JP2006018931A - Optical disk discrimination method and signal processing circuit for optical disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk discrimination method which can simply, surely and in a short period of time discriminate that the loaded optical disk is a DVD-RAM. <P>SOLUTION: The DVD-RAM is determined by detecting a specific noise component contained in an AS signal when discriminating a disk. As one means, a noise component is extracted from an AS signal, and the synchronization of a noise occurrence cycle with a passage cycle of CAPA position which is decided by rotating speed of the disk is set as a criterion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical disc discrimination method and an optical disc signal processing circuit.

  A disc-shaped recording medium called CD (Compact Disc) or DVD (Digital Versatile Disk) is formed by recording a recess called a pit or a chemical change of a phase change film in a spiral shape from the inner periphery to the outer periphery. An optical disk reproducing apparatus using this disk-shaped recording medium (hereinafter referred to as an optical disk) irradiates the optical disk with a laser and determines the presence or absence of pits from the amount of reflected laser light.

  In order to read this pit, the optical disk playback device uses rotation control to rotate the optical disk at a constant rotational speed, focus control to control the focal position of the laser, and correctly scans the laser beam into the spirally recorded pit. Tracking control is performed.

  Below, a focus error signal (hereinafter referred to as FE signal) used for focus control, an all-sum signal (hereinafter referred to as AS signal), a push-pull tracking error signal (hereinafter referred to as PPTE signal) used for tracking control, and phase difference tracking An error signal (hereinafter referred to as a DPDTE signal) and a wobble signal will be described.

FIG. 25 shows the optical pickup 3 and its peripheral circuit of the optical disk reproducing apparatus.
The optical pickup 3 is operated by a quadrant photodetector 30 for generating an error signal in addition to the laser light emitting element, and a focus driving circuit 40B for controlling the focus of the beam spot. A focus drive unit 31 that moves the objective lens up and down and a tracking drive circuit 40C to follow the track on the recording surface of the optical disc 1 and to slightly shift the track across the track of the optical disc 1 to control tracking. The tracking drive drive 32 is provided. Reference numeral 33 denotes a sled drive unit that is operated by the traverse drive circuit 40A and moves the entire optical pickup 3 in the radial direction of the optical disc 1. A spindle motor 2 rotates the optical disk 1.

The AS signal 34 is a signal obtained by adding all the outputs a to d of the four-divided photo detector 30. This signal is treated as a signal indicating the level of the amount of reflected light.
The FE signal 37 is a signal obtained by adding the diagonal outputs of the output of the four-divided photodetector 30. This signal is treated as a signal representing the deviation amount from the focus.

  The PPTE signal 35 is a signal obtained by adding two signals parallel to the track direction in the four-divided photodetector 30. The DPDTE signal 38 is a signal obtained by outputting the diagonal phase difference amount of the four-divided photodetector 30 by the phase comparator 39. The PPTE signal and the DPDTE signal are treated as signals representing a deviation amount from the tracking center.

  A controller 40 operates the optical pickup 3 through the traverse drive circuit 40A, the focus drive circuit 40B, and the tracking drive circuit 40C with the AS signal 34, PPTE signal 35, FE signal 37, DPDTE signal 38, etc. as input signals. .

  A plurality of types of optical discs 1, substrate thicknesses, track pitches or recording densities are different. The optical disk playback apparatus must be compatible with the plurality of types of optical disks 1 by itself. For this reason, it is necessary to discriminate the type of the disc loaded in the recording / reproducing apparatus and to make the state of the apparatus suitable for each optical disc 1.

  Several methods have been proposed for discriminating the types of optical disks such as CDs and DVDs. According to Japanese Patent Laid-Open No. 61-283035, the optical disc is discriminated by discriminating the optical reflectivity of the optical disc from the focus error signal obtained by the focus servo and the peak value obtained based on the focus error signal. ing.

  Japanese Patent Application Laid-Open No. 62-76061 discloses a method for discriminating the type of a disc based on the level of a signal obtained from an optical pickup in a state where the focal position of the optical disc has been reached.

  When discriminating the type of the optical disk by these methods, in the case of a two-laser type optical disk reproducing apparatus equipped with both a CD laser and a DVD laser, the CD laser, The signal level is measured with both DVD lasers, and the type of the optical disk is discriminated from the ratio and characteristics of each feature amount.

  First, after determining whether or not there is an optical disk (150), if there is an optical disk, the feature quantity of the optical disk is extracted by turning on the CD laser (151) (152). Similarly, the feature quantity is extracted by the DVD laser (153) (154). Then, it is discriminated whether it is a DVD or a CD from the characteristics of the extracted feature quantity, and the parameter is set to a state suitable for the optical disk to be used (156).

In recent years, DVD-RAM (Digital Versatile Disk Random Access Memory) has become mainstream as a writable optical disk.
Such a recordable DVD-RAM has a structure having an embossed non-recordable address portion called CAPA (Complementary Allocated Pit Address) and a recordable data portion. In such a recordable optical disc, as shown in FIG. 27, a CAPA representing an address portion and a data portion representing data are paired and recorded on the optical disc.

  A data recording portion (land or groove) between CAPA and CAPA is formed to meander in the radial direction, and the shape of this meander is called wobble. The wobble period is recorded so as to be always constant. When a track has wobbles, a wobble signal output as a signal is referred to as a wobble signal (hereinafter referred to as a WBL signal) and corresponds to reference numeral 36 in FIG. The WBL signal 36 is generally detected through a narrow band pass filter (BPF) 36A in order to improve the S / N ratio.

  However, when the optical disc playback apparatus determines that the DVD-RAM is a playback target, it is not easy to determine using the above-described determination method. This is because the DVD-RAM is a DVD at the signal level obtained by the disc discriminating method described above because it has a physical shape similar to other writable optical discs (DVD-R and DVD-RW). This is because it is not possible to obtain a sufficient margin for determining whether the disc is a DVD-RAM.

  Therefore, as a method for discriminating between DVD and DVD-RAM, in the conventional optical disc reproducing apparatus, first, disc type discriminating method is used to discriminate between DVD and CD. Whether it is a DVD or a DVD-RAM is determined according to how much the tracking error amplitude generated by PPTE is obtained by the method shown in FIG.

  In FIG. 28, first, the conventional CD / DVD discrimination shown in FIG. 26 is performed (157), and the focus is turned on (158). If it is a DVD, the PPTE amplitude is measured for a certain time (160). When the PPTE amplitude is obtained above a certain level (161), it is determined as a DVD-RAM (162), otherwise it is determined as not a DVD-RAM (163). It is generally known that the relative amplitude of PPTE amplitude differs depending on the guide groove depth between the land and the groove, and a clear difference is obtained between DVD and DVD-RAM as shown in FIG.

  The DVD-RAM is divided into sections called zones for each track number determined from the inner periphery to the outer periphery of the optical disc, and the data portion is called a land / groove, which is a spiral track from the inner periphery to the outer periphery. Pits are recorded on both the land and groove.

  In a spiral track composed of pit rows, such as conventional CDs and DVDs, zone division is not particularly performed, and recording is performed at the same recording density at a constant linear velocity from the inner periphery to the outer periphery. Therefore, such an optical disc is rotated using CLV control for rotation control.

  However, DVD-RAM differs in the number of sectors recorded in one track for each zone, and it is necessary to specify the number of rotations for each zone. Therefore, a ZCLV (Zone Constant Linear Velocity) method for controlling rotation at a constant rotation speed for each zone is used. When a certain zone is reproduced using the ZCLV method, the rotational speed is constant and the number of sectors recorded in one track circumference is also constant, so that the linear velocity is different between the inner circumference side and the outer circumference side of the zone.

In order to perform ZCLV control, the conventional optical disk reproducing apparatus generally uses FG control for controlling the rotation speed of the disk motor to be constant by using an FG pulse detected from a brushless motor used for rotation control, or a wobble signal. Wobble CLV control is used in which control is performed to keep the rotational speed of the disk motor constant so that the average frequency becomes constant.
Japanese Patent Laid-Open No. 61-283035 JP-A-62-076061 JP 09-320180 A

  In the conventional optical disc discrimination method described above, discrimination is performed by measuring the amplitude of an error signal such as a PPTE signal in order to discriminate that the disc is a DVD-RAM. However, when such a determination method is used, processing for measuring an error signal is required, so that it takes time to determine, and a playback image or the like is displayed after the optical disk is loaded and the operation is started. There is a problem that it takes a relatively long time to appear as an image on the screen of the apparatus.

  In addition, in the conventional optical disk reproducing apparatus, it is necessary to use FG control or wobble CLV control as disk rotation control when reproducing a DVD-RAM disk. When wobble CLV control is used, the wobble signal is rotated. Although it is used as a control signal, in order to obtain a wobble signal, it is necessary to pass a band pass filter in order to remove the pit component and the tracking control signal component from the signal component obtained from the optical disc 1. There is a problem that a wobble signal cannot be normally obtained until a certain number of revolutions is reached.

  According to the present invention, it is possible to reliably determine that the loaded disc is a DVD-RAM in a simpler manner and in a shorter time than in the past, and playback on the screen of the display device after loading the optical disc and starting operation. An object of the present invention is to provide an optical disc discriminating method and an optical disc signal processing circuit capable of displaying an image in a relatively short time.

  The optical disc discrimination method according to claim 1 of the present invention detects a noise component from an output signal of a light receiving device that irradiates a recording surface of a rotationally driven optical disc and receives the light beam reflected by the recording surface. The correlation between the noise component and the address part of the DVD-RAM is determined to determine the type of the optical disk.

According to a second aspect of the present invention, in the optical disk discrimination method according to the first aspect, when detecting the noise component, the light receiving device is moved so as to cross the focal position.
According to a third aspect of the present invention, there is provided an optical disc discrimination method according to the first aspect, wherein when detecting a noise component, the light receiving device is moved so as to maintain the focal position.

According to a fourth aspect of the present invention, in the optical disc discrimination method according to the first aspect of the present invention, when detecting the noise component, the light receiving device is moved in the vicinity of the focal position.
According to a fifth aspect of the present invention, there is provided an optical disc discrimination method according to any one of the second to fourth aspects, wherein the optical disc is detected from a signal of intensity of reflected light received by the light receiving device or an AS signal converted from the signal. The type of the optical disk is determined by comparing the amplitude level of the noise component and the set threshold level to determine the presence or absence of noise.

  According to a sixth aspect of the present invention, there is provided an optical disc discrimination method according to any one of the second to fourth aspects, wherein a noise component is generated from a signal of intensity of reflected light received by the light receiving device or an AS signal converted from the signal. , And the type of the optical disc is discriminated based on the level difference between the amplitude level of the noise component and the amplitude level of the signal component passed through the low-pass filter.

  According to a seventh aspect of the present invention, there is provided an optical disc discrimination method according to any one of the second to fourth aspects, wherein a noise component is generated from a signal of the intensity of reflected light received by the light receiving device or an AS signal converted from the signal. , And the type of the optical disk is determined according to the noise generation interval.

  According to an eighth aspect of the present invention, there is provided an optical disc discrimination method according to any one of the second to fourth aspects, wherein a noise component is generated from a signal of intensity of reflected light received by the light receiving device or an AS signal converted from the signal. The measurement start timing to start measuring the signal amplitude and the measurement interruption timing to interrupt the measurement of the signal amplitude are generated, and the noise component in the section from the measurement interruption timing to the next measurement start timing is masked. It is characterized in that the type of the optical disc is discriminated without measuring.

  According to a ninth aspect of the present invention, there is provided an optical disc signal processing circuit comprising: a noise detecting unit for detecting a noise component from a signal corresponding to an intensity of a light beam reflected by a recording surface of a rotationally driven optical disc; and the noise detecting unit. Disc discriminating means for discriminating the type of the loaded disc using the noise detection result in the case where a noise component corresponding to the position of the DVD-RAM address portion is detected and the type of the loaded disc is changed to DVD. -It is characterized in that it is determined to be RAM.

  The signal processing circuit for an optical disk according to claim 10 of the present invention is the signal processing circuit according to claim 9, wherein the noise detecting means holds a threshold level for a signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disk. A holding means for comparing the signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disc with the threshold level held by the threshold level holding means and corresponding to the position of the DVD-RAM address section; The type of the loaded disc is determined to be DVD-RAM by detecting the presence or absence of noise components.

  According to an eleventh aspect of the present invention, there is provided the signal processing circuit for an optical disc according to the ninth aspect, wherein the noise detecting means detects the interval of the signal according to the intensity of the light beam reflected by the recording surface of the optical disc. And a signal interval measuring means for measuring a noise component interval corresponding to the position of the DVD-RAM address portion and comparing it with a reference value to determine the type of the loaded disc as DVD-RAM. And

  According to a twelfth aspect of the present invention, there is provided the optical disk signal processing circuit according to the ninth aspect, wherein the noise detecting means prevents passage of unnecessary noise from a signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disk. A noise component corresponding to the position of the DVD-RAM address part is compared by comparing a noise elimination filter with a signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disc and the signal amplitude passed through the noise elimination filter. And a signal amplitude measuring unit configured to determine the type of the disc loaded by detection as a DVD-RAM.

  According to a thirteenth aspect of the present invention, in the signal processing circuit for an optical disc according to the ninth aspect, the noise detecting means prevents passage of unnecessary noise from a signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disc. A signal amplitude measuring means that compares the signal amplitude of a signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disc and the signal amplitude that has passed through the noise removal filter to determine the presence or absence of noise. And a window function forming means for generating a timing at which the light receiving means passes through the CAPA region and instructing the signal amplitude measuring means to indicate a signal amplitude measurement period and a non-measurement masking period.

According to a fourteenth aspect of the present invention, there is provided an optical disk reproducing apparatus comprising the optical disk signal processing circuit according to any one of the ninth to thirteenth aspects.
According to a fifteenth aspect of the present invention, there is provided an optical disc reproducing apparatus comprising: a noise detecting unit that detects a noise component from a signal corresponding to an intensity of a light beam reflected by a recording surface of a rotationally driven optical disc; A disc discriminating unit for discriminating the type of the loaded disc using the noise detection result, and detecting the noise component corresponding to the position of the DVD-RAM address portion, the type of the loaded disc is changed to the DVD-RAM; And a signal interval measuring means for measuring an interval of noise components corresponding to the position of the DVD-RAM address portion detected by the noise detecting means, and a rotational drive speed when the optical disc is a DVD-RAM. Target interval information holding means for storing the interval of the position of the DVD-RAM address part when the signal reaches the target value, and the signal A rotation control means for controlling the rotation of a spindle motor for rotating the optical disc so that a deviation between an interval of noise components detected by the distance measuring means and an interval held by the target interval information holding means is small; And the rotation control means controls the rotation of the spindle motor when the type of the disk loaded with the disk determination means is determined to be DVD-RAM.

  According to the optical disc discriminating method of the present invention, a noise component is detected from an output signal of a light receiving device that irradiates a recording surface of a rotationally driven optical disc, receives the light beam reflected by the recording surface, and detects the noise. Since the type of the optical disk is determined by determining the correlation between the components and the address part of the DVD-RAM, it is possible to determine in a short time and reliably that the loaded optical disk is a DVD-RAM. Become.

Hereinafter, the optical disc discrimination method of the present invention will be described based on specific embodiments.
(Embodiment 1)
1, 2 and 3 show (Embodiment 1) of the present invention.

FIG. 1 shows an optical disk reproducing apparatus having a function of executing the optical disk discrimination method of the present invention.
In this optical disk reproducing apparatus, an optical disk 1 such as a DVD or a CD is rotationally driven by a spindle motor 2. An optical pickup 3 is located below the optical disk 1. Although not shown, the optical pickup 3 irradiates the optical disk 1 with a laser beam from a semiconductor laser or the like via an actuator lens, and the reflected light is received and detected by a quadrant or two-divided detector. The light receiving device 3a has a light receiving device moving means 3b for moving the actuator lens up and down during focusing control and horizontally moving it during tracking control.

The electric signal generating means 4 converts the light receiving device 3a into an electric signal corresponding to the intensity of the reflected light of the laser beam received from the optical disc 1.
A signal processing circuit 5 having an optical disc discrimination function generates an AS signal indicating the level of the amount of reflected light from the recording surface of the optical disc 1, detects its noise component, and detects the detected noise component and the address portion of the DVD-RAM. The type of the optical disc is discriminated by determining the correlation between the servo signal generating means 6 and the servo signal generating means 6, the noise detecting means 7 and the disc discriminating means 8.

  Specifically, the servo signal generating means 6 generates a focus error signal (FE signal), a tracking error signal (TE signal), an all-sum signal (AS signal), etc., and moves the light receiving device for focusing control and tracking control. In addition to being sent to the means 3b, it is also sent to the noise detecting means 7. The noise detection means 7 is configured to detect a noise signal corresponding to the CAPA part of the address part of the DVD-RAM from the AS signal. The disc discriminating unit 8 is configured to determine the type of the loaded disc using the result of noise detection by the noise detecting unit 7.

FIG. 2 shows an optical disc discrimination flow in the optical disc reproducing apparatus configured as described above.
Here, the position of the light receiving device 3a when the laser beam is focused on the recording surface of the optical disc 1 is defined as a focal position.

  First, the signal processing circuit 5 uses the light receiving device moving means 3b to move the light receiving device 3a perpendicularly to the recording surface of the disk 1 so as to cross the focal position (100). When the light receiving device 3a just passes through the focal position, the reflected light amount of the laser beam received by the light receiving device 3a is maximized, and when the light receiving device 3a is not near the focal position, the reflected light amount is very weak.

Next, when the light receiving device 3a passes near the focal position, the reflected light received by the light receiving device 3a is converted into an electric signal by the electric signal generating means 4 (101).
Next, servo signals such as an FE signal, a TE signal, and an AS signal are generated from the electrical signal converted by the servo signal generating means 6 (102).

Next, the AS signal is sent to the noise detection means 7, and it is confirmed whether or not the AS signal includes a noise signal corresponding to the CAPA part of the DVD-RAM (103) (104).
If the noise detection means 7 determines that the noise signal corresponding to the CAPA part of the DVD-RAM is not included, it is determined that the loaded disc is not a DVD-RAM (107), and the noise detection means If it is determined in step 7 that a noise signal is included, it is confirmed whether the noise signal corresponds to the CAPA position of the DVD-RAM (105).

  If the noise signal corresponds to the CAPA position of the DVD-RAM, it is determined that the loaded disc is a DVD-RAM (106), and the noise signal corresponds to the CAPA position of the DVD-RAM. If not, it is determined that the loaded disc is not a DVD-RAM (107).

  FIG. 3 shows an example of the FE signal and the AS signal when the light receiving device crosses the focal position from the bottom to the top. If the AS signal when the DVD-ROM is loaded is normal, the signal level becomes maximum near the focal position and a signal waveform without noise can be observed. However, the AS signal when the DVD-RAM is loaded is the light receiving device 3. When the signal passes the CAPA position, a noise component is superimposed and observed. By detecting this noise component, the type of the loaded disc can be determined.

The signal processing circuit 5 can be configured by a semiconductor integrated circuit and supplied to the market.
With this configuration, the type of the loaded disc is discriminated in a short time, and various parameters for control such as the optical pickup 3, the electric signal generating unit 4, and the servo signal generating unit 6 are determined based on the discrimination result. By setting the value suitable for the loaded optical disc 1, it is possible to display the reproduced video on the screen of the display device in a relatively short time after the disc is loaded and the operation is started.

  Further, although noise detection is performed based on the AS signal, noise detection can be performed based on an electric signal that converts the intensity of reflected light received by the light receiving device into an electric signal instead of the AS signal.

(Embodiment 2)
4 and 5 show (Embodiment 2) of the present invention.
In (Embodiment 1), the noise component in the AS signal when the light receiving device 3a is moved so as to cross the focal position is detected to determine the type of the optical disk. The only difference is that the signal processing circuit 5 is configured so as to determine the type of the optical disc 1 from the interval of noise components in the AS signal when the device 3a is in the focus on state. It is equivalent to FIG.

A specific configuration of the signal processing circuit 5 of the (second embodiment) is shown in FIG.
Specifically, first, the light receiving device 3a is moved perpendicularly to the recording surface of the optical disc 1 by using the light receiving device moving means 3b, and the focus is turned on (108). In the focus ON state, the reflected light amount of the laser beam received by the light receiving device 3a is maintained at a maximum state, so that the reflected light received by the light receiving device 3a is converted into an electric signal using the electric signal generating means 5 at an arbitrary timing. (101).

Next, servo signals such as an FE signal, a TE signal, and an AS signal are generated from the electrical signal converted by the servo signal generating means 6 (102).
Next, the AS signal is sent to the noise detection means 7, and it is determined whether or not the AS signal includes a noise signal corresponding to the CAPA section of the DVD-RAM (103, 104).

  If the noise signal corresponding to the CAPA portion of the DVD-RAM is not included in the noise detecting means 7, it is determined that the loaded disc is not a DVD-RAM (107).

  If the noise detection means 7 includes a noise signal corresponding to the CAPA portion of the DVD-RAM, it is determined whether the noise signal corresponds to the CAPA position of the DVD-RAM (105). If the noise signal corresponds to the CAPA position of the DVD-RAM, it is determined that the loaded disc is a DVD-RAM (106), and the noise signal corresponds to the CAPA position of the DVD-RAM. If not, it is determined that the loaded disc is not a DVD-RAM (107).

  The AS signal in the focus ON state is that when the DVD-ROM is loaded, the AS signal is normally the maximum signal level near the focal position, and a waveform maintaining that level can be observed. As shown in FIG. 5, the AS signal in the case of loading is observed by superimposing the noise component signal N when the optical pickup 3 passes the CAPA position. By detecting this noise component, the type of the loaded optical disk is discriminated.

The detection of the noise component can be realized by any one of the following (Example 1) to (Example 3).
(Example 1)
The signal amplitude of the AS signal is measured, the signal amplitude of a signal that has passed through a filter for removing the noise component of the AS signal is measured, and the presence or absence of noise is determined according to the two signal amplitudes.

(Example 2)
When the signal amplitude level of the AS signal is measured, and the presence or absence of noise is determined by comparing this signal amplitude level with a set threshold level.
In (Example 1) (Example 2), a step of generating a measurement start timing to start measuring the signal amplitude of the AS signal, and starting the amplitude measurement of the AS signal according to the measurement start timing; By generating a measurement interruption timing for interrupting the measurement of the signal amplitude of the AS signal and providing a step of interrupting the amplitude measurement of the AS signal according to the measurement interruption timing, the type of the optical disk can be determined more accurately. .

(Example 3)
The noise component signal N of the AS signal is extracted, the interval T1 between arbitrary signals of the extracted noise component signal is measured, and the noise component signal is correlated with the CAPA of the DVD-RAM according to the measured interval between the signals. Determine whether the noise signal is present. Specifically, as shown in FIGS. 6 and 7, first, a signal from which a noise component included in the AS signal is extracted is generated using the noise extraction filter 22 (128). Next, using the time interval measuring means 23, the interval T1 between adjacent noise components extracted by the noise extraction filter 22 is measured (123). Next, the measurement result is compared with the reference value (129). However, the reference value is a value determined by the standard and the reproduction speed. If this measurement result is a value near the reference value, it is determined that the noise component extracted by the noise extraction filter 22 is a noise signal corresponding to the CAPA unit, and the loaded disc is a DVD-RAM. (106). If this measurement result is not a value near the reference value, it is determined that the noise component extracted by the noise extraction filter 22 is not a noise signal corresponding to the CAPA unit, and the loaded disc is a disc other than the DVD-RAM. (107).

  In the above (Example 1) to (Example 3) and the like, noise detection is performed based on the AS signal, but instead of the AS signal, the intensity of the reflected light received by the light receiving device is converted into an electric signal. Noise detection can also be performed from an electrical signal.

  With this configuration, the type of the loaded disc is discriminated in a short time, and various control parameters such as the optical pickup 3, the electric signal generator 4, the servo signal generator are loaded based on the discrimination result. By setting the value suitable for the optical disc, the playback video can be displayed on the screen of the display device in a relatively short time after the disc is loaded and the operation is started.

(Embodiment 3)
FIG. 8 shows (Embodiment 3) of the present invention.
In (Embodiment 1), the noise component in the AS signal when the light receiving device 3a is moved so as to cross the focal position is detected to determine the type of the optical disc. The only difference is that the signal processing circuit 5 is configured to discriminate the type of the optical disk from the interval of the noise component in the AS signal when the apparatus 3a is fixed in the vicinity of the focal position. The configuration is the same as in FIG.

A specific configuration of the signal processing circuit 5 of the (Embodiment 3) is shown in FIG.
Specifically, first, the light receiving device 3a is moved perpendicularly to the recording surface of the optical disc 1 using the light receiving device moving means 3b, and is fixed in the vicinity of the focal position (109). In this state, since the focus is not ON, the reflected light amount of the laser beam received by the light receiving device 3a is not guaranteed to be kept at a maximum due to the influence of the surface shake of the disk recording surface, but the light receiving device 3a has no reflected light. Can be expected.

Next, at an arbitrary timing, the reflected light received by the light receiving device 3a is converted into an electric signal using the electric signal generating means 4 (101).
Next, servo signals such as an FE signal, a TE signal, and an AS signal are generated from the electrical signal converted by the servo signal generating means 6 (102).

Next, the AS signal is sent to the noise detection means 7 and it is confirmed whether or not the AS signal includes a noise signal corresponding to the CAPA part of the DVD-RAM (103, 104).
If the noise signal corresponding to the CAPA portion of the DVD-RAM is not included in the noise detecting means 7, it is determined that the loaded disc is not a DVD-RAM (107).

  If the noise signal corresponding to the CAPA portion of the DVD-RAM is included in the noise detection means 7, it is confirmed whether the noise signal corresponds to the CAPA position of the DVD-RAM (105). If the noise signal corresponds to the CAPA position of the DVD-RAM, it is determined that the loaded disc is a DVD-RAM (106), and the noise signal corresponds to the CAPA position of the DVD-RAM. If not, it is determined that the loaded disc is not a DVD-RAM (107).

  As the AS signal when the light receiving device 3 is fixed near the focal position, it can be expected that the AS signal as shown in FIG. 5 can be observed. Therefore, noise detection is performed using the generated AS signal, and the type of the loaded disc can be determined by detecting the CAPA of the DVD-RAM.

In this (Embodiment 3), the configuration for determining the correlation between the noise component and the CAPA of the address portion of the DVD-RAM can be realized in the same manner as in (Embodiment 2).
With this configuration, the type of the loaded disc is discriminated in a short time, and various control parameters such as the optical pickup 3, the electric signal generator 4, the servo signal generator are loaded based on the discrimination result. By setting the value suitable for the optical disc, the playback video can be displayed on the screen of the display device in a relatively short time after the disc is loaded and the operation is started.

(Embodiment 4)
9, FIG. 10 and FIG. 11 show (Embodiment 4) of the present invention.
FIG. 9 shows a detailed configuration of the noise detection means 7 in FIG.

As shown in FIG. 9, the noise detection means 7 includes a signal amplitude measurement means 9 and a noise removal filter 10.
The noise removal filter 10 is a low-pass filter adjusted so that the noise signal component of the AS signal sent from the servo signal generation means 6 is removed. The signal amplitude measuring means 9 measures the signal amplitude of the AS signal sent from the servo signal generating means 6 and compares it with the signal that has passed through the noise removal filter 10.

The noise detection means 7 and the disk discrimination means 8 are configured to execute the flowchart of FIG.
Specifically, the noise signal detection process (103) and subsequent steps in FIG. 2 are configured as shown in FIG.

First, the signal amplitude of the AS signal sent from the servo signal generating means 6 is measured using the signal amplitude measuring means 9 (110).
Next, the noise component is removed by passing the AS signal sent from the servo signal generation means 6 through the noise removal filter 10, and the signal amplitude of the signal obtained by extracting only the original AS signal using the signal amplitude measurement means 9 is obtained. Measure (111).

  The above two signal amplitudes are compared (112, 113), and if there is an amplitude difference exceeding the reference value between them, it is determined that the noise is detected as a DVD-RAM (106), and the reference value If there is no difference exceeding, noise is not detected, so that it is not a DVD-RAM (107), and the noise detection process is terminated.

FIG. 11 shows an AS signal waveform example before and after passing through the noise removal filter 10 for the AS signal when the light receiving device 3a crosses the focal position from the bottom to the top.
As shown in FIG. 11, the AS signal when the DVD-RAM is loaded is observed with a noise component superimposed when the pickup passes the CAPA position. This signal amplitude is measured and set to “amplitude 1”.

  Next, the AS signal is passed through the noise removal filter 10 to obtain a signal amplitude “amplitude 2” of the noise-removed signal. If the difference between “amplitude 1” and “amplitude 2” exceeds an arbitrary reference value, it is determined that noise is superimposed on the AS signal, and the type of the loaded disc is determined to be DVD-RAM.

The signal processing circuit 5 can be configured by a semiconductor integrated circuit and supplied to the market.
(Embodiment 5)
12, FIG. 13 and FIG. 14 show (Embodiment 5) of the present invention.

FIG. 12 shows a detailed configuration of the noise detection means 7 in FIG.
The noise detection means 7 comprises a signal amplitude measurement means 9 and a threshold level holding means 11 as shown in FIG.

  Since the signal amplitude measuring means 9 is the same as the constituent elements of (Embodiment 4), description thereof is omitted. The threshold level holding means 11 is used to determine whether or not a noise signal corresponding to the CAPA part of the DVD-RAM is included in the AS signal, and holds the threshold level of the amplitude of the AS signal.

  The noise detection means 7 and the disk discrimination means 8 are configured to execute the flowchart of FIG. Specifically, the noise signal detection process (103) and subsequent steps in FIG. 2 are configured as shown in FIG.

  First, a threshold level is set for the threshold level holding means 11 (114). The signal amplitude of the AS signal sent from the servo signal generating means 6 is measured using the signal amplitude measuring means 9 (110).

  Next, the threshold level holding means 11 is referred to (115). When the above two signal amplitudes are compared (116) and there is a difference exceeding the reference value, it is determined that the DVD-RAM is detected because noise is detected (106), and there is no difference exceeding the reference value. Since no noise is detected, it is determined that the disc is not a DVD-RAM (107), and the noise detection process is terminated.

  FIG. 14 shows an AS signal waveform example on the input side of the signal amplitude measuring means 9 for the AS signal when the optical pickup 3 crosses the focal position from the bottom to the top. As shown in FIG. 14, the AS signal when the DVD-RAM is loaded is observed with the noise component N superimposed when the pickup passes the CAPA position. This signal amplitude is measured, and the signal amplitude measuring means 9 measures the amplitude of the noise component from time to time to obtain “amplitude 1”. Next, when “amplitude 1” is compared with the threshold level held in the threshold level holding means 11 and “amplitude 1” exceeds the threshold level more than a specified level, it is assumed that noise is superimposed on the AS signal. The type of the loaded disc is discriminated as DVD-RAM.

The signal processing circuit 5 can be configured by a semiconductor integrated circuit and supplied to the market.
(Embodiment 6)
This (Embodiment 6) is a modification of (Embodiment 4) shown in FIG. 9, and FIGS. 15, 16 and 17 show (Embodiment 6) of the present invention.

FIG. 15 shows a detailed configuration of the noise detection means 7 in FIG.
As shown in FIG. 15, the noise detection means 7 includes a signal amplitude measurement means 9, a noise removal filter 10, a signal amplitude control means 14, and a timing generation means 15.

Since the signal amplitude measuring means 9 and the noise removal filter 10 are equivalent to the constituent elements of (Embodiment 4), the description thereof is omitted.
The timing generation unit 15 generates a measurement start timing for starting measurement of the signal amplitude of the AS signal and a measurement interruption timing for interrupting the measurement. Specifically, a time interval in which the light receiving device 3a passes near the CAPA region is generated. The physical distance between adjacent CAPAs is determined by the standard, and the time interval for the light receiving device 3a to pass near the CAPA area is determined from the rotational speed of the disk and the physical distance between adjacent CAPAs.

The signal amplitude control unit 14 performs start-up control and interruption control of the signal amplitude measurement unit 9 based on the timing generated using the timing generation unit 15.
Next, the procedure for actual operation will be described using the configuration shown in FIG. 15 and FIG. Specifically, the processing in FIG. 10 is changed as shown in FIG.

  First, the timing generation means 15 is activated (118). The timing generation unit 15 generates a timing at which the light receiving device 3a is predicted to pass near the CAPA region, and executes a subroutine by interruption. In the subroutine, the signal amplitude control means 14 is set to start amplitude measurement (120, 121 and 122).

  The signal amplitude control means 14 activates the signal amplitude measurement means 9 and measures the signal amplitude of the AS signal not passing through the noise removal filter 10 (110). This signal amplitude is the “amplitude 1”.

  Next, the timing generation unit 15 generates a timing at which the light receiving unit completes passing through the CAPA region, and sets the signal amplitude control unit 14 to interrupt amplitude measurement by the interruption (120, 121, and 122). The signal amplitude control means 14 controls the signal amplitude measurement means 9 to interrupt the measurement of the signal amplitude of the AS signal.

  If the timing is to measure the signal amplitude of the AS signal, the signal amplitude measuring means 9 may be used to measure the signal amplitude of the AS signal sent from the servo signal generating means 6 and not to measure the signal amplitude of the AS signal. For example, the signal amplitude of the AS signal is not measured and zero amplitude is output.

  Next, the noise component is removed by passing the AS signal sent from the servo signal generation means 6 through the noise removal filter 10, and the signal amplitude of the signal obtained by extracting only the original AS signal using the signal amplitude measurement means 9 is obtained. taking measurement. This signal amplitude is the “amplitude 2”.

  Next, “amplitude 1” and “amplitude 2” are compared (112). If there is a difference exceeding the reference value, it is determined that the DVD-RAM is detected as noise is detected (113, 106). If there is no difference exceeding the reference value, it is determined that the disc is not a DVD-RAM because no noise is detected, and the noise detection process is terminated (113, 107).

  FIG. 17 shows the contents of this signal processing, and the AS signal includes noise N1 corresponding to the CAPA position and noise N2 that is not necessary for disc discrimination. A window function is generated for the AS signal by the timing generation means 15 and the signal amplitude control means 14, and only the signal amplitude of the AS signal in the vicinity of the CAPA area is measured by multiplying both of them, and noise N2 other than in the vicinity of the CAPA area Therefore, it is less likely to be affected by noise signals generated from wiring on the substrate or noise signals caused by scratches on the disk surface. Therefore, the discriminating accuracy of disc discrimination is improved.

The signal processing circuit 5 can be configured by a semiconductor integrated circuit and supplied to the market.
(Embodiment 7)
18 and 19 show an optical disk reproducing apparatus having a function of executing the disk discriminating method of (Embodiment 7) of the present invention.

  In the optical disk reproducing apparatus shown in FIG. 1, the AS signal converted by the servo signal generating means 6 is input to the noise detecting means 7 and processed, and the type of the optical disk is determined by the disk determining apparatus 8. FIG. In the signal processing circuit 5A shown in FIG. 4, the intensity of the reflected light received by the light receiving device generated at the output of the electric signal generating means 4 is directly input to the noise detecting means 7 for processing. The only difference is that the discriminating device 8 discriminates the type of the optical disc.

  FIG. 19 shows the configuration, and the difference is that step 102 in the flowchart in FIG. 2 is deleted in the disc discrimination process, and the type of the optical disc can be discriminated more quickly.

  Also in the discrimination methods of (Embodiment 2) to (Embodiment 6), as in this (Embodiment 7), the light receiving device generated at the output of the electric signal generating means 4 instead of the AS signal The intensity of the reflected light received in step 1 can be directly inputted to the noise detecting means 7 and processed, and the disc discriminating device 8 can discriminate the type of the optical disc.

(Embodiment 8)
FIG. 20 shows that when the noise is detected when discriminating the type of the optical disc, the light receiving device 3a is moved so as to cross the focal position, and it is discriminated whether it is a DVD-RAM or not based on the detected noise interval. When the loaded optical disk is a DVD-RAM, the optical disk reproducing apparatus is configured to control the rotation of the spindle motor 2 so that the detected noise interval approaches the DVD-RAM interval.

FIG. 21 shows the part of the rotation control in FIG. 20 extracted. First, FIG. 21 will be described.
Here, a case where a DVD-RAM disk is loaded will be described.

In FIG. 21, the optical pickup 3, the electric signal generating means 4, the servo signal generating means 6, and the noise detecting means 7 are the same as those in the above embodiment.
The portion related to the rotation control of the signal processing circuit 5B is composed of the following.

  The noise interval measuring means 17 measures the time required for the light receiving device 3 to pass through the adjacent CAPA area by measuring the time interval of the noise signal corresponding to the CAPA portion of the DVD-RAM detected by the noise detecting means 7. To do. A specific configuration is the same as that in FIGS. 6 and 7 described above.

The target interval information holding means 20 holds time information required for the light receiving device 3 to pass through the adjacent CAPA area when the target disk rotation speed is reached.
The rotation control unit 21 performs control to increase or decrease the rotation speed of the spindle motor 2 so that the time interval detected by the noise interval measurement unit 17 approaches the time interval held by the target interval information holding unit 20. .

FIG. 22 shows a flowchart of the configuration extracted in FIG.
First, the light receiving device 3a is moved perpendicularly to the recording surface of the optical disc so as to cross the focal position (100).

Next, when the light receiving device 3a passes near the focal position, the reflected light received by the light receiving device 3a is converted into an electric signal by the electric signal generating means 4 (101).
Next, servo signals such as an FE signal, a TE signal, and an AS signal are generated from the electrical signal converted by the servo signal generating means 6 (102).

Next, the AS signal is sent to the noise detection means 7, and it is confirmed whether or not the AS signal includes a noise signal corresponding to the CAPA part of the DVD-RAM (103).
The noise detection method here may be any of the above embodiments.

  Next, the time interval between adjacent noise components of the noise component detected by the noise detecting means 7 is measured using the interval measuring means 17 (123). Specifically, as shown in FIG. 23A, the noise components are counted with a constant count clock, and the count number up to the next noise component is used as time interval information.

  Next, the target interval information holding unit 20 is referred to and compared with the noise interval measured using the noise interval measuring unit 17 (124). If the time measured using the noise interval measuring means 17 is longer, it is considered that the target disk rotation speed has not been reached, so control is performed to increase the disk rotation speed (127). ). If the time information held by the target interval information holding means 20 is larger, it is considered that the target disk rotation speed is higher than the target disk rotation speed, so control for increasing the disk rotation speed is performed. (125). If both are equal, it is considered that the disk is rotating at the target disk rotation speed, and therefore control is performed to maintain the current rotation speed (126).

  If the means for performing this rotational speed control is described in a block diagram, as shown in FIG. 23 (b), the drive output to the spindle motor 2, the output of the target interval information holding means 20, and the output of the interval measuring means 17 are sometimes shown. Can be displayed as an adder 50. The adder 50 corrects the drive output to the spindle motor 2 so as to eliminate the deviation of the interval, and controls the output voltage applied to the spindle motor 2. Control the speed of the disc.

  When the optical disk loaded in this way is a DVD-RAM disk, the rotation of the DVD-RAM disk can be stabilized more quickly than before by the output of the rotation control means 21 based on the output of the noise detection means 7. This can contribute to displaying the playback video on the screen of the display device in a relatively short time after the optical disk is loaded and the operation is started.

  In the flowchart of FIG. 24 showing the configuration of FIG. 21, the step of the disc discrimination means 8 for discriminating the type of the optical disc based on the output of the noise detection means 7 is the step 123 of the noise interval measurement processing in the flowchart of FIG. It is interposed between the step 124 for comparing the noise interval measured with the noise interval measuring means 17 with reference to the interval information holding means 20.

  In FIG. 24, after step 123 of the noise interval measurement process, in step 131, the noise interval detected by the noise detecting means 7 is correlated with the correlation with the address part CAPA of the DVD-RAM. If it is determined, in step 106, it is determined that the optical disk being loaded is a DVD-RAM, and an optical disk loaded with various control parameters such as the optical pickup 3, the electric signal generating means 4, and the servo signal generating means. Step 124 is executed.

  If it is determined in step 131 that there is no correlation with the address part CAPA of the DVD-RAM, it is determined in step 107 that the optical disk being loaded is not a DVD-RAM, and switching to parameters for DVD-RAM is executed. Without performing the conventional rotation control 132. Conventional rotation control is control that increases the rotation speed to a target value using an FG signal as an input signal.

  In this embodiment, the noise detection means 7 is controlled by using, for example, the AS signal output from the servo signal generation means 6 as an input signal, but the output from the electric signal generation means 4 is processed as an input signal as in the previous embodiment. You can also

  Note that the signal processing circuit 5B of FIG. 20 can be configured by a semiconductor integrated circuit and supplied to the market. 21 and 22 have been described as a part of the optical disk signal processing circuit of the optical disk reproducing apparatus, but only this can be configured as a semiconductor integrated circuit and supplied to the market to contribute to rotation control.

  The optical disc discriminating method and optical disc signal processing circuit of the present invention are useful for disc discriminating processing for discriminating the types of a plurality of optical discs. Further, the mechanism and function for detecting the CAPA of a DVD-RAM disk can be applied to the purpose of controlling the rotational speed of the disk.

1 is a configuration diagram of an optical disk reproducing apparatus according to a first embodiment that executes an optical disk discrimination method of the present invention. Flow chart of optical disc discrimination process of the embodiment Waveform diagram of AS signal when the optical pickup crosses the focal position in the same embodiment Flowchart of the optical disc discrimination process of the optical disc reproducing apparatus according to the second embodiment for executing the optical disc discrimination method of the present invention. Waveform diagram of AS signal when optical pickup is in focus ON state in the embodiment Configuration diagram of the main part of the same embodiment Flowchart of FIG. Flowchart of optical disc discrimination process of optical disc reproducing apparatus according to Embodiment 3 for executing optical disc discrimination method of the present invention Configuration diagram of a main part of an optical disk reproducing apparatus according to a fourth embodiment for executing the optical disk discrimination method of the present invention Flowchart of optical disc discrimination process of optical disc playback apparatus of same embodiment AS signal example before and after the noise removal filter of the same embodiment Configuration diagram of a main part of an optical disc reproducing apparatus according to a fifth embodiment for executing the optical disc discrimination method of the present invention Flowchart of optical disc discrimination process of optical disc playback apparatus of same embodiment Illustration of AS signal example and CAPA detection threshold level in the same embodiment Configuration diagram of a main part of an optical disc reproducing apparatus according to a sixth embodiment for executing the optical disc discrimination method of the present invention Flowchart of optical disc discrimination process of optical disc playback apparatus of same embodiment Signal waveform diagram of main part of the same embodiment Configuration diagram of optical disc reproducing apparatus according to Embodiment 7 for executing optical disc discrimination method of the present invention Flowchart of optical disc discrimination process of optical disc playback apparatus of same embodiment Configuration diagram of optical disk reproducing apparatus according to Embodiment 8 for executing optical disk discrimination method of the present invention Configuration diagram of rotation control system of optical disk reproducing apparatus of the embodiment FIG. 21 is a flowchart of the rotation control system. 21 is an explanatory diagram for measuring the interval of CAPA in FIG. 21 and an explanatory diagram of a specific circuit. Flow chart of the same embodiment General configuration diagram of an optical disk playback device Conventional disc identification flow diagram Illustration of physical address and data formation in DVD-RAM Conventional DVD-RAM discrimination flow chart Amplitude waveform diagram of PPTE signal for each disk

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 2 Spindle motor 3 Optical pick-up 4 Electric signal generation means 5, 5B Signal processing circuit 6 Servo signal generation means 7 Noise detection means 8 Disc discrimination means 9 Signal amplitude measurement means 10 Noise removal filter 11 Threshold level holding means 14 Signal amplitude measurement Means 15 Timing generation means 16 Window function forming means 17 Interval measurement means 20 Target interval information holding means 21 Rotation control means 22 Noise extraction filter 23 Signal interval measurement means 34 AS signal

Claims (15)

A light beam is applied to the recording surface of the optical disk that is driven to rotate, a noise component is detected from an output signal of a light receiving device that receives the light beam reflected by the recording surface, and the noise component and the address portion of the DVD-RAM Disc discriminating method for discriminating the type of optical disc by judging the correlation between the optical discs. The optical disc discrimination method according to claim 1, wherein when detecting a noise component, the light receiving device is moved so as to cross a focal position. The optical disc discrimination method according to claim 1, wherein when detecting a noise component, the light receiving device is moved so as to maintain the focus position. The optical disc discrimination method according to claim 1, wherein when detecting the noise component, the light receiving device is moved in the vicinity of the focal position. The type of optical disc is determined by comparing the amplitude level of the noise component detected from the reflected light intensity signal received by the light receiving device or the AS signal converted from this signal with the set threshold level to determine the presence or absence of noise. The optical disc discrimination method according to any one of claims 2 to 4, wherein the disc is discriminated. The noise component is detected from the signal of the intensity of the reflected light received by the light receiving device or the AS signal converted from the signal, and the amplitude level of the noise component and the amplitude level of the signal component passed through the low-pass filter are detected. 5. The optical disc discrimination method according to claim 2, wherein the type of the optical disc is discriminated based on the level difference. 5. A noise component is detected from a signal of intensity of reflected light received by the light receiving device or an AS signal converted from the signal, and the type of the optical disc is determined according to the noise generation interval. An optical disc discrimination method according to any one of the above. A noise component is detected from the signal of the intensity of the reflected light received by the light receiving device or the AS signal converted from this signal,
An optical disc without generating a measurement start timing for starting signal amplitude measurement and a measurement stop timing for interrupting signal amplitude measurement, and masking and measuring the noise component in a section from the measurement stop timing to the next measurement start timing The optical disc discriminating method according to claim 2, wherein the disc type is discriminated. Noise detection means for detecting a noise component from a signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disk to be rotated;
A disc discriminating unit for discriminating the type of the disc loaded using the noise detection result of the noise detecting unit, and the disc loaded when the noise component corresponding to the position of the DVD-RAM address part is detected; Signal processing circuit for an optical disk configured to determine the type of DVD-RAM. Noise detection means
Threshold level holding means for holding a threshold level for a signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disc;
The signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disc is compared with the threshold level held by the threshold level holding means to determine whether there is a noise component corresponding to the position of the DVD-RAM address portion. 10. The signal processing circuit for an optical disk according to claim 9, wherein the type of the detected and loaded disk is determined to be DVD-RAM. Noise detection means
A signal interval measuring means for detecting a signal interval according to the intensity of the light beam reflected by the recording surface of the optical disc;
10. The signal interval measuring means according to claim 9, further comprising: a signal interval measuring means for measuring a noise component interval corresponding to the position of the DVD-RAM address portion and comparing it with a reference value to determine that the type of the loaded disc is DVD-RAM. Optical signal processing circuit. Noise detection means
A noise removal filter for blocking unnecessary noise from passing through a signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disc;
A signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disc is compared with a signal amplitude that has passed through the noise removal filter, and a noise component corresponding to the position of the DVD-RAM address portion is detected and loaded. 10. The signal processing circuit for an optical disk according to claim 9, further comprising signal amplitude measuring means configured to determine the type of the disk as a DVD-RAM. Noise detection means
A noise removal filter for blocking unnecessary noise from passing through a signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disc;
A signal amplitude measuring means for comparing the signal amplitude of the signal according to the intensity of the light beam reflected by the recording surface of the optical disc and the signal amplitude passed through the noise removal filter to determine the presence or absence of noise;
10. The optical disk signal processing according to claim 9, further comprising window function forming means for generating a timing at which the light receiving means passes through the CAPA region and instructing the signal amplitude measuring means to specify a signal amplitude measurement period and a masking interval during which measurement is not performed. circuit.   An optical disk reproducing device comprising the optical disk signal processing circuit according to any one of claims 9 to 13. Noise detection means for detecting a noise component from a signal corresponding to the intensity of the light beam reflected by the recording surface of the optical disk to be rotated;
A disc discriminating unit for discriminating the type of the disc loaded using the noise detection result of the noise detecting unit, and the disc loaded when the noise component corresponding to the position of the DVD-RAM address part is detected; The type is determined to be DVD-RAM,
A signal interval measuring means for measuring an interval of noise components corresponding to the position of the DVD-RAM address portion detected by the noise detecting means;
Target interval information holding means for storing the interval of the position of the DVD-RAM address portion when the rotational drive speed reaches a target value when the optical disc is a DVD-RAM;
Rotation control for controlling the rotation of a spindle motor that rotationally drives the optical disc so that a deviation between an interval of noise components detected by the signal interval measuring unit and an interval held by the target interval information holding unit becomes small. An optical disk reproducing apparatus configured to control rotation of the spindle motor by the rotation control means when the type of the disk loaded with the disk determination means is determined to be DVD-RAM.

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