WO1998033180A1 - Recorded information reproducing device, speed control method, and disc controller - Google Patents

Abstract

The rotation of a disc is so controlled as to have a constant angular velocity (CAV) in the inner region of the disc and as to have a constant linear reading velocity (CLV) for reading by a pickup in the outer region of the disc. The control mode is switched between the CAV control and the CLV control at the position where the angular reading velocity in accordance with the CAV control agree with the linear reading velocity in accordance with the CLV control. Control data for determining the switching position between the CAV control and the CLV control are set in a recorded information reproducing device. Making reference to frame synchronization signals, etc., which are generated in accordance with reading signals which are obtained from the disc in a reproducing operation, it is judged whether or not the scanning position of the pickup reaches the switching position determined by the control data. When it does, the control mode is switched from the CLV control to the CAV control. In order to allow the target values to reflect the variations in eccentricity and surface instability of the discs, the target data can be obtained by utilizing a training period. With this constitution, the maximum rotational speed of the disc is set as high as possible in accordance with the variations of the discs to switch the CAV control and the CLV control easily.

Description

 Description Recorded information reproducing apparatus, speed control method, and disk controller

 The present invention relates to a technology for switching the rotation of a disk having an information signal recorded on a spiral track at a constant linear velocity to a constant angular velocity or a constant linear velocity, and in particular, to eccentricity, surface runout, and a recording line for each disk. It relates to technology that optimizes switching between constant angular velocity (CAV) and constant linear velocity (CLV) speed control for speed variations. For example, the present invention is effective for high-speed and stable access to an optical disc such as a data CD—R0M (Compact Disk-Read Only Memory) in which the read speed of recorded information is higher than that of an audio CD. Technology. Background art

 A disk reproducing apparatus such as a CD-R〇M in which an information signal is recorded on a spiral track at a constant linear velocity reads the information signal by scanning the spiral track with a pickup while rotating the disk. Initially, disc playback devices such as CD-ROMs played at a constant linear speed by drawing a stream of audio CDs. In other words, control is performed so that the rotation speed of the disk is made slower on the outside of the disk than on the inside, and the rotation speed of the disk is increased on the outside of the disk, so that the linear read speed due to the big-up operation is kept constant.

It is predicted that the speed of reading recorded information from a disc typified by CD-R0M will be 8x to 16x, and even 20x, the standard linear speed of the audio CD standard. Is done. Double speed of linear speed is high The angular velocity of the disk when accessing the inside of the disk is remarkably increased as the disk is accessed. If the angular velocity of the disk is too high, the vibration of the disk due to the eccentricity or runout of the disk becomes too large, and the big-bub servos such as tracking servos and focusing servos cannot be used. As a result, the pickup cannot follow the track, the reproduction operation becomes unstable, and the reproduction becomes impossible.

 For this reason, when the double speed of the readout linear velocity is equal to or more than a certain value (for example, 16 times), there is a method in which the angular velocity is controlled at a constant angular velocity at a limit angular velocity that can be handled by the big up-servo. For example, Japanese Unexamined Patent Publication No. Hei 7-31208 discloses a technique for determining the CAV control or the CLV control in accordance with the data request content from an external device and setting the operation mode of the system.

 The factors that determine the maximum speed of reading from the disk include the maximum rotation speed of the disk which can stably scan the track by the pickup, or the maximum angular speed (which is not possible for the disk) that can be handled by the pickup servo. In addition to the angular velocity just before the desired vibration occurs, there is the maximum operating speed (limit operating frequency) of the processing circuit for the recorded information read from the disk. The limit operating frequency includes the upper limit of the frequency band of the preamplifier and the upper limit of the operation speed of error correction such as ECC. This limit operating frequency determines the limit of the speed at which the recorded information is read (the signal read limit speed). The signal reading limit speed can be grasped as a linear speed that is twice as fast as the recording linear speed of the general disk.

Given both limits, the disk rotation must be controlled to the lower limit. For example, Fig. 4 shows that the change in the rotational speed of the disk in the radial direction during CLV control of the CD-ROM (the linear velocity during information recording is 1.3 [m / s]) is 1 Example for 6x speed Have been. When the limit rotation speed of the disk motor is 10 ° [rps = rotation / second], the limit of the readout linear speed (linear speed of scanning by the pickup) determined from the limit operating frequency of the processing circuit for the recorded information is 8 If the speed is equivalent to double speed (the rotation speed of the innermost track is 100 [rps] or less), CLV control at 8x speed must be adopted. This is because a circuit whose readout linear velocity limit determined by the limit operating frequency is equivalent to 8 × speed cannot process recorded information read at a rotational speed of 100 [rps]. On the other hand, even if the linear velocity limit is equivalent to 16 times speed (the rotational speed of the innermost track is about 130 [rps]), if the limit angular velocity is 50 [rps], 50 The recorded information must be read using the CAV method near [rps].

 However, if the angular velocity at the force limit is, for example, 66 [rps] shown by Pj in Fig. 4 and the linear velocity limit is equivalent to 16x speed, the disk shown by Pi at 66 [rps] CAV control The linear velocity limit is exceeded for tracks closer to the outer circumference than the radial position of the disk, and the limit angular velocity is exceeded for tracks closer to the inner circumference than the radial position of the disk indicated by Pi with 16x CLV control. Would. In this case, if the disc rotation is controlled within the capability range by either CLV or CAV, the reading speed of the recorded information is limited by the angular speed limit and the linear speed limit (more precisely, the signal reading limit speed). ) Significantly lower than both.

Therefore, in such a case, the present inventors perform CAV control near the limit of the angular velocity near the inner periphery of the disk, and perform CLV control near the limit of the linear velocity near the outer periphery of the disk. By switching the speed control between CAV and CLV at the position indicated by Pi in the figure, the signal processing circuit can fully utilize its capabilities near the limits of angular speed and linear speed. And found that the recorded information could be read at the highest speed. That is, the inner circumference Starts playback of a disc on which information is recorded from CAV to the outer circumference in CAV. Since the circumference of the track becomes longer in proportion to the diameter, the linear velocity at the time of reading becomes gradually higher as the reading track advances toward the outer periphery of the disk. Switch to CLV control when the read linear velocity reaches the limit of linear velocity.

 However, the limit of the angular velocity at which the disk starts to vibrate undesirably depends not only on the performance of the disk motor, but also on the eccentricity and runout of the disk. Furthermore, the constant linear velocity for recording information on a disc is, for example, in the range of 1.2 [m / s] to 1.4 [m / s] in the CD-ROM standard. The angular velocity limit is equally dependent on velocity variations. For this reason, it is not possible to accurately determine the point at which the control between CAV and CLV is switched so as not to exceed the performance limit without considering such individual differences of the disks.

 In addition, when the limits of angular velocity and linear velocity are defined, if the point at which control of CAV and CLV is switched is determined based on the read linear velocity, the actual read bit rate of the information signal is monitored during CAV reproduction. In addition, the readout linear velocity must be known. In CAV control, the linear velocity changes every moment, so the calculation requires a relatively long time, and a calculation error that cannot be ignored is expected. If a relatively large error is expected in the calculation of the readout linear velocity, which changes every moment under CAV control, the performance of the limit of the motor and the signal processing circuit cannot be fully exhibited.

 An object of the present invention is to make it possible to easily perform switching control between CAV and CLV when reading recorded information on a disc by using both CAV control and CLV control.

Another object of the present invention is to provide a method for reading recorded information on a disc by using both CAV control and CLV control, such as eccentricity of the disc and deviation of the disc. The purpose is to be able to accurately and easily grasp the point at which CAV and CLV control is switched in consideration of individual differences.

 Still another object of the present invention is to increase the speed of operation by sufficiently exhibiting the maximum operation performance of a motor for rotating a disk and a circuit for processing signal information read from the disk. It is in.

 The above and other objects and novel features of the present invention will become apparent from the following description of the present specification. Disclosure of the invention

 According to the present invention, CAV control is performed on the inner circumference side of the disk, and CLV control is performed on the outer circumference side. Switching between CAV control and CLV control is performed at a point where the linear velocity read by CAV control substantially matches the linear velocity read by CLV control. I do. At this time, control data for determining the switching point between the CAV control and the CLV control is set inside the recording information reproducing apparatus, and information generated based on a read signal from the disc during a disc reproducing operation. It is determined whether or not the scanning position by the pick-up has reached the switching point determined by the control data, and when it reaches the switching point, switching between the CLV control and the CAV control is performed.

 The first invention determines arrival at the target value data using a synchronization signal such as a frame synchronization signal, and the second invention uses absolute position information (absolute time information or absolute time information) such as A time. (Also referred to as time information). In order to reflect the individual difference of the disk in the target value data, the training period (the operation period for detecting the characteristics of the disk prior to the start of the reproducing operation by the recording information reproducing apparatus) is used to obtain the target value data. You can get an overnight.

Switching between CAV control and CLV control using a synchronization signal according to the first invention The replacement will be described.

That is, an information signal is recorded on the disk at a constant linear velocity at a predetermined bit cycle. For example, the recorded information on an audio CD disc is obtained by sampling, quantizing, and encoding audio information. According to the CD standard, the sampling frequency is 44. Ι 、, and one frame contains six pieces of sampled data. Therefore, writing of signal information to the disk is performed at a constant linear velocity so that one frame is 44.1 KHz / 6 = 7.35 KHz. A synchronization pattern is provided at the beginning of the frame format. When reading the recorded information from the disk, if the rotation of the disk is controlled so that the synchronization pattern can be detected at 7.35 KHz, the reading linear velocity by the pickup can be kept constant. According to the CD standard, the standard frequency of one frame is absolute, such as 7.35 KHz (the bit period or bit rate is approximately 230 ns accordingly), but there is an allowable range for the linear writing speed. It has been done. Even if the write linear velocity fluctuates within the allowable range, if the rotation of the disc is controlled so that the detection frequency of the synchronization pattern becomes the standard frequency and the recording information is read, the recording information is automatically recorded at the linear velocity at the time of recording. Can be read. CD-ROMs for overnight use also conform to the above standards. When playing back a CD-ROM at 8x speed, if the disc rotation is controlled so that the detection frequency of the sync pattern is 8 times the standard frequency, the recorded information is read and processed at a constant linear velocity. be able to. The present invention focuses on the fact that the bit cycle defined by the standard frequency is constant irrespective of the variation in the linear writing speed, and when reading the signal information from the disk by pick-up, Using the frequency of the synchronization signal obtained in a cycle proportional to the reading speed (for example, the detection frequency of the synchronization signal), the rotation control of the motor is changed from CAV to CLV. Switch.

The frequency at which the above switching is performed depends on the limit rotation speed of the disc model that can stably scan the spiral track by pick-up, and the amplifier and digital for processing the signal information read from the disc. It can be determined in consideration of the limit operating frequency of the signal processing circuit and the like. CAV control is performed at a constant angular speed close to the limit rotation speed. The CLV control is performed, for example, by controlling the detection frequency of the frame synchronization pattern to a double speed value (for example, 16) of the signal reading with respect to the standard speed. At this time, when the limit angular velocity is, for example, 66 [rps] shown by Pj in FIG. 4, the limit operation frequency follows the processing of the read signal at a constant linear velocity of 16 times as illustrated in FIG. If the frequency is possible (if the limit (limit linear speed) of the readout linear velocity determined based on the limit operating frequency is equivalent to 16 times speed), switching from CAV to CLV is indicated by Pi in FIG. Perform in position. The switching is performed when the frequency of the synchronization signal reaches a target frequency for keeping the reading linear velocity constant. For example, according to FIG. 4, when the detection frequency of the frame synchronization pattern becomes a multiple of the signal reading speed (16 times) of the standard speed, the control is switched from CAV to CLV. Switching from CLV to CAV is performed when the rotational angular velocity of the disk reaches the constant angular velocity. As described above, when switching the disc rotation control from CAV to CLV when reading the recording information of the disc by using both the CAV control and the CLV control, the frequency of the synchronization signal obtained from the read signal depends on the frequency of the read. It may be monitored whether the target frequency reaches a constant linear velocity. Variations in the linear writing speed of the disk do not affect the frequency detection of the synchronization signal. While variations in the write linear velocity are allowed, the actual linear velocity that changes sequentially under CAV control does not have to be calculated. According to Thus, it is possible to accurately and easily grasp the point at which the control between CAV and CLV is switched. As a result, the means for rotating and scanning the disk and the circuit for processing the signal information read from the disk can be fully utilized to achieve the maximum operating performance, and the speed of the signal reading operation or the reproducing operation can be increased.

 The switching point from CAV to CLV can be roughly predicted from the critical performance such as the critical angular velocity and critical linear velocity. The prediction point can be specified from the absolute time information or the absolute address information obtained from the record information. Predictable points in time will have errors within the allowed linear velocity variation. It is sufficient to determine whether or not the frequency of the synchronization signal reaches the target frequency for keeping the reading linear velocity constant within a range that can cover the error. In the case of a de nosque in which signal information is recorded from the inner circumference to the outer circumference, the prediction range in which the error can be covered is specified in advance using absolute time information or absolute address information read from the recorded information, and absolute When the time information or the absolute address information becomes the lower limit of the specified range, the determination can be started.

 The same is true at the time of switching from CLV to CAV, and the operation for determining whether the rotational angular velocity of the disk reaches the target angular velocity for keeping the angular velocity constant is based on absolute time information or absolute address read from recorded information. It should be started when the source information reaches the upper limit of the prediction range in which the error can be covered.

 The synchronization signal may be a synchronization signal other than the frame synchronization signal. It may be a synchronous clock signal generated by a PLL circuit for identifying the pulse width of the information signal read from the disk as data.

From another viewpoint, the speed control according to the first invention is realized. The recording information reproducing apparatus has a register unit for storing information for specifying a switching point between the control of constant angular velocity and the control of constant linear velocity, and the information generated based on the information signal read from the disc and the information By comparing the information set in the register means with the constant linear velocity control or the constant angular velocity control.

 More specifically, the speed control means of the recording information reproducing apparatus includes a register for setting the target rotational speed data of the disk for controlling the angular velocity constant and the target frequency data for controlling the linear velocity constant. Means for determining whether the linear velocity under the constant angular velocity constant velocity control has reached the target linear velocity constant linear velocity and the frequency of the synchronization signal synchronized with the reading speed of the information signal read from the pickup. The control is performed by comparing the target frequency data set in the register means with the target frequency data, and using the result of the determination, the control of constant angular velocity is switched to the control of constant linear velocity.

 At this time, the speed control means determines whether or not the angular velocity under the control of the constant linear velocity has reached the target angular velocity of the constant angular velocity by comparing the rotational speed of the disk with the target rotational speed data, Using the result of the determination, the constant linear velocity control can be switched to the constant angular velocity control.In addition, the velocity control means determines that the linear velocity under the constant angular velocity control has reached the target linear velocity with the constant linear velocity. When switching from constant angular velocity control to constant linear velocity control by judging the state, the absolute position information of the track generated by the information signal read from the disk is acquired as switching position information, and the acquired switching position information and disk reading are obtained. Based on the magnitude relationship with the absolute position information generated from the information, it is possible to select either constant angular velocity control or constant linear velocity control. Can.

Next, switching between CAV control and CLV control using absolute position information on a track according to the second invention will be described. The maximum rotational speed of the disk in terms of the follow-up performance of the pickup servo is affected by the state of the disk such as eccentricity and runout. In order to reflect the maximum rotation speed affected by such an influence at the time of switching between the CAV and CLV control, the speed control means for controlling the rotation of the disk at a constant angular speed or a constant reading linear speed by pick-up, the rotation of the disk is controlled by the aforementioned method. Assuming that the linear velocity is constant, switching information determined based on the track position when the angular velocity of the disk reaches the limit angular velocity before undesired vibration occurs on the disk is obtained, and this switching information is used. When the specified state is detected, the constant linear velocity and the constant angular velocity control are switched to each other.

 In this way, by taking into account the individual differences of individual disks such as eccentricity and runout, the maximum rotational speed of the disk is set to the limit of the capacity according to the individual differences, and the difference between CAV and CLV is determined. The switching point can be controlled. Therefore, it is possible to optimize the switching point between the constant angular velocity and the constant linear velocity speed control with respect to the eccentricity, surface runout, and variation of the recording linear velocity for each disk, and read the data from the disk rotating the disk or the disk. The maximum operational performance of the circuit that processes the signal information can be fully exhibited, and the speed of the signal reading operation or the reproducing operation can be increased.

 As a more detailed aspect, for example, the absolute position information of the track included in the information signal recorded on the spiral track can be used as the switching information. For example, a CD-ROM disc uses absolute position information as absolute time information from the start of the innermost track to the end of the outermost track. DVD includes absolute address information as absolute position information.

When the switching time between CAV and CLV is managed by absolute position information, the switching time causes unwanted vibration on the disk and the It is determined by the limit angular velocity before the signal cannot be responded and the signal read limit speed determined based on the limit operation frequency of the amplifier and digital signal processing circuit for processing the signal information read from the disk. The signal reading limit speed is understood as double speed of the recording linear speed of the disk.

 In order to grasp the switching time point, obtain the limit angular velocity just before the disk becomes unviable due to undesired vibration and cannot respond to pick-up servo by evening, and a predetermined double speed (recording of the disk as signal limit speed) When the disk is rotated at a constant linear velocity (double the linear velocity), the switching position information on the track is determined in advance based on the track position at which the rotation of the disk reaches the limit angular velocity. Then, it is monitored whether or not the absolute position information sequentially read from the speed-controlled disk reaches the switching position information. When the arrival is detected, the constant angular velocity control is applied to the constant linear velocity control. The constant speed control is switched to the constant angular speed control.

 The switching position information is obtained, for example, by obtaining a half-disc of the disk reaching the limit angular velocity when the disk is rotated at a constant linear velocity at a predetermined multiple of the measured disk recording linear velocity, and the radius and the maximum of the disk are obtained. Time information obtained by dividing the area of the disk between the radius of the inner track and the product of the track pitch and the recording linear velocity can be used.

 Since the switching point between CAV and CLV is specified by the absolute position information, the actual read bit rate of the information signal is monitored and changes every moment, as in the case of switching control using the read linear velocity under CAV speed control. The switching control can be performed accurately and easily, compared to a method of calculating the actual linear velocity and calculating the actual linear velocity, which has a large error.

The limit angular velocity is set during the training period after detecting the mounting of the disc. The measurement may be performed in accordance with the state of eccentricity and surface runout specific to the disk, or may be obtained as a double speed maximum angular speed that is guaranteed in advance. In the former case, for example, the disk is gradually accelerated while monitoring the amplitude of the pickup servo signal for the spiral track, and the angular velocity of the disk when the amplitude of the peak-up error signal reaches a predetermined value. Can be defined as the limiting angular velocity. When determining the limit angular velocity in this way, considering the individual difference of each disk such as eccentricity and runout, the limit angular velocity can be set to a point at the limit of the capacity according to the individual difference.

 As described above, it is possible to optimize the switching point of the speed control at the constant angular velocity and the constant linear velocity with respect to the eccentricity, the runout and the variation of the recording linear velocity for each disk. Therefore, it is possible to sufficiently develop the limit operation performance of the circuit for processing the signal information read from the disk disk rotating disk, thereby realizing a high-speed signal reading operation or reproducing operation. From a different viewpoint, the recording information reproducing apparatus for realizing the speed control according to the second invention controls the rotation of the disk at a constant angular velocity on the inner peripheral side of the disk, and picks up on the outer peripheral side of the disk. Speed control means for controlling the rotation speed of the disk so as to keep the reading linear velocity constant, and the speed control means controls the linear velocity under the constant angular velocity control to reach the linear velocity under the constant linear velocity control. A switching means for storing the absolute position information of the disc as switching position information, the absolute position information generated based on the information signal read from the disc, and the switching position information set in the registration means. By comparing the magnitudes of the two, the control with constant linear velocity or the control with constant angular velocity is selected. BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 shows the switching between CAV control and CLV control using the frame synchronization signal. FIG. 3 is a block diagram of an example of a replaceable CD-ROM playback device.

 FIG. 2 is an explanatory view schematically showing the relationship between the disk radial position and the disk rotation speed when driving the disk by switching between CAV control and CLV control.

 FIG. 3 is an explanatory diagram showing states of a frame synchronization signal and a disk rotation frequency signal in each of the CAV control and the CLV control.

 FIG. 4 is an explanatory diagram exemplifying a change in the number of rotations of the disk according to the radial position during the CLV control of the CD-ROM from a standard speed to a 16-times speed.

 FIG. 5 is an explanatory diagram of an allowable range regarding a linear velocity of information recording on a CD-ROM disc.

 FIG. 6 is an explanatory diagram showing the relationship between the linear velocity of recorded information and the reproduction time on a CD-ROM disc.

 FIG. 7 is an explanatory diagram of a frame format of recorded information on a CD-ROM disc.

 FIG. 8 is an explanatory diagram of a subcode frame format on a CD-ROM disc.

 Fig. 9 is an illustration of the Q-code frame format in CD-ROM.

 FIG. 10 is a block diagram of a CD-R0M reproducing apparatus in which the function of the CAV speed error detection circuit in FIG. FIG. 11 is an explanatory diagram showing a CAV control state focusing on the subvolume of the CD-ROM reproducing apparatus of FIG.

 FIG. 12 is an explanatory diagram showing a CLV control state focusing on the subvolume of the CD-ROM reproducing apparatus of FIG.

Fig. 13 shows switching between CAV control and CLV control using A time FIG. 1 is a block diagram showing an example of a CD-R 0 M playback device that is enabled.

 FIG. 14 is an explanatory diagram showing an example of a calculation process for acquiring switching position information.

 FIG. 15 is an explanatory diagram showing an example of a method for acquiring a recording linear velocity. FIG. 16 is an explanatory diagram showing an example of a state in which the switching time between the CAV control and the CLV control is different depending on the limit angular velocity and the recording linear velocity. FIG. 17 is a flowchart of a process of acquiring the limit angular velocity from the table and calculating the switching position information.

 FIG. 18 is a flowchart of a process of measuring the limit angular velocity and calculating switching position information.

 FIG. 19 is a flowchart in the case where the switching position information is acquired using the table during the training period every time the disc is mounted.

 FIG. 20 is a block diagram of a CD-R0M reproducing apparatus in which the function of the CAV speed error detecting circuit in FIG. 13 is realized by a micro computer. BEST MODE FOR CARRYING OUT THE INVENTION

 << CD-ROM disc >>

As shown in Fig. 6, CD-ROM disk 1 (hereinafter simply referred to as disk 1) has information recorded on spiral tracks at a constant linear velocity (Constant Linear Velocity). The unit of the recording format is called a frame FRM. As shown in (A) of FIG. 7, a frame synchronization pattern exists first, followed by, for example, a subcode, data overnight, parity, data, and so on. One night, there is a parity one area. One frame is defined as 588 channel bits. The information contained in the frame is particularly restricted However, a modulation method called EFM (Eight to Fourteen Modulation) is adopted. This EFM is a process for converting data of 8 bits per symbol into 14 bits. Further, a 3-bit margin bit is added to remove the DC component after the conversion, and NRZI modulation is performed. The data of one frame is stored by being divided into 12 symbols. The numerical value shown under each area of the frame format shown in (A) of FIG. 7 is the number of channel bits in the corresponding area. Disc 1 conforms to the standard for audio CDs, and the recorded information on audio CDs is obtained by sampling, quantizing, and encoding audio information. The sampling frequency at this time is 44.1 KHz, and one frame includes six sampling frequencies. Therefore, the writing control at a constant linear velocity on the disk 1 is performed so that one frame is 44.1 KHz / 6 = 7.35 KHz. In CLV control with the same linear velocity as the writing linear velocity (also referred to as recording linear velocity), the synchronization pattern located at the head of the frame format can be detected at 7.35 kHz. That is, the detection frequency of the frame synchronization pattern is compared with the reference frequency (7.35 KHz) to control the rotation speed of the disk 1. For example, if it takes 7Γ · r1 track scanning distance to demodulate 10 frames of data on a track of radius r 1 shown in Fig. 7 (B), then a track of radius r 2 requires 10 frames. Requires a track scan distance of 7Γ · r 1 for demodulation of the data.

As shown in Fig. 8, the subcode following the frame synchronization pattern is assigned to eight channels of P, Q,, S, T, U, V, and W, and each content is completed in 98 frames. I do. That is, the information of eight channels, P, Q, R, S, T, U, V, W, is meaningful only for 98 frames. The first two bits S0 and S1 of the eight subcode channels are A subcode synchronization signal indicating the beginning of the code. The subcode P channel (P code) is used as a data cue signal. The subcode Q channel (Q code) records time information and control information, which are examples of absolute position information described later. The R to W channels record graphic information.

FIG. 9 shows an example of the Q code format (Q code frame format) of Q1 to Q96. The control gives a distinction whether the data of the frame is audio information or data. The address has four bits Q5 to Q8, and when the 4-bit (code) power is s (000 1), the Q code frame format shown in FIG. 9 is obtained. TN〇 indicates the track number to which the 98 frame belongs. That is, the track can be distinguished into one or more areas by the track number TN #. X indicates a region obtained by further subdividing TN0. MIN, SEC, and FRAME indicate the relative time (time within the track number) from the start of the area of the track number indicated by TNO to the 98th frame. MIN indicates minutes, SEC indicates seconds, and FRAME indicates 0/75 seconds to 74/75 seconds. AMIN, ASEC, and AFR AME indicate the absolute time (A time) from the program start position of the track (0 minutes 0 seconds). The A time is an example of the absolute position information. AMIN indicates minutes, ASEC indicates seconds, and AFR AME indicates 0/75 seconds to 74/75 seconds. 0 is a delimiter code. Here, the values of FRAME and AFRAME are times in which the unit time of every 98 frames is the minimum unit. That is, one frame is 7.35 KHZ, and the time of 98 frames is (1 / 7.35 KHZ)-98 = 1/75 second. Therefore, the track number time that can be recognized from MIN, SEC, and FRAME, and the A time that can be recognized from AMIN, ASE C, and AFR AME are the time for every 98 frames (1/75 second). Is done.

 Therefore, the absolute time (A time) as the absolute position information from the program start position of the track (◦ minute 0 second) can be obtained by demodulating the Q code in the subcode of 98 frames on disk 1. be able to. The program start position is the start position of the first frame of recording information such as audio information.

 At this time, the standard specification regarding the linear velocity of the disc 1 allows a width of 1.2 m / sec to 1.4 m / sec, and the linear velocity is determined when the disc 1 is manufactured. The A time and the time in the track number are times according to the write linear velocity determined in the manufacturing stage. However, at any linear velocity, the frame synchronization pattern must appear at 7.35 KHz as described above. The difference in linear velocity is manifested as a difference in the physical length of one frame on a track, and the lower the linear velocity, the higher the information recording density. For example, as shown in Fig. 6, the A-time at a radius of 58 mm of the outermost track of disk 1 is 74 minutes at a linear velocity of 1.2 m / sec and 64 minutes at a linear velocity of 1.4 m / sec. . As described above, in the disk 1, even at the same radial position, the A time is different due to the difference in the linear velocity. Even if there is such a difference in the linear velocity in the disc 1, when the spiral track TRK is continuously reproduced, the rotation of the disc 1 is controlled by servo control of the rotation of the disc 1 using the frame synchronization pattern. There is no hindrance to control at a constant speed.

 《CD-ROM playback device》

FIG. 1 shows a block diagram of a CD-ROM playback device. The CD-ROM reproducing device shown in FIG. 1 is a device for reproducing the information of the disk 1, and is interfaced with a host device 9 such as a personal computer. The one indicated by 8 controls the entire CD-ROM playback device. This is a micro-computer that constitutes a system controller for operation. Data information obtained by reading from the disk 1 and performing signal processing is provided to the host device 9 via a CD-ROM decoder 6. The disk 1 is rotated by a spindle motor 2 and information recorded on the disk 1 is read out using a pickup 3 moved in the radial direction of the disk 1. As the rotation speed of spindle motor 2 increases, the signal reading speed by pickup must also increase. The rotational speed of the spindle motor 2 has a limit, and if it exceeds this limit, the spindle motor 2 will generate undesired vibration. If undesired vibrations occur in the spindle motor 2, tracking servos, etc., cannot respond. Also, if the angular velocity of the disk is too high, the vibration of the disk due to the eccentricity and runout of the disk becomes too large, and the tracking servo and the like cannot cope. Thus, there is a limit to the maximum angular velocity of the disk when reading signal information from the disk 1.

 The pickup 3 is configured to irradiate the disk 1 with laser light from a semiconductor laser source via an objective lens or the like (not shown), receive the reflected light by a light receiving unit including a photodiode, and perform photoelectric conversion. . Pickup 3 is a focusing mechanism that moves the objective lens in the depth direction to focus the objective lens on the disc signal surface, and a tracking actuator that moves the objective lens along the track TRK. Prepare for the evening. Since the operating range of the tracking operation is limited, a thread mode (not shown) is provided to move the entire pickup 3 in the radial direction of the disc 1.

The information signal read from the pickup 3 is supplied to a signal detection and shaping circuit 4 including a high-frequency amplifier as a preamplifier, a waveform shaping circuit, and a data slice circuit. High frequency amplifier exceeds the upper limit of its frequency band Can not work. The upper limit is the operation limit of the amplifier. The signal detection and shaping circuit 4 outputs an EFM signal 58, a focus error signal FER, and a tracking error signal TER based on the input signal information.

 The focus error signal F E R and the tracking error signal T E

R is supplied to the big-up servo circuit 11 and the microcomputer 8. The tracking error signal TER is a frequency signal having an amplitude corresponding to the relative position between the pickup 3 and the track, and the focus error signal FER is a frequency signal having an amplitude corresponding to the relative distance between the objective lens and the disk signal surface. is there. Although not particularly limited, the amplitude of the signals T ER and F ER is proportional to the magnitude of the deviation from the track and the deviation from the optimum depth of focus. The pickup servo circuit 11 generates a pickup servo control signal 80 for canceling the deviation based on the focus error signal F ER and the tracking error signal T ER. The pickup servo control is a focusing servo and a tracking servo. The focusing servo controls the objective lens so that the relative distance between the objective lens and the disc signal surface is kept constant with respect to the runout of the disc 1, and the disc signal surface is located within the focal depth of the laser beam. Operation. The tracking servo is a control for accurately tracing the laser beam of the pickup 3 along the track TRK even when the disk 1 rotates eccentrically. In addition, the pickup servo circuit 11 controls the thread feed of the pickup 3. Thread feed is performed by controlling the movement of a track (not shown) to forcibly cause the pickup 3 to jump from the current track position to another desired track position. is there.

As a result, the pickup 3 becomes an eccentric or out-of-plane disk 1. It can also follow the track. However, as the rotation of the disk 1 increases, the repetition period of the eccentricity and the runout becomes shorter, and the amplitudes of the tracking error signal TER and the focus error signal FER increase. If the rotation of the disk 1 is too high, the amplitude of the tracking error signal TER and the focus error signal FER will be too large, and the tracking and focus servo will not be able to cope.

 The digital signal processing circuit 5 includes, but is not limited to, a PLL circuit 50, a demodulation circuit 51, a data control circuit 52, a RAM 53, a subcode processing circuit 54, a pickup servo circuit 11, And a spindle sensor circuit 7.

 The PLL circuit 50 is a circuit for identifying the pulse width of the EFM signal 58 that has been sliced overnight as the data, and outputs a bit clock 56 and an EFM data 57. ? ] ^ The operation reference clock signal of the circuit 50 is given from a crystal oscillation circuit (not shown). The frequency of the bit clock 56 changes according to the frequency of the EFM signal 58, that is, the speed at which the recording information is read from the disk 1 (read linear speed). The changing point of EFM de 57 is synchronized with the bit clock 56. The bit clock 56 is used as a synchronization signal for determining the operation speed of the subsequent demodulation circuit 51, subcode processing circuit 54, data control circuit 52, and the like. That is, the signal processing speed in the digital signal processing circuit 5 is changed to follow the speed of reading recorded information from the disk. If the reading speed exceeds the limit, the digital signal processing circuit 5 cannot perform the following operation. A circuit portion that does not need to follow the signal reading speed is operated in synchronization with a predetermined clock signal obtained by dividing the oscillation output of the crystal oscillation circuit (not shown).

The demodulation circuit 51 demodulates the EFM data 57. Data control circuit 5 2 receives the demodulated frame data and parity, corrects the error, extracts data from the error-corrected information in accordance with the information format of the disk 1, and extracts the extracted data information as CD-ROM data. Supply to coder 6. The CD-ROM decoder 6 further performs an error correction specific to the CD-ROM format for the input data on the input data and transfers the error-corrected data information to the host device 9. Then, the data is converted to a predetermined data format and output. The RAM 53 is used as a work area of the data control circuit 52 or a data storage area. The sub-code processing circuit 54 receives the information of the frame sub-code area output from the demodulation circuit 51 and supplies the microcomputer 8 with an 8-channel sub-code signal SIG1 every 98 frames. As a result, the microcomputer 8 can recognize the head of the subcode using, for example, the subcode synchronization signals S0 and S1, and recognize the A time from the Q code every 98 frames. it can. SIG1 includes subcode synchronization signals S0, S1 and other eight channels (P, Q, R, S, T, U, V, W). The Α time recognized in this way is used for calculation of linear velocity and track jumping. The microcomputer 8 gives a Q code to the host device 9, for example, so that the host device 9 can display the current playback time based on the A time.

 The CLV speed error detection circuit 70 receives the frame synchronization signal from the demodulation circuit 51.

-Detected signal (frame synchronization signal) SIG2, compares the detected frequency with a target frequency that is a predetermined multiple (for example, 16 times) of the 7.35 KHz reference frequency, and calculates the servo corresponding to the difference. Outputs error signal SIG3. The spindle servo circuit 7 controls the frequency based on the servo error signal SIG3 when the motor control at a constant linear velocity is instructed by the speed control mode instruction signal SIG4 output from the microcomputer 8. The driver control signal SIG 6 of the driver 10 is controlled so as to cancel the difference. By this negative feedback control, the rotation of the spindle motor 2 can be controlled such that the linear velocity of the recording information readout by the big group 3 is constant. As illustrated in FIG. 3, when the CLV control is performed, the frame synchronization signal SIG2 is set to a constant frequency, and the frequency of the rotation frequency signal SIG7 is reduced as it approaches the outer circumference. The data indicating the target frequency is read from, for example, the ROM 82 and set in the register REG 1 of the microcomputer 8. According to this example, the setting data can be regarded as data indicating a double speed value such as 16 times speed. The CLV speed error detection circuit 70 receives the target frequency data SIG 8 corresponding to the double speed value data from the register REG 1 and sets the frequency of the frame synchronization signal SIG 2 to a frequency twice as high as the reference frequency. Then, it outputs the signal SIG 3 of the sensor vowel.

The motor driver 10 has a generator that outputs a rotation frequency signal SIG 7 corresponding to the rotation speed of the spindle motor 2. This frequency signal SIG 7 is given to the CAV speed error detection circuit 71. The CAV speed error detection circuit 71 detects the rotation angular speed (rotation speed) of the spindle motor 2 based on the frequency signal SIG7. The CAV speed error detection circuit 71 generates a difference between the angular speed detected from the frequency signal SIG 7 and the target angular speed when the spindle servo circuit 7 is instructed to control the motor at a constant angular speed by the speed control mode instruction signal SIG 4. Outputs the corresponding servo error signal SIG5. The CAV speed error detection circuit 71 cancels the difference between the angular velocities based on the servo error signal SIG5 when the motor control instruction with the constant angular velocity is received by the speed control mode instruction signal SIG4. Control the drive control signal SIG 6 of the motor driver 10. With this negative feedback control, the spin 2 can be rotated at a constant angular velocity. As illustrated in FIG. 3, under the CAV control, the frequency of the frame synchronization signal SIG2 increases as it approaches the outer periphery of the disk, and the rotation frequency signal SIG7 has a constant frequency. The data indicating the target angular velocity is set in the register REG2 as a limit angular velocity detected according to, for example, a process described later. The CAV speed error detection circuit 71 receives the target angular velocity data SIG 9 from the register REG 2 and outputs the servo error signal SIG 5 by comparing with the angular velocity of the rotation frequency signal SIG 7. .

 《Basic control of switching between CAV and CLV》

As described above, the speed control of the disk 1 for reading the information signal from the disk 1 can be CAV control or CLV control. The switching point between the CAV control and the CLV control is a point where the reading linear velocity by the CAV control and the reading linear velocity by the CLV control mutually match, as exemplified in FIG. As a prerequisite for switching the speed control at the point, the target frequency data is limited so that the playback capacity can be used to the fullest according to the individual difference of the disc and the hardware capacity of the CD-ROM playback device. Set the target angular velocity data to register REG2. In other words, the target angular velocity data is based on the individual difference of the disk such as the eccentricity and runout of the disk 1, and furthermore, depending on the maximum rotation capacity of the spindle 2 and the disk 2, the disk 1 generates an undesired vibration and the tracking servo決定 Determined in consideration of the limit angular velocity before the focusing servo cannot respond. The target frequency data is calculated based on the maximum recording linear velocity that can be reproduced in accordance with the capabilities (such as the maximum operating frequency) of the signal detection and shaping circuit 4 and the digital signal processing circuit 5. It is determined as a double speed with respect to the recording linear velocity of 1. This target frequency is not affected by the individual difference of the disc 1. The CD-ROM playback device shown in FIG. 1 uses the frame synchronization signal SIG2 to detect the switching position. In the CD-ROM reproducing apparatus shown in FIG. 13 described later, the A time is used for detecting the switching position.

 《Determination of target angular velocity data》

 As described above, the target angular velocity data is affected by individual differences of disks such as eccentricity and runout. Therefore, it is optimal to determine the target angular velocity data by actually measuring the effects of eccentricity and runout when the disk 1 is rotated. Alternatively, the target angular velocity data is determined in advance in consideration of the allowable range for the eccentricity and runout of the disk and the disk motor's two rotation capabilities, stored in the ROM 82, and the above-described R0M82 is used for each reproduction operation. You may load it to Regis Evening REG 2.

Here, a method for determining the target angular velocity data by actually measuring the effects of eccentricity and runout when the disk 1 is rotated will be described. The determination of the target angular velocity data is performed by, for example, the microcomputer 8 during the training period after the detection of the mounting of the disk 1. That is, the microcomputer 8 monitors the amplitude of the tracking error signal TER and the focus error signal FER so as to determine the limit angular velocity so that the state of eccentricity and runout inherent to the disk can be considered. The rotation of 1 is accelerated, and the angular velocity (for example, the number of revolutions per second) of the disk when one of the amplitude of the tracking error signal TER and the focus error signal FER reaches a predetermined value is detected as the limit angular velocity. The detected limit angular velocity is stored in the register REG2 of Microcomputer Night8. The predetermined values of the amplitudes of the tracking error signal TER and the focus error signal FER are amplitudes at which the tracking and focusing servos cannot be handled, and can be uniquely determined by the servo control capability. This The predetermined value of the amplitude is not particularly limited, but the value read from the ROM 82 and set in the register REG3 is used. Thus deciding the limit angle speed, the can in consideration of individual differences of the individual disk such as eccentricity and surface wobbling, Note _c can be set to point ability barely limit angular velocity according to the individual difference, the disk 1 Although not specifically shown, the mounting of the disk 1 can be detected by a change in the output of an optical sensor that detects that the disk 1 is mounted on the tray.

 《CAV and CLV switching control using frame synchronization signal》

 First, control of switching between CAV and CLV using a frame synchronization signal will be described with reference to FIG.

 The microcomputer 8 shown in Fig. 1 implements the control logic for switching between CAV and CLV, and implements the imaginary counters CNT1, CNT2, REG1, REG2, REG6 to REG8, and the comparator. It is realized by overnight CMP 1 to CMP 4 and the switching judgment unit LOG. These control logics are realized by a CPU (Central Processing Unit), a CPU operation program, and peripheral circuits built into the microcomputer. The ROM 82 stores an operation program of the CPU, constant data, and the like. The RAM 83 is used as a work area of the CPU or a temporary storage area of data.

The target frequency data set in the register REG 1 is actually double speed value data with respect to the standard speed, and the double speed data which is within the maximum operating frequency of the signal detection and shaping circuit 4 and the digital signal processing circuit is high speed. Value data. The target angular velocity data set in the register REG2 is the data measured as described above or data read from the ROM 82. For example, if the critical linear velocity of a CD-ROM playback device is a linear velocity equivalent to 16 times speed and the critical angular velocity is 66 [rps], the register RE G 1 has 16 times The double speed value data corresponding to the speed is set, and the register value REG 2 is set to 66 [rps].

 The evening counter CN T1 counts and outputs the number of cycles of the frame synchronization signal SIG2 every period of the reference frequency of 7.35 KHz. For example, if the frame synchronization signal has a frequency corresponding to 16 × speed, the count value 16 is output every cycle of the 7.35 KHz reference frequency. The CMP1 comparator compares the output of the imaginary counter CNT1 with the set value of the register EG1 and determines that the output value of the imaginary counter CNT1 is equal to or greater than the set value of the register REG1. Assert control signal ø1. For example, when the double speed value of the register REG 1 is 16 times faster, the target frequency is 16 times the reference frequency. When the switching determination unit LOG instructs the servo circuit 7 to perform CAV control, the frequency of the frame synchronization signal SIG 2 reaches the target frequency for CLV control according to the assertion state of the control signal ø1. , The CLV control is instructed to the servo circuit 7 by the speed control mode instruction signal SIG4. As a result, the control of the spindle 2 is switched from CAV to CLV.

The evening counter CN T2 counts and outputs the number of cycles of the rotation frequency signal SIG7, for example, every second. The comparator CMP 2 compares the output of the timer counter CNT 2 with the set value of the register REG 2, and when the output value of the CNT 2 is equal to or greater than the set value of the register REG 2, the control signal is output. Assert ø2. When the CLV control is instructed to the servo circuit 7, the switching determination unit LOG determines whether the angular velocity of the disk 1 (the number of revolutions per second) reaches the target angular velocity for the CAV control depending on the assertion state of the control signal ø2. Is detected, CAV control is instructed to the servo circuit 7 by the speed control mode instruction signal SIG4. This allows The control of spindle motor 2 is switched from CLV to CAV. In this example, recording of information on the disk 1 is performed from the inner periphery to the outer periphery of the disk. Therefore, the need to switch from CLV control to CAV control arises in the case of a track jump. . The switching of the speed control from 8 to (: 1 ^ V) occurs not only during a track jump, but also during the reading operation to be reproduced.

 When the CD-ROM reproducing device is operated in the above-described settings for the registers REG1 and REG2, the switching point between the CAV control and the CLV control is performed at the radial position indicated by Pi in FIG. As is clear from the above description, the determination at the time of switching only requires a comparison and determination operation with the target frequency at a constant linear velocity or the target angular velocity at a constant angular velocity. Variations in the writing linear velocity with respect to the disk 1 have no effect on the frequency detection of the frame synchronization signal SIG2. When trying to determine the switching time by focusing on the linear writing speed where variation is allowed, the actual linear speed that changes every moment according to the radius of the scanning position under CAV control is calculated sequentially However, in the case of the above judgment method, there is no necessity. When calculating the actual linear velocity that changes sequentially, the processing is complicated and time-consuming, and therefore, there is also a calculation error 7 that cannot be ignored. In the case of the comparison judgment operation with the target frequency or the target angular velocity, the processing is simple and the error is small. Therefore, it is possible to accurately and easily grasp the point at which the control between CAV and CLV is switched. As a result, the spindle motor 2 for rotating the disk 1 and the circuits 4 and 5 for processing the information signal read from the disk 1 can be operated at the upper limit of the performance limit, and the operation performance of those circuits is sufficiently exhibited. Thus, the speed of the signal reading operation or the reproducing operation can be increased.

In FIG. 1, ATG is based on the subcode signal SIG 1 It is a logical means to grasp the system. The register REG 6 holds the A time recognized by the logic means ATG. The switching determination unit L0G asserts the control signal ø3 when the control signal ø1 is asserted during the reading operation of the data to be reproduced (when it is not a track jump), and registers the signal. Evening REG 6 latches the A time as switching position information. The comparator CMP3 asserts the control signal 04 when the A-time generated by the logic means ATG is equal to or longer than the A-time latched by the register REG6. After asserting the control signal ø3 once, the switching judgment unit L0G monitors the control signal ø4 instead of the control signals 01, 02 and replaces the control signal ø4, unless the disk is replaced. Switches between CAV control and CLV control according to the ø4 assert state and negated state.

 The switching point from CAV to CLV can be roughly predicted from the critical performance such as the critical angular velocity and critical linear velocity. The prediction time can be specified by the A time acquired from the record information. Predictable points in time will have errors within the accepted linear velocity variation. If the comparison and judgment operation for switching between CAV and CLV is performed within a range where the error can be covered, the load on the microcomputer 8 for speed control can be reduced.

The variation range of the linear velocity is considered as the error range. The limit linear velocity and the limit angular velocity can be determined in advance from the performance of the hardware of the CD-ROM playback device. For example, in FIG. 5, assuming that the limit angular velocity is 66 [rps] and the limit linear velocity is a linear velocity equivalent to 16 times speed, some margin is taken for the range E1 of variation of the write linear velocity, and The range indicated by E2 in the figure is the range of the error. If the limit linear velocity and the limit angular velocity are determined, the lower limit and upper limit A times A i and A j of the error range E 2 can be predicted in advance. A time A obtained in advance in that way i and A j are set in the register REG 7 and REG 8 of the microcomputer 8. As described above, the microcomputer 8 can grasp the current A time based on the subcode signal SIG1. Comparator evening CMP 4 determines whether the current A-time is between the lower limit A-time A i and the upper limit A-time A j stored in Regis evening REG 7, If so, assert control signal 5. The switching determination unit L 0 G causes the comparators CMP 1 and CMP 2 to perform a comparison operation when the control signal 5 is asserted. Even with such processing, it is possible to accurately and easily grasp the point at which the control between CAV and CLV is switched, as described above. In particular, the switching process is further simplified because the determination period of the frequency and angular velocity for detecting the switching point between CAV and CLV can be shortened.

 When performing the monitoring operation at the time of switching between CAV and CLV only in the error range, when it is necessary to switch between CAV control and CLV control as a result of a track jump outside the error range, the register setting is performed. This can be handled using the A times A i and A j of G 7 and RE G 8. That is, when the A time at the jump destination track is a time before the A time A i at the lower limit of the error range, the control of the spindle motor 2 is forcibly switched to C AV. Similarly, when the A time at the jump destination track is later than the A time A j at the upper limit of the error range, the control of the spindle motor 2 is forcibly switched to the CLV control.

 It should be noted that the speed control may not use the CMP 3 and CMP 4 during the comparison. Further, either the comparator CMP3 or the comparator CMP4 may be used together with the comparators CMP1 and CMP2.

FIG. 10 shows the function of the CAV speed error detection circuit 71 by microcontroller. This shows the CD-R0M playback device realized by View8. That is, the CAV speed error detection circuit 71 shown in FIG. In addition, in FIG. 10, the peak observer 11 is not shown. Other configurations are the same as those in FIG. 1, and thus detailed description is omitted. Similarly, in the CD-ROM reproducing apparatus shown in FIG. 10, the reading of the information signal from the disk 1 can be performed by CAV control or CLV control. Fig. 11 shows the CAV control state focusing on the servo loop of the configuration shown in Fig. 10. CAV control is performed in the loop of the motor driver 10, micro computer 8, and servo circuit 7. . FIG. 12 shows the CLV control state focusing on the servo loop of the configuration shown in FIG. 10, which includes a dryino'10, a signal detection and shaping circuit 4, a digital signal processing circuit 5, and a servo circuit 7. CLV control is performed in the loop. In the configuration of FIG. 10 as well, the microcomputer 8 receives the frame synchronization signal SIG 2 even under CAV control, and determines whether the frequency of the frame synchronization signal SIG 2 reaches the target frequency for CLV control. Monitor. The target frequency is obtained from the double speed value set in the register REG1. For example, when the double speed value data indicates 16 times speed, the target frequency is 16 times the reference frequency. When the microcomputer 8 instructs the servo circuit 7 to perform the CAV control, and detects that the frequency of the frame synchronization signal SEG2 reaches the target frequency for CLV control, the microcomputer 8 issues a speed control mode instruction signal. SIG 4 instructs the servo circuit to perform CLV control. As a result, control of spindle motor 2 is switched from CAV to CLV. Also, the microcomputer 8 receives the frequency signal SIG7 even under the CLV control, and monitors whether the rotation speed of the motor obtained from the frequency signal SIG7 reaches the target angular speed of the CAV control. . The target frequency is the data set in the register REG2. Get from the evening. When the microcomputer 8 instructs the servo circuit 7 to perform CLV control and detects that the motor rotation speed obtained from the frequency signal SIG 7 reaches the target angular speed, the microcomputer 8 issues a speed control mode instruction signal SIG. 4 instructs the servo circuit to perform CAV control. As a result, the control of Spindlemo 2 is switched from CLV to CAV.

 According to the CD-ROM reproducing apparatus shown in FIGS. 1 and 10 using the frame synchronization signal SIG 2 for switching control between CAV control and CLV control, the following operational effects are obtained.

 The determination at the time of switching between the CAV control and the CLV control can be performed simply by comparing the frequency of the synchronization signal such as the frame synchronization signal SIG2 with the target frequency, or comparing the angular velocity of the disk with the target angular velocity. Variations in the writing linear velocity with respect to the disk have no effect on the frequency detection of the synchronization signal. When trying to determine the switching point by paying attention to the writing linear velocity where variation is allowed, the actual linear velocity that changes every moment according to the radius of the scanning position under CAV control is obtained by sequential calculation It must be monitored, but in the case of the present invention there is no need at all. When calculating the actual linear velocity that changes sequentially, the processing is complicated and time-consuming, and therefore, a calculation error that cannot be ignored occurs. In the case of the comparison judgment operation with the target frequency or the target angular velocity, the processing is simple and the error is small. Therefore, it is possible to accurately and easily grasp the point at which the control between CAV and CLV is switched. As a result, it is possible to operate the spindle motor 2 for rotating the disk 1 and the circuits 4 and 5 for processing the signal information read from the disk 1 at the upper limit of the performance limit, and to sufficiently operate the circuits. It is possible to realize a high speed signal reading operation or reproducing operation.

《Switching control between CAV and CLV using A-time》 Next, switching control between CAV and CLV using A-time will be described. FIG. 13 shows a CD-ROM playback device employing such control. The CD-ROM playback device shown in the figure, like the CD-ROM playback device described above, controls the speed of the disc when reading information signals from the disc 1 between CAV control and CLV control. You can switch with. At this time, the switching time point between CAV control and CLV control is managed or controlled by the A time. In FIG. 13, the same circuit elements as those in FIG. 1 are denoted by the same reference numerals. The microcomputer 8 shown in FIG. 13 includes a CPU 84, a ROM 85 in which an operation program of the CPU 84 and constant data are stored, a work area of the CPU 84, and a temporary storage area for data. RAM 83, registers REG1 to REG6, and peripheral circuits not shown.

 At the time of switching, the limit angular velocity before the tracking servo is unable to respond due to undesired vibration of the disk 1 and the signal detection and shaping circuit 4 for processing the signal information read from the disk, The signal reading limit speed is determined based on the limit operating frequency of the digital signal processing circuit 5 or the like. The signal reading limit speed is grasped as a double speed of the recording linear speed of the disc 1, such as 16 times speed.

To determine the switching point between CAV control and CLV control, obtain the limit angular velocity before the tracking servo or focusing servo cannot respond due to the occurrence of undesired vibration on Disk 1, and obtain a predetermined multiple of the recording linear velocity (signal reading). (Determined on the basis of the limit speed), it is assumed that the disk is rotated at a constant linear velocity. When the rotation of the disk reaches the limit angular speed, the switching position information on the track is determined on the basis of the track position. get. Then, sequentially read from the speed-controlled disk 1 It monitors whether the taken A-time reaches the switching position information, and when the arrival is detected, switches the CAV control to the CLV control and the CLV control to the CAV control. The predetermined double speed of the recording linear velocity is determined in consideration of the upper limit of the signal processing speed in the digital signal processing circuit 5, the upper limit of the operating frequency band in the signal detection and shaping circuit 4, and the like. As described above, the upper limit of the signal processing speed and the upper limit of the operating frequency band determine the upper limit of the signal reading linear speed (signal reading limit speed) by the pickup. The predetermined double speed of the recording linear speed is a signal reading linear speed determined within a range not exceeding the signal reading limit speed, and is a linear speed of a predetermined double speed with respect to the recording linear speed (standard linear speed).

FIG. 14 shows an example of a process for obtaining switching position information for specifying the switching time. The processing shown in the figure is performed by the microcomputer 8 during the training period after the attachment of the disk 1 is detected. First, the limit angular speed is detected (S1). That is, the microcomputer 8 monitors the amplitudes of the tracking error signal TER and the focus error signal FER in order to determine the limit angular velocity so that the state of eccentricity and runout inherent to the disk can be considered. The rotation of the disk 1 is accelerated, and the angular velocity of the disk when either one of the tracking error signal TER and the focus error signal FER reaches a predetermined value is detected as the limit angular speed. The detected limit angular velocity is stored in the register REG 2 of the microcomputer 8. The predetermined values of the amplitudes of the tracking error signal TER and the focus error signal FER are amplitudes at which the tracking and focusing servos cannot be handled, and can be uniquely determined by the servo control ability. The predetermined value of the amplitude is read from the power ROM which is not particularly limited, and the value set in the register REG 3 is used. If the limit angular velocity is determined in this way, there is no eccentricity or runout. The individual difference of each disk can be considered, and the limit angular velocity can be set at the very limit according to the individual difference. As described above, the mounting of the disk can be detected by a change in the output of an optical sensor that detects that the disk 1 is mounted on the tray, though not particularly shown in the drawing.

Next, the recording linear velocity of the disk is measured (S2). The recording linear velocity can be measured, for example, by the method shown in FIG. In other words, from the program start position (0 minute 0 second) where the radius of disk 1 is known, n (positive integer, for example, 1) track jump is performed, and the jump destination A is detected, as shown in Fig. 15 Calculate the linear velocity using the following equation (3-1). In Fig. 15, when one track jumps from A time 0 [0 minutes 0 seconds], the jump positions are A time 1 [X minutes {Y + ZZ75} seconds] and A time 2 [X minutes { Y + (Z + 1) / 7 5} seconds]. Here, in the correspondence with the Q-code frame format in FIG. 9, X, Υ, and Z are equivalent to X = AM IN, Y = ASEAN, and Z-AFRAME '75. Since the A time can be detected in 1/7 5 second increments as described above, the first detectable A time after jumping one track from the A time 0 (0 minute 0 second) is A time 3 (X Min (Y + (Z + 2) / 7 5} seconds] _{c The} above equation (3-1) indicates that the spiral (track) length from the position of the A time 0 to the jump position JP 1 is represented by the A time 0 The error in linear velocity detection can be minimized when the time required to scan the track from the position of the jump position to the jump position JP1 can be minimized, but in actuality, A time 3 that can be detected from the Q code is used. However, there is some error in the linear velocity obtained by the calculation of equation (3-1). The A-TIME in the notation (3-1) is the A-time that can be read immediately after jumping one track from the A-time 0, and is A-time 3 according to FIG. In order to detect the recording linear velocity with higher accuracy, the power of omitting the description is disclosed in Japanese Patent Application Laid-Open No. 8-2799714. The technology described may be employed. The recording linear velocity of the disk thus detected is stored in the register REG 4 of the microcomputer 8. Next, the radius of the disk reaching the limit angular velocity when the disk 1 is rotated at a constant linear velocity at a predetermined multiple speed of the measured disk recording linear velocity is acquired (S3). The microcomputer 8 performs, for example, the calculation shown by the equation (3-2) in FIG. 14 to obtain the disk radius. In the formula (3-2), “set C LVn double speed” is a double speed value, and means a value “16” if the predetermined double speed of the recording linear speed is 16 times the recording linear speed. In the formula (3-2), the microphone computer 8 sets the value of “setting CL Vn double speed” from the register REG 1 and the value of “recording linear speed” from the register REG 4 to “rotational speed (limit angular speed)”. From Regis Evening Reg 2. The disk radius (the radius of the disk 1 at the switching position) calculated based on them is stored in the register REG5 of the microcomputer _c . The switching position information for switching between CAV and CLV is obtained based on the calculation represented by the equation (3-3) (S4). The contents of the calculation of the equation (3-3) are as follows: the disk radius (the value of REG 5) obtained in step S 3 and the innermost radius of the disk 1 (the radius of the innermost track in a precise expression) Is divided by the product of the track pitch and the recording linear velocity to obtain time information. This time information is the time on the track starting from the A time 0 (0 minutes 0 seconds), and the A time closest to this is used to specify the switching point between CLV and CAV. Switching position information. Note that, in the equation (3-3), the track pitch and the innermost radius are known according to the disc 1 standard. The disc radius is obtained from the value of REG5, and the measured recording linear velocity is obtained from the value of REG4. The calculated switching position information is stored in the register REG 6 of the microphone computer 8. If the limit angular velocity (rotation speed per second) obtained in step S1 is, for example, the angular velocity at point Pa in FIG. 16, as shown in FIG. 16, the predetermined multiple of the measurement recording linear velocity is 16 ×. At this time, when the recording linear velocity measured in step S2 is 1.4 [m / s], the switching position information is the A time of Pb3. Similarly, when the measured recording linear velocity is 1.3 [m / s], the switching position information is the A time of Pb2, and the measured recording linear velocity is 1.2 [m / s]. ], The switching position information is the A time of Pb1.

 FIG. 17 shows another example of processing for acquiring the A time for specifying the switching time. That is, in step S5, the limit angular velocity is determined as the maximum angular velocity of the double speed guaranteed by the child. For example, as shown in the figure, according to the performance guaranteed for normal operation that does not cause undesired vibration on the disk 1, for example, the performance such as 8 × speed at a recording linear velocity of 1.3 [m / s], the microcontroller Pyu-Yu calculates the limit angular velocity by the equation (3-4). In the equation (3-4), “set C A V n double speed” means a double speed value of the guaranteed performance described above, and is set to “8” when the speed is eight times higher. The set linear velocity means the recording linear velocity of the guaranteed performance. Other processes are the same as those in FIG. 14, and the same processes are denoted by the same reference numerals and detailed description thereof will be omitted. As shown in Fig. 17, when determining the above-mentioned limit angular velocity as the maximum angular velocity of the double speed guaranteed in advance, instead of performing the calculation of equation (3-4), a data table of the limit angular velocity according to the performance is used. It is also possible to use the limit angular velocity of the data table in the calculation of equation (3-2).

As described in Fig. 14, when the method of determining the limit angular velocity in consideration of the individual difference of each disk such as eccentricity and runout and acquiring the switching point between CAV and CLV is adopted, As shown in Figure 18, It is best to determine the switching time each time a replacement of the disk 1 is detected. That is, when the replacement of the disk 1 (that is, the mounting of the disk) is detected (S10), the limit angular velocity at which vibration does not occur is measured as described above (S1), and then the recording linear velocity of the disk 1 is measured (S10). S 2), and calculates the switching time based on them (S 3, S 4). After performing these processes during the training period, playback of the disc is started, and the control of CAV and CLV is switched at the calculated switching point (S11).

 In the process of step S11, assuming that the switching position information is the A time of Pb2 in FIG. 16, the microcomputer 8 determines that the A time of the sequentially supplied subcode is included in the switching position information. Determine if it will arrive. When the microcomputer 8 instructs the spindle control circuit 7 to perform CAV control and detects a state in which the A-time matches the switching position information, the microcomputer 8 uses the speed control mode instruction signal SIG 4 to control the spindle control. Instruct circuit 7 to perform CLV control. As a result, the control of spindle motor 2 is switched from CAV to CLV. When the microcomputer 8 detects a state in which the A time coincides with the switching position information under the CLV control (in this case, caused by a track jump), the microcomputer 8 performs a speed control mode instruction signal SIG. 4 instructs the spindle servo circuit 7 to perform CAV control. As a result, the control of spindle motor 2 is switched from CLV to CAV.

The calculation of the switching time performed in the steps S 3 and S 4 can be replaced with the processing using a data table. For example, if the reading linear velocity is fixed at 16 times the recording linear velocity, the switching time is stored in advance with the limit angular velocity and the measured linear velocity as parameters as shown in step S12 of Fig. 19. Prepare the switching time table shown in the table and record the limit angular velocity obtained in step S1 and the disc obtained in step S2. Obtain the switching time corresponding to the recording line speed from the switching time table. According to this, the calculation time for acquiring the switching time can be reduced. Other processes are the same as those in FIG. 18, and the same processes are denoted by the same reference numerals and detailed description thereof will be omitted.

 The method described in Fig. 17 does not determine the limit angular velocity by directly considering the individual difference of each disk such as eccentricity and runout, so after obtaining the switching point of CAV and CLV, If it is saved, the switching time does not have to be calculated every time the disk is replaced. In FIG. 17, the method of step S12 in FIG. 19 can be adopted.

 FIG. 20 shows a CD-R〇M reproducing apparatus in which the function of the CAV speed error detecting circuit 71 is realized by a microcomputer 8. That is, the CAV speed error detection circuit 71 of FIG. 20 is built in the microcomputer 8. Other configurations are the same as those in FIG. 13, and thus detailed description is omitted.

 According to the CD-R0M reproducing apparatus described above, the following operational effects can be obtained.

Switching position information for specifying the mutual switching point between CAV and CLV control is determined in advance. At that time, the limit angular velocity before the pick-up servo cannot respond due to undesired vibration of the disc 1, the signal detection and shaping circuit 4 for processing the signal information read from the disc, and the digital signal processing Consider a signal reading limit speed determined based on a limit operating frequency of the circuit 5 or the like. The switching position information is determined based on the track position at which the disk reaches the limit angular velocity when it is assumed that the disk is rotated at a predetermined linear velocity (the speed before the signal reading limit velocity) at a constant linear velocity at a predetermined speed. It is the position information on the track. Judgment at the time of switching between CAV control and CLV control during playback operation Is performed by comparing and determining whether or not the absolute position information matches the switching position information. When trying to determine the switching time by paying attention to the writing linear velocity where variation is allowed, the actual linear velocity that changes every moment according to the radius of the scanning position under CAV control is calculated sequentially. Observe and monitor, but in the case of the above judgment method, there is no necessity. When calculating the actual linear velocity that changes sequentially, the processing is complicated and time-consuming, and therefore, a calculation error that cannot be ignored occurs. The process of comparing and determining the absolute position information such as the A time and the switching position information is simple and has few errors. Therefore, it is possible to accurately and easily grasp the point at which the control between CAV and CLV is switched.

 When determining the limit angular velocity, by considering the individual differences of the individual disks 1 such as eccentricity and runout, the limit angular velocity can be set to a point at the limit of the capability according to the individual difference.

 As described above, it is possible to optimize the switching point of the speed control between CAV and CLV with respect to the eccentricity, surface runout, and variation of the recording linear speed for each disk 1. Therefore, it is possible to realize the maximum operation performance of the circuits 4 and 5 for processing the signal information read from the spindle motor 2 and the disk 1, thereby realizing high-speed signal reading operation or reproduction operation. The power which specifically described the invention made by the present inventor The present invention is not limited to this, and it goes without saying that various modifications can be made without departing from the scope of the invention.

For example, a disc on which signal information is recorded at a constant linear velocity is not limited to a CD-ROM, but an LD (laser disc), MD (mini disc), LV (laser vision), CDV (compact disc video) or DVD ( The disc may be a disc conforming to a standard such as a digital video disc. The present invention can be applied to such disk speed control. Wear. Although the above description is consistent throughout the description focusing on the case of reproducing signal information recorded on a disk, it goes without saying that the present invention can be applied to an apparatus having a writing function.

 Further, the digital signal processing circuit 5 and the spindle servo circuit 7 may be formed of a one-chip semiconductor integrated circuit, or may be built in a microcomputer 8 to form a one-chip disk controller LSI. It is.

 In the above description, the double speed value has been described as 16 times. However, it is needless to say that the present invention can be applied to a case of a double speed value of 20 times or more. Also, depending on the type of disc, ID information such as an absolute address on the disc can be used as absolute position information instead of the A time.

 In addition, the measurement of the critical angular velocity of the disk is not limited to the method performed by the microcomputer based on TERR and FER, and can be changed as appropriate.

 As described above, the present invention can be widely applied to an apparatus for reproducing recorded information of a disc on which signal information is recorded at a constant linear velocity, such as a CD-ROM, LD, MD, LV, CDV, or DVD. .

Claims

The scope of the claims

1. A recording information reproducing apparatus for scanning a disc on which a linear signal is recorded at a constant linear velocity on a spiral track by reading up the information signal and reproducing the data from the read information signal,

 On the inner peripheral side of the disk, there is provided speed control means for controlling the rotation of the disk at a constant angular velocity, and on the outer peripheral side of the disk, controlling the rotational speed of the disk at a constant linear reading speed by a pickup.

 The speed control means includes a register for storing information for specifying a switching point between the constant angular velocity control and the constant linear velocity control, and includes information generated based on an information signal read from a disk. The recording information reproducing apparatus is characterized in that a constant linear velocity control or a constant angular velocity control is selected by comparing the information set in the register means.

2.A recorded information reproducing apparatus for scanning a disk having an information signal recorded at a constant linear velocity on a spiral track by a pick-up to read the information signal, and reproducing the data from the read information signal,

 Speed control means for controlling the rotation of the disk at a constant angular velocity on the inner peripheral side of the disk, and controlling the rotational speed of the disk at a constant reading linear velocity by pick-up on the outer peripheral side of the disk;

The speed control means includes a register means for setting a target rotation speed data of the disk for controlling the angular velocity constant and a target frequency data for controlling the linear velocity constant, Whether the linear velocity under the constant velocity control has reached the target linear velocity or not is determined by the frequency of the synchronization signal synchronized with the reading speed of the information signal read from the pickup and the registration means. Compare with the set target frequency A recording information reproducing apparatus characterized in that constant angular velocity control is switched to constant linear velocity control using the result of the determination.

The speed control means determines whether or not the angular velocity under the constant linear velocity control has reached the constant angular velocity target angular velocity by comparing the disk rotational velocity with the target rotational velocity data, and the determination result 3. The recording information reproducing apparatus according to claim 2, wherein the control for switching the constant linear velocity to the constant angular velocity control is performed using the control.

The speed control means determines a state in which the linear velocity under the constant angular velocity constant speed control has reached a target linear velocity with constant linear velocity, and when the control of constant angular velocity is switched to the control with constant linear velocity, reads from the disk. The absolute position information of the track generated by the obtained information signal is acquired as the switching position information, and the constant angular velocity is controlled based on the magnitude relationship between the acquired switching position information and the absolute position information generated from the information read from the disc. 3. The recording information reproducing apparatus according to claim 2, wherein a control for keeping the linear velocity constant is selected.

 A recording information reproducing apparatus for reading a disk with an information signal recorded on a spiral track at a constant linear velocity by picking up the information signal and reproducing data from the read information signal,

 On the inner peripheral side of the disk, there is provided speed control means for controlling the rotation of the disk at a constant angular velocity, and on the outer peripheral side of the disk, controlling the rotational speed of the disk at a constant linear reading speed by a pickup.

The speed control means includes register means for storing absolute position information of the disk as switching position information when the linear velocity under the constant angular velocity control reaches the linear velocity under the constant linear velocity control; Absolute position information generated based on the information signal read from the disk The recording information reproducing apparatus is characterized in that control of constant linear velocity or control of constant angular velocity is selected by comparing magnitude with switching position information set in the register means.

6. In a recording information reproducing apparatus for reading the information signal by scanning a disk in which an information signal is recorded at a constant linear velocity at a predetermined bit cycle on a spiral track by a pickup, and reproducing data from the read information signal. A speed control method for controlling the rotation of the disk by switching the rotation to a constant angular velocity or a constant reading linear velocity by a pickup;

 The switching point of the speed control from the constant angular velocity to the constant linear velocity is detected by monitoring whether the frequency of the synchronization signal synchronized with the reading speed of the information signal reaches the target frequency with the constant linear velocity, and

 A speed control method characterized in that a switching point of the speed control from a constant linear velocity to a constant angular velocity is detected by monitoring whether the rotational speed of the disk reaches a target angular velocity with a constant angular velocity.

7. A recording information reproducing apparatus for reading a disc having a spiral track on which an information signal is recorded at a constant linear velocity at a predetermined bit cycle by a pickup, reading the information signal, and reproducing data from the read information signal. hand,

 Speed control means for controlling the rotation of the disk by switching to a constant angular velocity or a constant read linear velocity by pick-up,

The speed control means detects a synchronization signal having a frequency corresponding to the reading speed of the information signal, detects the rotational angular speed of the disk, and switches from a constant angular speed to a constant reading linear speed by changing the frequency of the synchronization signal. Is performed when the target frequency at the constant reading linear velocity is reached, and the switching from the constant reading linear velocity to the constant angular velocity is performed when the rotational angular velocity of the disk reaches the target angular velocity at the constant angular velocity. And a recorded information reproducing apparatus.

 When controlling the rotation of the disk at a constant angular velocity, the speed control means adjusts the frequency of the synchronization signal to the constant reading linear velocity on condition that the absolute position information read from the recording information is equal to or greater than a predetermined value. 8. The recorded information reproducing apparatus according to claim 7, wherein the apparatus determines whether or not the frequency reaches the frequency.

 When controlling the rotation of the disk at a constant linear velocity, the speed control means sets the rotational angular velocity of the disk to the target angular velocity at the constant angular velocity, provided that the absolute position information read from the recording information is equal to or less than a predetermined value. 9. The recording information reproducing apparatus according to claim 7, wherein the recording information reproducing apparatus is configured to determine whether or not the recording information is reached.

 10. The recorded information reproduction according to claim 7, wherein the synchronization signal is a frame synchronization signal synchronized with a reading cycle of a frame synchronization pattern included in each unit frame of the information signal. apparatus. 11. The synchronization signal according to claim 7, wherein the synchronization signal is a synchronization clock signal generated by a PLL circuit for identifying a pulse width of the information signal read from a disk as a delay. The recorded information reproducing device described in the item.

 12. The speed control means adjusts the frequency of a frame synchronization signal synchronized with a reading cycle of a frame synchronization pattern included in each unit frame of the information signal to the target frequency in the rotation control at a constant reading linear velocity. In this manner, the rotation of the disk is subjected to a feedback control, and the rotation of the disk is controlled so that the detected rotation angular velocity is constant in the rotation control with the constant angular velocity. Item 7. The recorded information re-apparatus according to Item 7.

1 3. The target angular velocity is determined by scanning the spiral track by the pickup. An angular velocity determined based on a limit speed of a disk mode that can be performed stably, and the target frequency is a line determined based on a limit operating frequency of a circuit that processes an I information signal read from a disk. 8. The recorded information reproducing apparatus according to claim 7, wherein the frequency is a frequency corresponding to the speed.

4. A disk controller for reading and reproducing the information signal by scanning the disk in which the information signal is recorded at a constant linear velocity at a predetermined bit cycle on the spiral track, and controls the rotation of the disk. It controls switching to constant angular velocity or constant reading linear velocity by pick-up, and includes a digital signal processing circuit, servo circuit, and control circuit.

The digital signal processing circuit identifies the pulse width of the information signal read from the disk as data, demodulates the identified data, and starts demodulating the control information and the demodulated data. Information is obtained, and a speed error signal generated from an error between a frequency of a synchronization signal having a frequency corresponding to a reading speed of the information signal and a target frequency is read. The control circuit detects the rotational angular velocity of the disk, and supplies an error signal from the target angular velocity to the servo circuit for controlling the disk rotation at a constant angular velocity. When a certain disc rotation control is instructed, the above-mentioned sub signal is provided on condition that the frequency of the synchronizing signal reaches a target frequency for fixing the reading linear velocity. When the servo circuit is instructed to switch the disk rotation control with constant angular velocity to the disk rotation control with constant linear velocity, and when the servo circuit is instructed to perform disk rotation control with constant reading linear velocity, the rotation angular velocity of the disk is reduced. The servo circuit is provided on condition that the angular velocity reaches a target angular velocity for constant. A disk controller for giving an instruction to switch from a disk rotation control with a constant reading linear velocity to a disk rotation control with a constant angular velocity.

 5. A disk controller for reading and reproducing the information signal by scanning a disk in which an information signal is recorded at a constant linear velocity at a predetermined bit cycle on a spiral track, and controls the rotation of the disk. A control circuit for controlling switching to a constant angular velocity or a constant reading linear velocity by pick-up, and a digital signal processing circuit;

 The digitizing signal processing circuit identifies the pulse width of the information signal read from the disk as data, demodulates the identified data, and extracts control information and data information from the demodulated data. Acquiring and forming a first speed error signal generated from an error between a frequency of a synchronization signal having a frequency corresponding to a reading speed of the information signal and a target frequency for controlling disk rotation at a constant reading linear speed; A second speed error signal generated from an error between the disk rotation angular speed and the target angular speed is formed for disk rotation control with a constant angular speed,

The control circuit, when instructing the digital signal processing circuit to control the disk rotation at a constant angular velocity using the second velocity error signal, sets the frequency of the synchronization signal to the target frequency for the constant reading linear velocity. The digital signal processing circuit is instructed to switch to disk rotation control with a constant linear velocity on condition that the disk speed is reached, and a disk with a constant linear velocity using the first velocity error signal is sent to the digital signal processing circuit. When the rotation control is instructed, the digital signal processing circuit switches the disk rotation control to the constant angular velocity control on the condition that the rotational angular velocity of the disk reaches the target angular velocity for the constant angular velocity. A disc controller characterized by instructions.

6. In a recorded information reproducing apparatus for reading the information signal by scanning a disk having an information signal recorded at a constant linear velocity on a spiral track by a pickup, and reproducing the data from the read information signal, A speed control method for controlling rotation by switching the rotation to a constant angular velocity or a constant reading linear velocity by pick-up,

 A first step of obtaining a limit angular velocity just before undesired vibration occurs in the disk, a second step of obtaining a recording linear velocity of information recorded on the disk, and a linear velocity obtained in the second step Assuming that the disk is rotated at a constant linear velocity at a predetermined multiple of, the switching position information on the track determined based on the track position that reaches the limit angular velocity obtained in the first step is obtained. 3 steps and are included in the training operation period,

 During the reproduction operation of the recorded information, a fourth step of controlling the disk at a constant angular velocity at the limit angular velocity obtained in the first step, and a linear velocity of the disk at a predetermined multiple of the linear velocity obtained in the second step. The fifth step of constant speed control, and the magnitude relationship between the absolute position information sequentially read from the speed-controlled disk and the switching position Δit information obtained in the third step is determined, and the angular velocity is determined according to the determination result. A speed control method, comprising: a sixth step of switching between constant speed control and constant linear speed control.

 7. The first step is to gradually increase the angular velocity of the disk while monitoring the amplitude of the pick-up servo error signal for the spiral track, and when the amplitude of the big up servo error signal reaches a predetermined value. 17. The speed control method according to claim 16, wherein the angular velocity of the disk is set to the limit angular velocity.

8. The third step is the step of calculating the linear velocity obtained in the second step. Assuming that the disk is rotated at a predetermined linear speed and a constant linear velocity, the radius of the disk reaching the limit angular velocity obtained in the first step is obtained, and the radius of the disk between this radius and the radius of the innermost track of the disk is obtained. 17. The switching position information according to claim 16, wherein time information obtained by dividing an area by a product of a track pitch and a linear velocity obtained in the second step is used as the switching position information. The speed control method described in paragraph 7.

 9.A recorded information reproducing apparatus which scans a disc having an information signal recorded on a spiral track at a constant linear velocity by a pickup to read the information signal, and reproduces data from the read information signal,

 Speed control means for controlling the rotation of the disk to a constant angular speed or a constant linear reading speed by pi-zup;

 The speed control means is determined based on a track position at which the angular velocity of the disk reaches a limit angular velocity before an undesired vibration occurs in the disk, assuming that the rotation of the disk is constant at the linear velocity. The constant linear velocity and the constant angular velocity control are mutually switched based on the front-rear relationship between the position specified by the switching position information and the scanning position by the pickup. Recording information reproducing device.

 0. A disc in which an information signal containing absolute position information is recorded on a spiral track at a constant linear velocity for each of a plurality of frames is scanned by a pickup, the information signal is read, and data is reproduced from the read information signal. A device,

The rotation of the disk is controlled to a constant angular velocity or a constant linear velocity read out by pick-up, and when predetermined absolute position information is detected from the read information signal, the speed control for the constant linear velocity and the constant angular velocity are mutually performed. It has speed control means for switching, The predetermined absolute position information is based on a track position at which the angular velocity of the disk reaches a limit angular velocity before an undesired vibration occurs on the disk, assuming that the rotation of the disk is constant at the linear velocity. Recording information reproducing apparatus, characterized in that the switching position information is determined by the switching position information.

21. Upon detecting the mounting of the disk, the speed control means calculates and obtains the limit angular velocity just before undesired vibration occurs in the disk and the recording linear velocity of the information recorded on the disk. The switching position information determined based on the position on the track that reaches the limit angular velocity when the disk is rotated at a constant linear velocity at a constant linear velocity. 21. The recorded information reproducing apparatus according to claim 20, wherein

2 2.Recording to read the information signal by picking up a disk on which information signals including absolute position information are recorded at a constant linear velocity on a spiral track for each of a plurality of frames, and to reproduce data from the read information signals An information reproducing apparatus,

 Speed control means for controlling the rotation of the disk by switching to a constant angular velocity or a constant read linear velocity by pick-up,

The speed control means includes: first storage means for storing a limit angular velocity before an undesired vibration occurs on the disk; second storage means for storing a recording linear velocity of information recorded on the disk; When it is assumed that the disk is rotated at a constant linear velocity at a predetermined multiple of the linear velocity stored in the second storage means, the switching determined based on the track position reaching the limit angular velocity held by the first storage means A third storage means for storing position information, wherein the speed of the disk is controlled to a constant angular velocity with the rotation speed stored in the first storage means, and the predetermined linear velocity stored in the second storage means is provided. Speed control of the disc at a constant linear speed at double speed, speed control It is monitored whether the absolute position information sequentially read from the read disks reaches the switching position information stored in the third storage means. When the absolute position information reaches the switching position information, the constant angular velocity control is changed to a constant linear velocity control. A recording information reproducing apparatus characterized in that speed control at a constant linear velocity is switched to speed control at a constant angular velocity.

 3. The recorded information reproduction according to claim 22, wherein the predetermined speed is a signal reading speed determined based on a limit signal processing speed of a circuit for reproducing an information signal read from a disk. apparatus.

 4. A disk controller for reading and reproducing the information signal by scanning a disk in which an information signal including absolute position information is recorded on a spiral track at a constant linear velocity for each of a plurality of frames. A processing circuit, a servo circuit, and a control circuit,

 When detecting the mounting of the disk, the control circuit obtains a limit angular velocity just before undesired vibration occurs in the disk and a recording linear velocity of information recorded on the disk, and obtains the obtained recording line. When the disk is rotated at a constant linear velocity at a predetermined multiple of the velocity, the switching position information on the track, which is determined based on the track position that reaches the limit angular velocity before d, is acquired.

 The digital signal processing circuit identifies the pulse width of the information signal read from the disk as data, demodulates the identified data, and extracts control information and data information from the demodulated data. A speed error signal generated from an error between a frequency of a synchronization signal having a frequency corresponding to the reading speed of the information signal and a target frequency is read, and the servo circuit is read to the servo circuit for linear speed-constant disk rotation control. And providing the control information to the control circuit.

The control circuit further detects a rotational angular velocity of the disk, and calculates a target angular velocity. Is supplied to the servo circuit for controlling the disk rotation at a constant angular velocity, and the magnitude of the absolute position information generated from the control information and the switching position information is discriminated, and according to the discrimination result, A disk controller for switching between constant angular velocity and constant linear velocity control.

 5. A disk controller for reading and reproducing the information signal by scanning a disk in which an information signal including absolute position information is recorded on a spiral track at a constant linear velocity for each of a plurality of frames, and a digital signal processing. Circuit and a control circuit,

 When detecting the mounting of the disk, the control circuit obtains a limit angular velocity just before undesired vibration occurs in the disk and a recording linear velocity of information recorded on the disk, and obtains the obtained recording line. Assuming that the disk is rotated at a constant linear velocity at a predetermined multiple speed of the velocity, switching position information on the track determined based on the track position reaching the limit angular velocity is obtained.

 The digital signal processing circuit identifies the pulse width of the information signal read from the disk as data, demodulates the identified data, and extracts control information and data information from the demodulated data. Obtaining a first speed error signal generated from an error between a frequency of a synchronization signal having a frequency corresponding to a reading speed of the information signal and a target frequency, and detecting a rotational angular speed of the disk to obtain a target angular speed The second speed error signal generated from the error with

The control circuit further receives supply of control information from the digital signal processing circuit, generates absolute position information indicating a scanning position on a track from the control information, and generates an absolute position information of the generated absolute position information and the switching position information. Big A disc controller characterized in that it discriminates small and switches speed control with constant angular velocity or constant linear velocity according to the discrimination result.