JP2000187861A - Reproducer of optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To judge abnormality of a reproducer with a simple constitution. SOLUTION: When a reproducing operation is started, a tracking servo is on/off controlled (100) and tracking error signals are taken in (101). If the amplitudes of the signals are prescribed value or below A while the tracking servo is turned on, it is judged that the system is normal (106). If the amplitudes exceed the value A, it is discriminated that the system is abnormal (108). If the amplitudes of the signals exceed the value A while the tracking servo is turned off, it is judged that the system is normal (112). If the amplitudes are the value A or below, it is discriminated that the system is abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus for an optical information recording medium, and more particularly to a reproduction-only optical information recording medium such as a CD-ROM and a DVD-ROM, and a CD-R and a CD-ROM.
The present invention relates to an optical information recording medium reproducing apparatus for reproducing information recorded on a recordable optical information recording medium such as RW, DVD-R, and DVD-RAM.

[0002]

2. Description of the Related Art
Recordable optical information recording media (recordable recording media) such as R, CD-RW, DVD-R, and DVD-RAM include:
A meandering wobble groove is formed to keep the linear velocity of the disc constant during recording and reproduction. When reproducing information recorded on such a recordable recording medium, tracking is performed using a wobble groove.
A meandering signal corresponding to the wobble groove is superimposed on the tracking error signal, and the amplitude of the tracking error signal increases as shown in FIG. Note that FIG.
FIG. 4B shows a tracking error signal in a tracking servo-on state during reproduction of a CD-R as a recordable recording medium, and FIG. 4B shows a tracking error signal in a tracking servo off state during reproduction of a CD-R. Also,
FIG. 5A shows a tracking error signal in a tracking servo ON state before recording on a CD-R, and FIG.
-R is a tracking error signal in a tracking servo off state before recording.

On the other hand, since a wobble groove is not formed in a CD-ROM which is a read-only optical information recording medium (read-only recording medium), a meandering signal is not superimposed on a tracking error signal. As shown in FIG. 6A, the amplitude of the tracking error signal in the tracking servo ON state is smaller than the tracking error signal of FIG. FIG. 6B shows a tracking error signal in a tracking servo off state.

Therefore, in a reproducing apparatus that reproduces both a recordable recording medium and a read-only recording medium, it is determined whether or not a meandering signal is superimposed on a tracking error signal, that is, by determining the amplitude of the tracking error signal. It is possible to determine whether the medium to be reproduced is a recordable recording medium or a reproduction-only recording medium.

[0005] However, despite being a recordable medium, a signal with a small amplitude, such as a read-only medium, is
When input to the circuit for determining the type of the optical information recording medium, the type of the medium cannot be determined. Also,
When only one of the tracking error signals is output due to an abnormality of the reproducing apparatus or the like, there is a problem that the type of the optical information recording medium cannot be determined.

The present invention has been made in order to solve the above problems, and provides an optical information recording medium reproducing apparatus having a function of determining whether or not a tracking error signal has become abnormal. The purpose is to:

[0007]

According to a first aspect of the present invention, there is provided an optical information recording medium reproducing apparatus comprising: an on / off means for turning on / off a tracking servo; A determination unit configured to determine whether at least one of the frequencies changes and determine whether or not the reproducing apparatus of the optical information recording medium is abnormal.

If the reproducing apparatus is normal, the amplitude and frequency of the tracking error signal change by turning on and off the tracking servo. Therefore, the amplitude, frequency, or the amplitude and frequency of the tracking error signal change according to the tracking servo on / off. By determining whether or not the tracking error signal has changed, it can be determined whether or not the tracking error signal has become abnormal, that is, whether or not the reproducing apparatus has become abnormal.

Further, the invention according to claim 2 is an on / off means for turning on / off a tracking servo, a speed changing means for changing the rotation speed of the optical information recording medium, and controlling the speed changing means in a tracking servo off state to control the optical information. The rotation speed of the recording medium is changed, and it is determined whether the frequency of at least one of the tracking error signal and the reproduction RF signal changes according to the change in the rotation speed, and whether the reproduction apparatus of the optical information recording medium is abnormal or not. And a judgment means for judging.

The zero-cross point of the tracking error signal in the tracking servo off state corresponds to the time when the optical pickup crosses the groove or the land. Therefore, when the rotation speed of the optical information recording medium is changed when the reproducing apparatus is normal, the frequency of the tracking error signal changes according to the change in the rotation speed. Therefore, by determining whether or not the frequency of the tracking error signal has changed in accordance with the change in the rotation speed, it can be determined whether or not the reproducing apparatus has become abnormal. Further, since the frequency of the reproduced RF signal is different between the case where the reproducing apparatus is normal and the case where the reproducing apparatus is abnormal, it is determined whether or not the frequency of the reproduced RF signal has changed according to the change in the rotation speed. It can be determined whether or not the device has become abnormal. Note that it may be determined whether or not the frequencies of the tracking error signal and the reproduction RF signal change.

According to a third aspect of the present invention, there is provided an on / off means for turning on / off a tracking servo, and determining whether or not a wobble detection signal is superimposed on a tracking error signal or a reproduced RF signal in a tracking servo off state. Determining means for determining whether or not the playback device is abnormal.

In the case of an optical information recording medium in which a wobble groove is formed, a wobble detection signal is superimposed on a tracking error signal and a reproduced RF signal in a tracking servo off state. On the other hand, in the case of an optical information recording medium in which no wobble groove is formed, the wobble detection signal is not superimposed on the tracking error signal and the reproduced RF signal in the tracking servo off state. Therefore, by determining whether or not the wobble detection signal is superimposed on the tracking error signal or the reproduced RF signal, it is determined whether or not the optical information recording medium inserted in the reproducing apparatus is the optical information recording medium to be reproduced. However, it is possible to detect an abnormality when the optical information recording medium inserted into the reproducing apparatus is different from the optical information recording medium to be reproduced.

According to a fourth aspect of the present invention, an on / off means for turning on / off a tracking servo, and determining whether or not the amplitude of a tracking error signal is greater than or equal to a predetermined value when the tracking servo is off, causes an abnormality in the optical information recording medium reproducing apparatus. And determination means for determining whether or not this is the case.

If the reproducing apparatus is normal, the amplitude of the tracking error signal becomes larger than a predetermined value in the tracking servo off state. Therefore, it is determined whether or not the amplitude of the tracking error signal becomes larger than the predetermined value in the tracking servo off state. This makes it possible to determine whether or not the playback device has become abnormal.

According to the first to fourth aspects of the present invention, when the reproducing apparatus becomes abnormal, it is possible to perform the processing at the time of abnormality such that the reproduction is stopped or an alarm is issued.

Further, the invention of claim 2 and the invention of claim 3 are combined to turn on / off the tracking servo, and whether the wobble detection signal is superimposed on the tracking error signal or the reproduced RF signal in the tracking servo off state. First determining means for determining whether the optical information recording medium is rotating, changing the rotational speed of the optical information recording medium, and controlling the speed changing means in a tracking servo off state to change the rotational speed of the optical information recording medium. Second determining means for determining whether the frequency of at least one of the tracking error signal and the reproduced RF signal changes according to the change in the speed, and determining whether or not the reproducing apparatus of the optical information recording medium is abnormal; A reproducing means for reproducing based on the judgment result of the first judging means and the judgment result of the second judging means may be included. In the reproducing means, the first judging means judges that the wobble detection signal is not superimposed, and
When the playback device determines that the playback device is normal, playback can be performed.

Further, the invention of claim 3 and the invention of claim 4 are combined to turn on / off the tracking servo, and whether the wobble detection signal is superimposed on the tracking error signal or the reproduced RF signal in the tracking servo off state. Determining means for determining whether the amplitude of the tracking error signal is greater than or equal to a predetermined value in a tracking servo off state, and determining whether or not the reproducing apparatus of the optical information recording medium is abnormal. And the first
And reproducing means for reproducing based on the judgment result of the judgment means and the judgment result of the second judgment means. In the reproducing means, the reproduction can be performed when the first judging means judges that the wobble detection signal is not superimposed and the second judging means judges that the reproducing apparatus is normal. .

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention in which the present invention is applied to a reproducing apparatus for reproducing M and CD-R will be described in detail.

As shown in FIG. 1, an optical pickup 12 composed of a semiconductor laser and a plurality of photodetectors is arranged on the back side of a disk 10 as an optical information recording medium. The output signal of the photodetector of the optical pickup 12 is input to an RF amplifier unit 14 including a focus error signal generation circuit and a tracking error signal generation circuit.

The focus error signal generated by the RF amplifier section 14 is input to a servo control circuit 16. The tracking error signal output from the tracking error signal generation circuit is input to the servo control circuit 16 and an abnormality determination circuit 20 including an A / D converter for converting an analog signal into a digital signal and a microcomputer. Is input to In the abnormality determination circuit 20,
The tracking error signal is converted into a digital signal by an A / D converter and input to a microcomputer to determine abnormality.

The servo control circuit 16 performs tracking servo and focus servo of the optical pickup 12 according to the input tracking error signal and focus error signal. The servo control circuit 16 controls a feed motor 22 for moving the optical pickup 12 to a predetermined position and a spindle motor 2 for rotating the disk 10.
4 is also controlled. The operation of the servo control circuit 16 is controlled by the system controller 26.

The reproduced RF signal obtained by the RF amplifier unit 14 is EFM (Eight to Fourteen Modulatio).
n) and CIRC (Cross Interleave Reed-Solomon Cor)
The signal is input to the decoder (DEC) 28 of d), demodulation processing is performed, and error correction processing is performed. The compressed and coded data corrected by the decoder 28 is temporarily stored in the DRAM 32 via the memory controller 30. The compressed encoded data stored in the DRAM 32 is sequentially read out under the control of the memory controller 30 and supplied to the decoder 34 via the memory controller 30 to perform the decompression decoding processing. And
The digital audio data output from the decoder 34 is converted into a digital-analog converter (D / A converter) 34.
And the output audio signal SA from the output terminal 36
out is output.

The system controller 26 is connected with an operation key unit 38 for the user to perform various operations, and a display 40 for displaying an operation procedure by the operation key unit 38, a system state, and the like. .

Next, an abnormality determination routine executed by the abnormality determination circuit according to the first embodiment will be described with reference to FIG. When the power of the reproducing apparatus is turned on, the rotation of the spindle motor, laser emission, focus servo, and the like are performed, and the reproducing operation is started. In step 100, a signal is transmitted to the system controller 26, and the tracking servo is turned on and off at a predetermined cycle. Control. Step 101
In step 102, it is determined whether or not the tracking servo signal is turned on. If the tracking servo signal is turned on, the tracking error signal output from the tracking error signal generation circuit of the RF amplifier is converted into a digital signal in step 104. It is determined whether or not the amplitude of the obtained signal is equal to or smaller than a predetermined value A.

The predetermined value A is used to distinguish between a tracking error signal in a tracking servo on state and a tracking error signal in a tracking servo off state.
The amplitude is larger than the amplitude of the tracking error signal in the tracking servo ON state of the CD-R and CD-ROM, and C
The value is set to be smaller than the amplitude of the tracking error signal in the tracking servo off state of the DR and CD-ROM.

When it is determined in step 104 that the amplitude is equal to or smaller than the predetermined value A, the reproducing apparatus is determined to be normal since a tracking error signal having a small amplitude is output when the tracking servo is turned on.
Resets the normal / abnormal judgment flag F.

On the other hand, when it is determined in step 104 that the amplitude exceeds the predetermined value A, a tracking error signal having a large amplitude is output in spite of the tracking servo ON, so that the reproducing apparatus is abnormal. Is determined, the flag F is set in step 108.

If the tracking servo is turned off in step 102, it is determined in step 110 whether the amplitude of the tracking error signal is equal to or smaller than a predetermined value A, as in step 104.

If it is determined in step 110 that the amplitude exceeds the predetermined value A, it means that a tracking error signal having a large amplitude is being output while the tracking servo is off, and it is determined that the reproducing apparatus is normal. do it,
At step 112, the flag F is reset.

On the other hand, when it is determined in step 110 that the amplitude is equal to or smaller than the predetermined value A, it means that a tracking error signal having a small amplitude is output in spite of the tracking servo off. Is determined to be abnormal, and a flag F is set in step 114.

In the next step 118, it is determined whether or not the normal / abnormal judgment flag F has been set. When the flag has been reset, it is normal, and the reproduction is started in step 120. On the other hand, when the flag F is reset, it is abnormal, so that the process at the time of abnormality is performed in step 122, and the fact that the process at the time of abnormality has been executed is displayed on the display unit 40. The processing at the time of abnormality includes, for example, stopping reproduction and ejecting the disc, and performing only partial reproduction without reproducing the entire recorded information.

In the above description, an example has been described in which the amplitude of the tracking error signal is compared with a predetermined value to determine whether or not the reproducing apparatus is abnormal. The on-off state is different, and the tracking error signal has a slow frequency amplitude when the tracking servo is off. Accordingly, by judging whether the frequency of the tracking error signal has changed in accordance with the tracking servo on / off or whether the amplitude and frequency of the tracking error signal have changed in accordance with the tracking servo on / off, whether or not the reproducing apparatus has become abnormal is determined. May be determined. Also,
The amplitude at a specific frequency may be measured by a spectrum analyzer or FFT to determine whether or not the frequency is abnormal as described above.

Next, an abnormality determination routine of the abnormality determination circuit according to the second embodiment will be described. When the power of the reproducing apparatus is turned on, the rotation of the spindle motor, laser emission, focus servo, and the like are performed, and the reproducing operation is started. In step 130, the tracking servo is turned off. Change.

At step 133, the digitally converted tracking error signal is fetched, and at step 134, it is determined whether or not the rotational speed has been changed to be higher. At 136, it is determined whether or not the frequency of the signal obtained by digitally converting the tracking error signal is increased. The frequency can be obtained by calculation from the interval between the zero-cross points and the interval between the peaks of the captured signal.

When the frequency is increased, the frequency of the tracking error signal is changed to be increased by increasing the rotation speed of the disk. Therefore, it is determined that the tracking error signal is normal. Reset.

On the other hand, if it is determined in step 136 that the frequency has not become higher, it means that the frequency of the tracking error signal does not change even though the rotation speed of the disk is changed. Is determined, the flag F is set in step 140.

If the rotational speed has been changed to decrease in step 134, it is determined in step 142 whether the frequency of the tracking error signal has changed to decrease. When the frequency becomes low, it means that the frequency of the tracking error signal is lowered by lowering the rotation speed of the disk. Therefore, it is determined that the frequency is normal, and the flag F is reset in step 144.

On the other hand, if it is determined in step 142 that the frequency has not become low, it means that the frequency of the tracking error signal does not change despite the fact that the rotational speed of the disk has been changed. Is determined, the flag F is set in step 146.

In the next step 118, similarly to the first embodiment, it is determined whether or not the flag F is set. When the flag F is reset, it is normal, and the reproduction is started in step 120. I do. On the other hand, when the flag F is reset, it is abnormal, so the same abnormal processing as described above is performed in step 122, and the fact that the abnormal processing has been performed is displayed on the display 40.

In the second embodiment, the abnormal state is determined based on the change in the frequency of the tracking error signal. However, the reproduction RF signal is used in place of the tracking error signal, and based on the change in the frequency of the reproduction RF signal. The abnormal state may be determined by using the tracking error signal and the reproduction R signal.
An abnormal state may be determined based on a change in the frequency of the F signal. In addition, any signal other than the tracking error signal and the reproduced RF signal can be used as long as the signal is obtained from the pickup and the frequency changes due to the fluctuation of the rotation speed of the disk.

Next, an abnormality determination routine of the abnormality determination circuit according to the third embodiment will be described. When the power of the reproducing apparatus is turned on, rotation of the spindle motor, laser emission, focus servo, and the like are performed to start a reproducing operation. In step 150, the tracking servo is turned off. At step 152, the digitally converted tracking error signal is fetched. At step 154, the zero-cross point of the tracking error signal is detected. Calculate time intervals.

FIG. 8A shows a change in the time interval of the zero cross point of the tracking error signal in the tracking servo off state of the CD-ROM.
(B) shows the derivative of the time interval of (A), that is, the difference D of the time interval. FIG. 9A shows the recorded C
FIG. 9B shows the change in the time interval of the zero-cross point of the tracking error signal in the tracking servo OFF state of DR, and FIG. 9B shows the difference D in the time interval in FIG. 9A. As can be seen from the figure, the CD-ROM
The difference D in the time interval in the case of (1) is substantially constant except for a case where the wobble detection signal, which is a meandering signal corresponding to the wobble groove, is not superimposed. Since the wobble detection signal is superimposed, the time interval difference D fluctuates even if it does not greatly change.
It is possible to determine whether the reproduction is from a ROM or a recorded CD-R.

Therefore, in step 156, the difference D in the time interval between the zero cross points is calculated, and in step 158, it is determined whether or not the difference D in the time interval is equal to or greater than a predetermined value. If the difference D between the time intervals is equal to or larger than the predetermined value, the count value n is incremented by one in step 160, and
At 62, it is determined whether a predetermined time has elapsed. If the predetermined time has not elapsed, the process returns to step 154 to repeat the above processing.

If the predetermined time has elapsed, step 16
At 4, it is determined whether the count value n is equal to or greater than a predetermined value,
If the difference is greater than or equal to the predetermined value, it is determined that the wobble detection signal is superimposed because the ratio of the time interval difference D being equal to or greater than the predetermined value is high.

If it is determined at step 164 that the wobble detection signal is superimposed on the tracking error signal, the CD-ROM is to be reproduced even though the CD-ROM is to be reproduced.
It is determined that the CD-R has been inserted as a playback target, and in step 122, the same abnormal processing as described above is performed, and the fact that the abnormal processing has been performed is displayed on the display 40.

On the other hand, if the count value n is less than the predetermined value, the disc inserted is determined to be the same as the disc inserted, so that it is determined that the disc is in a normal state, and reproduction is started in step 120.

In the third embodiment, it may be determined whether or not the wobble detection signal is superimposed on the reproduced RF signal in place of the tracking error signal to determine whether or not there is an abnormality.

Next, an abnormality determination routine of the abnormality determination circuit according to the fourth embodiment will be described. In this embodiment,
A wobble inspection circuit for determining the presence or absence of a wobble detection signal when the tracking servo is on is provided in the servo control circuit. In the present embodiment, it is determined whether a normal signal is input to the wobble inspection circuit.

When the power of the reproducing apparatus is turned on, rotation of the spindle motor, laser emission, focus servo, and the like are performed, and a reproducing operation is started. In step 170, a signal is transmitted to the system controller 26 to turn on the tracking servo. I do. At step 172, the digitally converted tracking error signal is fetched, and at step 174, it is determined whether or not the amplitude of the digitally converted tracking error signal output from the tracking error signal generation circuit of the RF amplifier section is smaller than a predetermined value a. .

The predetermined value a is the difference between the amplitude of the tracking error signal in the tracking servo ON state when the CD-ROM is to be reproduced and the amplitude of the tracking error signal in the tracking servo ON state when the CD-R is to be reproduced. It is set to a value between. If it is determined in step 174 that the amplitude is less than the predetermined value a, it is determined that the CD-ROM is to be reproduced because the tracking error signal with a small amplitude is output when the tracking servo is turned on. Sets the flag F1.

On the other hand, if it is determined in step 174 that the amplitude is equal to or larger than the predetermined value a, the CD-R is reproduced because a tracking error signal having a large amplitude is output despite the tracking servo being on. It is determined that it is the target, and the flag F1 is reset in step 176.

In the next step 180, the tracking servo is turned off. In step 182, a tracking error signal is fetched. In step 182, it is determined whether or not the amplitude of the tracking error signal exceeds a predetermined value b. The predetermined value b is set to a value smaller than the amplitude of the tracking error signal in the tracking servo off state.

If it is determined in step 184 that the amplitude exceeds the predetermined value, it is determined that a normal tracking error signal has been input to the wobble check circuit, that is, it is determined that the reproducing apparatus is normal, and in step 186, the flag F2 is reset. set.

On the other hand, if it is determined in step 184 that the amplitude is equal to or smaller than the predetermined value b, it is determined that a normal tracking error signal is not input, that is, it is determined that the reproducing apparatus is abnormal, and in step 188, the flag F2 is reset. .

In the next step 190, it is determined whether or not the product of the flag F1 and the flag F2 is 1. If the product is 1, it is determined that the medium is a CD-ROM and a normal tracking error signal is input. Since there is, reproduction is started in step 120. On the other hand, if the product is 0, the medium is a CD-ROM
If the tracking error signal is abnormal (F1 = 1 and F2 = 0) in the case of, the medium is CD-R and the tracking error signal is normal (F1 = 0 and F2 = 1), the medium is the CD-R.
Since the tracking error signal is abnormal in R (F1 = 0 and F2 = 0), the processing at the time of abnormality is performed in step 122, and the fact that the processing at the time of abnormality is executed is displayed on the display unit 40. . In the process at the time of this abnormality, a different process may be performed in each of the above cases.

Further, any one of the processing of steps 170 to 178 and the processing of steps 180 to 188 may be executed first.

By the way, a software file that is not originally permitted to be copied is recorded on an optical information recording medium (CD-R), and a pseudo tracking error signal simulating a small amplitude signal generated at the time of reproduction of a reproduction-only medium is generated. And
When the reproduction is to be performed using the pseudo tracking error signal, it is determined as abnormal by the abnormality determination routine of the first to fourth embodiments. Therefore, the abnormality determination routine is used to determine whether or not the optical information recording medium on which the software file to which copying is not originally permitted is reproduced is in an abnormal state. It is possible to prevent the execution (reproduction or execution of a program) of the software of the optical information recording medium in which the software file which has not been recorded is recorded.

In the present invention, the above-described second and third embodiments can be combined. In this case, the flag F3 is provided. When it is determined in step 164 that the wobble detection signal is superimposed on the tracking error signal, the flag F3 is reset, and it is determined that the wobble detection signal is not superimposed. In this case, the flag F3 is set. Then, the product of the flag F and the flag F3 shown in FIG. 3 which is set and reset according to the frequency is calculated. If the product is 1, the medium is a CD-ROM and the reproducing apparatus is normal, so that reproduction is started. I do. On the other hand, when the product is 0, the medium is CD-ROM and the reproducing apparatus is abnormal (F3 = 1 and F = 0), and when the medium is CD-R and the reproducing apparatus is normal (F3 = 0 and F2 = 1) If the medium is a CD-R and the reproducing apparatus is abnormal (F3 = 0 and F2
= 0), the processing at the time of abnormality is performed.

Although the above description has been given of a reproducing apparatus for reproducing a CD-ROM and a CD-R, a CD-ROM or a DVD-ROM and a CD-RW, a DVD-R, a DVD-R are described.
The present invention can also be applied to a playback device that plays back AM.

[0060]

As described above, according to the first to fourth aspects of the present invention, a reproducing apparatus for reproducing information recorded on a read-only optical information recording medium and a recordable optical information recording medium with a simple structure. The effect that abnormality can be determined can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an abnormality determination routine according to the first embodiment.

FIG. 3 is a flowchart illustrating an abnormality determination routine according to a second embodiment.

FIG. 4A is a waveform diagram showing a tracking error signal in a tracking servo-on state of a CD-R after recording, and FIG. 4B is a waveform diagram showing a tracking error signal in a tracking servo-off state of the CD-R after recording. FIG.

5A is a waveform diagram showing a tracking error signal of a CD-R before recording in a tracking servo-on state, and FIG. 5B is a waveform diagram showing a tracking error signal of the CD-R in a tracking servo off state before recording. FIG.

FIG. 6A is a waveform diagram showing a tracking error signal in a tracking servo-on state of a CD-ROM,
(B) is a waveform diagram showing a tracking error signal in a tracking servo off state of the CD-ROM.

FIG. 7 is a flowchart illustrating an abnormality determination routine according to a third embodiment.

8A is a diagram showing a time interval of a zero-cross point of a tracking error signal in a tracking servo off state of the CD-ROM, and FIG. 8B is a diagram showing a derivative of the time interval of FIG.

9A is a diagram showing a time interval of a zero-cross point of a tracking error signal in a tracking servo off state of a recorded CD-R, and FIG. 9B is a diagram showing a derivative of the time interval of FIG. is there.

FIG. 10 is a flowchart illustrating an abnormality determination routine according to a fourth embodiment.

[Explanation of symbols]

 12 disk 16 servo control circuit 20 abnormality judgment circuit

Claims (4)

[Claims] An on / off means for turning on / off a tracking servo, and determining whether at least one of an amplitude and a frequency of a tracking error signal changes in accordance with the tracking servo on / off, to determine whether an apparatus for reproducing an optical information recording medium is abnormal. And a determination means for determining whether or not the optical information recording medium is reproduced. 2. An on / off means for turning on / off a tracking servo; a speed changing means for changing a rotation speed of an optical information recording medium; and controlling the speed changing means in a tracking servo off state to change a rotation speed of the optical information recording medium. Determining means for determining whether the frequency of at least one of the tracking error signal and the reproduction RF signal changes according to the change in the rotation speed, and determining whether the reproduction apparatus of the optical information recording medium is abnormal; An optical information recording medium reproducing apparatus including: 3. An on / off means for turning on / off a tracking servo, and determining whether a wobble detection signal is superimposed on a tracking error signal or a reproduced RF signal in a tracking servo off state to determine whether a reproducing apparatus for an optical information recording medium is abnormal. And a determination means for determining whether or not the optical information recording medium is reproduced. 4. An on / off means for turning on / off a tracking servo, and judging whether or not the amplitude of a tracking error signal is greater than or equal to a predetermined value in a tracking servo off state to judge whether or not the reproducing apparatus of the optical information recording medium is abnormal. Means for reproducing an optical information recording medium, comprising: