 modulation method is recorded in the sync mark, and address information corresponding to the position where playback is being performed is recorded in the sector address and track address. Because it is a reserved area, signals cannot be written in either field.Unlike other areas, it is an area that is allowed to emit light with any laser power, and the drive can record signals on its own. It is also possible to do so.

The present invention (1) Area where information is never recorded.

It reproduces a specific test signal recorded in one or more of the following: (2) an area where no information is recorded; and (3) a specific area.

Specifically, for example, one or more areas such as (1) an area of the servo byte where wobbling pits are not recorded, (2) a laser power control field, and (3) a data area for the user, etc. It can be used as a test signal recording area.

Note that in the explanation of the test signal recording position in this embodiment, the sampled servo according to the ISO standard was explained, but the explanation is not limited to this. The configuration, arrangement, etc. do not matter as long as the area can be independently recorded by the drive without any adverse effects.

Next, a test signal recorded on the magneto-optical disk 1 for deriving optimal reproduction conditions in the first embodiment of the present invention will be described.

The test signal conditions are as follows: (1) Changes in the error rate due to differences in the characteristics of the magneto-optical disk and drive should clearly appear, and (2) The error rate of the test signal and the error rate of the user's recorded data should clearly appear. (3) No need to make major changes to conventional equipment.

Ability to record.

(4) The optimum reproduction conditions can be clearly understood.

An example of a signal that satisfies the above conditions is 1, for example.

Random data, data consisting of a combination of shortest pulses,
Among the data actually recorded, there are combinations of data that have a small margin for discrimination. Random data has the characteristic that the measured error rate is approximately equal to the error rate of information recorded by the user, so that the actual error rate can be known.

Also, the data consisting of the combination of the shortest pulses.

It is characterized in that when determining playback conditions, changes in error rate due to differences in one-time axis resolution, that is, delay time, are noticeable.

In addition, data consisting of a combination of data with a small discrimination margin has a characteristic that the optimum conditions can be accurately known because changes in error rate due to differences in characteristics are noticeable.

Next, a second embodiment of the present invention will be described.

The second embodiment of the present invention is completely the same as the magneto-optical disk recording/reproducing apparatus of the first embodiment except for the block configuration. I will only explain about.

FIG. 8 is a block diagram showing the configuration of a magneto-optical disk recording/reproducing apparatus according to a second embodiment of the present invention.

In the first embodiment, the optical intensity signal and the magneto-optical signal were mixed in the output signals of the photodetectors 3a and 3b, and could not be obtained without calculating both output signals.
The second embodiment is different in that the optical head 2 is provided with a photodetector 3c for detecting only the optical intensity signal, so the optical intensity signal can be obtained without calculation by an adding circuit. ing.

In this example, since the number of photodetectors increases by one,
This has the disadvantage that the optical system becomes complicated, but on the other hand, it has the advantage that the optical intensity signal system and the magneto-optical signal system can be completely separated. Therefore, in configuring the circuit, it is only necessary to add a circuit for obtaining a magneto-optical signal to the circuit of the write-once optical disc reproducing device, and the manufacturing and design are easy.

Next, a third embodiment of the present invention will be described.

The third embodiment of the present invention is different from the magneto-optical disk recording/reproducing apparatus of the first embodiment in the configuration of the error detection system of the signal processing circuit 12. Since they are completely the same, including their configurations, explanations of the same parts will be omitted and only the different parts will be explained.

FIG. 9 is a block diagram showing the configuration of a signal processing circuit 12 of a magneto-optical disk recording and reproducing apparatus according to a third embodiment of the present invention.

In this embodiment, the selector 32 for switching the recorded data to the test signal from the test data memory 40 for detecting errors is arranged in front of the ECC encoder 33, as in the first embodiment.

On the other hand, error detection from the reproduced signal uses error syndrome information obtained when error correction is performed by an ECC decoder, rather than using the method of detecting data mismatch as in the first embodiment.

Therefore, in this embodiment, the error information memory is
Since error information can be obtained directly from the decoder, a circuit for detecting data mismatch is not required, and the configuration is simpler than that of the first embodiment.

Next, a fourth embodiment of the present invention will be described.

The fourth embodiment of the present invention has a recording system, a reproduction system, and a clock reproduction system, except that the structure of the error detection system of the magneto-optical disk recording and reproducing device of the first embodiment and the signal processing circuit engineer 2 is different. Since they are completely the same, including their configurations, explanations of the same parts will be omitted and only the different parts will be explained.

FIG. 10 is a block diagram showing the configuration of a signal processing circuit 12 of a magneto-optical disk recording/reproducing apparatus according to a fourth embodiment of the present invention.

In this embodiment, the selector 32 for switching the recorded data to the test signal from the test data memory 40 for error detection is located at the first . E as in the second embodiment
It is placed not in front of the CC encoder 33 but in front of the modulation circuit 34. Further, error detection from the reproduced signal uses the method of detecting a mismatch between the recorded signal and the reproduced signal, which was used in the first embodiment. Therefore, the mismatch detection circuit 38
The output signal of the demodulation circuit 35 is also used for the reproduced data inputted to the demodulation circuit 35 so as to correspond to the recorded data.

In this embodiment, unlike the first embodiment, error correction by the ECC decoder is not performed, so the original error rate of the signal recording and reproducing system can be known, and the error rate after error correction becomes O. Even for a magneto-optical disk with a low error rate, it is possible to easily obtain optimal playback conditions.

Next, a fifth embodiment of the present invention will be described.

The fifth embodiment of the present invention is a recording system except that the structure of the error detection system of the signal processing circuit 12 is different from that of the magneto-optical disk recording/reproducing apparatus of the first embodiment.

Since they are completely the same, including the configurations of the reproduction system and clock reproduction system, explanations of the same parts will be omitted and only the different parts will be explained.

FIG. 11 is a block diagram showing the configuration of a signal processing circuit 12 of a magneto-optical disk recording/reproducing apparatus according to a fifth embodiment of the present invention.

In this embodiment, the position of the selector 32 that switches the recorded data to the test signal from the test data memory 4o for error detection is not in front of the FCC encoder 33 as in the first and second embodiments. , in front of the modulation port Hr34 as in the fourth embodiment. On the other hand, errors in the reproduced signal are detected not by the method of detecting discrepancies as in the first embodiment, but by counting the number of pieces of data that do not follow the decoding rules when demodulating in the demodulation circuit 35. Use.

Therefore, in this embodiment, since the error information memory can obtain error information directly from the demodulation circuit 35, a circuit for detecting data mismatch is not required, and the first
This embodiment has a feature that the configuration is simpler than that of the embodiment.

Next, a sixth embodiment of the present invention will be described.

The sixth embodiment of the present invention is different from the magneto-optical disk recording/reproducing apparatus of the first embodiment in the configuration of the error detection system of the signal processing circuit 12. Since they are completely the same, including their configurations, explanations of the same parts will be omitted and only the different parts will be explained.

FIG. 12 is a block diagram showing the configuration of a signal processing circuit 12 of a magneto-optical disk recording/reproducing apparatus according to a sixth embodiment of the present invention.

In this embodiment, the position of the selector for switching the recorded data to the test signal from the test data memory 40 for error detection is 1. It is placed after the modulation circuit 34 instead of before the FCC encoder 33 and the modulation circuit 34 as in the second and third embodiments. Further, error detection from the reproduced signal uses the method of detecting a mismatch between the recorded signal and the reproduced signal, which was used in the first embodiment. Therefore,
The reproduced data input to the mismatch detection circuit 38 uses the output data of the binarization circuit 42 so as to correspond to the recorded data.

In this embodiment, as compared with the first embodiment, error correction by the FCC decoder is not performed, so the original error rate of the signal recording and reproducing system can be known, and the error rate after error correction becomes O. This makes it easy to obtain optimal playback conditions even for discs with low error rates. Furthermore, since the correspondence between the data recording position on the magneto-optical disk 1 and the data can be easily seen, the correspondence with the position of a defect on the magneto-optical disk 1 can be easily determined.

Note that the third to sixth embodiments described above are not exclusive to the second embodiment, and it is obvious that they can be implemented in the information recording/reproducing apparatus having the configuration shown in the second embodiment.

Next, a seventh embodiment of the present invention will be described.

Since the seventh embodiment of the present invention is a magneto-optical disk reproducing device, it is different from the magneto-optical disk recording and reproducing device of the first embodiment in that the recording system of the signal processing circuit 2 is omitted, and the error The difference is that the configuration of the detection system has changed. However, in other respects, including the configurations of the reproducing system and clock reproducing system, they are completely the same, so a description of the same parts will be omitted and only the different parts will be described.

FIG. 13 shows the magneto-optical day V reproducing device 0 signal processing circuit lI! of the seventh embodiment of the present invention. 12 is a block diagram showing the configuration of No. 12. FIG.

In this embodiment, the data itself requested by the host computer is used as a signal for error detection, and the error information is error syndrome information obtained when error correction is performed on this data by an FCC decoder. use Therefore.

This embodiment does not need to record information, and can be implemented in an information reproducing apparatus that only reproduces information without recording it.

Next, an eighth embodiment of the present invention will be described.

The eighth embodiment of the present invention differs from the magneto-optical disk reproducing apparatus of the seventh embodiment in the configuration of the error detection system of the signal processing circuit 12, including the configurations of the reproduction system and clock reproduction system. Since they are exactly the same, a description of the same parts will be omitted and only the different parts will be explained.

FIG. 14 is a block diagram showing the configuration of the signal processing mill f112 of the magneto-optical disk reproducing apparatus according to the eighth embodiment of the present invention.

In this embodiment, as a signal for error detection,
As in the seventh embodiment, the data itself requested by the host computer is used, and the error information is generated by counting the number of pieces of data that do not follow the decoding rules when the data is demodulated by the demodulation circuit 35. use

Therefore, in this embodiment, as in the seventh embodiment, there is no need to record information, so it can be implemented even in an information reproducing apparatus that does not record information but only reproduces it. Since it is closer to the raw data from the magneto-optical disk, errors can be detected more accurately.

Note that the seventh and eighth embodiments described above can be implemented with any device that can reproduce information, so it is obvious that they can be implemented not only with information reproducing devices but also with information recording and reproducing devices.
Also, 3rd. The present invention can also be implemented in the information recording/reproducing apparatus having the configuration shown in the fifth embodiment.

〔Effect of the invention〕

As explained above, in the magneto-optical disk recording and reproducing apparatus and the magneto-optical disk reproducing apparatus of the present invention, when an error occurs when reproducing a recorded signal, a retry is performed while changing the characteristics of the reproducing circuit. A magneto-optical disk recording device that eliminates variations in the characteristics of the recording medium and records information by determining the optimal reproduction conditions that minimize errors and sending the information reproduced under the optimal reproduction conditions to the host device. variations and magneto-optical disk playback devices,
To prevent increases in error rates due to changes in characteristics of magneto-optical disk recording and reproducing devices, improve compatibility with recording media and magneto-optical disk recording devices, and prevent deterioration in information reliability due to aging, etc. I can do it. Note that it is possible to reduce the number of adjustment items during manufacturing.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a magneto-optical disk recording and reproducing apparatus according to a first embodiment of the present invention, FIG. 2 is a schematic diagram for explaining the recording state of signals and reproduction signals on the magneto-optical disk, FIG. 3 is a block diagram showing the configuration of the signal processing circuit in the first embodiment of the present invention, FIG. 4 is a flowchart showing the processing performed by the signal processing circuit in the first embodiment of the invention, and FIG. A flowchart showing a process for deriving optimal playback conditions in the first embodiment of the present invention, FIG. 6 is a flowchart showing a part of the process for deriving optimal playback conditions in the first embodiment of the present invention,
FIG. 7 is a schematic diagram for explaining the data format of a sampled servo type optical disk according to the ISO standard, and FIG. 8 is a block diagram showing the configuration of a magneto-optical disk recording and reproducing apparatus according to a second embodiment of the present invention. FIG. 9 is a block diagram showing the configuration of a signal processing circuit of a magneto-optical disk recording and reproducing apparatus according to a third embodiment of the present invention, and FIG. 10 is a block diagram showing a configuration of a magneto-optical disk recording and reproducing apparatus according to a fourth embodiment of the present invention. FIG. 11 is a block diagram showing the configuration of a signal processing circuit of a magneto-optical disk recording/reproducing apparatus according to a fifth embodiment of the present invention, and FIG. FIG. 13 is a block diagram showing the configuration of a signal processing circuit of a magneto-optical disk recording and reproducing apparatus according to a seventh embodiment of the present invention; FIG. FIG. 14 is a block diagram showing the configuration of a signal processing circuit of a magneto-optical disk reproducing apparatus according to an eighth embodiment of the present invention. 1... magneto-optical disk, 2... optical head, 3...
Photodetector, 4... Semiconductor laser element, 5... Current-voltage conversion circuit, 6... Amplifier, 7... Variable amplifier, 8
...Delay circuit, 9...Variable delay circuit, 10...Addition circuit, 11...Differential amplifier circuit, 12...Signal processing circuit, 17...Virtual track, 18...Control Microcomputer, 19...Host computer interface, 2
0... Laser fighting circuit, 30... Data interface, 31... Data buffer, 32... Selector, 33... FCC encoder, 34... Modulation circuit,
35... Demodulation circuit, 36... FCC decoder, 37
...data buffer, 38...mismatch detection circuit, 3
9...Error information memory, 4°...Test data memory, 41...Control logic, 42...Binarization circuit. Ka 2 Zueizu 10 Danfu 5 Eidai Zuka 7 Zuka 6 Illustrated Zu No. 0 Side 1% V approval g wH Kozudake S 1st! Enkaikyo signal f3

Claims (1)

[Scope of Claims] 1. In a magneto-optical disk reproducing device for reproducing information from a magneto-optical disk, information reproducing means for reproducing information recorded on the magneto-optical disk, and information reproduced by the information reproducing means; 1. A magneto-optical disk reproducing apparatus comprising: an error detecting means for detecting the degree of occurrence of an error; and a reproducing characteristic controlling means for controlling the information reproducing means from error information output from the error detecting means. 2. In a magneto-optical disk recording and reproducing device for recording and reproducing information on a magneto-optical disk having a test information recording area for determining the extent of error occurrence, an information recording means for recording information on the magneto-optical disk; information reproducing means for reproducing information recorded on a magnetic disk; error detecting means for detecting the degree of occurrence of an error from the information reproduced by the information reproducing means; and detecting the information from error information output from the error detecting means. 1. A magneto-optical disk recording and reproducing apparatus, comprising a reproduction characteristic control means for controlling a reproduction means. 3. The information reproducing means includes a magneto-optical signal detecting means for detecting a magneto-optical signal recorded on the magneto-optical disk corresponding to the magnetization direction of the signal recording film, and a magneto-optical signal detecting means corresponding to the reflectance of the signal recording film. and a signal delay time control means for controlling the relative time relationship between the magneto-optical signal and the optical intensity signal, 3. The magneto-optical disk reproducing apparatus according to claim 1, or the magneto-optical disk recording and reproducing apparatus according to claim 2, wherein said signal delay time control means is controlled by said reproduction characteristic control means. 4. The magneto-optical signal detection means detects the difference between two different signals corresponding to the magnetization direction of the signal recording film to obtain a magneto-optical signal, and the magneto-optical signal is input to the differential amplification means. signal delay time control means for controlling the relative time relationship between the two signals input to the differential amplification means; and signal amplitude control means for controlling the amplitude ratio between the two signals input to the differential amplification means. The magneto-optical disk reproducing apparatus according to claim 1, wherein the signal delay time control means and the signal amplitude control means are controlled by the reproduction characteristic control means. magneto-optical disk recording and reproducing device. 5. In the error detection means, the information for detecting the degree of error occurrence is information reproduced from a specific area of a magneto-optical disk specified by a host device. Magneto-optical disk playback device. 6. The information for detecting the degree of error occurrence in the error detection means may be information reproduced from a specific area of the magneto-optical disk specified by the host device, or information recorded in advance by the magneto-optical disk recording/reproducing device as test information. 3. The magneto-optical disk recording and reproducing apparatus according to claim 2, wherein the information is recorded in a region. 7. The magneto-optical disk reproducing apparatus according to claim 1, or claim 2, wherein the error detection means detects error information based on the degree of occurrence of information that does not comply with decoding rules when reproducing information. The magneto-optical disk recording and reproducing device described above. 8. The magneto-optical disk reproducing apparatus according to claim 1, or the magneto-optical disk reproducing apparatus according to claim 2, wherein the error detection means detects error information using an error syndrome generated from an error correction detection code included in the reproduction information. Magneto-optical disk recording and reproducing device. 9. The optical system according to claim 2, wherein the error detection means compares the information recorded in the test information recording area and the information reproduced from the test information recording area on a one-to-one basis to detect a mismatched portion. Magnetic disk recording and reproducing device. 10. Claim 1, wherein the reproduction characteristic control means controls the information reproduction means when the error information is greater than or equal to a predetermined value.
The magneto-optical disk reproducing apparatus according to claim 1, or the magneto-optical disk recording and reproducing apparatus according to claim 2. 11. The magneto-optical disk reproducing device according to claim 1, or the magneto-optical disk recording device according to claim 2, wherein the reproduction characteristic control means repeatedly controls the information reproduction means until the error information becomes equal to or less than a predetermined value. playback device. 12. The magneto-optical disk recording and reproducing apparatus according to claim 2, wherein the test information recording area is an area in which no user information is recorded. 13. The magneto-optical disk recording and reproducing apparatus according to claim 2, wherein the test information recording area is an area in which no information is recorded. 14. The magneto-optical disk recording and reproducing apparatus according to claim 2, wherein the test information recording area is a predetermined specific position. 15. The magneto-optical disk recording and reproducing apparatus according to claim 2, wherein the test information is a combination of pulse signals having a width that is an integral multiple of a signal with the shortest pulse width among the pulse signals used when recording information. 16. The magneto-optical disk recording and reproducing apparatus according to claim 2, wherein the information recording means is capable of recording recorded data on the magneto-optical disk as information corresponding to the magnetization direction of the signal recording film.